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  • What Counts for A DBA - Logic

    - by drsql
    "There are 10 kinds of people in the world. Those who will always wonder why there are only two items in my list and those who will figured it out the first time they saw this very old joke."  Those readers who will give up immediately and get frustrated with me for not explaining it to them are not likely going to be great technical professionals of any sort, much less a programmer or administrator who will be constantly dealing with the common failures that make up a DBA's day.  Many of these people will stare at this like a dog staring at a traffic signal and still have no more idea of how to decipher the riddle. Without explanation they will give up, call the joke "stupid" and, feeling quite superior, walk away indignantly to their job likely flipping patties of meat-by-product. As a data professional or any programmer who has strayed  to this very data-oriented blog, you would, if you are worth your weight in air, either have recognized immediately what was going on, or felt a bit ignorant.  Your friends are chuckling over the joke, but why is it funny? Unfortunately you left your smartphone at home on the dresser because you were up late last night programming and were running late to work (again), so you will either have to fake a laugh or figure it out.  Digging through the joke, you figure out that the word "two" is the most important part, since initially the joke mentioned 10. Hmm, why did they spell out two, but not ten? Maybe 10 could be interpreted a different way?  As a DBA, this sort of logic comes into play every day, and sometimes it doesn't involve nerdy riddles or Star Wars folklore.  When you turn on your computer and get the dreaded blue screen of death, you don't immediately cry to the help desk and sit on your thumbs and whine about not being able to work. Do that and your co-workers will question your nerd-hood; I know I certainly would. You figure out the problem, and when you have it narrowed down, you call the help desk and tell them what the problem is, usually having to explain that yes, you did in fact try to reboot before calling.  Of course, sometimes humility does come in to play when you reach the end of your abilities, but the ‘end of abilities’ is not something any of us recognize readily. It is handy to have the ability to use logic to solve uncommon problems: It becomes especially useful when you are trying to solve a data-related problem such as a query performance issue, and the way that you approach things will tell your coworkers a great deal about your abilities.  The novice is likely to immediately take the approach of  trying to add more indexes or blaming the hardware. As you become more and more experienced, it becomes increasingly obvious that performance issues are a very complex topic. A query may be slow for a myriad of reasons, from concurrency issues, a poor query plan because of a parameter value (like parameter sniffing,) poor coding standards, or just because it is a complex query that is going to be slow sometimes. Some queries that you will deal with may have twenty joins and hundreds of search criteria, and it can take a lot of thought to determine what is going on.  You can usually figure out the problem to almost any query by using basic knowledge of how joins and queries work, together with the help of such things as the query plan, profiler or monitoring tools.  It is not unlikely that it can take a full day’s work to understand some queries, breaking them down into smaller queries to find a very tiny problem. Not every time will you actually find the problem, and it is part of the process to occasionally admit that the problem is random, and everything works fine now.  Sometimes, it is necessary to realize that a problem is outside of your current knowledge, and admit temporary defeat: You can, at least, narrow down the source of the problem by looking logically at all of the possible solutions. By doing this, you can satisfy your curiosity and learn more about what the actual problem was. For example, in the joke, had you never been exposed to the concept of binary numbers, there is no way you could have known that binary - 10 = decimal - 2, but you could have logically come to the conclusion that 10 must not mean ten in the context of the joke, and at that point you are that much closer to getting the joke and at least won't feel so ignorant.

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  • Collaborative Whiteboard using WebSocket in GlassFish 4 - Text/JSON and Binary/ArrayBuffer Data Transfer (TOTD #189)

    - by arungupta
    This blog has published a few blogs on using JSR 356 Reference Implementation (Tyrus) as its integrated in GlassFish 4 promoted builds. TOTD #183: Getting Started with WebSocket in GlassFish TOTD #184: Logging WebSocket Frames using Chrome Developer Tools, Net-internals and Wireshark TOTD #185: Processing Text and Binary (Blob, ArrayBuffer, ArrayBufferView) Payload in WebSocket TOTD #186: Custom Text and Binary Payloads using WebSocket One of the typical usecase for WebSocket is online collaborative games. This Tip Of The Day (TOTD) explains a sample that can be used to build such games easily. The application is a collaborative whiteboard where different shapes can be drawn in multiple colors. The shapes drawn on one browser are automatically drawn on all other peer browsers that are connected to the same endpoint. The shape, color, and coordinates of the image are transfered using a JSON structure. A browser may opt-out of sharing the figures. Alternatively any browser can send a snapshot of their existing whiteboard to all other browsers. Take a look at this video to understand how the application work and the underlying code. The complete sample code can be downloaded here. The code behind the application is also explained below. The web page (index.jsp) has a HTML5 Canvas as shown: <canvas id="myCanvas" width="150" height="150" style="border:1px solid #000000;"></canvas> And some radio buttons to choose the color and shape. By default, the shape, color, and coordinates of any figure drawn on the canvas are put in a JSON structure and sent as a message to the WebSocket endpoint. The JSON structure looks like: { "shape": "square", "color": "#FF0000", "coords": { "x": 31.59999942779541, "y": 49.91999053955078 }} The endpoint definition looks like: @WebSocketEndpoint(value = "websocket",encoders = {FigureDecoderEncoder.class},decoders = {FigureDecoderEncoder.class})public class Whiteboard { As you can see, the endpoint has decoder and encoder registered that decodes JSON to a Figure (a POJO class) and vice versa respectively. The decode method looks like: public Figure decode(String string) throws DecodeException { try { JSONObject jsonObject = new JSONObject(string); return new Figure(jsonObject); } catch (JSONException ex) { throw new DecodeException("Error parsing JSON", ex.getMessage(), ex.fillInStackTrace()); }} And the encode method looks like: public String encode(Figure figure) throws EncodeException { return figure.getJson().toString();} FigureDecoderEncoder implements both decoder and encoder functionality but thats purely for convenience. But the recommended design pattern is to keep them in separate classes. In certain cases, you may even need only one of them. On the client-side, the Canvas is initialized as: var canvas = document.getElementById("myCanvas");var context = canvas.getContext("2d");canvas.addEventListener("click", defineImage, false); The defineImage method constructs the JSON structure as shown above and sends it to the endpoint using websocket.send(). An instant snapshot of the canvas is sent using binary transfer with WebSocket. The WebSocket is initialized as: var wsUri = "ws://localhost:8080/whiteboard/websocket";var websocket = new WebSocket(wsUri);websocket.binaryType = "arraybuffer"; The important part is to set the binaryType property of WebSocket to arraybuffer. This ensures that any binary transfers using WebSocket are done using ArrayBuffer as the default type seem to be blob. The actual binary data transfer is done using the following: var image = context.getImageData(0, 0, canvas.width, canvas.height);var buffer = new ArrayBuffer(image.data.length);var bytes = new Uint8Array(buffer);for (var i=0; i<bytes.length; i++) { bytes[i] = image.data[i];}websocket.send(bytes); This comprehensive sample shows the following features of JSR 356 API: Annotation-driven endpoints Send/receive text and binary payload in WebSocket Encoders/decoders for custom text payload In addition, it also shows how images can be captured and drawn using HTML5 Canvas in a JSP. How could this be turned in to an online game ? Imagine drawing a Tic-tac-toe board on the canvas with two players playing and others watching. Then you can build access rights and controls within the application itself. Instead of sending a snapshot of the canvas on demand, a new peer joining the game could be automatically transferred the current state as well. Do you want to build this game ? I built a similar game a few years ago. Do somebody want to rewrite the game using WebSocket APIs ? :-) Many thanks to Jitu and Akshay for helping through the WebSocket internals! Here are some references for you: JSR 356: Java API for WebSocket - Specification (Early Draft) and Implementation (already integrated in GlassFish 4 promoted builds) Subsequent blogs will discuss the following topics (not necessary in that order) ... Error handling Interface-driven WebSocket endpoint Java client API Client and Server configuration Security Subprotocols Extensions Other topics from the API

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  • Some Early Considerations

    - by Chris Massey
    Following on from my previous post, I want to say "thank you" to everyone who has got in touch and got involved – you are pioneers! An update on where we are right now: paper prototypes v1 To be more specific, we’ve picked two of the ideas that seem to have more pros than cons, turned them into Balsamiq mockups, and are getting them fleshed out with realistic content. We’ll initially make these available to the aforementioned pioneers (thank you again), roll in the feedback, and then open up to get more data on what works and what doesn’t. If you’ve got any questions about this (or what we’re working on right now), feel free to ask me in the comments below. I’ve had a few people express an interest in the process we’re going through, and I’m more than happy to share details more frequently as we go along – not least because you, dear reader, will help us stay on target and create something Good. To start with, here’s a quick flashback to bring you all up to speed. A Brief Retrospective As you may already know, we’re creating a new publishing asset specifically focused on providing great content for web developers. We don’t yet know exactly what this thing will look like, or exactly how it will work, but we know we want to create something that is useful different. For my part, I’m seriously excited at the prospect of building a genuinely digital publishing system (as opposed to what most publishing is these days, which is print-style publishing which just happens to be on the web). The main challenge at this point is working out our build-measure-assess loop to speed up our experimental turn-around, and that’ll get better as we run more trials. Of course, there are a few things we’ve been pondering at this early conceptual stage: Do we publishing about heterogeneous technology stacks from day 1, or do we start with ASP.NET (which we’re familiar with) & branch out later? There are challenges with either approach. What publishing "modes" are already being well-handled? For example, the likes of Pluralsight, TekPub, and Treehouse have pretty much nailed video training (debate about price, if you like), and unless we think we can do it faster / better / cheaper (unlikely, for the record), we should leave them to it. Where should we base whatever we create? Should we create a completely new asset under a new name, graft something onto Simple-Talk (like the labs), or just build something directly into Simple-Talk? It sounds trivial, but it does have at least some impact on infrastructure and what how we manage the different types of content we (will) have. Are there any obvious problems or niches that we think could address really well, or should we just throw ideas out and see what readers respond to? What kind of users do we want to provide for? This actually deserves a little bit of unpacking… Why are you here? We currently divide readers into (broadly) the categories: Category 1: I know nothing about X, and I’d like to learn about it. Category 2: I know something about X, but I’d like to learn how to do something specific with it. Category 3: Ah man, I have a problem with X, and I need to fix it now. Now that I think about it, I might also include a 4th class of reader: Category 4: I’m looking for something interesting to engage my brain. These are clearly task-based categorizations, and depending on which task you’re performing when you arrive here, you’re going to need different types of content, or will have specific discovery needs. One of the questions that’s at the back of my mind whenever I consider a new idea is “How many of the categories will this satisfy?” As an example, typical video training is very well suited to categories 1, 2, and 4. StackOverflow is very well suited to category 3, and serves as a sign-posting system to the rest. Clearly it’s not necessary to satisfy every category need to be useful and popular, but being aware of what behavior readers might be exhibiting when they arrive will help us tune our ideas appropriately. < / Flashback > We don’t have clean answers to most of these considerations – they’re things we’re aware of, and each idea we look at is going to be best suited to a different mix of the options I’ve described. Our first experimental loop will be coming full circle in the next few days, so we should start to see how the different possibilities vary between ideas. Free to chime in with questions and suggestions about anything I’ve just brain-dumped, or at any stage as we go along. If you see anything that intrigued or enrages you, or just have an idea you’d like to share, I’d love to hear from you.

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  • Database Partitioning and Multiple Data Source Considerations

    - by Jeffrey McDaniel
    With the release of P6 Reporting Database 3.0 partitioning was added as a feature to help with performance and data management.  Careful investigation of requirements should be conducting prior to installation to help improve overall performance throughout the lifecycle of the data warehouse, preventing future maintenance that would result in data loss. Before installation try to determine how many data sources and partitions will be required along with the ranges.  In P6 Reporting Database 3.0 any adjustments outside of defaults must be made in the scripts and changes will require new ETL runs for each data source.  Considerations: 1. Standard Edition or Enterprise Edition of Oracle Database.   If you aren't using Oracle Enterprise Edition Database; the partitioning feature is not available. Multiple Data sources are only supported on Enterprise Edition of Oracle   Database. 2. Number of Data source Ids for partitioning during configuration.   This setting will specify how many partitions will be allocated for tables containing data source information.  This setting requires some evaluation prior to installation as       there are repercussions if you don't estimate correctly.   For example, if you configured the software for only 2 data sources and the partition setting was set to 2, however along came a 3rd data source.  The necessary steps to  accommodate this change are as follows: a) By default, 3 partitions are configured in the Reporting Database scripts. Edit the create_star_tables_part.sql script located in <installation directory>\star\scripts   and search for partition.  You’ll see P1, P2, P3.  Add additional partitions and sub-partitions for P4 and so on. These will appear in several areas.  (See P6 Reporting Database 3.0 Installation and Configuration guide for more information on this and how to adjust partition ranges). b) Run starETL -r.  This will recreate each table with the new partition key.  The effect of this step is that all tables data will be lost except for history related tables.   c) Run starETL for each of the 3 data sources (with the data source # (starETL.bat "-s2" -as defined in P6 Reporting Database 3.0 Installation and Configuration guide) The best strategy for this setting is to overestimate based on possible growth.  If during implementation it is deemed that there are atleast 2 data sources with possibility for growth, it is a better idea to set this setting to 4 or 5, allowing room for the future and preventing a ‘start over’ scenario. 3. The Number of Partitions and the Number of Months per Partitions are not specific to multi-data source.  These settings work in accordance to a sub partition of larger tables with regard to time related data.  These settings are dataset specific for optimization.  The number of months per partition is self explanatory, optimally the smaller the partition, the better query performance so if the dataset has an extremely large number of spread/history records, a lower number of months is optimal.  Working in accordance with this setting is the number of partitions, this will determine how many "buckets" will be created per the number of months setting.  For example, if you kept the default for # of partitions of 3, and select 2 months for each partitions you would end up with: -1st partition, 2 months -2nd partition, 2 months -3rd partition, all the remaining records Therefore with records to this setting, it is important to analyze your source db spread ranges and history settings when determining the proper number of months per partition and number of partitions to optimize performance.  Also be aware the DBA will need to monitor when these partition ranges will fill up and when additional partitions will need to be added.  If you get to the final range partition and there are no additional range partitions all data will be included into the last partition. 

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  • Processing Text and Binary (Blob, ArrayBuffer, ArrayBufferView) Payload in WebSocket - (TOTD #185)

    - by arungupta
    The WebSocket API defines different send(xxx) methods that can be used to send text and binary data. This Tip Of The Day (TOTD) will show how to send and receive text and binary data using WebSocket. TOTD #183 explains how to get started with a WebSocket endpoint using GlassFish 4. A simple endpoint from that blog looks like: @WebSocketEndpoint("/endpoint") public class MyEndpoint { public void receiveTextMessage(String message) { . . . } } A message with the first parameter of the type String is invoked when a text payload is received. The payload of the incoming WebSocket frame is mapped to this first parameter. An optional second parameter, Session, can be specified to map to the "other end" of this conversation. For example: public void receiveTextMessage(String message, Session session) {     . . . } The return type is void and that means no response is returned to the client that invoked this endpoint. A response may be returned to the client in two different ways. First, set the return type to the expected type, such as: public String receiveTextMessage(String message) { String response = . . . . . . return response; } In this case a text payload is returned back to the invoking endpoint. The second way to send a response back is to use the mapped session to send response using one of the sendXXX methods in Session, when and if needed. public void receiveTextMessage(String message, Session session) {     . . .     RemoteEndpoint remote = session.getRemote();     remote.sendString(...);     . . .     remote.sendString(...);    . . .    remote.sendString(...); } This shows how duplex and asynchronous communication between the two endpoints can be achieved. This can be used to define different message exchange patterns between the client and server. The WebSocket client can send the message as: websocket.send(myTextField.value); where myTextField is a text field in the web page. Binary payload in the incoming WebSocket frame can be received if ByteBuffer is used as the first parameter of the method signature. The endpoint method signature in that case would look like: public void receiveBinaryMessage(ByteBuffer message) {     . . . } From the client side, the binary data can be sent using Blob, ArrayBuffer, and ArrayBufferView. Blob is a just raw data and the actual interpretation is left to the application. ArrayBuffer and ArrayBufferView are defined in the TypedArray specification and are designed to send binary data using WebSocket. In short, ArrayBuffer is a fixed-length binary buffer with no format and no mechanism for accessing its contents. These buffers are manipulated using one of the views defined by one of the subclasses of ArrayBufferView listed below: Int8Array (signed 8-bit integer or char) Uint8Array (unsigned 8-bit integer or unsigned char) Int16Array (signed 16-bit integer or short) Uint16Array (unsigned 16-bit integer or unsigned short) Int32Array (signed 32-bit integer or int) Uint32Array (unsigned 16-bit integer or unsigned int) Float32Array (signed 32-bit float or float) Float64Array (signed 64-bit float or double) WebSocket can send binary data using ArrayBuffer with a view defined by a subclass of ArrayBufferView or a subclass of ArrayBufferView itself. The WebSocket client can send the message using Blob as: blob = new Blob([myField2.value]);websocket.send(blob); where myField2 is a text field in the web page. The WebSocket client can send the message using ArrayBuffer as: var buffer = new ArrayBuffer(10);var bytes = new Uint8Array(buffer);for (var i=0; i<bytes.length; i++) { bytes[i] = i;}websocket.send(buffer); A concrete implementation of receiving the binary message may look like: @WebSocketMessagepublic void echoBinary(ByteBuffer data, Session session) throws IOException {    System.out.println("echoBinary: " + data);    for (byte b : data.array()) {        System.out.print(b);    }    session.getRemote().sendBytes(data);} This method is just printing the binary data for verification but you may actually be storing it in a database or converting to an image or something more meaningful. Be aware of TYRUS-51 if you are trying to send binary data from server to client using method return type. Here are some references for you: JSR 356: Java API for WebSocket - Specification (Early Draft) and Implementation (already integrated in GlassFish 4 promoted builds) TOTD #183 - Getting Started with WebSocket in GlassFish TOTD #184 - Logging WebSocket Frames using Chrome Developer Tools, Net-internals and Wireshark Subsequent blogs will discuss the following topics (not necessary in that order) ... Error handling Custom payloads using encoder/decoder Interface-driven WebSocket endpoint Java client API Client and Server configuration Security Subprotocols Extensions Other topics from the API

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  • Increasing efficiency of N-Body gravity simulation

    - by Postman
    I'm making a space exploration type game, it will have many planets and other objects that will all have realistic gravity. I currently have a system in place that works, but if the number of planets goes above 70, the FPS decreases an practically exponential rates. I'm making it in C# and XNA. My guess is that I should be able to do gravity calculations between 100 objects without this kind of strain, so clearly my method is not as efficient as it should be. I have two files, Gravity.cs and EntityEngine.cs. Gravity manages JUST the gravity calculations, EntityEngine creates an instance of Gravity and runs it, along with other entity related methods. EntityEngine.cs public void Update() { foreach (KeyValuePair<string, Entity> e in Entities) { e.Value.Update(); } gravity.Update(); } (Only relevant piece of code from EntityEngine, self explanatory. When an instance of Gravity is made in entityEngine, it passes itself (this) into it, so that gravity can have access to entityEngine.Entities (a dictionary of all planet objects)) Gravity.cs namespace ExplorationEngine { public class Gravity { private EntityEngine entityEngine; private Vector2 Force; private Vector2 VecForce; private float distance; private float mult; public Gravity(EntityEngine e) { entityEngine = e; } public void Update() { //First loop foreach (KeyValuePair<string, Entity> e in entityEngine.Entities) { //Reset the force vector Force = new Vector2(); //Second loop foreach (KeyValuePair<string, Entity> e2 in entityEngine.Entities) { //Make sure the second value is not the current value from the first loop if (e2.Value != e.Value ) { //Find the distance between the two objects. Because Fg = G * ((M1 * M2) / r^2), using Vector2.Distance() and then squaring it //is pointless and inefficient because distance uses a sqrt, squaring the result simple cancels that sqrt. distance = Vector2.DistanceSquared(e2.Value.Position, e.Value.Position); //This makes sure that two planets do not attract eachother if they are touching, completely unnecessary when I add collision, //For now it just makes it so that the planets are not glitchy, performance is not significantly improved by removing this IF if (Math.Sqrt(distance) > (e.Value.Texture.Width / 2 + e2.Value.Texture.Width / 2)) { //Calculate the magnitude of Fg (I'm using my own gravitational constant (G) for the sake of time (I know it's 1 at the moment, but I've been changing it) mult = 1.0f * ((e.Value.Mass * e2.Value.Mass) / distance); //Calculate the direction of the force, simply subtracting the positions and normalizing works, this fixes diagonal vectors //from having a larger value, and basically makes VecForce a direction. VecForce = e2.Value.Position - e.Value.Position; VecForce.Normalize(); //Add the vector for each planet in the second loop to a force var. Force = Vector2.Add(Force, VecForce * mult); //I have tried Force += VecForce * mult, and have not noticed much of an increase in speed. } } } //Add that force to the first loop's planet's position (later on I'll instead add to acceleration, to account for inertia) e.Value.Position += Force; } } } } I have used various tips (about gravity optimizing, not threading) from THIS question (that I made yesterday). I've made this gravity method (Gravity.Update) as efficient as I know how to make it. This O(N^2) algorithm still seems to be eating up all of my CPU power though. Here is a LINK (google drive, go to File download, keep .Exe with the content folder, you will need XNA Framework 4.0 Redist. if you don't already have it) to the current version of my game. Left click makes a planet, right click removes the last planet. Mouse moves the camera, scroll wheel zooms in and out. Watch the FPS and Planet Count to see what I mean about performance issues past 70 planets. (ALL 70 planets must be moving, I've had 100 stationary planets and only 5 or so moving ones while still having 300 fps, the issue arises when 70+ are moving around) After 70 planets are made, performance tanks exponentially. With < 70 planets, I get 330 fps (I have it capped at 300). At 90 planets, the FPS is about 2, more than that and it sticks around at 0 FPS. Strangely enough, when all planets are stationary, the FPS climbs back up to around 300, but as soon as something moves, it goes right back down to what it was, I have no systems in place to make this happen, it just does. I considered multithreading, but that previous question I asked taught me a thing or two, and I see now that that's not a viable option. I've also thought maybe I could do the calculations on my GPU instead, though I don't think it should be necessary. I also do not know how to do this, it is not a simple concept and I want to avoid it unless someone knows a really noob friendly simple way to do it that will work for an n-body gravity calculation. (I have an NVidia gtx 660) Lastly I've considered using a quadtree type system. (Barnes Hut simulation) I've been told (in the previous question) that this is a good method that is commonly used, and it seems logical and straightforward, however the implementation is way over my head and I haven't found a good tutorial for C# yet that explains it in a way I can understand, or uses code I can eventually figure out. So my question is this: How can I make my gravity method more efficient, allowing me to use more than 100 objects (I can render 1000 planets with constant 300+ FPS without gravity calculations), and if I can't do much to improve performance (including some kind of quadtree system), could I use my GPU to do the calculations?

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  • The design of a generic data synchronizer, or, an [object] that does [actions] with the aid of [helpers]

    - by acheong87
    I'd like to create a generic data-source "synchronizer," where data-source "types" may include MySQL databases, Google Spreadsheets documents, CSV files, among others. I've been trying to figure out how to structure this in terms of classes and interfaces, keeping in mind (what I've read about) composition vs. inheritance and is-a vs. has-a, but each route I go down seems to violate some principle. For simplicity, assume that all data-sources have a header-row-plus-data-rows format. For example, assume that the first rows of Google Spreadsheets documents and CSV files will have column headers, a.k.a. "fields" (to parallel database fields). Also, eventually, I would like to implement this in PHP, but avoiding language-specific discussion would probably be more productive. Here's an overview of what I've tried. Part 1/4: ISyncable class CMySQL implements ISyncable GetFields() // sql query, pdo statement, whatever AddFields() RemFields() ... _dbh class CGoogleSpreadsheets implements ISyncable GetFields() // zend gdata api AddFields() RemFields() ... _spreadsheetKey _worksheetId class CCsvFile implements ISyncable GetFields() // read from buffer AddFields() RemFields() ... _buffer interface ISyncable GetFields() AddFields($field1, $field2, ...) RemFields($field1, $field2, ...) ... CanAddFields() // maybe the spreadsheet is locked for write, or CanRemFields() // maybe no permission to alter a database table ... AddRow() ModRow() RemRow() ... Open() Close() ... First Question: Does it make sense to use an interface, as above? Part 2/4: CSyncer Next, the thing that does the syncing. class CSyncer __construct(ISyncable $A, ISyncable $B) Push() // sync A to B Pull() // sync B to A Sync() // Push() and Pull() only differ in direction; factor. // Sync()'s job is to make sure that the fields on each side // match, to add fields where appropriate and possible, to // account for different column-orderings, etc., and of // course, to add and remove rows as necessary to sync. ... _A _B Second Question: Does it make sense to define such a class, or am I treading dangerously close to the "Kingdom of Nouns"? Part 3/4: CTranslator? ITranslator? Now, here's where I actually get lost, assuming the above is passable. Sometimes, two ISyncables speak different "dialects." For example, believe it or not, Google Spreadsheets (accessed through the Google Data API "list feed") returns column headers lower-cased and stripped of all spaces and symbols! That is, sys_TIMESTAMP is systimestamp, as far as my code can tell. (Yes, I am aware that the "cell feed" does not strip the name so; however cell-by-cell manipulation is too slow for what I'm doing.) One can imagine other hypothetical examples. Perhaps even the data itself can be in different "dialects." But let's take it as given for now, and not argue this if possible. Third Question: How would you implement "translation"? Note: Taking all this as an exercise, I'm more interested in the "idealized" design, rather than the practical one. (God knows that shipped sailed when I began this project.) Part 4/4: Further Thought Here's my train of thought to demonstrate I've thunk, albeit unfruitfully: First, I thought, primitively, "I'll just modify CMySQL::GetFields() to lower-case and strip field names so they're compatible with Google Spreadsheets." But of course, then my class should really be called, CMySQLForGoogleSpreadsheets, and that can't be right. So, the thing which translates must exist outside of an ISyncable implementor. And surely it can't be right to make each translation a method in CSyncer. If it exists outside of both ISyncable and CSyncer, then what is it? (Is it even an "it"?) Is it an abstract class, i.e. abstract CTranslator? Is it an interface, since a translator only does, not has, i.e. interface ITranslator? Does it even require instantiation? e.g. If it's an ITranslator, then should its translation methods be static? (I learned what "late static binding" meant, today.) And, dear God, whatever it is, how should a CSyncer use it? Does it "have" it? Is it, "it"? Who am I? ...am I, "I"? I've attempted to break up the question into sub-questions, but essentially my question is singular: How does one implement an object A that conceptually "links" (has) two objects b1 and b2 that share a common interface B, where certain pairs of b1 and b2 require a helper, e.g. a translator, to be handled by A? Something tells me that I've overcomplicated this design, or violated a principle much higher up. Thank you all very much for your time and any advice you can provide.

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  • JDeveloper does not recognize existing subversion working directory

    - by Bob Webster
    Just a quick note about an issue where JDeveloper no longer recognized an existing subversion working directory. Symptom:  JDeveloper Versioning menu offers to Version an Application that is already versioned in svn. Cause: The repository url contained in the hidden .svn folders of the working directory is no longer valid. Solution: Determine the correct url for the Subversion repository and update the .svn working directory.Fix the url contained in the svn folders of the working directory using the svn switch command. Example:           In a shell change directory to the Application folder.           Run the svn info command to confirm the current settings.                $ svn info                   Path: .                   URL: http://192.168.1.128/repos/jdeveloperrepo/AsyncExamples/BPELCallAsync/trunk                   Repository Root: http://192.168.1.128/repos/jdeveloperrepo                   Repository UUID: 3dc5eb88-3001-0010-8d6e-fd6f73825647                   Revision: 145                   Node Kind: directory                   Schedule: normal                   Last Changed Rev: 145                   Last Changed Date: 2012-06-07 07:15:56 -0700 (Thu, 07 Jun 2012)            In this case, the IP address in the repository URL is incorrect,           the svn server is located at 192.168.56.1           Note: The IP Address currently set is displayed after the Project Name in the            Application Navigator.  See the screen snapshot above.            Run the svn switch command with the --relocate option            Provide as much of the urls as necessary to correctly rewrite the url from current to new.            For example,            to change the repository server address from 192.168.1.128   to   192.168.56.1                     $  svn switch --relocate  http://192.168.1.128   http://192.168.56.1  .                               (Note the trailing period in the above command)           When the url is correct, JDeveloper should recognize the Subversion Working Directory.

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  • Mousin' down the PathListBox

    - by T
    While modifying the standard media player with a new look and feel for Ineta Live I saw a unique opportunity to use their logo with a dotted I with and attached arc as the scrub control. So I created a PathListBox that I wanted an object to follow when a user did a click and drag action.  Below is how I solved the problem.  Please let me know if you have improvements or know of a completely different way.  I am always eager to learn. First, I created a path using the pen tool in Expression Blend (see the yellow line in image below).  Then I right clicked that path and chose [Path] --> [Make Layout Path].   That created a new PathListBox.  Then I chose the object I want to move down the new PathListBox and Placed it as a child in the Objects and Timeline window (see image below).  If the child object (the thing the user will click and drag) is XAML, it will move much smoother than images. Just as another side note, I wanted there to be no highlight when the user selects the “ball” to drag and drop.  This is done by editing the ItemContainerStyle under Additional Templates on the PathListBox.  Post a question if you need help on this and I will expand my explanation. Here is a pic of the object and the path I wanted it to follow.  I gave the path a yellow solid brush here so you could see it but when I lay this over another object, I will make the path transparent.   To animate this object down the path, the trick is to animate the Start number for the LayoutPath.  Not the StartItemIndex, the Start above Span. In order to enable animation when a user clicks and drags, I put in the following code snippets in the code behind. the DependencyProperties are not necessary for the Drag control.   namespace InetaPlayer { public partial class PositionControl : UserControl { private bool _mouseDown; private double _maxPlayTime; public PositionControl() { // Required to initialize variables InitializeComponent(); //mouse events for scrub control positionThumb.MouseLeftButtonDown += new MouseButtonEventHandler(ValueThumb_MouseLeftButtonDown); positionThumb.MouseLeftButtonUp += new MouseButtonEventHandler(ValueThumb_MouseLeftButtonUp); positionThumb.MouseMove += new MouseEventHandler(ValueThumb_MouseMove); positionThumb.LostMouseCapture += new MouseEventHandler(ValueThumb_LostMouseCapture); } // exposed for binding to real slider using a DependencyProperty enables animation, styling, binding, etc.... public double MaxPlayTime { get { return (double)GetValue(MaxPlayTimeProperty); } set { SetValue(MaxPlayTimeProperty, value); } } public static readonly DependencyProperty MaxPlayTimeProperty = DependencyProperty.Register("MaxPlayTime", typeof(double), typeof(PositionControl), null);   // exposed for binding to real slider using a DependencyProperty enables animation, styling, binding, etc....   public double CurrSliderValue { get { return (double)GetValue(CurrSliderValueProperty); } set { SetValue(CurrSliderValueProperty, value); } }   public static readonly DependencyProperty CurrSliderValueProperty = DependencyProperty.Register("CurrSliderValue", typeof(double), typeof(PositionControl), new PropertyMetadata(0.0, OnCurrSliderValuePropertyChanged));   private static void OnCurrSliderValuePropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { PositionControl control = d as PositionControl; control.OnCurrSliderValueChanged((double)e.OldValue, (double)e.NewValue); }   private void OnCurrSliderValueChanged(double oldValue, double newValue) { _maxPlayTime = (double) GetValue(MaxPlayTimeProperty); if (!_mouseDown) if (_maxPlayTime!=0) sliderPathListBox.LayoutPaths[0].Start = newValue / _maxPlayTime; else sliderPathListBox.LayoutPaths[0].Start = 0; }   //mouse control   void ValueThumb_MouseMove(object sender, MouseEventArgs e) { if (!_mouseDown) return; //get the offset of how far the drag has been //direction is handled automatically (offset will be negative for left move and positive for right move) Point mouseOff = e.GetPosition(positionThumb); //Divide the offset by 1000 for a smooth transition sliderPathListBox.LayoutPaths[0].Start +=mouseOff.X/1000; _maxPlayTime = (double)GetValue(MaxPlayTimeProperty); SetValue(CurrSliderValueProperty ,sliderPathListBox.LayoutPaths[0].Start*_maxPlayTime); }   void ValueThumb_MouseLeftButtonUp(object sender, MouseButtonEventArgs e) { _mouseDown = false; } void ValueThumb_LostMouseCapture(object sender, MouseEventArgs e) { _mouseDown = false; } void ValueThumb_MouseLeftButtonDown(object sender, MouseButtonEventArgs e) { _mouseDown = true; ((UIElement)positionThumb).CaptureMouse(); }   } }   I made this into a user control and exposed a couple of DependencyProperties in order to bind it to a standard Slider in the overall project.  This control is embedded into the standard Expression media player template and is used to replace the standard scrub bar.  When the player goes live, I will put a link here.

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  • The Dreaded Startup Repair Loop on Win 7

    - by HighAltitudeCoder
    For most people, upgrading to Windows 7 has been a relatively painless process.  Not me.  I am in the unlucky 1% or less who had a somewhat less pleasant experience.  First, I cloned my entire onto a larger (and much faster) solid state hard drive, only experiencing minimal problems. Then, I bought the Retail version of Windows 7 Ultimate, took a deep breath and... oh yeah, I almost forgot - BACK UP THE COMPUTER.  The next morning I upgraded to Win 7 and everything seemed fine, until... I rebooted the system, the nice Windows 7 launch graphics come up, it's about to launch and AWWW, are you kidding me?!?!  Back to the BIOS splash screen?  Next comes the sequence of failure - attempt repair - unable to repair - do you want to wipe your hard drive decisions. Because I purchased the retail version, a number is provided where I could call Microsoft Tech support.  When I did, they instructed me to click "Install" from my installation CD, which did not work.  When I tried the "Upgrade" option, it reaches an impasse, telling you that yoiu have a newer version of Win 7, and thus cannot Upgrade.  If you choose "Install" you willl lose everything... files, programs, EVERYTHING.  Or at least this is what it tells you.  I was not willing to take the risk. To make things worse, I had installed a new antivirus software application before I realized my system was unstable (Trend Micro Titanium Internet Security), and this was causing additional problems. One interesting thing, and the only saving grace as it turns out, was that my system WOULD successfully reboot into the OS if I chose to restart it, rather than shut it down.  If I chose to shut down, I would have to go through the loop again until I was given the option to restart. As it turned out, I needed to update my BIOS.  I assumed that since I had updated my BIOS a long time ago to settings that were stable under Windows Vista Ultimate x64, I incorrectly expected Win 7 to adopt the same settings and didn't expect there to be any problems.  WRONG. My BIOS had a setting to halt the boot cycle if various kinds of errors were detected.  Windows Vista didn't care about this, but forget it under Windows 7.  I turned immediately corrected that BIOS setting.  Next, there were the two separate BIOS settings: enable USB mouse and enable USB keyboard.  The only sequence of events that would work were to start my reboot process over from stratch with a hard-wired non-usb keyboard and mouse.  Whent the system booted under these settings, it doesn't detect any errors due to either the mouse or keyboard, and actually booted for the first time in a long while (let me tell ya, that's an amazing experience after fiddling with settings for two entire weekends!) Next step: leave your old mouse and keyboard connected, but also connect your other two devices (mouse, keyboard) that use USB connections.  During the boot cycle, the operating system will not fail due to missing requirements during startup, and it will then pick up the new drivers necessary to use your new hardware. If you think you are in the clear here, you are wrong.  The next VERY IMPORTANT step is to remember to change your settings in the BIOS upon next startup.  Specifically, yoiu will need ot change your BIOS to enable USB mouse and enable USB keyboard input.  If you don't, Windows will detect an incompatibility upon the next startup, and you will be stuck once again in the endless cycle of reboot/Startup Repair/reboot/Startup Repair, without ever reaching a successful boot. Here's the thing - the BIOS and the drivers registered in Win 7 need to match.  If they don't, you're going to lose another weekend worrying and fiddling, all the while wondering if you've permanently damaged your hard drive beyond repair. (Sigh).  In the end, things worked out.  I must note that it is saddening to see how many posts there are out there that recommend just doing a clean install, as if it's the only option.  How many countless poor souls have lost their data, their backups, their pictures and videos, all for nothing other than the fact that the person giving advice just didn't know what to do at that point? My advice to you, try having a look at your BIOS settings first and making sure Win 7 can find your BIOS settings, and also disabling in your BIOS anything that might halt your system boot-up process if it encounters errors.

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  • Mousin' down the PathListBox

    - by T
    While modifying the standard media player with a new look and feel for Ineta Live I saw a unique opportunity to use their logo with a dotted I with and attached arc as the scrub control. So I created a PathListBox that I wanted an object to follow when a user did a click and drag action.  Below is how I solved the problem.  Please let me know if you have improvements or know of a completely different way.  I am always eager to learn. First, I created a path using the pen tool in Expression Blend (see the yellow line in image below).  Then I right clicked that path and chose [Path] --> [Make Layout Path].   That created a new PathListBox.  Then I chose the object I want to move down the new PathListBox and Placed it as a child in the Objects and Timeline window (see image below).  If the child object (the thing the user will click and drag) is XAML, it will move much smoother than images. Just as another side note, I wanted there to be no highlight when the user selects the “ball” to drag and drop.  This is done by editing the ItemContainerStyle under Additional Templates on the PathListBox.  Post a question if you need help on this and I will expand my explanation. Here is a pic of the object and the path I wanted it to follow.  I gave the path a yellow solid brush here so you could see it but when I lay this over another object, I will make the path transparent.   To animate this object down the path, the trick is to animate the Start number for the LayoutPath.  Not the StartItemIndex, the Start above Span. In order to enable animation when a user clicks and drags, I put in the following code snippets in the code behind. the DependencyProperties are not necessary for the Drag control. namespace InetaPlayer{ public partial class PositionControl : UserControl { private bool _mouseDown; private double _maxPlayTime; public PositionControl() { // Required to initialize variables InitializeComponent(); //mouse events for scrub control positionThumb.MouseLeftButtonDown += new MouseButtonEventHandler(ValueThumb_MouseLeftButtonDown); positionThumb.MouseLeftButtonUp += new MouseButtonEventHandler(ValueThumb_MouseLeftButtonUp); positionThumb.MouseMove += new MouseEventHandler(ValueThumb_MouseMove); positionThumb.LostMouseCapture += new MouseEventHandler(ValueThumb_LostMouseCapture); } // exposed for binding to real slider using a DependencyProperty enables animation, styling, binding, etc.... public double MaxPlayTime { get { return (double)GetValue(MaxPlayTimeProperty); } set { SetValue(MaxPlayTimeProperty, value); } } public static readonly DependencyProperty MaxPlayTimeProperty = DependencyProperty.Register("MaxPlayTime", typeof(double), typeof(PositionControl), null);   // exposed for binding to real slider using a DependencyProperty enables animation, styling, binding, etc....   public double CurrSliderValue { get { return (double)GetValue(CurrSliderValueProperty); } set { SetValue(CurrSliderValueProperty, value); } }   public static readonly DependencyProperty CurrSliderValueProperty = DependencyProperty.Register("CurrSliderValue", typeof(double), typeof(PositionControl), new PropertyMetadata(0.0, OnCurrSliderValuePropertyChanged));   private static void OnCurrSliderValuePropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { PositionControl control = d as PositionControl; control.OnCurrSliderValueChanged((double)e.OldValue, (double)e.NewValue); }   private void OnCurrSliderValueChanged(double oldValue, double newValue) { _maxPlayTime = (double) GetValue(MaxPlayTimeProperty); if (!_mouseDown) if (_maxPlayTime!=0) sliderPathListBox.LayoutPaths[0].Start = newValue / _maxPlayTime; else sliderPathListBox.LayoutPaths[0].Start = 0; }  //mouse control   void ValueThumb_MouseMove(object sender, MouseEventArgs e) { if (!_mouseDown) return; //get the offset of how far the drag has been //direction is handled automatically (offset will be negative for left move and positive for right move) Point mouseOff = e.GetPosition(positionThumb); //Divide the offset by 1000 for a smooth transition sliderPathListBox.LayoutPaths[0].Start +=mouseOff.X/1000; _maxPlayTime = (double)GetValue(MaxPlayTimeProperty); SetValue(CurrSliderValueProperty ,sliderPathListBox.LayoutPaths[0].Start*_maxPlayTime); }   void ValueThumb_MouseLeftButtonUp(object sender, MouseButtonEventArgs e) { _mouseDown = false; } void ValueThumb_LostMouseCapture(object sender, MouseEventArgs e) { _mouseDown = false; } void ValueThumb_MouseLeftButtonDown(object sender, MouseButtonEventArgs e) { _mouseDown = true; ((UIElement)positionThumb).CaptureMouse(); }   }}  I made this into a user control and exposed a couple of DependencyProperties in order to bind it to a standard Slider in the overall project.  This control is embedded into the standard Expression media player template and is used to replace the standard scrub bar.  When the player goes live, I will put a link here.

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  • IsNumeric() Broken? Only up to a point.

    - by Phil Factor
    In SQL Server, probably the best-known 'broken' function is poor ISNUMERIC() . The documentation says 'ISNUMERIC returns 1 when the input expression evaluates to a valid numeric data type; otherwise it returns 0. ISNUMERIC returns 1 for some characters that are not numbers, such as plus (+), minus (-), and valid currency symbols such as the dollar sign ($).'Although it will take numeric data types (No, I don't understand why either), its main use is supposed to be to test strings to make sure that you can convert them to whatever numeric datatype you are using (int, numeric, bigint, money, smallint, smallmoney, tinyint, float, decimal, or real). It wouldn't actually be of much use anyway, since each datatype has different rules. You actually need a RegEx to do a reasonably safe check. The other snag is that the IsNumeric() function  is a bit broken. SELECT ISNUMERIC(',')This cheerfully returns 1, since it believes that a comma is a currency symbol (not a thousands-separator) and you meant to say 0, in this strange currency.  However, SELECT ISNUMERIC(N'£')isn't recognized as currency.  '+' and  '-' is seen to be numeric, which is stretching it a bit. You'll see that what it allows isn't really broken except that it doesn't recognize Unicode currency symbols: It just tells you that one numeric type is likely to accept the string if you do an explicit conversion to it using the string. Both these work fine, so poor IsNumeric has to follow suit. SELECT  CAST('0E0' AS FLOAT)SELECT  CAST (',' AS MONEY) but it is harder to predict which data type will accept a '+' sign. SELECT  CAST ('+' AS money) --0.00SELECT  CAST ('+' AS INT)   --0SELECT  CAST ('+' AS numeric)/* Msg 8115, Level 16, State 6, Line 4 Arithmetic overflow error converting varchar to data type numeric.*/SELECT  CAST ('+' AS FLOAT)/*Msg 8114, Level 16, State 5, Line 5Error converting data type varchar to float.*/> So we can begin to say that the maybe IsNumeric isn't really broken, but is answering a silly question 'Is there some numeric datatype to which i can convert this string? Almost, but not quite. The bug is that it doesn't understand Unicode currency characters such as the euro or franc which are actually valid when used in the CAST function. (perhaps they're delaying fixing the euro bug just in case it isn't necessary).SELECT ISNUMERIC (N'?23.67') --0SELECT  CAST (N'?23.67' AS money) --23.67SELECT ISNUMERIC (N'£100.20') --1SELECT  CAST (N'£100.20' AS money) --100.20 Also the CAST function itself is quirky in that it cannot convert perfectly reasonable string-representations of integers into integersSELECT ISNUMERIC('200,000')       --1SELECT  CAST ('200,000' AS INT)   --0/*Msg 245, Level 16, State 1, Line 2Conversion failed when converting the varchar value '200,000' to data type int.*/  A more sensible question is 'Is this an integer or decimal number'. This cuts out a lot of the apparent quirkiness. We do this by the '+E0' trick. If we want to include floats in the check, we'll need to make it a bit more complicated. Here is a small test-rig. SELECT  PossibleNumber,         ISNUMERIC(CAST(PossibleNumber AS NVARCHAR(20)) + 'E+00') AS Hack,        ISNUMERIC (PossibleNumber + CASE WHEN PossibleNumber LIKE '%E%'                                          THEN '' ELSE 'E+00' END) AS Hackier,        ISNUMERIC(PossibleNumber) AS RawIsNumericFROM    (SELECT CAST(',' AS NVARCHAR(10)) AS PossibleNumber          UNION SELECT '£' UNION SELECT '.'         UNION SELECT '56' UNION SELECT '456.67890'         UNION SELECT '0E0' UNION SELECT '-'         UNION SELECT '-' UNION SELECT '.'         UNION  SELECT N'?' UNION SELECT N'¢'        UNION  SELECT N'?' UNION SELECT N'?34.56'         UNION SELECT '-345' UNION SELECT '3.332228E+09') AS examples Which gives the result ... PossibleNumber Hack Hackier RawIsNumeric-------------- ----------- ----------- ------------? 0 0 0- 0 0 1, 0 0 1. 0 0 1¢ 0 0 1£ 0 0 1? 0 0 0?34.56 0 0 00E0 0 1 13.332228E+09 0 1 1-345 1 1 1456.67890 1 1 156 1 1 1 I suspect that this is as far as you'll get before you abandon IsNumeric in favour of a regex. You can only get part of the way with the LIKE wildcards, because you cannot specify quantifiers. You'll need full-blown Regex strings like these ..[-+]?\b[0-9]+(\.[0-9]+)?\b #INT or REAL[-+]?\b[0-9]{1,3}\b #TINYINT[-+]?\b[0-9]{1,5}\b #SMALLINT.. but you'll get even these to fail to catch numbers out of range.So is IsNumeric() an out and out rogue function? Not really, I'd say, but then it would need a damned good lawyer.

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  • Who could ask for more with LESS CSS? (Part 1 of 3&ndash;Features)

    - by ToStringTheory
    It wasn’t very long ago that I first began to get into CSS precompilers such as SASS (Syntactically Awesome Stylesheets) and LESS (The Dynamic Stylesheet Language) and I had been hooked on the idea since.  When I finally had a new project come up, I leapt at the opportunity to try out one of these languages. Introduction To be honest, I was hesitant at first to add either framework as I didn’t really know much more than what I had read on their homepages, and I didn’t like the idea of adding too much complexity to a project - I couldn’t guarantee I would be the only person to support it in the future. Thankfully, both of these languages just add things into CSS.  You don’t HAVE to know LESS or SASS to do anything, you can still do your old school CSS, and your output will be the same.  However, when you want to start doing more advanced things such as variables, mixins, and color functions, the functionality is all there for you to utilize. From what I had read, SASS has a few more features than LESS, which is why I initially tried to figure out how to incorporate it into a MVC 4 project. However, through my research, I couldn’t find a way to accomplish this without including some bit of the Ruby on Rails framework on the computer running it, and I hated the fact that I had to do that.  Besides SASS, there is little chance of me getting into the RoR framework, at least in the next couple years.  So in the end, I settled with using LESS. Features So, what can LESS (or SASS) do for you?  There are several reasons I have come to love it in the past few weeks. 1 – Constants Using LESS, you can finally declare a constant and use its value across an entire CSS file. The case that most people would be familiar with is colors.  Wanting to declare one or two color variables that comprise the theme of the site, and not have to retype out their specific hex code each time, but rather a variable name.  What’s great about this is that if you end up having to change it, you only have to change it in one place.  An important thing to note is that you aren’t limited to creating constants just for colors, but for strings and measurements as well. 2 – Inheritance This is a cool feature in my mind for simplicity and organization.  Both LESS and SASS allow you to place selectors within other selectors, and when it is compiled, the languages will break the rules out as necessary and keep the inheritance chain you created in the selectors. Example LESS Code: #header {   h1 {     font-size: 26px;     font-weight: bold;   }   p {     font-size: 12px;     a     {       text-decoration: none;       &:hover {         border-width: 1px       }     }   } } Example Compiled CSS: #header h1 {   font-size: 26px;   font-weight: bold; } #header p {   font-size: 12px; } #header p a {   text-decoration: none; } #header p a:hover {   border-width: 1px; } 3 - Mixins Mixins are where languages like this really shine.  The ability to mixin other definitions setup a parametric mixin.  There is really a lot of content in this area, so I would suggest looking at http://lesscss.org for more information.  One of the things I would suggest if you do begin to use LESS is to also grab the mixins.less file from the Twitter Bootstrap project.  This file already has a bunch of predefined mixins for things like border-radius with all of the browser specific prefixes.  This alone is of great use! 4 – Color Functions This is the last thing I wanted to point out as my final post in this series will be utilizing these functions in a more drawn out manner.  Both LESS and SASS provide functions for getting information from a color (R,G,B,H,S,L).  Using these, it is easy to define a primary color, and then darken or lighten it a little for your needs.  Example: Example LESS Code: @base-color: #111; @red:        #842210; #footer {   color: (@base-color + #003300);   border-left:  2px;   border-right: 2px;   border-color: desaturate(@red, 10%); } Example Compiled CSS: #footer {    color: #114411;    border-left:  2px;    border-right: 2px;    border-color: #7d2717; } I have found that these can be very useful and powerful when constructing a site theme. Conclusion I came across LESS and SASS when looking for the best way to implement some type of CSS variables for colors, because I hated having to do a Find and Replace in all of the files using the colors, and in some instances, you couldn’t just find/replace because of the color choices interfering with other colors (color to replace of #000, yet come colors existed like #0002bc).  So in many cases I would end up having to do a Find and manually check each one. In my next post, I am going to cover how I’ve come to set up these items and the structure for the items in the project, as well as the conventions that I have come to start using.  In the final post in the series, I will cover a neat little side project I built in LESS dealing with colors!

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  • Linux fsck.ext3 says "Device or resource busy" although I did not mount the disk.

    - by matnagel
    I am running an ubuntu 8.04 server instance with a 8GB virtual disk on vmware 1.0.9. For disk maintenance I made a copy of the virtual disk (by making a copy of the 2 vmdk files of sda on the stopped vm on the host) and added it to the original vm. Now this vm has it's original virtual disk sda plus a 1:1 copy (sdd). There are 2 additional disk sdb and sdc which I ignore.) I would expect sdb not to be mounted when I start the vm. So I try tp do a ext2 fsck on sdd from the running vm, but it reports fsck reported that sdb was mounted. $ sudo fsck.ext3 -b 8193 /dev/sdd e2fsck 1.40.8 (13-Mar-2008) fsck.ext3: Device or resource busy while trying to open /dev/sdd Filesystem mounted or opened exclusively by another program? The "mount" command does not tell me sdd is mounted: $ sudo mount /dev/sda1 on / type ext3 (rw,relatime,errors=remount-ro) proc on /proc type proc (rw,noexec,nosuid,nodev) /sys on /sys type sysfs (rw,noexec,nosuid,nodev) varrun on /var/run type tmpfs (rw,noexec,nosuid,nodev,mode=0755) varlock on /var/lock type tmpfs (rw,noexec,nosuid,nodev,mode=1777) udev on /dev type tmpfs (rw,mode=0755) devshm on /dev/shm type tmpfs (rw) devpts on /dev/pts type devpts (rw,gid=5,mode=620) /dev/sdc1 on /mnt/r1 type ext3 (rw,relatime,errors=remount-ro) /dev/sdb1 on /mnt/k1 type ext3 (rw,relatime,errors=remount-ro) securityfs on /sys/kernel/security type securityfs (rw) When I ignore the warning and continue the fsck, it reported many errors. How do I get this under control? Is there a better way to figure out if sdd is mounted? Or how is it "busy? How to unmount it then? How to prevent ubuntu from automatically mounting. Or is there something else I am missing? Also from /var/log/syslog I cannot see it is mounted, this is the last part of the startup sequence: kernel: [ 14.229494] ACPI: Power Button (FF) [PWRF] kernel: [ 14.230326] ACPI: AC Adapter [ACAD] (on-line) kernel: [ 14.460136] input: PC Speaker as /devices/platform/pcspkr/input/input3 kernel: [ 14.639366] udev: renamed network interface eth0 to eth1 kernel: [ 14.670187] eth1: link up kernel: [ 16.329607] input: ImPS/2 Generic Wheel Mouse as /devices/platform/i8042/serio1/ kernel: [ 16.367540] parport_pc 00:08: reported by Plug and Play ACPI kernel: [ 16.367670] parport0: PC-style at 0x378, irq 7 [PCSPP,TRISTATE] kernel: [ 19.425637] NET: Registered protocol family 10 kernel: [ 19.437550] lo: Disabled Privacy Extensions kernel: [ 24.328857] loop: module loaded kernel: [ 24.449293] lp0: using parport0 (interrupt-driven). kernel: [ 26.075499] EXT3 FS on sda1, internal journal kernel: [ 28.380299] kjournald starting. Commit interval 5 seconds kernel: [ 28.381706] EXT3 FS on sdc1, internal journal kernel: [ 28.381747] EXT3-fs: mounted filesystem with ordered data mode. kernel: [ 28.444867] kjournald starting. Commit interval 5 seconds kernel: [ 28.445436] EXT3 FS on sdb1, internal journal kernel: [ 28.445444] EXT3-fs: mounted filesystem with ordered data mode. kernel: [ 31.309766] eth1: no IPv6 routers present kernel: [ 35.054268] ip_tables: (C) 2000-2006 Netfilter Core Team mysqld_safe[4367]: started mysqld[4370]: 100124 14:40:21 InnoDB: Started; log sequence number 0 10130914 mysqld[4370]: 100124 14:40:21 [Note] /usr/sbin/mysqld: ready for connections. mysqld[4370]: Version: '5.0.51a-3ubuntu5.4' socket: '/var/run/mysqld/mysqld.sock' port: 3 /etc/mysql/debian-start[4417]: Upgrading MySQL tables if necessary. /etc/mysql/debian-start[4422]: Looking for 'mysql' in: /usr/bin/mysql /etc/mysql/debian-start[4422]: Looking for 'mysqlcheck' in: /usr/bin/mysqlcheck /etc/mysql/debian-start[4422]: This installation of MySQL is already upgraded to 5.0.51a, u /etc/mysql/debian-start[4436]: Checking for insecure root accounts. /etc/mysql/debian-start[4444]: Checking for crashed MySQL tables.

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  • HTTP 500 Internal Server Error on IIS 7.5 with MVC3

    - by Tor Haugen
    I am trying to install an MVC3 application on our production server with no luck. The application is from a 3rd party (compiled), and so debugging is not available to me. Besides, I strongly suspect the error occurs before any code in the site has a chance to execute. Our staging server is - as far as I can determine - set up excactly like the production server. Both run Windows Server 2008 Standard R2, both also run a Sharepoint 2010 site (though this install doesn't touch that in any way). IIS is version 7.5, and .NET Framework 4.0 (required by the MVC app) is (recently) installed (by me, with a reboot after). The application is very small and simple and, as far as I can tell sticks to fairly standard functionality - including forms authentication (ie. it doesnt' pull any dirty tricks). The error message shown in the browser is very general: HTTP Error 500.0 - Internal Server Error An error message detailing the cause of this specific request failure can be found in the application event log of the web server. Please review this log entry to discover what caused this error to occur. The bit about 'An error message detailing the cause' being in the application event log seems to be just speculation - a pious hope that whatever code actually caused the error will log it. Nothing useful is to be found in the event log (only the very same message, logged by IIS). Module: AspNetInitClrHostFailureModule Notification: BeginRequest Handler: StaticFile Error Code: 0x80070002 Requested URL: http://xxxxxx.xxxxxx.xx:80/ Physical Path: C:\Xxxxxxx\Prod\WebClient Logon Method: Not yet determined Logon User: Not yet determined Using Failed Request Tracing, I have been able to track the error (as also indicated above) to the AspNetInitClrHostFailureModule: 103. -NOTIFY_MODULE_START ModuleName AspNetInitClrHostFailureModule Notification 1 fIsPostNotification false Notification BEGIN_REQUEST 104. -SET_RESPONSE_ERROR_DESCRIPTION ErrorDescription An error message detailing the cause of this specific request failure can be found in the application event log of the web server. Please review this log entry to discover what caused this error to occur. 105. -MODULE_SET_RESPONSE_ERROR_STATUS ModuleName AspNetInitClrHostFailureModule Notification 1 HttpStatus 500 HttpReason Internal Server Error HttpSubStatus 0 ErrorCode 2147942402 ConfigExceptionInfo Notification BEGIN_REQUEST ErrorCode The system cannot find the file specified. (0x80070002) So there you have it. Seemingly, the AspNetInitClrHostFailureModule fails to find some file. So some questions are: What is the AspNetInitClrHostFailureModule? It is not listed in the fairly exhausting list of modules configurable in IIS manager for the site. I have had no success googling it either. Maybe it's secret.. I access the root URL of the site. This is supposed to be redirected to /Account/LogOn by the FormsAuthenticationModule. Why then is the handler StaticFile? Is that a clue? I have tried removing the infamous system.webserver/modules/runAllManagedModulesForAllRequests attribute, and that makes the error go away (but MVC not actually working, of course). I am prepared to specify all necessary modules manually if that's what it takes, but if the AspNetInitClrHostFailureModule is actually needed, I will be just as stuck. Does anyone know, or can anyone direct me to someone who knows, exactly what modules a typical MVC3 application actually needs? This question might well be a duplicate of this one, but he didn't get any useful answer, and also asked less specific questions. So I'll have my own go. Hoping for some help here :) Edit: I have now tried setting up a trivial MVC 3 project on the server. I created a new project using the MVC Application template, compiled it and deployed it to the server. It behaves in exactly the same way. The server simply cannot run MVC 3 projects.

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  • Yet another (13)Permission denied error on Apache2 server

    - by lollercoaster
    I just can't figure it out. I'm running apache2 on a Ubuntu 10.04 i386 server. Whenever I visit my server (has an IP address, and is connected to internet with static IP xxx.xxx.xxx.xxx) so that's not the problem) in browser, mysub.domain.edu (renamed here), I get the following: Forbidden You don't have permission to access /index.html on this server The apache2 error log confirms this: [Mon Apr 18 02:38:20 2011] [error] [client zzz.zzz.zzz.zzz] (13)Permission denied: access to / denied I'll try to provide all necessary information below: 1) Contents of /etc/apache2/httpd.conf DirectoryIndex index.html index.php 2) Contents of /etc/apache2/sites-available/default <VirtualHost *:80> ServerAdmin [email protected] DocumentRoot /home/myusername/htdocs <Directory /> Options FollowSymLinks AllowOverride None </Directory> <Directory "/home/myusername/htdocs/"> Options Indexes FollowSymLinks MultiViews AllowOverride None order allow,deny allow from all DirectoryIndex index.html index.php Satisfy any </Directory> ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/ <Directory "/usr/lib/cgi-bin"> AllowOverride None Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch Order allow,deny Allow from all </Directory> ErrorLog /var/log/apache2/error.log # Possible values include: debug, info, notice, warn, error, crit, # alert, emerg. LogLevel warn CustomLog /var/log/apache2/access.log combined Alias /doc/ "/usr/share/doc/" <Directory "/usr/share/doc/"> Options Indexes MultiViews FollowSymLinks AllowOverride None Order deny,allow Deny from all Allow from 127.0.0.0/255.0.0.0 ::1/128 </Directory> ServerName mysub.domain.edu </VirtualHost> 3) Contents of /etc/apache2/sites-enabled/000-default <VirtualHost *:80> ServerAdmin [email protected] DocumentRoot /home/myusername/htdocs <Directory /> Options FollowSymLinks AllowOverride None </Directory> <Directory "/home/myusername/htdocs/"> Options Indexes FollowSymLinks MultiViews AllowOverride None order allow,deny allow from all DirectoryIndex index.html index.php Satisfy any </Directory> ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/ <Directory "/usr/lib/cgi-bin"> AllowOverride None Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch Order allow,deny Allow from all </Directory> ErrorLog /var/log/apache2/error.log # Possible values include: debug, info, notice, warn, error, crit, # alert, emerg. LogLevel warn CustomLog /var/log/apache2/access.log combined Alias /doc/ "/usr/share/doc/" <Directory "/usr/share/doc/"> Options Indexes MultiViews FollowSymLinks AllowOverride None Order deny,allow Deny from all Allow from 127.0.0.0/255.0.0.0 ::1/128 </Directory> ServerName mysub.domain.edu </VirtualHost> 4) Result of ls -l (when I'm using sudo -i to be root): root@myserver:/home/myusername# ls -l total 4 drwxr-xr-x 2 www-data root 4096 2011-04-18 03:04 htdocs 5) ps auxwww | grep -i apache root@myserver:/home# ps auxwww | grep -i apache root 15121 0.0 0.4 5408 2544 ? Ss 16:55 0:00 /usr/sbin/apache2 -k start www-data 15122 0.0 0.3 5180 1760 ? S 16:55 0:00 /usr/sbin/apache2 -k start www-data 15123 0.0 0.5 227020 2788 ? Sl 16:55 0:00 /usr/sbin/apache2 -k start www-data 15124 0.0 0.5 227020 2864 ? Sl 16:55 0:00 /usr/sbin/apache2 -k start root 29133 0.0 0.1 3320 680 pts/0 R+ 16:58 0:00 grep --color=auto -i apache 6) ls -al /home/myusername/htdocs/ root@myserver:/# ls -al /home/myusername/htdocs/ total 20 drwxr-xr-x 2 www-data root 4096 2011-04-18 03:04 . drw-r--r-- 4 myusername myusername 4096 2011-04-18 02:13 .. -rw-r--r-- 1 root root 69 2011-04-18 02:14 index.html I'm not currently using any .htaccess files in my web root (htdocs) folder in my user folder. I don't know what is wrong, I've been trying to fix his for over 12 hours and I've gotten nowhere. If you have any suggestions, I'm all ears...

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  • How do you handle authentication across domains?

    - by William Ratcliff
    I'm trying to save users of our services from having to have multiple accounts/passwords. I'm in a large organization and there's one group that handles part of user authentication for users who are from outside the facility (primarily for administrative functions). They store a secure cookie to establish a session and communicate only via HTTPS via the browser. Sessions expire either through: 1) explicit logout of the user 2) Inactivity 3) Browser closes My team is trying to write a web application to help users analyze data that they've taken (or are currently taking) while at our facility. We need to determine if a user is 1) authenticated 2) Some identifier for that user so we can store state for them (what analysis they are working on, etc.) So, the problem is how do you authenticate across domains (the authentication server for the other application lives in a border region between public and private--we will live in the public region). We have come up with some scenarios and I'd like advice about what is best practice, or if there is one we haven't considered. Let's start with the case where the user is authenticated with the authentication server. 1) The authentication server leaves a public cookie in the browser with their primary key for a user. If this is deemed sensitive, they encrypt it on their server and we have the key to decrypt it on our server. When the user visits our site, we check for this public cookie. We extract the user_id and use a public api for the authentication server to request if the user is logged in. If they are, they send us a response with: response={ userid :we can then map this to our own user ids. If necessary, we can request additional information such as email-address/display name once (to notify them if long running jobs are done, or to share results with other people, like with google_docs). account_is_active:Make sure that the account is still valid session_is_active: Is their session still active? If we query this for a valid user, this will have a side effect that we will reset the last_time_session_activated value and thus prolong their session with the authentication server last_time_session_activated: let us know how much time they have left ip_address_session_started_from:make sure the person at our site is coming from the same ip as they started the session at } Given this response, we either accept them as authenticated and move on with our app, or redirect them to the login page for the authentication server (question: if we give an encrypted portion of the response (signed by us) with the page to redirect them to, do we open any gaping security holes in the authentication server)? The flaw that we've found with this is that if the user visits evilsite.com and they look at the session cookie and send a query to the public api of the authentication server, they can keep the session alive and if our original user leaves the machine without logging out, then the next user will be able to access their session (this was possible before, but having the session alive eternally makes this worse). 2) The authentication server redirects all requests made to our domain to us and we send responses back through them to the user. Essentially, they act as a proxy. The advantage of this is that we can handshake with the authentication server, so it's safe to be trusted with the email address/name of the user and they don't have to reenter it So, if the user tries to go to: authentication_site/mysite_page1 they are redirected to mysite. Which would you choose, or is there a better way? The goal is to minimize the "Yet Another Password/Yet another username" problem... Thanks!!!!

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  • disk-to-disk backup without costly backup redundancy?

    - by AaronLS
    A good backup strategy involves a combination of 1) disconnected backups/snapshots that will not be affected by bugs, viruses, and/or security breaches 2) geographically distributed backups to protect against local disasters 3) testing backups to ensure that they can be restored as needed Generally I take an onsite backup daily, and an offsite backup weekly, and do test restores periodically. In the rare circumstance that I need to restore files, I do some from the local backup. Should a catastrophic event destroy the servers and local backups, then the offsite weekly tape backup would be used to restore the files. I don't need multiple offsite backups with redundancy. I ALREADY HAVE REDUNDANCY THROUGH THE USE OF BOTH LOCAL AND REMOTE BACKUPS. I have recovery blocks and par files with the backups, so I already have protection against a small percentage of corrupt bits. I perform test restores to ensure the backups function properly. Should the remote backups experience a dataloss, I can replace them with one of the local backups. There are historical offsite backups as well, so if a dataloss was not noticed for a few weeks(such as a bug/security breach/virus), the data could be restored from an older backup. By doing this, the only scenario that poses a risk to complete data loss would be one where both the local, remote, and servers all experienced a data loss in the same time period. I'm willing to risk that happening since the odds of that trifecta negligibly small, and the data isn't THAT valuable to me. So I hope I have emphasized that I don't need redundancy in my offsite backups because I have covered all the bases. I know this exact technique is employed by numerous businesses. Of course there are some that take multiple offsite backups, because the data is so incredibly valuable that they don't even want to risk that trifecta disaster, but in the majority of cases the trifecta disaster is an accepted risk. I HAD TO COVER ALL THIS BECAUSE SOME PEOPLE DON'T READ!!! I think I have justified my backup strategy and the majority of businesses who use offsite tape backups do not have any additional redundancy beyond what is mentioned above(recovery blocks, par files, historical snapshots). Now I would like to eliminate the use of tapes for offsite backups, and instead use a backup service. Most however are extremely costly for $/gb/month storage. I don't mind paying for transfer bandwidth, but the cost of storage is way to high. All of them advertise that they maintain backups of the data, and I imagine they use RAID as well. Obviously if you were using them to host servers this would all be necessary, but for my scenario, I am simply replacing my offsite backups with such a service. So there is no need for RAID, and absolutely no value in another layer of backups of backups. My one and only question: "Are there online data-storage/backup services that do not use redundancy or offer backups(backups of my backups) as part of their packages, and thus are more reasonably priced?" NOT my question: "Is this a flawed strategy?" I don't care if you think this is a good strategy or not. I know it pretty standard. Very few people make an extra copy of their offsite backups. They already have local backups that they can use to replace the remote backups if something catastrophic happens at the remote site. Please limit your responses to the question posed. Sorry if I seem a little abrasive, but I had some trolls in my last post who didn't read my requirements nor my question, and were trying to go off answering a totally different question. I made it pretty clear, but didn't try to justify my strategy, because I didn't ask about whether my strategy was justifyable. So I apologize if this was lengthy, as it really didn't need to be, but since there are so many trolls here who try to sidetrack questions by responding without addressing the question at hand.

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  • Network authentication + roaming home directory - which technology should I look into using?

    - by Brian
    I'm looking into software which provides a user with a single identity across multiple computers. That is, a user should have the same permissions on each computer, and the user should have access to all of his or her files (roaming home directory) on each computer. There seem to be many solutions for this general idea, but I'm trying to determine the best one for me. Here are some details along with requirements: The network of machines are Amazon EC2 instances running Ubuntu. We access the machines with SSH. Some machines on this LAN may have different uses, but I am only discussing machines for a certain use (running a multi-tenancy platform). The system will not necessarily have a constant amount of machines. We may have to permanently or temporarily alter the amount of machines running. This is the the reason why I'm looking into centralized authentication/storage. The implementation of this effect should be a secure one. We're unsure if users will have direct shell access, but their software will potentially be running (under restricted Linux user names, of course) on our systems, which is as good as direct shell access. Let's assume that their software could potentially be malicious for the sake of security. I have heard of several technologies/combinations to achieve my goal, but I'm unsure of the ramifications of each. An older ServerFault post recommended NFS & NIS, though the combination has security problems according to this old article by Symantec. The article suggests moving to NIS+, but, as it is old, this Wikipedia article has cited statements suggesting a trending away from NIS+ by Sun. The recommended replacement is another thing I have heard of... LDAP. It looks like LDAP can be used to save user information in a centralized location on a network. NFS would still need to be used to cover the 'roaming home folder' requirement, but I see references of them being used together. Since the Symantec article pointed out security problems in both NIS and NFS, is there software to replace NFS, or should I heed that article's suggestions for locking it down? I'm tending toward LDAP because another fundamental piece of our architecture, RabbitMQ, has a authentication/authorization plugin for LDAP. RabbitMQ will be accessible in a restricted manner to users on the system, so I would like to tie the security systems together if possible. Kerberos is another secure authentication protocol that I have heard of. I learned a bit about it some years ago in a cryptography class but don't remember much about it. I have seen suggestions online that it can be combined with LDAP in several ways. Is this necessary? What are the security risks of LDAP without Kerberos? I also remember Kerberos being used in another piece of software developed by Carnegie Mellon University... Andrew File System, or AFS. OpenAFS is available for use, though its setup seems a bit complicated. At my university, AFS provides both requirements... I can log in to any machine, and my "AFS folder" is always available (at least when I acquire an AFS token). Along with suggestions for which path I should look into, does anybody have any guides which were particularly helpful? As the bold text pointed out, LDAP looks to be the best choice, but I'm particularly interested in the implementation details (Keberos? NFS?) with respect to security.

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  • Excel: conditionally format a cell using the format of another, content-matching cell

    - by Eric A. Meyer
    I have an Excel spreadsheet where I’d like to be able to create a “key” of formatted cells with unique values, and then in another sheet format cells using the key formatting. So for example, my key is as follows, with one value per cell and the visual formatting indicated in parentheses: A (red background) B (green background) C (blue background) So that’s on one sheet (or in a remote corner of the current sheet—whichever is better). Then, in an area that I mark for conditional formatting, I can type one of those three letters and have the cell where I typed it visually formatted according to the key. So if I type a “B” into one of the conditionally formatted cells, it gets a green background. (Note that I’m using backgrounds here solely for ease of explanation: ideally I want to have all visual formatting copied over, whether it’s foreground color, background color, font weight, borders, or whatever. But I’ll take what I can get, obviously.) And—just to make it extra-tricky—if I change the formatting in the key, that change should be reflected in cells that reference the key. Thus, if I change the “B” formatting in the key from a green background to a purple background, any “B” in the main sheet should switch to the new color. Similarly, it should be possible to add or remove values from the key and have those changes applied to the main data set. I’m okay with the formatting-update-on-key-change being triggered by clicking a button or something. I suspect that if any of this is possible it will require VBA, but I’ve never used it so I’ve no idea where to start if that’s the case. I’m hoping it’s possible without VBA. I know it’s possible to just use multiple conditional formats, but my use case here is that I’m trying to create the above-described capability for someone who isn’t conversant with conditional formatting. I’d like to let them be able to define a key, update it if necessary, and keep on truckin’ without me having to rewrite the spreadsheet’s formatting rules for them. --- UPDATE --- So I think I was a bit unclear about my original request. Let me try again with an image. The image shows the “key” on the left, where values and styles are defined using keyboard and mouse input. On the right, you see the data that should be formatted to match the key. Thus if I type a “C” into a cell in the Data area, it should be blue-backed. Furthermore, if I change the formatting of “C” in the Key to have a purple background, all the “C” cells should switch from blue to purple. For further craziness, if I add more to the Key (say, “D” with a yellow background) then any “D” cells will be styled to match; if I remove a Key entry, then matching values in the Data area should revert to default styling. So. Is that more clear? Is it possible, in whole or in part? I don’t have to use conditional formatting for this; in fact, at this point I suspect I probably shouldn’t. But I’m open to any approach!

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  • DHCP and DNS services configuration for VOIP system, windows domain, etc

    - by Stemen
    My company has numerous physical offices (for purposes of this discussion, 15 buildings). Some of them are well-connected to our primary data center via fiber. Others will be connected to the data center by P2P T1. We are in the beginning stages of implementing an Avaya VOIP telephone system, and we will be replacing a significant portion of our network infrastructure in the process. In tandem with the phone system implementation, we are going to be re-addressing some of our networks, and consolidating most of our Windows domains into one (not all domains, just most). We currently have quite a few Windows domains, and they of course each have their own DNS zones. A few of those networks currently use DHCP, but the majority use static IP assignments for every device. I'm tired of managing static assignments -- I want to use DHCP configuration on everything except servers. Printers and etc will have DHCP reservations. The new IP phones will need to get IP addresses from DHCP, though they need to be in a separate VLAN from the computers/printers/etc. The computers and printers need to be registered in DNS. That's currently handled by the Windows DHCP servers on each of the respective domains. We need to place a priority on DHCP and DNS being available on a per-site basis (in case something were to interrupt the WAN connection) for computers and (primarily) phones. Smaller locations (which will have IP phones but not be a member of any Windows domain) will not have any Windows DNS/DHCP server(s) available. We also are looking for the easiest way to replace a part if it were to fail. That is to say, if a server/appliance/router hosting DHCP were to crash hard, and we couldn't extremely quickly recover the DHCP reservations and leases (and subsequently restore them onto a cold spare), we anticipate that bad things could happen. What is the best idea for how to re-implement DNS and DHCP keeping all of the above in mind? Some thoughts that have been raised (by myself or my coworkers): Use Windows DNS and DHCP servers, where they exist, and use IP helpers to route DHCP requests to some other Windows server if necessary. May not be acceptable if the WAN goes down and clients don't get a DHCP response. Use Windows DNS (everywhere, over WAN in some cases) and a mix of Windows DHCP and DHCP provided by Cisco routers. Every site would be covered for DHCP, but from what I've read, Cisco routers can't handle dynamic registration of DHCP clients to Windows DNS servers, which might create a problem where Cisco routers are used for DHCP. Use Windows DNS (everywhere, over WAN in some cases) and a mix of Windows DHCP and DHCP provided by some service running on an extremely low-price linux server. Is there any such software that would allow DHCP leases granted by these linux boxes to be dynamically registered on the Windows DNS servers? Come up with a Linux solution for both DNS and DHCP, and deploy low-price linux servers to every site. Requirements would be that the DNS zone be multi-master (like Windows DNS integrated with Active Directory), that DHCP be able to make dynamic DNS registrations in that zone, for every lease (where a hostname is provided and is thus possible), and that multiple servers be either authoritative for the same DHCP scope or at least receiving a real-time copy / replication / sync of the leases table so that if one server dies, we still know which MAC has what address. Purchase dedicated DNS/DHCP appliances, deploying to all sites. From what I read/see, this solves all of our technical problems. Then come the financial problems... I don't have a ton of money to spend on this. Or, some other solution that we've thus far overlooked and will consider upon recommendation. Can Cisco routers or Windows servers sync DHCP lease tables so that multiple servers can be authoritative (or active/passive for all I care) for the same scope, in case one of the partners were to fail? I've read online (repeatedly) that ISC's DHCP is able to maintain the same lease table across multiple servers, in order to solve this problem. Does anyone have any experience or advice to regarding that?

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  • creating a heirarchy of terminals or workspaces

    - by intuited
    <rant This question occurred to me ('occurred' meaning 'whispered seductively in my ear for the 100th time') while using GNU-screen, so I'll make that my example. However this is a much more general question about user interfaces and what I perceive as a flawmissing feature in every implementation I've yet seen. I'm wondering if there is some way to create a heirarchy/tree of terminals in a screen session. EG I'd like to have something like 1 bash 1.1 bash 1.2 bash 2 bash 3 bash 3.1 bash 3.1.1 bash 3.1.2 bash It would be good if the terminals could be labelled instead of having to be navigated to via some arrangement that I suspect doesn't exist. So then you could jump to one using eg ^A:goto happydays or ^A:goto dykstra.angry. So to generalize that: Firefox, Chrome, Internet Explorer, gnome-terminal, roxterm, konsole, yakuake, OpenOffice, Microsoft Office, Mr. Snuffaluppagus's Funtime Carousel™, and Your Mom's Jam Browser™ all offer the ability to create a flat set of tabs containing documents of an identical nature: web pages, terminals, documents, fun rideable animals, and jams. GNU-screen implements the same functionality without using tabs. Linux and OS/X window managers provide the ability to organize windows into an array of workspaces, which amounts to again, the same deal. Over the past few years, this has become a more or less ubiquitous concept which has been righteously welcomed into the far reaches of the computer interface funfest. Heavy users of these systems quickly encounter a problem with it: the set of entities is flat. In the case of workspaces, an option may be available to create a 2d array. However none of these applications furnish their users with the ability to create heirarchies, similar to filesystem directory structures, containing instances of their particular contained type. I for one am consistently bothered by this, and am wondering if the community can offer some wisdom as to why this has not happened in any of the foremost collections of computational functionality our culture has yet produced. Or if perhaps it has and I'm just an ignorant savage. I'd like to be able to not only group things into a tree structure, but also to create references (aka symbolic links, aka pointers) from one part of the structure to another, as well as apply properties (eg default directory, colorscheme, ...) recursively downward from a given node. I see no reason why we shouldn't be able to save these structures as known sessions, and apply tags to particular instances. So then you can sort through them by tag, find them by name, or just use the arrow keys (with an appropriate modifier) to move left or right and in or out of a given level. Another key combo would serve to create a branch in the place of the current terminal/webpage/lifelike statue/spreadsheet/spreadsheet sheet/presentation/jam and move that entity into the new branch, then create a fresh one as a sibling to it: a second leaf node within the same branch node. They would get along well. I find it a bit astonishing that this hasn't happened yet, and the only reason I can venture as a guess is that the creators of these fine systems do not consider such functionality to be useful to a significant portion of their userbase. I posit that the probability that that such an assumption would be correct is pretty low. On the other hand, given the relative ease with which such structures can be implemented using modern libraries/languages, it doesn't seem likely that difficulty of implementation would be a major roadblock. If it could be done in 1972 or whenever within the constraints of a filesystem driver, it should be relatively painless to implement in 2010 in a fullblown application. Given that all of these systems are capable of maintaining a set of equivalent entities, it seems unlikely that a major infrastructure overhaul would be necessary in order to enable a navigable heirarchy of them. </rant Mostly I'm just looking to start up a discussion and/or brainstorming on this topic. Any ideas, examples, criticism, or analysis are quite welcome. * Mr. Snuffaluppagus's Funtime Carousel is a registered trademark of Children's Television Workshop Inc. * Your Mom's Jam Browser is a registered trademark of Your Mom Inc.

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  • Exchange 2003-Exchange 2010 post migration GAL/OAB problem

    - by user68726
    I am very new to Exchange so forgive my newbie-ness. I've exhausted Google trying to find a way to solve my problem so I'm hoping some of you gurus can shed some light on my next steps. Please forgive my bungling around through this. The problem I cannot download/update the Global Address List (GAL) and Offline Address Book (OAB) on my Outlook 2010 clients. I get: Task 'emailaddress' reported error (0x8004010F) : 'The operation failed. An object cannot be found.' ---- error. I'm using cached exchange mode, which if I turn off Outlook hangs completely from the moment I start it up. (Note I've replaced my actual email address with 'emailaddress') Background information I migrated mailboxes, public store, etc. from a Small Business Server 2003 with Exchange 2003 box to a Server 2008 R2 with Exchange 2010 based primarily on an experts exchange how to article. The exchange server is up and running as an internet facing exchange server with all of the roles necessary to send and receive mail and in that capacity is working fine. I "thought" I had successfully migrated everything from the SBS03 box, and due to huge amounts of errors in everything from AD to the Exchange install itself I removed the reference to the SBS03 server in adsiedit. I've still got access to the old SBS03 box, but as I said the number of errors in everything is preventing even the uninstall of Exchange (or the starting of the Exchange Information Store service), so I'm quite content to leave that box completely out of the picture while trying to solve my problem. After research I discovered this is most likely because I failed to run the “update-globaladdresslist” (or get / update) command from the Exchange shell before I removed the Exchange 2003 server from adsiedit (and the network). If I run the command now it gives me: WARNING: The recipient "domainname.com/Microsoft Exchange System Objects/Offline Address Book - first administrative group" is invalid and couldn't be updated. WARNING: The recipient "domainname.com/Microsoft Exchange System Objects/Schedule+ Free Busy Information – first administrative group" is invalid and couldn't be updated. WARNING: The recipient "domainname.com/Microsoft Exchange System Objects/ContainernameArchive" is invalid and couldn't be updated. WARNING: The recipient "domainname.com/Microsoft Exchange System Objects/ContainernameContacts" is invalid and couldn't be updated. (Note that I’ve replaced my domain with “domainname.com” and my organization name with “containername”) What I’ve tried I don’t want to use the old OAB, or GAL, I don’t care about either, our GAL and distribution lists needed to be organized anyway, so at this point I really just want to get rid of the old reference to the “first administrative group” and move on. I’ve tried to create a new GAL and tell Exchange 2010 to use that GAL instead of the old GAL, but I'm obviously missing some of the commands or something dumb I need to do to start over with a blank slate/GAL/OAB. I'm very tempted to completely delete the entire "first administrative group" tree from adsiedit and see if that gets rid of the ridiculous reference that no longer exists but I dont want to break something else. Commands run to try to create a new GAL and tell exch10 to use that GAL: New-globaladdresslist –name NAMEOFNEWGAL Set-globaladdresslist GUID –name NAMEOFNEWGAL This did nothing for me except now when I run get-globaladdresslist or with the | FL pipe I see two GALs listed, the “default global address list” and the “NAMEOFNEWGAL” that I created. After a little more research this morning it looks like you can't change/delete/remove the default address list, and the only way to do what I'm trying to do would be to maybe remove the default address list via adsiedit and recreate with a command something like new-GlobalAddressList -Name "Default Global Address List" -IncludedRecipients AllRecipients. This would be acceptable but I've searched and searched and can't find instructions or a breakdown of where exactly the default GAL lives in AD, and if I'd have to remove multiple child references/records. ** Of interest** I'm getting an event ID 9337 in my application log OALGen did not find any recipients in address list ‘\Global Address List. This offline address list will not be generated. -\NAMEOFMYOAB --------- on my Exchange 2010 box, which pretty much to me seems to confirm my suspicion that the empty GAL/OAB is what's causing the Outlook client 0x8004010F error. Help please!

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  • CakePhp on IIS: How can I Edit URL Rewrite module for SSL Redirects

    - by AdrianB
    I've not dealt much with IIS rewrites, but I was able to import (and edit) the rewrites found throughout the cake structure (.htaccess files). I'll explain my configuration a little, then get to the meat of the problem. So my Cake php framework is working well and made possible by the url rewrite module 2.0 which I have successfully installed and configured for the site. The way cake is set up, the webroot folder (for cake, not iis) is set as the default folder for the site and exists inside the following hierarchy inetpub -wwwroot --cakePhp root ---application ----models ----views ----controllers ----WEBROOT // *** HERE *** ---cake core --SomeOtherSite Folder For this implementation, the url rewrite module uses the following rules (from the web.config file) ... <rewrite> <rules> <rule name="Imported Rule 1" stopProcessing="true"> <match url="^(.*)$" ignoreCase="false" /> <conditions logicalGrouping="MatchAll"> <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" /> <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" /> </conditions> <action type="Rewrite" url="index.php?url={R:1}" appendQueryString="true" /> </rule> <rule name="Imported Rule 2" stopProcessing="true"> <match url="^$" ignoreCase="false" /> <action type="Rewrite" url="/" /> </rule> <rule name="Imported Rule 3" stopProcessing="true"> <match url="(.*)" ignoreCase="false" /> <action type="Rewrite" url="/{R:1}" /> </rule> <rule name="Imported Rule 4" stopProcessing="true"> <match url="^(.*)$" ignoreCase="false" /> <conditions logicalGrouping="MatchAll"> <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" /> <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" /> </conditions> <action type="Rewrite" url="index.php?url={R:1}" appendQueryString="true" /> </rule> </rules> </rewrite> I've Installed my SSL certificate and created a site binding so that if i use the https:// protocol, everything is working fine within the site. I fear that attempts I have made at creating a rewrite are too far off base to understand results. The rules need to switch protocol without affecting the current set of rules which pass along url components to index.php (which is cake's entry point). My goal is this- Create a couple of rewrite rules that will [#1] redirect all user pages (in this general form http://domain.com/users/page/param/param/?querystring=value ) to use SSL and then [#2} direct all other https requests to use http (is this is even necessary?). [e.g. http://domain.com/users/login , http://domain.com/users/profile/uid:12345 , http://domain.com/users/payments?firsttime=true] ] to all use SSL [e.g. https://domain.com/users/login , https://domain.com/users/profile/uid:12345 , https://domain.com/users/payments?firsttime=true] ] Any help would be greatly appreciated.

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  • VirtualBox - Public Static IP for a Debian Guest on a Dedicated Server

    - by user86296
    Goal: I want to run a Debian-squeeze-Guest in VirtualBox and it's own public static ip. I found tons of threads about this topic, but all in all I'm now trying for 10 hours (reading the manual, the forums, trying to learn about networking concepts & commands) to give a Guest his own public static ip (so that the Guest is similar to a vServer you can order from a hosting company), but wasn't able to. Since I'm a big noob as far as networking stuff is concerned, I'm probably doing something wrong.(please bear with me :-) ) Situation: VirtualBox 4.0.10 (headless no gui) is running on a dedicated Debian-Server, the Guest OS is Debian as well. The server has a static ip and I ordered an additional ip for a VM. Problem description: Upto now I was able to use NAT to access the VM from the outside and to setup an internal network between several Guests and all of this worked very well. When setting NIC 1 to bridged and configuring a public static ip on the guest, the guest was unpingable. (neither from outside, nor from the host) I could connect to the guest via the internal network, from another vm, though. ( VBoxManage controlvm VMGuest nic1 bridged eth0 ) ( configuration attempt of static-ip on the guest '/etc/network/interfaces' is below) Please let me know what I'm doing wrong, or what I can try to get it to work, or if you need more info. I think I've read that with a current VirtualBox-version for bridged networking no special host-configuration is necessary, is that accurate, or might that be the problem? Additional Info Info I got from the hosting company about the additional IP Please note that you can use the IP address only for this server. IP: 46.4.xx.xx Gateway: 46.4.xx.xx Mask: 255.255.255.248 VBoxManage showvminfo VMGuest |less ... NIC 1: MAC: 080027D72F7B, Attachment: Bridged Interface 'eth0', Cable connected: on, Trace: off (file: none), Type: 82540EM, Reported speed: 0 Mbps, Boot priority: 0 NIC 2: MAC: 080027B03B75, Attachment: Internal Network 'InternalNet1', Cable connected: on, Trace: off (file: none), Type: Am79C973, Reported speed: 0 Mbps, Boot priority: 0 NIC 3: disabled (...rest is disabled) cat /etc/network/interfaces on the Host-machine # Loopback device: auto lo iface lo inet loopback # device: eth0 auto eth0 iface eth0 inet static address 46.4.xx.xx broadcast 46.4.xx.xx netmask 255.255.255.224 gateway 46.4.xx.xx post-up mii-tool -F 100baseTx-FD eth0 # default route to access subnet up route add -net 46.4.xx.xx netmask 255.255.255.224 gw 46.4.xx.xx eth0 cat /etc/network/interfaces on the Guest-VM # This file describes the network interfaces available on your system # and how to activate them. For more information, see interfaces(5). # The loopback network interface auto lo iface lo inet loopback # The primary network interface allow-hotplug eth0 auto eth0 iface eth0 inet static address 46.4.xx.xx netmask 255.255.255.248 gateway 46.4.xx.xx auto eth1 iface eth1 inet dhcp ifconfig -a on the Guest shows the correct static ip for eth0 but the Guest is unreachable "over eth0" eth0 Link encap:Ethernet HWaddr 08:00:27:d7:2f:7b inet addr:46.4.xx.xx Bcast:46.4.xx.xx Mask:255.255.255.248 inet6 addr: fe80::a00:27ff:fed7:2f7b/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:21 errors:0 dropped:0 overruns:0 frame:0 TX packets:69 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:1260 (1.2 KiB) TX bytes:3114 (3.0 KiB) eth1 Link encap:Ethernet HWaddr 08:00:27:b0:3b:75 inet addr:192.168.10.3 Bcast:192.168.10.255 Mask:255.255.255.0 inet6 addr: fe80::a00:27ff:feb0:3b75/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:142 errors:0 dropped:0 overruns:0 frame:0 TX packets:92 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:15962 (15.5 KiB) TX bytes:14540 (14.1 KiB) Interrupt:16 Base address:0xd240 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:123 errors:0 dropped:0 overruns:0 frame:0 TX packets:123 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:25156 (24.5 KiB) TX bytes:25156 (24.5 KiB)

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