Search Results

Search found 4109 results on 165 pages for 'plan'.

Page 137/165 | < Previous Page | 133 134 135 136 137 138 139 140 141 142 143 144  | Next Page >

• How do I disable the network connection from .Net without needing admin priveledges?

  - by Brad Mathews

  I may be SOL on this but I thought I would give throw it out for possible solutions. I am writing a computer access control service to help me control my kids' computer use. Plan on open sourcing it when I have it working. It is written in VB.Net and needs to work on XP through 7. I am running into all sorts of security and desktop access issues on Windows 7. The service needs to run as admin to execute the NetSh command to disable the network. But I cannot interact with the desktop from the service so I IPC to a UI to handle other stuff, but I still cannot detect from the service if the desktop is locked. Argghh! I could get it all working from a hidden windows form app if I could just lick the one piece that needs admin permissions: disabling the network. It does no good if a kid logs on and denies the popup asking if the program should run as administrator and he says no. Also windows 7 will not start a program set to run as admin using HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run Anyone know how to get this working? Or have an outside the box solution? Thanks! Brad

  Read the article

• Divide a path into N sections using Java or PostgreSQL/PostGIS

  - by Guido

  Imagine a GPS tracking system that is following the position of several objects. The points are stored in a database (PostgreSQL + PostGIS). Each path is composed by a different number of points. That is the reason why, in order to compare a pair of paths, I need to divide every path in a set of 100 points. Do you know any PostGIS function that already implement this algorithm? I've not been able to find it. If not, I'd like to solve it using Java. In this case I'd like to know an efficient and easy to implement algorithm to divide a path into N points. The most simple example could be to divide this path into three points: position 1 : x=1, y=2 position 2 : x=1, y=3 And the result should be: position 1 : x=1, y=2 (starting point) position 2 : x=5, y=2.5 position 3 : x=9, y=3 (end point) Edit: By 'compare a pair of paths' I mean to calculate the distance between two paths. I plan to divide each path in 100 points, and sum the euclidean distance between each one of these points as the distance between the two paths.

  Read the article

• With regards to urllib AttributeError: 'module' object has no attribute 'urlopen'

  - by Matt

  import re import string import shutil import os import os.path import time import datetime import math import urllib from array import array import random filehandle = urllib.urlopen('http://www.google.com/') #open webpage s = filehandle.read() #read print s #display #what i plan to do with it once i get the first part working #results = re.findall('[<td style="font-weight:bold;" nowrap>$][0-9][0-9][0-9][.][0-9][0-9][</td></tr></tfoot></table>]',s) #earnings = '$ ' #for money in results: #earnings = earnings + money[1]+money[2]+money[3]+'.'+money[5]+money[6] #print earnings #raw_input() this is the code that i have so far. now i have looked at all the other forums that give solutions such as the name of the script, which is parse_Money.py, and i have tried doing it with urllib.request.urlopen AND i have tried running it on python 2.5, 2.6, and 2.7. If anybody has any suggestions it would be really welcome, thanks everyone!! --Matt ---EDIT--- I also tried this code and it worked, so im thinking its some kind of syntax error, so if anybody with a sharp eye can point it out, i would be very appreciative. import shutil import os import os.path import time import datetime import math import urllib from array import array import random b = 3 #find URL URL = raw_input('Type the URL you would like to read from[Example: http://www.google.com/] :') while b == 3: #get file name file1 = raw_input('Enter a file name for the downloaded code:') filepath = file1 + '.txt' if os.path.isfile(filepath): print 'File already exists' b = 3 else: print 'Filename accepted' b = 4 file_path = filepath #open file FileWrite = open(file_path, 'a') #acces URL filehandle = urllib.urlopen(URL) #display souce code for lines in filehandle.readlines(): FileWrite.write(lines) print lines print 'The above has been saved in both a text and html file' #close files filehandle.close() FileWrite.close()

  Read the article

• SQL Server Index cost

  - by yellowstar

  I have read that one of the tradeoffs for adding table indexes in SQL Server is the increased cost of insert/update/delete queries to benefit the performance of select queries. I can conceptually understand what happens in the case of an insert because SQL Server has to write entries into each index matching the new rows, but update and delete are a little more murky to me because I can't quite wrap my head around what the database engine has to do. Let's take DELETE as an example and assume I have the following schema (pardon the pseudo-SQL) TABLE Foo col1 int ,col2 int ,col3 int ,col4 int PRIMARY KEY (col1,col2) INDEX IX_1 col3 INCLUDE col4 Now, if I issue the statement DELETE FROM Foo WHERE col1=12 AND col2 > 34 I understand what the engine must do to update the table (or clustered index if you prefer). The index is set up to make it easy to find the range of rows to be removed and do so. However, at this point it also needs to update IX_1 and the query that I gave it gives no obvious efficient way for the database engine to find the rows to update. Is it forced to do a full index scan at this point? Does the engine read the rows from the clustered index first and generate a smarter internal delete against the index? It might help me to wrap my head around this if I understood better what is going on under the hood, but I guess my real question is this. I have a database that is spending a significant amount of time in delete and I'm trying to figure out what I can do about it. When I display the execution plan for the deletion, it just shows an entry for "Clustered Index Delete" on table Foo which lists in the details section the other indices that need to be updated but I don't get any indication of the relative cost of these other indices. Are they all equal in this case? Is there some way that I can estimate the impact of removing one or more of these indices without having to actually try it?

  Read the article

• Need help in tuning a sql-query

  - by Viper

  Hello, i need some help to boost this SQL-Statement. The execution time is around 125ms. During the runtime of my program this sql (better: equally structured sqls for different tables) will be called 300.000 times. The average row count in the tables lies around 10.000.000 rows and new rows (updates/inserts) will be added with a timestamp each day. Data which are interesting for this particular export-program lies in the last 1-3 days. Maybe this is helpful for an index to create. The data i need is the current valid row for a given id and the forerunner datarow to get the updates (if exists). We use a Oracle 11g database and Dot.Net Framework 3.5 SQL-Statement to boost: select ID_SOMETHING, -- Number(12) ID_CONTRIBUTOR, -- Char(4 Byte) DATE_VALID_FROM, -- DATE DATE_VALID_TO -- DATE from TBL_SOMETHING XID where ID_SOMETHING = :ID_INSTRUMENT and ID_CONTRIBUTOR = :ID_CONTRIBUTOR and DATE_VALID_FROM <= :EXPORT_DATE and DATE_VALID_TO >= :EXPORT_DATE order by DATE_VALID_FROM asc; Here i uploaded the current Explain-Plan for this query. I'm not a database expert so i don't know which index-type would fit best for this requirement. I have seen that there are many different possible index-types which could be applied. Maybe Oracle Optimizer Hints are helpful, too. Does anyone has a good idea for tuning this sql or can point me in a right direction?

  Read the article

• Access ADP - For/Against?

  - by webworm

  I have been tasked with taking an Access 97 application and moving the back-end data to SQL Server while moving the front end to Access 2003 (using Access Data Projects). In the process of this migration the back-end data structures will be changed significantly to support new functionality. If I had my wish we would not be using Access as the front end. I think our application would be much better served by WinForms, WPF, or a web application. We have the time needed to properly plan a business logic layer and implement an excellent solution but powers above me want to stay with Access because that is what they are familiar with. What I could use help with is pros/cons of continuing down this path of Access development. What are some legitimate arguments for and against using Access 2003? Here is what I have come up with so far. Pro Access: Already own Access 2003 licenses Easy GUI development Reports look nice Against Access Having to use VBA (Visual Basic for Applications) ADO vs DAO. Didn't Microsoft change things from Access 2002 to Access 2003? Not tied to Access runtime Choice in front end (WPF, WinForms, even ASP.NET) Maintainability True separation of logic from UI not possible Does Microsoft still support Access ADP? Perhaps there are other issues I am not aware off both for and against Access for application development. I am trying to keep an open mind while at the same time trying to maintain my sanity. I have been using C# since .NET was released and the thought of going back to VBA for six months makes my head hurt. Especially when I feel I could offer so much more if allowed to develop with modern languages and tools?

  Read the article

• Maven Mojo & SCM Plugin: Check for a valid working directory

  - by Patrick Bergner

  Hi there. I'm using maven-scm-plugin from within a Mojo and am trying to figure out how to determine if a directory D is a valid working directory of an SCM URL U (i.e. a checkout of U to D already happened). The context is that I want to do a checkout of U if D is a working set or do an update if it isn't. The plan is to check out U to D if D does not exist, update D if D is a valid working directory of U, display an error if D exists and is not a valid working directory of U. What I tried is to call ScmManager.status(), ScmManager.list() and ScmManager.changelog() and try to guess something from their results. But that didn't work. The results from status and changelog always return something positive (isSuccess() = true, getChangedFiles() = valid List, no exceptions to catch), whereas list throws an exception in any case. ScmRepository and ScmFileSet don't seem to provide suitable methods as well. An option would be to always do an update if D exists but then I cannot tell if it is a working directory of U or any SCM working directory at all. The ideal solution would be independent of the actual SCM system and a specific ScmVersion. Thanks for your help! Patrick

  Read the article

• Partial Evaluation of ConstantExpression in ExpressionTreeVisitor

  - by Andrew Theken

  Hi all, I am not an Expression Tree master by any stretch of the imagination, what I have is code that looks like this: int external = 10; using(var session = new Session()) { session.Add(new Product { Name = "test1", Price = 20 }); session.Add(new Product {Name = "test", Price = 10}); var product = session.Products.Where(p => p.Price == external).FirstOrDefault(); Assert.Equal(10, product.Price); } Session implements all the IQueryProvider, IQueryable interfaces you'd come to expect from a LINQ Provider. When I execute the query, everything goes to plan until I read the ConstantExpression for "external", at which point, I am at a loss as to how to move forward because: //constant is ConstantExpression for "external" on the right side of the "p.Price == external" expression above. var t = constant.GetType(); //evaluates to class called "<>c__DisplayClass2" - with a member named "external" that has the value 10. The question is basically.. How can I just access the value of the member "external" - is there a way to accomplish this without using reflection? or am I cooked? What am I missing?

  Read the article

• Are short tags *that* bad?

  - by Col. Shrapnel

  Everyone here on SO says it's bad, for 3 main reasons: XML is used everywhere You can't control where your script is going to be run short tags are going to be removed in PHP6 But let's see closer at them: Last one is easy - it's just not true. XML is not really a problem. If you want to use short tags, it won't be a problem for you to write a single tag using PHP echo, <?="<?XML...?>"?>. Anyway, why not to leave such a trifle thing for one's own judgment? PHP configuration access. Oh yes, the only thing that can be really considered as a reason. Of course in case you plan to spread your code wide. But if you don't? I think most of scripts being written not for the wide spread, but just for one place. If you can use short tags in that place - why to abandon them? Anyway, it's the only template we are talking about. If you don't like short tags, PHP native template is probably not for you, why not to try Smarty then? Well, the question is: is there any other real reasons to abandon short tags and make it strict recommendation? Or, as it was said, better to leave short tags alone?

  Read the article

• ImageMagick Reflection

  - by dbruns

  Brief: convert ( -size 585x128 gradient: ) NewImage.png How do I change the above ImageMagick command so it takes the width and height from an existing image? I need it to remain a one line command. Details: I'm trying to programatically create an image reflection using ImageMagick. The effect I am looking for is similar to what you would see when looking at an object on the edge of a pool of water. There is a pretty good thread on what I am trying to do here but the solution isn't exactly what I am looking for. Since I will be calling ImageMagick from a C#.Net application I want to use one call without any temp files and return the image through stdout. So far I have this... convert OriginalImage.png ( OriginalImage.png -flip -blur 3x5 \ -crop 100%%x30%%+0+0 -negate -evaluate multiply 0.3 \ -negate ( -size 585x128 gradient: ) +matte -compose copy_opacity -composite ) -append NewImage.png This works ok but doesn't give me the exact fade I am looking for. Instead of a nice solid fade from top to bottom it is giving me a fade from top left to bottom right. I added the (-negate -evaluate multiply 0.3 -negate) section in to lighten it up a bit more since I wasn't getting the fade I wanted. I also don't want to have to hard code in the size of the image when creating the gradient ( -size 585x128 gradient: ) I'm also going to want to keep the original image's transparency if possible. To go to stdout I plan on replacing "NewImage.png" with "-"

  Read the article

• Choosing the right web service

  - by Ratan Sharma

  My website currently working in ASP.NET 1.1 Old Process In our database we have huge amount of data stored for a decoding purpose. We have to update this huge set of data table each week(Data is supplied from a vendor). In our website (in asp.net 1.1) we query our database to decode information. New process Now instead of storing data in our database and query them, we want to replace this through the web service, AS now the vendor is supplying us a DLL, which will give us the decoded information. Information on the DLL provided by the vendor The DLL provided, can only be added in 4.0 sites. SO that also impleies that i can not directly add the dll to my 1.1 site. This DLL is exposing certain methods, we simply have to add the DLL refernce in our web service and call the method and fetch the needed information. Thus we will not have to store those information in our database. So which type of web service I should go for (asmx OR WCF) that will use the DLLs provided by vendor to fetch the decoded information ?? Flexibility i am looking for in the web service are: It can be consumed from asp.net 1.1 site directly and also using jQuery ajax. It can be consumed from other web services running on the server. It can be consumed from some windows services running from the server. NOTE : Moreover we have a plan to migrate our website from asp.net 1.1 to 4.0 version in future.So it should be that much supportive for future upgrade.

  Read the article

• Images in database vs file system

  - by Jesse

  We have a project coming up where we will be building a whole backend CMS system that will power our entire extranet and intranet with one package. The question I have been trying to find an answer to is which is better: storing images in the database (SQL Server 2005) so we may have integrity, single replication plan, etc OR storing on the file system? One issue we have is that we have multiple servers load balanced that require to have the same data at all times. As of now we have SQL replication taking care of that but file replication seems to be a little tougher. Another concern we have is that we would like to have multiple resolutions of the same image, we are not sure if creating and storing each version on the file system would be best or maybe dynamically pulling and creating the resolution image we would like upon request. Our concerns are the with the following: Data integrity Data replication Multiple resolutions Speed of database vs file system Overhead load of database vs file system Data management and backup Does anyone have a similar situation or have any input on what would be recommended? Thanks in advance for the help!

  Read the article

• Use Lambda in Attribute constructor to get method's parameters

  - by Anthony Shaw

  I'm not even sure if this is possible, but I've exhausted all of my ideas trying to figure this out, so I figured I'd send this out to the community and see what you thought. And, if it's not possible, maybe you'd have some ideas as well. I'm trying to make an Attribute class that I can add to a method that would allow me to use a lambda expression to get each parameter of the method public ExampleAttribute : Attribute { public object Value { get; set; } public ExampleAttribute(--something here to make the lambda work--, object value) { Value = value; } } I'd like to be able to something like this below: [Example(x=x.Id, 4)] [Example(x=x.filter, "string value")] public ActionResult Index(int Id, string filter) { return View(); } I understand that I might be completely dreaming with this idea. I'm basically trying to write a model to allow for self-documenting REST API Documentation. In a recent project here at work we wrote a dozen or so services with 5 to 15 methods on each, I figure it's easier to write something to do this, than to hand code a documentation page for each. I would plan to eventually release this as an open-source project once I have it in a place that I feel it's releasable.

  Read the article

• calling .ajax() from an eventHandler c# asp.ent

  - by ibininja

  Good day...! In the code behind (upload.aspx) I have an event that returns the number of bytes being streamed; and as I debug it, it works fine. I wanted to reflect the numbers returned from the eventHandler on a progress bar and this is where I got lost. I tried using jQuery's .ajax() function. this is how I implemented it: In the EventHandler in my code behind I added this code to call the .ajax() function: Page.ClientScript.RegisterStartupScript(this.GetType(), "UpdateProgress", "<script type='text/javascript'>updateProgress();</script>"); My plan is whenever the eventHandler function changes the values of bytes being streamed it calls the javascript function "updateProgress()" The .ajax() function "UpdateProgress()" is as: function updateProgress() { $.ajax({ type: "POST", url: "upload.aspx/GetData", data: "{}", contentType: "application/json; charset=utf-8", dataType: "json", async: true, success: function (msg) { $("#progressbar").progressbar("option", "value", msg.d); } }); } I made sure that the function GetData() is [System.Web.Services.WebMethod] and that it is static as well. so the workflow of what I am trying to implement is as: - Click On Upload button - The Behind code starts executing and EventHandler triggers - The EventHandler calls .ajax() function - The .ajax() function retrieves the bytes being streamed and updates progress bar. When I ran the code; all runs well except that the .ajax() is only executed when upload is finished (and progress bar also updates only when finished upload); even though I call .ajax() function every time in the eventHandler function as reflected above... What am I doing wrong? Am I thinking of this right? is there anything else I should add maybe an updatePanel or something? thank you

  Read the article

• ECM (Niche Vs Mass Market)

  - by Luj Reyes

  Hi Everyone, I recently started a little company with a couple of guys. Ours is the typical startup, a lot of ideas, dreams, talent and work hours :P. Our initial business plan was to develop a DM (Document Manager) with several features found on DropBox and other tools but with a big differentiator. Then we got in the team this Business Guy (I must say that several of us could be called 'Business Guys' but we are mainly hackers, he is just Another 'Networking Guy'), and along with him came this market analysis for a DM aimed at a very specific and narrow niche. We have many elements to believe in his market study and the idea is the classic "The market is X million, so if we grab a 10%...", and the market is really there to grab because all big providers deemed it too little and fled, let's say that the market is 5 million USD and demand very specific features. If we decide to go for this niche product we face a sales cycle of about 7 months, and the main goal of these revenue is to develop more ambitious projects. (Institutional VC is out of the question if you want to keep a marginal ownership of your company in my country). The only overlap between the niche and the mass market product features is the ability to store documents; everything else requires that we focus all of our efforts towards one or the other. I've studied a lot about the differences between Mass and Niche Markets, but I want to hear from people with actual experience. So everything comes down to this: If you have a really “saleable” idea what is the right thing to do: to go for the niche or go for the big prize and target primarily the mass market? Thanks for your input

  Read the article

• Can a large transaction log cause cpu hikes to occur

  - by Simon Rigby

  Hello all, I have a client with a very large database on Sql Server 2005. The total space allocated to the db is 15Gb with roughly 5Gb to the db and 10 Gb to the transaction log. Just recently a web application that is connecting to that db is timing out. I have traced the actions on the web page and examined the queries that execute whilst these web operation are performed. There is nothing untoward in the execution plan. The query itself used multiple joins but completes very quickly. However, the db server's CPU hikes to 100% for a few seconds. The issue occurs when several simultaneous users are working on the system (when I say multiple .. read about 5). Under this timeouts start to occur. I suppose my question is, can a large transaction log cause issues with CPU performance? There is about 12Gb of free space on the disk currently. The configuration is a little out of my hands but the db and log are both on the same physical disk. I appreciate that the log file is massive and needs attending to, but I'm just looking for a heads up as to whether this may cause CPU spikes (ie trying to find the correlation). The timeouts are a recent thing and this app has been responsive for a few years (ie its a recent manifestation). Many Thanks,

  Read the article

• Best practices for managing updating a database with a complex set of changes

  - by Sarge

  I am writing an application where I have some publicly available information in a database which I want the users to be able to edit. The information is not textual like a wiki but is similar in concept because the edits bring the public information increasingly closer to the truth. The changes will affect multiple tables and the update needs to be automatically checked before affecting the public tables. I'm working on the design and I'm wondering if there are any best practices that might help with some particular issues. I want to provide undo capability. I want to show the user the combined result of all their changes. When the user says they're done, I need to check the underlying public data to make sure it hasn't been changed by somebody else. My current plan is to have the user work in a set of tables setup to be a private working area. Once they're ready they can kick off a process to check everything and update the public tables. Undo can be recorded using Command pattern saving to a table. Are there any techniques I might have missed or useful papers or patterns? Thanks in advance!

  Read the article

• Using a class within a class?

  - by Josh

  I built myself a MySQL class which I use in all my projects. I'm about to start a project that is heavily based on user accounts and I plan on building my own class for this aswell. The thing is, a lot of the methods in the user class will be MySQL queries and methods from the MySQL class. For example, I have a method in my user class to update someone's password: class user() { function updatePassword($usrName, $newPass) { $con = mysql_connect('db_host', 'db_user', 'db_pass'); $sql = "UPDATE users SET password = '$newPass' WHERE username = '$userName'"; $res = mysql_query($sql, $con); if($res) return true; mysql_close($con); } } (I kind of rushed this so excuse any syntax errors :) ) As you can see that would use MySQL to update a users password, but without using my MySQL class, is this correct? I see no way in which I can use my MySQL class within my users class without it seeming dirty. Do I just use it the normal way like $DB = new DB();? That would mean including my mysql.class.php somewhere too... I'm quite confused about this, so any help would be appreciated, thanks.

  Read the article

• Getting identity from Ado.Net Update command

  - by rboarman

  My scenario is simple. I am trying to persist a DataSet and have the identity column filled in so I can add child records. Here's what I've got so far: using (SqlConnection connection = new SqlConnection(connStr)) { SqlDataAdapter adapter = new SqlDataAdapter("select * from assets where 0 = 1", connection); adapter.MissingMappingAction = MissingMappingAction.Passthrough; adapter.MissingSchemaAction = MissingSchemaAction.AddWithKey; SqlCommandBuilder cb = new SqlCommandBuilder(adapter); var insertCmd = cb.GetInsertCommand(true); insertCmd.Connection = connection; connection.Open(); adapter.InsertCommand = insertCmd; adapter.InsertCommand.CommandText += "; set ? = SCOPE_IDENTITY()"; adapter.InsertCommand.UpdatedRowSource = UpdateRowSource.OutputParameters; var param = new SqlParameter("RowId", SqlDbType.Int); param.SourceColumn = "RowId"; param.Direction = ParameterDirection.Output; adapter.InsertCommand.Parameters.Add(param); SqlTransaction transaction = connection.BeginTransaction(); insertCmd.Transaction = transaction; try { assetsImported = adapter.Update(dataSet.Tables["Assets"]); transaction.Commit(); } catch (Exception ex) { transaction.Rollback(); // Log an error } connection.Close(); } The first thing that I noticed, besides the fact that the identity value is not making its way back into the DataSet, is that my change to add the scope_identity select statement to the insert command is not being executed. Looking at the query using Profiler, I do not see my addition to the insert command. Questions: 1) Why is my addition to the insert command not making its way to the sql being executed on the database? 2) Is there a simpler way to have my DataSet refreshed with the identity values of the inserted rows? 3) Should I use the OnRowUpdated callback to add my child records? My plan was to loop through the rows after the Update() call and add children as needed. Thank you in advance. Rick

  Read the article

• Safe way to set computed environment variables

  - by sfink

  I have a bash script that I am modifying to accept key=value pairs from stdin. (It is spawned by xinetd.) How can I safely convert those key=value pairs into environment variables for subprocesses? I plan to only allow keys that begin with a predefined prefix "CMK_", to avoid IFS or any other "dangerous" variable getting set. But the simplistic approach function import () { local IFS="=" while read key val; do case "$key" in CMK_*) eval "$key=$val";; esac done } is horribly insecure because $val could contain all sorts of nasty stuff. This seems like it would work: shopt -s extglob function import () { NORMAL_IFS="$IFS" local IFS="=" while read key val; do case "$key" in CMK_*([a-zA-Z_]) ) IFS="$NORMAL_IFS" eval $key='$val' IFS="=" ;; esac done } but (1) it uses the funky extglob thing that I've never used before, and (2) it's complicated enough that I can't be comfortable that it's secure. My goal, to be specific, is to allow key=value settings to pass through the bash script into the environment of called processes. It is up to the subprocesses to deal with potentially hostile values getting set. I am modifying someone else's script, so I don't want to just convert it to Perl and be done with it. I would also rather not change it around to invoke the subprocesses differently, something like #!/bin/sh ...start of script... perl -nle '($k,$v)=split(/=/,$_,2); $ENV{$k}=$v if $k =~ /^CMK_/; END { exec("subprocess") }' ...end of script...

  Read the article

• 1k of Program Space, 64 bytes of RAM. Is assembly an absolute must?

  - by Earlz

  (If your lazy see bottom for TL;DR) Hello, I am planning to build a new (prototype) project dealing with physical computing. Basically, I have wires. These wires all need to have their voltage read at the same time. More than a few hundred microseconds difference between the readings of each wire will completely screw it up. The Arduino takes about 114 microseconds. So the most I could read is 2 or 3 wires before the latency would skew the accuracy of the readings. So my plan is to have an Arduino as the "master" of an array of ATTinys. The arduino is pretty cramped for space, but it's a massive playground compared to the tinys. An ATTiny13A has 1k of flash ROM(program space), 64 bytes of RAM, and 64 bytes of (not-durable and slow) EEPROM. (I'm choosing this for price as well as size) The ATTinys in my system will not do much. Basically, all they will do is wait for a signal from the Master, and then read the voltage of 1 or 2 wires and store it in RAM(or possibly EEPROM if it's that cramped). And then send it to the Master using only 1 wire for data.(no room for more than that!). So far then, all I should have to do is implement trivial voltage reading code (using built in ADC). But this communication bit I'm worried about. Do you think a communication protocol(using just 1 wire!) could even be implemented in such constraints? TL;DR: In less than 1k of program space and 64 bytes of RAM(and 64 bytes of EEPROM) do you think it is possible to implement a 1 wire communication protocol? Would I need to drop to assembly to make it fit? I know that currently my Arduino programs linking to the Wiring library are over 8k, so I'm a bit concerned.

  Read the article

• How to distinguish between two different UDP clients on the same IP address?

  - by Ricket

  I'm writing a UDP server, which is a first for me; I've only done a bit of TCP communications. And I'm having trouble figuring out exactly how to distinguish which user is which, since UDP deals only with packets rather than connections and I therefore cannot tell exactly who I'm communicating with. Here is pseudocode of my current server loop: DatagramPacket p; socket.receive(p); // now p contains the user's IP and port, and the data int key = getKey(p); if(key == 0) { // connection request key = makeKey(p); clients.add(key, p.ip); send(p.ip, p.port, key); // give the user his key } else { // user has a key // verify key belongs to that IP address // lookup the user's session data based on the key // react to the packet in the context of the session } When designing this, I kept in mind these points: Multiple users may exist on the same IP address, due to the presence of routers, therefore users must have a separate identification key. Packets can be spoofed, so the key should be checked against its original IP address and ignored if a different IP tries to use the key. The outbound port on the client side might change among packets. Is that third assumption correct, or can I simply assume that one user = one IP+port combination? Is this commonly done, or should I continue to create a special key like I am currently doing? I'm not completely clear on how TCP negotiates a connection so if you think I should model it off of TCP then please link me to a good tutorial or something on TCP's SYN/SYNACK/ACK mess. Also note, I do have a provision to resend a key, if an IP sends a 0 and that IP already has a pending key; I omitted it to keep the snippet simple. I understand that UDP is not guaranteed to arrive, and I plan to add reliability to the main packet handling code later as well.

  Read the article

• FTP FileWatcher

  - by Meiscooldude

  So, I am in this little predicament where I am stuck watching a few ftp folders to see if they have new files added to them. If they do, it needs to throw an event with the file name. Thereby telling something else to download that file. This is a pretty simple object to make, I was just curious if anyone knew how expensive this operation would be? I plan on using the command NLIST because I don't need file size information, and there will be no sub-directories in the folder. Each file in the folder will have exactly 25 characters in its name. There could be anywhere from 10 to 'maybe' a couple thousand (max around 2000) files per folder (usually on the lower end, 100-300, but currently growing). The files are anywhere from 250kb to a very VERY unlikely 10mb (usually within the 250kb to 4mb range). There possibly could be up to a few hundred folders (in which case I could change the watch frequency depending on number of folders), but currently there are only a few (6-10ish). There also would be multiple logins for the ftp server, different logins would have access to different folders. I am not asking for an implementation, just if anyone has some first or second hand knowledge about FTP, how could this affect my network. I am not opposed to putting in file retention times or change the frequency in which I check for new files.

  Read the article

• What should a self-taught programmer with no degree learn/read?

  - by sjbotha

  I am a self-taught programmer and I do do not have any degrees. I started pretty young and I've got about 7 years of actual programming work experience. I believe I'm a pretty good programmer, but I admit that I have not played much with algorithms or delved into any really low-level aspects of programming such as how compilers work. I have worked with other programmers with and without degrees. Some were good and some not; having a degree didn't seem to make any difference as to which pot they fell into. Since then I've come to realize that it does depend on the school where the degree is obtained. Some people suggest that you really should get a degree; that there are things you'll learn in the process that you won't learn in the real world. Of course there is personal growth and discipline learned from completing a task of that magnitude, but let's just concentrate on the technical knowledge. What would I have been taught in a GOOD CS course that would aid me today and what can I read to fill the gap? I've heard the book "Algorithms" mentioned and I plan on reading that. What other books would you recommend? Edit: Clarification on 'actual work experience': Have worked for 2 small companies on teams with fewer than 5 people. About 2 years experience with Perl, Python, PHP, C, C++. About 5 years experience in Java, Applets, RMI, T-SQL, PL/SQL, VB6. 7 years experience in HTML, Javascript, bash, SQL. Most recently in Java designed and helped build an N-tier Java app with web frontend and RMI.

  Read the article

• SQL Server search filter and order by performance issues

  - by John Leidegren

  We have a table value function that returns a list of people you may access, and we have a relation between a search and a person called search result. What we want to do is that wan't to select all people from the search and present them. The query looks like this SELECT qm.PersonID, p.FullName FROM QueryMembership qm INNER JOIN dbo.GetPersonAccess(1) ON GetPersonAccess.PersonID = qm.PersonID INNER JOIN Person p ON p.PersonID = qm.PersonID WHERE qm.QueryID = 1234 There are only 25 rows with QueryID=1234 but there are almost 5 million rows total in the QueryMembership table. The person table has about 40K people in it. QueryID is not a PK, but it is an index. The query plan tells me 97% of the total cost is spent doing "Key Lookup" witht the seek predicate. QueryMembershipID = Scalar Operator (QueryMembership.QueryMembershipID as QM.QueryMembershipID) Why is the PK in there when it's not used in the query at all? and why is it taking so long time? The number of people total 25, with the index, this should be a table scan for all the QueryMembership rows that have QueryID=1234 and then a JOIN on the 25 people that exists in the table value function. Which btw only have to be evaluated once and completes in less than 1 second.

  Read the article

< Previous Page | 133 134 135 136 137 138 139 140 141 142 143 144  | Next Page >