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  • Windows Physical Direct Memory Mapping

    - by chrisjleaf
    I'm a bit disappointed there is almost no discussion of this no matter where I look so I guess I'll have to ask. I'm writing a cross platform memory bench marking application which requires direct physical address mapping rather than virtual addressing. EDIT The solution would look something like the Linux/Unix system calls: int fd = open("/dev/mem", O_RDONLY); mmap(NULL, len, PROT_READ, MAP_SHARED, fd, PHYSICAL_ADDRESS_OFFSET); which will require the kernel to either give you a virtual page mapping to the desired physical address or return that it failed. This does require supervisor privileges but that is ok. I have seen a lot of information about shared memory and memory mapped files but all of these reside on disc and are thus not really useful when I'm trying to make a system dependent read. It is very similar to writing an IO driver although I do no need write permissions to the physical address. This site gives an example of how to do it on a driver level using the Windows Driver Kit: NT Insider: Sharing Memory between drivers and applications This solution would probably require Visual Studio which currently I do not have access to. (I have downloaded the WDK api but it complained about my use of GCC for Windows). I'm traditionally a Linux programmer so I'm hoping there might be something really simple I'm missing. Thanks in advance if you know something I don't!

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  • cURL looking for CA in the wrong place

    - by andrewtweber
    On Redhat Linux, in a PHP script I am setting cURL options as such: curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, True); curl_setopt($ch, CURLOPT_CAINFO, '/home/andrew/share/cacert.pem'); Yet I am getting this exception when trying to send data (curl error: 77) error setting certificate verify locations: CAfile: /etc/pki/tls/certs/ca-bundle.crt CApath: none Why is it looking for the CAfile in /etc/pki/tls/certs/ca-bundle.crt? I don't know where this folder is coming from as I don't set it anywhere. Shouldn't it be looking in the place I specified, /home/andrew/share/cacert.pem? I don't have write permission /etc/ so simply copying the file there is not an option. Am I missing some other curl option that I should be using? (This is on shared hosting - is it possible that it's disallowing me from setting a different path for the CAfile?)

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  • Easy to use JSON Web Service Hosts?

    - by Serguei Fedorov
    I saw this being used by someone in a college class once and cannot find anything that is analogous to it. I am not sure if this is the right place to ask about something like this, but hopefully I can get some direction. I want to write an app which uses web services that can obtain and push data back to the client apps. Right now I am gathering up the design and documentation of this app. Not having to code the web service myself would reduce development time by a lot; instead using an easy to setup web service that will be easy to setup and manage. Either XML based on JSON based is totally fine; though I would prefer JSON for its reduced overhead. Like I said I have seen this demonstrated before; you define the data structure to be stored and how it is treated. I cannot find the person who demonstrated this; hopefully maybe someone can suggest something? The service he used was free with a limited amount of requests allowed. EDIT: He was using an online service to do this not a script which is installed onto an existing web hosting account. Thank you!

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  • If you have the full spec done, what is left for the developer to do?

    - by Leeho
    I'm working in a small company, started as a developer and coded pieces of a big system being provided with detailed specs. Over five years I moved towards analyst position. I know how existing parts of the system are build, so when we need a new subsystem I know how to connect it to the existing things. So I analyse requirements for a new subsystem to be done, design a new module, then code main parts of it. After that me with my colleagues who are proper analysts write detailed specs for junior developers to finish the module. The problem is that I don't see a new job for myself. I realise that jack-of-all-trades isn't considered to be good, and I don't see getting myself a job exactly like this in a big company. But if I look for a developer job, then I would be somewhat like junior again? Because if I will be provided with detailed description of what software has to do, all that seems to be left for me is merely translating spec to the code, which is plain boring. But developer is considered to solve problems, so which problems are those supposed to be? Only pure technical problems I can imagine is performance optimization. So basically my question is - what problems developers are supposed to face and solve, if all decisions of how application should work to meet customers needs are considered to be an analyst job? What problems do you solve at work?

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  • IIS 7 throws 401 responses on application whose physical directory has been shared

    - by tonyellard
    I have an IIS 7, Windows Server 2008 R2 box with a relatively fresh install. I've deployed a .NET 2.0 application using windows autentication to the server, and from the default website, added it as an application. I updated the IIS authentication to enable Windows Authentication. When I went to share out the physical directory for the application so that a developer could deploy updates, the users began to receive 401 errors. I can reliably recreate the issue by sharing out the directory of any newly created application. The IIS user has the necessary read/write access to the directory. What do I need to do to keep web users from receiving 401's while at the same time allowing this developer to have access to the physical directory for deployments? Thanks in advance!

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  • How useful is mounting /tmp noexec?

    - by Novelocrat
    Many people (including the Securing Debian Manual) recommend mounting /tmp with the noexec,nodev,nosuid set of options. This is generally presented as one element of a 'defense-in-depth' strategy, by preventing the escalation of an attack that lets someone write a file, or an attack by a user with a legitimate account but no other writable space. Over time, however, I've encountered arguments (most prominently by Debian/Ubuntu Developer Colin Watson) that noexec is a useless measure, for a couple potential reasons: The user can run /lib/ld-linux.so <binary> in an attempt to get the same effect. The user can still run system-provided interpreters on scripts that can't be run directly Given these arguments, the potential need for more configuration (e.g. debconf likes an executable temporary directory), and the potential loss of convenience, is this a worthwhile security measure? What other holes do you know of that enable circumvention?

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  • Session Evaluations

    - by BuckWoody
    I do a lot of public speaking. I write, teach, present and communicate at many levels. I love to do those things. And I love to get better at them. And one of the ways you get better at something is to get feedback on how you did. That being said, I have to confess that I really despise the “evaluations” I get at most venues. From college to technical events to other locations, at Microsoft and points in between, I find these things to be just shy of damaging, and most certainly useless. And it’s not always your fault. Ouch. That seems harsh. But let me ask you one question – and be as honest as you can with the answer – think about it first: “What is the point of a session evaluation?” I’m not saying there isn’t one. In fact, I think there’s a really important reason for them. In my mind, it’s really this: To make the speaker / next session better. Now, if you look at that, you can see right away that most session evals don’t accomplish this goal – not even a little. No, the way that they are worded and the way you (and I) fill them out, it’s more like the implied goal is this: Tell us how you liked this speaker / session. The current ones are for you, not for the speaker or the next person. It’s a popularity contest. Don’t get me wrong. I want to you have a good time. I want you to learn. I want (desperately, oh, please oh please) for you to like me. But in fact, that’s probably not why you went to the session / took the class / read that post. No, you want to learn, and to learn for a particular reason. Remember, I’m talking about college classes, sessions and other class environments here, not a general public event. Most – OK, all – session evaluations make you answer the second goal, not the first. Let’s see how: First, they don’t ask you why you’re there. They don’t ask you if you’re even qualified to evaluate the session or speaker. They don’t ask you how to make it better or keep it great. They use odd numeric scales that are meaningless. For instance, can someone really tell me the difference between a 100-level session and a 200-level one? Between a 400-level and a 500? Is it “internals” (whatever that means) or detail, or length or code, or what? I once heard a great description: A 100-level session makes me say, “wow - I’m smart.” A 500-level session makes me say “wow – that presenter is smart.” And just what is the difference between a 6 and a 7 answer on this question: How well did the speaker know the material? 1  2  3  4  5  6  7  8  9  10 Oh. My. Gosh. How does that make the next session better, or the speaker? And what criteria did you use to answer? And is a “10” better than a “1” (not always clear, and various cultures answer this differently). When it’s all said and done, a speaker basically finds out one thing from the current session evals: “They liked me. They really really liked me.” Or, “Wow. I think I may need to schedule some counseling for the depression I’m about to go into.” You may not think that’s what the speaker hears, but trust me, they do. Those are the only two reactions to the current feedback sheets they get. Either they keep doing what they are doing, or they get their feelings hurt. They just can’t use the information provided to do better. Sorry, but there it is. Keep in mind I do want your feedback. I want to get better. I want you to get your money and time’s worth, probably as much as any speaker alive. But I want those evaluations to be accurate, specific and actionable. I want to know if you had a good time, sure, but I also want to know if I did the right things, and if not, if I can do something different or better. And so, for your consideration, here is the evaluation form I would LOVE for you to use. Feel free to copy it and mail it to me any time. I’m going to put some questions here, and then I’ll even include why they are there. Notice that the form asks you a subjective question right away, and then makes you explain why. That’s work on your part. Notice also that it separates the room and the coffee and the lights and the LiveMeeting from the presenter. So many presenters are faced with circumstances beyond their control, and yet are rated high or low personally on those things. This form helps tease those apart. It’s not numeric. Numbers are easier for the scoring committees but are useless for you and me. So I don’t have any numbers. We’re actually going to have to read these things, not put them in a machine. Hey, if you put in the work to write stuff down, the least we could do is take the time to read it. It’s not anonymous. If you’ve got something to say, say it, and own up to it. People are not “more honest” when they are anonymous, they are less honest. So put your name on it. In fact – this is radical – I posit that these evaluations should be publicly available. Forever. Just like replies to a blog post. Hey, if I’m an organizer, I would LOVE to be able to have access to specific, actionable information on the attendees and the speakers. So if you want mine to be public, go for it. I’ll take the good and the bad. Enjoy. ------------------------------------------------------------------------------------------------------------------------------------------- Session Evaluation – Date, Time, Location, Topic Thanks for giving us your time today. We know that’s valuable, and we hope you learned something you can use from the session. If you can answer these questions as completely as you can, it will help the next person who attends a session here. Your Name: What you do for a living: (We Need your background to evaluate your evaluation) How long you have been doing that: (Again, we need your background to evaluate your evaluation) Paste Session Description Here: (This is what I said I would talk about) Did you like the session?                     No        Meh        Yes (General subjective question – overall “feeling”. You’ll tell us why in a minute.)  Tell us about the venue. Temperature, lights, coffee, or the online sound, performance, anything other than the speaker and the material. (Helps the logistics to be better or as good for the next person) 1. What did you expect to learn in this session? (How did you interpret that extract – did you have expectations that I should work towards for the next person?) 2. Did you learn what you expected to learn? Why? Be very specific. (This is the most important question there is. It tells us how to make the session better for someone like you.) 3. If you were giving this presentation, would you have done anything differently? What? (Helps us to gauge you, the listener, and might give us a great idea on how to do something better. Thanks!) 4. What will you do with the information you got? (Every presenter wants you to learn, and learn something useful. This will help us do that as well or better)  

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  • Simple dig output?

    - by knocte
    In a script I want to be able to write an IP address to somewhere easily, so I thought using dig (or a similar command) with back-ticks. However the simplest output I've been able to come up to wrt dig parameters is > dig -t A +noall +answer www.google.com www.google.com. 300 IN A 173.194.66.106 www.google.com. 300 IN A 173.194.66.104 Any way (extra arg, different tool instead of dig?) to get rid of the junk apart from the IP address?? (And please don't tell me to use sed.) Thanks

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  • Designs for outputting to a spreadsheet

    - by Austin Moore
    I'm working on a project where we are tasked to gather and output various data to a spreadsheet. We are having tons of problems with the file that holds the code to write the spreadsheet. The cell that the data belongs to is hardcoded, so anytime you need to add anything to the middle of the spreadsheet, you have to increment the location for all the fields after that in the code. There are random blank rows, to add padding between sections, and subsections within the sections, so there's no real pattern that we can replicate. Essentially, anytime we have to add or change anything to the spreadsheet it requires a many long and tedious hours. The code is all in this one large file, hacked together overtime in Perl. I've come up with a few OO solutions, but I'm not too familiar with OO programming in Perl and all my attempts at it haven't been great, so I've shied away from it so far. I've suggested we handle this section of the program with a more OO friendly language, but we can't apparently. I've also suggested that we scrap the entire spreadsheet idea, and just move to a webpage, but we can't do that either. We've been working on this project for a few months, and every time we have to change that file, we all dread it. I'm thinking it's time to start some refactoring. However, I don't even know what could make this file easier to work with. The way the output is formatted makes it so that it has to be somewhat hardcoded. I'm wondering if anyone has insight on any design patterns or techniques they have used to tackle a similar problem. I'm open to any ideas. Perl specific answers are welcome, but I am also interested in language-agnostic solutions.

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  • Code execution time out occationally

    - by Athul k Surendran
    I am working on an e-commerce website. There is a case where I need to fetch the whole data in database through third-party API and send it to an indexing engine. This third-party API has many functions like getproducts, getproductprice, etc., and each of that functions will return the data in XML format. From there I will take charge, I will use various API calls and will handle the XML data with XSLT. And will write to a CSV file. This file will be uploaded to an Indexing engine. Right now I have details of 8000 products to feed the engine, and almost all time the this process takes about 15 min to complete, and sometimes fails. I can't find a better solution for this. I am thinking about handling the XML data in C# itself and get rid of XSLT. As I think, XSLT is far slower than C#. Is it a good Idea? Or what else I can do to solve this issue?

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  • Retrieve a domain name based on an IP Address?

    - by Neil Kodner
    I'm reviewing some apache logs, specifically with respect to downloaded files. I'm interested in knowing, if possible, which domain is responsible for the download, given an IP address. I've given nslookup a try and it seems to (mostly) get the job done but it returns all sorts of extraneous information. Ideally, I pass in an IP and receive a domain back. Before I write a shell script to parse the output of nslookup to capture the domain, I'd like to know if this is the best way of approaching this problem, or if there is a more tried-and-true method of doing this. Specifically, I'd like to know if an address resolves to an amazonaws.com domain. I understand that this might be difficult because EC2 machines are dynamically created and destroyed - I'd like to know if the IP addresses for AWS/EC2/EMR machines fit any sort of addressing pattern.

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  • Firewire 800 with Windows

    - by Amitesh
    I have two windows machine with windows server 2003 installed on them. I am running a Lab View script on 1 machine and storing the data. But since it has less memory, I want to transfer data to another machine using firewire 800. Is it possible to configure out the second machine just as an external HDD attached to it and write data directly to it? (This is possible with MACs) Dont want to use the ethernet (internet/ TCP/IP prot.) to transfer the data. Is it possible? Thanks.

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  • How do you pronounce Linux?

    - by Xerxes
    I'm tired of the old fart at work who keeps coming upto my desk and telling me all about his "years of experience in working with Unix and Lye-nix". I couldn't vent it out at him because that would be wrong, so I'm going to vent it out here - because obviously (that's the right thing to do...). Anyway, for all the people that practice in this disgusting behaviour - the pronunciation is.... (Hmmm - anyone know phonetics?) - "Li-nix" Note: Despite hating him for this - he is otherwise a very nice (but sometimes rather annoying) person. Now... to formally make this a "question" - Could someone write the phonetics for pronouncing "Linux", and also the notorious "Lye-nix", so I can make a note of it for future ventings? I think this is right... L?n?x, NOT L?n?x. ...or perhaps... L?n?x, NOT L?n?x* Can someone confirm the correct phonetics? (Listen to Linus on the matter).

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  • How do I become a developer?

    - by ATester
    Since many of you are already there I figured this might be a great place to invite ideas and suggestion for becoming a software developer. My background I have some basic knowledge of programming in VB and C++ from a course I had pursued 8 years ago. My main drawback is a lack of experience in software since I was in a teaching career until a year ago. I am working as a QA tester and finally got a chance to write some automation tests scripts using C#. I didn't have any prior knowledge of C# but I was able to figure my way through it. Questions Given this context: Would anyone have any ideas as to what would be a good approach to learn enough to actually be able to work as a developer? Does anyone have any suggestions as to what kind of learning path to adopt and which approaches speed up learning curve? Would pursuing university course be helpful in terms of knowledge gained? Are certification exams a way to go for a beginner? Are community college courses useful? What about courses offered by private institutes/centers? Any suggestion for some good books?

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  • Attributes of an Ethical Programmer?

    - by ahmed
    Software that we write has ramifications in the real world. If not, it wouldn't be very useful. Thus, it has the potential to sweep across the world faster than a deadly manmade virus or to affect society every bit as much as genetic manipulation. Maybe we can't see how right now, but in the future our code will have ever-greater potential for harm or good. Of course, there's the issue of hacking. That's clearly a crime. Or is it that clear? Isn't hacking acceptable for our government in the event of national security? What about for other governments? Cases of life-and-death emergency? Tracking down deadbeat parents? Screening the genetic profile of job candidates? Where is the line drawn? Who decides? Do programmers have responsibility for how their code is used? What if a programmer writes code to pry into confidential information or copy-protected material? Does he bear responsibility along with the person who used the program? What about a programmer who knowingly or unknowingly writes code to "fix the books?" Should he be liable?

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  • Why do I get disk I/O errors booting the 3.2 kernel on a xen vps server?

    - by Doug
    I have a xen vps, which I just upgraded to the new LTS 12 Precise Pangolin. However, I see this error on booting: [ 12.848076] end_request: I/O error, dev xvda, sector 12841 [ 12.848093] end_request: I/O error, dev xvda, sector 12841 [ 12.848103] Buffer I/O error on device xvda1, logical block 1605 [ 12.848110] lost page write due to I/O error on xvda1 [ 12.848129] Aborting journal on device xvda1. Results in / being mounted read-only. Reboot: [ 3.087257] EXT3-fs (xvda1): warning: ext3_clear_journal_err: Marking fs in need of filesystem check. [ 3.087677] EXT3-fs (xvda1): recovery complete [ 3.088514] EXT3-fs (xvda1): mounted filesystem with ordered data mode Begin: Running /scripts/local-bottom ... done. done. Begin: Running /scripts/init-bottom ... done. fsck from util-linux 2.20.1 PRGMRDISK1 contains a file system with errors, check forced. Checking disk drives for errors. This may take several minutes. Press C to cancel all checks in progress PRGMRDISK1: ***** REBOOT LINUX ***** PRGMRDISK1: 371152/6001184 files (2.8% non-contiguous), 4727949/12000000 blocks mountall: fsck / [308] terminated with status 3 mountall: System must be rebooted: / [ 151.566949] Restarting system. Name ID Mem VCPUs State Time(s) shadowmint 236 2048 1 --p--- 0.0 Reboot - back to 1. This is definitely an issue with the 3.2 kernel, because booting the 3.0.0 or 2.6.38 kernel series make this issue magically disappear. I'm certain this is some kind of weird xen thing, but no idea. Anyone? Anyhow, until this is resolve I strongly recommend against upgrading if you're running a xen server.

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  • Configure GNU screen so that it stores command histories in files

    - by user65950
    I would like to configure GNU screen such that it stores the command histories of all the different windows in different files. I know by default GNU screen does not store the command histories (of its different windows) in a file at all (it stores them in memory instead), but it might be possible to tell it to store them in files instead? The different command history files should have the names <session>.<window>.history, or similar. Does anyone have an idea how to do that? (Just to be clear, I want each GNU screen window to write a different file. I like that each window has a different history, and I typically run different types of commands in the different windows.)

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  • How to store bitmaps in memory?

    - by Geotarget
    I'm working with general purpose image rendering, and high-performance image processing, and so I need to know how to store bitmaps in-memory. (24bpp/32bpp, compressed/raw, etc) I'm not working with 3D graphics or DirectX / OpenGL rendering and so I don't need to use graphics card compatible bitmap formats. My questions: What is the "usual" or "normal" way to store bitmaps in memory? (in C++ engines/projects?) How to store bitmaps for high-performance algorithms, such that read/write times are the fastest? (fixed array? with/without padding? 24-bpp or 32-bpp?) How to store bitmaps for applications handling a lot of bitmap data, to minimize memory usage? (JPEG? or a faster [de]compression algorithm?) Some possible methods: Use a fixed packed 24-bpp or 32-bpp int[] array and simply access pixels using pointer access, all pixels are allocated in one continuous memory chunk (could be 1-10 MB) Use a form of "sparse" data storage so each line of the bitmap is allocated separately, reusing more memory and requiring smaller contiguous memory segments Store bitmaps in its compressed form (PNG, JPG, GIF, etc) and unpack only when its needed, reducing the amount of memory used. Delete the unpacked data if its not used for 10 secs.

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  • The Start of a Blog

    - by dbradley
    So, here's my new blog up and running, who am I and what am I planning to write here?First off - here's a little about me:I'm a recent graduate from university (coming up to a year ago since I finished) studying Software Engineering on a four year course where the third year was an industrial placement. During the industrial placement I went to work for a company called Adfero in a "Technical Consultant" role as well as a junior "Information Systems Developer". Once I completed my placement I went back to complete my final year but also continued in my developer role 2/3 days a week with the company.Working part time while at uni always seems like a great idea until you get half way through the year. For me the problem was not so much having a lack of time, but rather a lack of interest in the course content having got a chance at working on real projects in a live environment. Most people who have been graduated a little while also find this - when looking back at uni work, it seem to be much more trivial from a problem solving point of view which I found to be true and I found key to uni work to actually be your ability to prove though how you talk about something that you comprehensively understand the basics.After completing uni I then returned full time to Adfero purely in the developer role which is where I've now been for almost a year and have now also taken on the title of "Information Systems Architect" where I'm working on some of the more high level design problems within the products.What I'm wanting to share on this blog is some of the interesting things I've learnt myself over the last year, the things they don't teach you in uni and pretty much anything else I find interesting! My personal favorite areas are text indexing, search and particularly good software engineering design - good design combined with good code makes the first step towards a well-written, maintainable piece of software.Hopefully I'll also be able to share a few of the products I've worked on, the mistake I've made and the software problems I've inherited from previous developers and had to heavily re-factor.

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  • General List of Common Programming Errors

    - by javamonkey79
    As one journey's from apprentice to journeyman to master I've noticed that one accumulates a list of best practices for things they've been bitten by. Personally, I write most of my stuff in java & SQL so my list tends to be slated towards them. I've accumulated the following: When doing list removal, always reverse iterate Avoid adding items to a list you are currently iterating on Watch out for NullPointerExceptions Now, I know there are language specific "common errors" links out there like this one. And I'm also aware of the pragmatic programmer tips, Martin Fowler's "code smells". Does anyone know of any good lists out there of things like I've listed above (re: list removal, adding items, etc). My guess is that there are some good QA folks out there that can probably throw me a bone here. I'm not looking for things the compiler can catch - I'm looking for common things that cause bugs. In the event that there isn't a list out there already then I welcome posting your own findings here. Thanks in advance!

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  • What are current options to scan or convert a hand written note to a file on my laptop?

    - by goldenmean
    I wonder how come there are not many options when it comes to scan or convert a device which could be connected to a laptop/desktop, which could - 1] Allow me to write with a digital pen on some special surface, which is connected to my laptop and thus converts my hand written notes to a pdf/jpg/word. (Microsoft's failed attempt at windows based tablet PC in past comes to mind, but not anymore) Any such solution I can use with my laptop? 2] A document scanning device, apart from a flat bed scanner, integrated these days into multi function printers; anything that is portable enough to connect to my laptop?

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  • Why did the web win the space of remote applications and X not?

    - by Martin Josefsson
    The X Window System is 25 years old, it had it's birthday yesterday (on the 15'th). As you probably are aware of, one of it's most important features is the separation of the server side and the client side in a way that neither Microsoft's, Apples or Wayland's windowing systems have. Back in the days (sorry for the ambiguous phrasing) many believed X would dominate over other ways to make windows because of this separation of server and client, allowing the application to be ran on a server somewhere else while the user clicks and types on her own computer at home. This use obviously still exists, but is marginalized at best. When we write and use programs that run on a server we almost always use the web with it's html/css/js. Why did the web win, and X not? The technologies used for the web (said html/css/js) are a mess. Combined with all the back-end-frameworks (Rails, Django and all) it really is a jungle to navigate thru. Still the web thrives with creativity and progress, while remote X apps do not.

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  • Is there a canonical source supporting "all-surrogates"?

    - by user61852
    Background The "all-PK-must-be-surrogates" approach is not present in Codd's Relational Model or any SQL Standard (ANSI, ISO or other). Canonical books seems to elude this restrictions too. Oracle's own data dictionary scheme uses natural keys in some tables and surrogate keys in other tables. I mention this because these people must know a thing or two about RDBMS design. PPDM (Professional Petroleum Data Management Association) recommend the same canonical books do: Use surrogate keys as primary keys when: There are no natural or business keys Natural or business keys are bad ( change often ) The value of natural or business key is not known at the time of inserting record Multicolumn natural keys ( usually several FK ) exceed three columns, which makes joins too verbose. Also I have not found canonical source that says natural keys need to be immutable. All I find is that they need to be very estable, i.e need to be changed only in very rare ocassions, if ever. I mention PPDM because these people must know a thing or two about RDBMS design too. The origins of the "all-surrogates" approach seems to come from recommendations from some ORM frameworks. It's true that the approach allows for rapid database modeling by not having to do much business analysis, but at the expense of maintainability and readability of the SQL code. Much prevision is made for something that may or may not happen in the future ( the natural PK changed so we will have to use the RDBMS cascade update funtionality ) at the expense of day-to-day task like having to join more tables in every query and having to write code for importing data between databases, an otherwise very strightfoward procedure (due to the need to avoid PK colisions and having to create stage/equivalence tables beforehand ). Other argument is that indexes based on integers are faster, but that has to be supported with benchmarks. Obviously, long, varying varchars are not good for PK. But indexes based on short, fix-length varchar are almost as fast as integers. The questions - Is there any canonical source that supports the "all-PK-must-be-surrogates" approach ? - Has Codd's relational model been superceded by a newer relational model ?

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  • Tool for purging unneeded backups

    - by Dana the Sane
    I'm in the common situation where the one of the linux servers I use for storing backups is filling up. I'm wondering what tools are available for doing this. Ideally, what I would like is something that keeps nightlies for the previous month, weeklies for the 2nd to 5th preceding months and retains monthlies (well, every 3rd week) for an indefinite period. Everything that falls outside of that would be deleted after the backups are run. I could write a script to do this, but I feel like there must be a standard tool for this task.

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  • MacOS X 10.6 Portable Home Directory sync fails due to FileSync agent crashing

    - by tegbains
    On one of our cleanly installed MacPro machines running MacOS X 10.6.6 connected to our MacOS X 10.6.6 Server, syncing data using Portable Home Directories fails. It seems to be due to the filesync agent crashing during the home sync. We get -41 and -8026 errors, which we are suspecting are indicating that there is too much data or filesync agent can't read the files. The user is the owner of the files and can read/write to all of the files. < Logout 0:: [11/02/04 13:10:42.751] Error -41 copying /Volumes/RCAUsers/earlpeng/Library/Mail/Mailboxes/email from old imac./Attachments/12081/2.2. (source = NO) < Logout 0:: [11/02/04 13:10:42.758] Error -8062 copying /Volumes/RCAUsers/earlpeng/Library/Mail/Mailboxes/email from old imac./Attachments/12081/2.2/[email protected]. (source = NO) < Logout 1:: [11/02/04 13:10:42.758] -[DeepCopyContext deepCopyError:sourceError:sourceRef:]: error = -8062, wasSource = NO: return shouldContinue = NO

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