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  • What are cross-platform free/Open source Framework to create Touch based web apps/site using HTML/CSS/JS available?

    - by Jitendra Vyas
    What are cross-platform and cross browser and license free/Open source framework to create Touch/Multitouch based Web apps/site using HTML/CSS/JS, for mobile devices, specially for latest versions of Android, Blackberry, Windows 7, iphone and ipad available? For desktop websites I'm a jQuery lover. I know Sencha but it's not free I think. I know jQtouch but it's only for iPhone and I also know jquery mobile but I'm not cofirm, is it as powerful as Sencha? It's not necessarily for me to go with jquery mobile, if there are another better framework available than this I want to make compatible with Android, Blackberry, Windows 7 also. not only for iphone and ipad.

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  • Do I need to change the package name for the free version of my app?

    - by teedyay
    I have an application that I'm going to publish to the Android market. I'm planning on releasing a paid-for version and a free version with restricted feature set. During development I've ensured I can turn features on and off by setting a few constant values, so I only have one codebase. However, now I come to release I'm not clear if I need to make a copy of the app with a different package name for the free version. The documentation on how the market works say updates will only be recognised if they have the same package name and are signed with the same key. Does this mean it's OK to release two applications with the same package name but signed with different keys, or will this break something? Or is it just bad practice?

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  • Which free HTML/CSS IDE has best readable code formatting ?

    - by jitendra
    Which free HTML/CSS IDE has best readable code formatting for XHTML and CSS ? in one click or from keyboard shortcut? I don't want to give more time to proper indention, tab ec, want to select whole code and give good-looking formatting. I need easliy scanable Code formatting and syntax highlighting. and missing things (if anything is not proper) should show error. I know many online tool to do this but don't want to go everytime to online tool. Edit; I need free Windows tool (portable would be better)

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  • Is there a browser independet bookmarktool supporting tags, date and free comments?

    - by bernd_k
    I am looking for a tool, which helps me to organize my personal bookmarks. I want to be able to assign tags and free comments to a bookmark. I want to search my bookmarks by tags date of bookmarking pattern in title pattern in url It would be nice to be web based to enable sharing my bookmarks between different machines. But for it would be OK, if it works on a single machine as long as it has some import/export way to transfer the links to a new machine replacing the old. As browsers I'm using Firefox and ChromePlus. It would be nice, if the solution works with both browsers. With free comments, I mean additional remarks stored for a bookmark, which is not essential for searching.

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  • Is there any free, open source php CMS\framework for described case?

    - by Ole Jak
    I want that cms\framework to create me tables like "Users" "Cameras" and so on and declare classes and simple default methods for them (like paged sql relults and so on). I mean I say to it: I want Users to have ID, SpecialNumber and Name Flilds. and I want to get from it class for table generation (to call it once) and class containing methods such as Search by ID, SpecialNumber and Name, Create User, Delit User and so on functions. Is there any framework/cms like this for working with CODE not ui's and so on... so to say PHP generator or something... The result should be as that framework free as possible. So Is there any free, open source php CMS\framework for described case?

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  • Free icons for mobile applications. Where?

    - by Geltrude
    I know that in the sdk folders I can find some (not very well grouped, imho) icon. But, there is a site online specialized that let you download free icons useful for mobile app? Ie world flags, up, down... save, revert..., next..., play, stop..., etc. It would be more appriciated also if you can find these sets in many different colors, and in 2 or 3 sizes (32x32, 64x64, etc.). Have a nice day (ot. Especially my mom - her 62 birthday :-) Edit: those are all good sites, but to green-check the answer I need a small set with the common icons (I think moreabout 50-70 icons), in many different colors and in 2 or 3 different sizes (for lo-mid-hi definition devices). - If a so done site exists for free :-)

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  • eBooks on iPad vs. Kindle: More Debate than Smackdown

    - by andrewbrust
    When the iPad was presented at its San Francisco launch event on January 28th, Steve Jobs spent a significant amount of time explaining how well the device would serve as an eBook reader. He showed the iBooks reader application and iBookstore and laid down the gauntlet before Amazon and its beloved Kindle device. Almost immediately afterwards, criticism came rushing forth that the iPad could never beat the Kindle for book reading. The curious part of that criticism is that virtually no one offering it had actually used the iPad yet. A few weeks later, on April 3rd, the iPad was released for sale in the United States. I bought one on that day and in the few additional weeks that have elapsed, I’ve given quite a workout to most of its capabilities, including its eBook features. I’ve also spent some time with the Kindle, albeit a first-generation model, to see how it actually compares to the iPad. I had some expectations going in, but I came away with conclusions about each device that were more scenario-based than absolute. I present my findings to you here.   Vital Statistics Let’s start with an inventory of each device’s underlying technology. The iPad has a color, backlit LCD screen and an on-screen keyboard. It has a battery which, on a full charge, lasts anywhere from 6-10 hours. The Kindle offers a monochrome, reflective E Ink display, a physical keyboard and a battery that on my first gen loaner unit can go up to a week between charges (Amazon claims the battery on the Kindle 2 can last up to 2 weeks on a single charge). The Kindle connects to Amazon’s Kindle Store using a 3G modem (the technology and network vary depending on the model) that incurs no airtime service charges whatsoever. The iPad units that are on-sale today work over WiFi only. 3G-equipped models will be on sale shortly and will command a $130 premium over their WiFi-only counterparts. 3G service on the iPad, in the U.S. from AT&T, will be fee-based, with a 250MB plan at $14.99 per month and an unlimited plan at $29.99. No contract is required for 3G service. All these tech specs aside, I think a more useful observation is that the iPad is a multi-purpose Internet-connected entertainment device, while the Kindle is a dedicated reading device. The question is whether those differences in design and intended use create a clear-cut winner for reading electronic publications. Let’s take a look at each device, in isolation, now.   Kindle To me, what’s most innovative about the Kindle is its E Ink display. E Ink really looks like ink on a sheet of paper. It requires no backlight, it’s fully visible in direct sunlight and it causes almost none of the eyestrain that LCD-based computer display technology (like that used on the iPad) does. It’s really versatile in an all-around way. Forgive me if this sounds precious, but reading on it is really a joy. In fact, it’s a genuinely relaxing experience. Through the Kindle Store, Amazon allows users to download books (including audio books), magazines, newspapers and blog feeds. Books and magazines can be purchased either on a single-issue basis or as an annual subscription. Books, of course, are purchased singly. Oddly, blogs are not free, but instead carry a monthly subscription fee, typically $1.99. To me this is ludicrous, but I suppose the free 3G service is partially to blame. Books and magazine issues download quickly. Magazine and blog subscriptions cause new issues or posts to be pushed to your device on an automated basis. Available blogs include 9000-odd feeds that Amazon offers on the Kindle Store; unless I missed something, arbitrary RSS feeds are not supported (though there are third party workarounds to this limitation). The shopping experience is integrated well, has an huge selection, and offers certain graphical perks. For example, magazine and newspaper logos are displayed in menus, and book cover thumbnails appear as well. A simple search mechanism is provided and text entry through the physical keyboard is relatively painless. It’s very easy and straightforward to enter the store, find something you like and start reading it quickly. If you know what you’re looking for, it’s even faster. Given Kindle’s high portability, very reliable battery, instant-on capability and highly integrated content acquisition, it makes reading on whim, and in random spurts of downtime, very attractive. The Kindle’s home screen lists all of your publications, and easily lets you select one, then start reading it. Once opened, publications display in crisp, attractive text that is adjustable in size. “Turning” pages is achieved through buttons dedicated to the task. Notes can be recorded, bookmarks can be saved and pages can be saved as clippings. I am not an avid book reader, and yet I found the Kindle made it really fun, convenient and soothing to read. There’s something about the easy access to the material and the simplicity of the display that makes the Kindle seduce you into chilling out and reading page after page. On the other hand, the Kindle has an awkward navigation interface. While menus are displayed clearly on the screen, the method of selecting menu items is tricky: alongside the right-hand edge of the main display is a thin column that acts as a second display. It has a white background, and a scrollable silver cursor that is moved up or down through the use of the device’s scrollwheel. Picking a menu item on the main display involves scrolling the silver cursor to a position parallel to that menu item and pushing the scrollwheel in. This navigation technique creates a disconnect, literally. You don’t really click on a selection so much as you gesture toward it. I got used to this technique quickly, but I didn’t love it. It definitely created a kind of anxiety in me, making me feel the need to speed through menus and get to my destination document quickly. Once there, I could calm down and relax. Books are great on the Kindle. Magazines and newspapers much less so. I found the rendering of photographs, and even illustrations, to be unacceptably crude. For this reason, I expect that reading textbooks on the Kindle may leave students wanting. I found that the original flow and layout of any publication was sacrificed on the Kindle. In effect, browsing a magazine or newspaper was almost impossible. Reading the text of individual articles was enjoyable, but having to read this way made the whole experience much more “a la carte” than cohesive and thematic between articles. I imagine that for academic journals this is ideal, but for consumer publications it imposes a stripped-down, low-fidelity experience that evokes a sense of deprivation. In general, the Kindle is great for reading text. For just about anything else, especially activity that involves exploratory browsing, meandering and short-attention-span reading, it presents a real barrier to entry and adoption. Avid book readers will enjoy the Kindle (if they’re not already). It’s a great device for losing oneself in a book over long sittings. Multitaskers who are more interested in periodicals, be they online or off, will like it much less, as they will find compromise, and even sacrifice, to be palpable.   iPad The iPad is a very different device from the Kindle. While the Kindle is oriented to pages of text, the iPad orbits around applications and their interfaces. Be it the pinch and zoom experience in the browser, the rich media features that augment content on news and weather sites, or the ability to interact with social networking services like Twitter, the iPad is versatile. While it shares a slate-like form factor with the Kindle, it’s effectively an elegant personal computer. One of its many features is the iBook application and integration of the iBookstore. But it’s a multi-purpose device. That turns out to be good and bad, depending on what you’re reading. The iBookstore is great for browsing. It’s color, rich animation-laden user interface make it possible to shop for books, rather than merely search and acquire them. Unfortunately, its selection is rather sparse at the moment. If you’re looking for a New York Times bestseller, or other popular titles, you should be OK. If you want to read something more specialized, it’s much harder. Unlike the awkward navigation interface of the Kindle, the iPad offers a nearly flawless touch-screen interface that seduces the user into tinkering and kibitzing every bit as much as the Kindle lulls you into a deep, concentrated read. It’s a dynamic and interactive device, whereas the Kindle is static and passive. The iBook reader is slick and fun. Use the iPad in landscape mode and you can read the book in 2-up (left/right 2-page) display; use it in portrait mode and you can read one page at a time. Rather than clicking a hardware button to turn pages, you simply drag and wipe from right-to-left to flip the single or right-hand page. The page actually travels through an animated path as it would in a physical book. The intuitiveness of the interface is uncanny. The reader also accommodates saving of bookmarks, searching of the text, and the ability to highlight a word and look it up in a dictionary. Pages display brightly and clearly. They’re easy to read. But the backlight and the glare made me less comfortable than I was with the Kindle. The knowledge that completely different applications (including the Web and email and Twitter) were just a few taps away made me antsy and very tempted to task-switch. The knowledge that battery life is an issue created subtle discomfort. If the Kindle makes you feel like you’re in a library reading room, then the iPad makes you feel, at best, like you’re under fluorescent lights at a Barnes and Noble or Borders store. If you’re lucky, you’d be on a couch or at a reading table in the store, but you might also be standing up, in the aisles. Clearly, I didn’t find this conducive to focused and sustained reading. But that may have more to do with my own tendency to read periodicals far more than books, and my neurotic . And, truth be known, the book reading experience, when not explicitly compared to Kindle’s, was still pleasant. It is also important to point out that Kindle Store-sourced books can be read on the iPad through a Kindle reader application, from Amazon, specific to the device. This offered a less rich experience than the iBooks reader, but it was completely adequate. Despite the Kindle brand of the reader, however, it offered little in terms of simulating the reading experience on its namesake device. When it comes to periodicals, the iPad wins hands down. Magazines, even if merely scanned images of their print editions, read on the iPad in a way that felt similar to reading hard copy. The full color display, touch navigation and even the ability to render advertisements in their full glory makes the iPad a great way to read through any piece of work that is measured in pages, rather than chapters. There are many ways to get magazines and newspapers onto the iPad, including the Zinio reader, and publication-specific applications like the Wall Street Journal’s and Popular Science’s. The New York Times’ free Editors’ Choice application offers a Times Reader-like interface to a subset of the Gray Lady’s daily content. The completely Web-based but iPad-optimized Times Skimmer site (at www.nytimes.com/timesskimmer) works well too. Even conventional Web sites themselves can be read much like magazines, given the iPad’s ability to zoom in on the text and crop out advertisements on the margins. While the Kindle does have an experimental Web browser, it reminded me a lot of early mobile phone browsers, only in a larger size. For text-heavy sites with simple layout, it works fine. For just about anything else, it becomes more trouble than it’s worth. And given the way magazine articles make me think of things I want to look up online, I think that’s a real liability for the Kindle.   Summing Up What I came to realize is that the Kindle isn’t so much a computer or even an Internet device as it is a printer. While it doesn’t use physical paper, it still renders its content a page at a time, just like a laser printer does, and its output appears strikingly similar. You can read the rendered text, but you can’t interact with it in any way. That’s why the navigation requires a separate cursor display area. And because of the page-oriented rendering behavior, turning pages causes a flash on the display and requires a sometimes long pause before the next page is rendered. The good side of this is that once the page is generated, no battery power is required to display it. That makes for great battery life, optimal viewing under most lighting conditions (as long as there is some light) and low-eyestrain text-centric display of content. The Kindle is highly portable, has an excellent selection in its store and is refreshingly distraction-free. All of this is ideal for reading books. And iPad doesn’t offer any of it. What iPad does offer is versatility, variety, richness and luxury. It’s flush with accoutrements even if it’s low on focused, sustained text display. That makes it inferior to the Kindle for book reading. But that also makes it better than the Kindle for almost everything else. As such, and given that its book reading experience is still decent (even if not superior), I think the iPad will give Kindle a run for its money. True book lovers, and people on a budget, will want the Kindle. People with a robust amount of discretionary income may want both devices. Everyone else who is interested in a slate form factor e-reading device, especially if they also wish to have leisure-friendly Internet access, will likely choose the iPad exclusively. One thing is for sure: iPad has reduced Kindle’s market, and may have shifted its mass market potential to a mere niche play. If Amazon is smart, it will improve its iPad-based Kindle reader app significantly. It can then leverage the iPad channel as a significant market for the Kindle Store. After all, selling the eBooks themselves is what Amazon should care most about.

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  • Mysql: Disk is full writing

    - by elma
    Hi there, I'm having some problems with my mysql server lately, so I've decided to check the error logs: [root@LSN-D1179 log]# tail -10 mysqld.log 100325 19:30:03 [ERROR] /usr/libexec/mysqld: Table './lfe/actions' is marked as crashed and should be repaired 100325 19:30:03 [ERROR] /usr/libexec/mysqld: Table './lfe/actions' is marked as crashed and should be repaired 100325 19:30:18 [ERROR] /usr/libexec/mysqld: Disk is full writing './omuz/ibf_task_logs.MYD' (Errcode: 122). Waiting for someone to free space... Retry in 60 secs 100325 19:34:34 [ERROR] /usr/libexec/mysqld: Disk is full writing './omuz/ibf_profile_portal_views.MYD' (Errcode: 122). Waiting for someone to free space... Retry in 60 secs 100325 19:39:46 [ERROR] /usr/libexec/mysqld: Disk is full writing './omuz/ibf_posts.TMD' (Errcode: 122). Waiting for someone to free space... Retry in 60 secs 100325 19:40:18 [ERROR] /usr/libexec/mysqld: Disk is full writing './omuz/ibf_task_logs.MYD' (Errcode: 122). Waiting for someone to free space... Retry in 60 secs 100325 19:44:34 [ERROR] /usr/libexec/mysqld: Disk is full writing './omuz/ibf_profile_portal_views.MYD' (Errcode: 122). Waiting for someone to free space... Retry in 60 secs 100325 19:49:46 [ERROR] /usr/libexec/mysqld: Disk is full writing './omuz/ibf_posts.TMD' (Errcode: 122). Waiting for someone to free space... Retry in 60 secs 100325 19:50:18 [ERROR] /usr/libexec/mysqld: Disk is full writing './omuz/ibf_task_logs.MYD' (Errcode: 122). Waiting for someone to free space... Retry in 60 secs 100325 19:54:34 [ERROR] /usr/libexec/mysqld: Disk is full writing './omuz/ibf_profile_portal_views.MYD' (Errcode: 122). Waiting for someone to free space... Retry in 60 secs And here's is my df -h output [root@LSN-D1179 log]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/VolGroup00-LogVol00 143G 6.2G 129G 5% / /dev/sda1 99M 12M 83M 13% /boot tmpfs 490M 0 490M 0% /dev/shm As you can see, I have plenty of free space; so I couldn't figure out these "Disk is full" errors in mysqld.log. Does anyone know what should I do to fix this? Ugur

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  • PDF to HTML - batch converter - most reliable and accurate free AND paid for software?

    - by therobyouknow
    I'm look for either a free or paid-for (about 50$/40pounds) BATCH PDF to HTML converter to convert several PDF files at once. Needs to be able to handle vectored and bitmap images within the file, outputting both as jpegs referenced by the html pages. I've tried iorigsoft paid-for PDF to HTML - problems it seems to hang or just go idle, and the stuff it actually converts have broken links - the wrong name is used for constituent chapters as html. Also tried application from intrapdf.com but this crashes near the beginning of the conversion, consitently. Update: intrapdf works on my Windows XP machine but not on my Windows 7 machine. The only glitch is with the framed index contents html - the graphics in the page do not display in the page in the frame - but if you open the frame only in a new tab then you can see them. That might be a browser glitch in chrome only. This solution is good enough for me - given that I've already spent the money (I had spent before I asked) but I can't accept my own answer as this does not work on Windows 7. Looked at opensource tools but they look equally flakey or use old PDF versions. Need it on Windows 7 32bit home. Thoughts?

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  • Is there any free software to check for issues with a DVD drive?

    - by AgentConundrum
    I don't usually play movies on my laptop (prefer the standalone with the tv), but I tried to watch one the other night, and noticed playback was really choppy and had audio artifacts in places. I thought it could be related to memory issues so I rebooted and tried again, but the results were the same. I considered that it could be an issue with the disc, so I tried to clean it but again there was no change. I don't think the problem is with the disc, because I tried another disc and it also had the same problem. I don't think I've ever watched the second disc since I've had it, so it should have been safe in its jewel case. Also, there were no issues when I watched an episode off the first disc in my standalone player. What I'm wondering is: are there are any (free) utilities that can check for issues with the drive itself? I looked around but most of the software I found focuses on integrity checks for the disc, not the drive. I have had issues with this laptop recently (had to replace the keyboard when the cat damaged it while I was cleaning dust out and the machine was ripped apart, also replaced part of the chassis after I cracked it when I tried to open it not knowing a screw was still in it) so I may have just replaced the drive incorrectly. I'm going to check on this while I await an answer to this question. Thanks.

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  • Is there a free PDF printer / distiller that creates signable documents?

    - by Coderer
    I've used various methods (mentioned elsewhere on this site) to create PDFs, using a printer driver or converting from PostScript, etc. The common problem is that if I open any of the output files in the newer versions of Adobe Reader, there's an option to "Place Signature" but it's greyed out, or gives an error message that the feature has been disabled for this document. As far as I can tell, there's an option set somewhere in the document metadata that tells Reader "allow the user to sign this document", or don't. None of the free/open source tools that have been been linked to in other SU posts have had this listed as an option (though to be fair I haven't actually downloaded and tried all of them). Is there a tool that does this? Can I just poke a bit with a hex editor somewhere to turn on this functionality? I can sometimes get access to Acrobat Professional to turn on this option, but doing it for every desired case would be more work than I care to do. The current workaround for single-page documents is: Print the document to PDF (possibly via postscript) Open a single-page blank PDF with the "signable" bit turned on in Reader create a custom "stamp" using the Reader markup tools, by importing the printed-to document "stamp" an image of the printed document on the blank page, hoping to get it centered about right place a signature over the document-but-not-really you just stamped This obviously does not scale well at all. It would be much better if I could: Print the document to PDF Drag the document to a simple shortcut / tool / whatever Open the document in Reader Place a signature in the document ETA: Sorry, maybe I should have been clearer -- I'm talking about the certificate-based digital signing available in Adobe Reader, not adding a virtual ink signature. Also, any solution really would have to be available offline.

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  • Has anyone had luck running 802.1x over ethernet using the stock Windows or other free supplicant?

    - by maxxpower
    I just wanted to see if anyone else has had luck implementing 802.1x over ethernet. So here's my basic setup. Switch sends out 3 eapol messages spaced out 5 seconds apart. if there's no response the machine gets put on a guest vlan with restricted access. If the machine is properly configured it will authenticate and be placed into a secure vlan. About 10% of my windows xp users are getting self assigned 169 addresses. I've used the Odyssey Access Client and it worked without a hitch. I'm using the setting to automatically use the users windows login to authenticate, but it's workign on 90% of the machines so I don't think that's the issue. Checking the logs on the dc it seems that the machines are trying to authenticate with computer credentials even though they are configured not to. I'm running Juniper switches with IAS for radius. I have radius configured for PEAP and MSvhapv2. Macs and linux boxes seem to have no issues authenticating. One last thing to add If I unplugging the ethernet cable and plug it back in usually resolves the issue, but I'd hardly call that acceptable for production. Kinda long winded and specific for a discussion, but just want to see if anyone else has had similar issues or experiences, or if anyone knows of a free XP supplicant that actually works with 802.1x over ethernet.

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  • How can I store logs and meet compliance requirements for free?

    - by Martin
    I am trying to keep long-term logs of an app in such a way, that it could plausibly demonstrated to third parties/court that the application has processed certain data at a given time. The data can be represented in XML or text format. A simple gzipped log is not plausible, as I may have added or modified data afterwards, whereas an external logging service would be an overkill. Cost is an issue, we are not dealing with financial data or so, but rather some simple user generated content, where some malicious users tried to blame the operator in the past when things escalated and went to court. My question: Is there some kind of signing software for Linux that signs each element of a log in such a way, that it can be easily shown that no element can be added or modified afterwards? Plug-Ins into some free Splunk Alternatives would be fine too. Ideally the software I am looking for should be under a GPL or similar license. I could probably achive something like this by using PGP/GPG sgning functions and including the previous elements signituares within the following element, but I would prefer to use some program where you do not have to argue about the validity of your own code. Note to mods: I am not asking this question on Stackoverflow, because I am not looking for writing own code for reasons described above. I think this question rather fits into serverfault than superuser, as server-side logging software is discussed rather here than on superuser.

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  • Which free RDBMS is best for small in-house development?

    - by Nic Waller
    I am the sole sysadmin for a small firm of about 50 people, and I have been asked to develop an in-house application for tracking job completion and providing reports based on that data. I'm planning on building it as a web application. I have roughly equal experience developing for MySQL, PostgreSQL, and MSSQL. We are primarily a Windows-based shop, but I'm fairly comfortable with both Windows and Linux system administration. These are my two biggest concerns: Ease of managability. I don't expect to be maintaining this database forever. For the sake of the person that eventually has to take over for me, which database has the lowest barrier to entry? Data integrity. This means transaction-safe, robust storage, and easy backup/recovery. Even better if the database can be easily replicated. There is not a lot of budget for this project, so I am restricted to working with one of the free database systems mentioned above. What would you choose?

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  • How to reduce memory consumption an AWS EC2 t1.micro instance (free tier) ubuntu server 14.04 LTS EBS

    - by CMPSoares
    Hi I'm working on my bachelor thesis and for that I need to host a node.js web application on AWS, in order to avoid costs I'm using a t1.micro instance with 30GB disk space (from what I know it's the maximum I get in the free tier) which is barely used. But instead I have problems with memory consumption, it's using all of it. I tried the approach of creating a virtual swap area as mentioned at Why don't EC2 ubuntu images have swap? with these commands: sudo dd if=/dev/zero of=/var/swapfile bs=1M count=2048 && sudo chmod 600 /var/swapfile && sudo mkswap /var/swapfile && echo /var/swapfile none swap defaults 0 0 | sudo tee -a /etc/fstab && sudo swapon -a But this swap area isn't used somehow. Is something missing in this approach or is there another process of reducing the memory consumption in these type of AWS instances? Bottom-line: This originates server freezes and crashes and that's what I want to stop either by using the swap, reducing memory usage or both.

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  • BNF – how to read syntax?

    - by Piotr Rodak
    A few days ago I read post of Jen McCown (blog) about her idea of blogging about random articles from Books Online. I think this is a great idea, even if Jen says that it’s not exciting or sexy. I noticed that many of the questions that appear on forums and other media arise from pure fact that people asking questions didn’t bother to read and understand the manual – Books Online. Jen came up with a brilliant, concise acronym that describes very well the category of posts about Books Online – RTFM365. I take liberty of tagging this post with the same acronym. I often come across questions of type – ‘Hey, i am trying to create a table, but I am getting an error’. The error often says that the syntax is invalid. 1 CREATE TABLE dbo.Employees 2 (guid uniqueidentifier CONSTRAINT DEFAULT Guid_Default NEWSEQUENTIALID() ROWGUIDCOL, 3 Employee_Name varchar(60) 4 CONSTRAINT Guid_PK PRIMARY KEY (guid) ); 5 The answer is usually(1), ‘Ok, let me check it out.. Ah yes – you have to put name of the DEFAULT constraint before the type of constraint: 1 CREATE TABLE dbo.Employees 2 (guid uniqueidentifier CONSTRAINT Guid_Default DEFAULT NEWSEQUENTIALID() ROWGUIDCOL, 3 Employee_Name varchar(60) 4 CONSTRAINT Guid_PK PRIMARY KEY (guid) ); Why many people stumble on syntax errors? Is the syntax poorly documented? No, the issue is, that correct syntax of the CREATE TABLE statement is documented very well in Books Online and is.. intimidating. Many people can be taken aback by the rather complex block of code that describes all intricacies of the statement. However, I don’t know better way of defining syntax of the statement or command. The notation that is used to describe syntax in Books Online is a form of Backus-Naur notatiion, called BNF for short sometimes. This is a notation that was invented around 50 years ago, and some say that even earlier, around 400 BC – would you believe? Originally it was used to define syntax of, rather ancient now, ALGOL programming language (in 1950’s, not in ancient India). If you look closer at the definition of the BNF, it turns out that the principles of this syntax are pretty simple. Here are a few bullet points: italic_text is a placeholder for your identifier <italic_text_in_angle_brackets> is a definition which is described further. [everything in square brackets] is optional {everything in curly brackets} is obligatory everything | separated | by | operator is an alternative ::= “assigns” definition to an identifier Yes, it looks like these six simple points give you the key to understand even the most complicated syntax definitions in Books Online. Books Online contain an article about syntax conventions – have you ever read it? Let’s have a look at fragment of the CREATE TABLE statement: 1 CREATE TABLE 2 [ database_name . [ schema_name ] . | schema_name . ] table_name 3 ( { <column_definition> | <computed_column_definition> 4 | <column_set_definition> } 5 [ <table_constraint> ] [ ,...n ] ) 6 [ ON { partition_scheme_name ( partition_column_name ) | filegroup 7 | "default" } ] 8 [ { TEXTIMAGE_ON { filegroup | "default" } ] 9 [ FILESTREAM_ON { partition_scheme_name | filegroup 10 | "default" } ] 11 [ WITH ( <table_option> [ ,...n ] ) ] 12 [ ; ] Let’s look at line 2 of the above snippet: This line uses rules 3 and 5 from the list. So you know that you can create table which has specified one of the following. just name – table will be created in default user schema schema name and table name – table will be created in specified schema database name, schema name and table name – table will be created in specified database, in specified schema database name, .., table name – table will be created in specified database, in default schema of the user. Note that this single line of the notation describes each of the naming schemes in deterministic way. The ‘optionality’ of the schema_name element is nested within database_name.. section. You can use either database_name and optional schema name, or just schema name – this is specified by the pipe character ‘|’. The error that user gets with execution of the first script fragment in this post is as follows: Msg 156, Level 15, State 1, Line 2 Incorrect syntax near the keyword 'DEFAULT'. Ok, let’s have a look how to find out the correct syntax. Line number 3 of the BNF fragment above contains reference to <column_definition>. Since column_definition is in angle brackets, we know that this is a reference to notion described further in the code. And indeed, the very next fragment of BNF contains syntax of the column definition. 1 <column_definition> ::= 2 column_name <data_type> 3 [ FILESTREAM ] 4 [ COLLATE collation_name ] 5 [ NULL | NOT NULL ] 6 [ 7 [ CONSTRAINT constraint_name ] DEFAULT constant_expression ] 8 | [ IDENTITY [ ( seed ,increment ) ] [ NOT FOR REPLICATION ] 9 ] 10 [ ROWGUIDCOL ] [ <column_constraint> [ ...n ] ] 11 [ SPARSE ] Look at line 7 in the above fragment. It says, that the column can have a DEFAULT constraint which, if you want to name it, has to be prepended with [CONSTRAINT constraint_name] sequence. The name of the constraint is optional, but I strongly recommend you to make the effort of coming up with some meaningful name yourself. So the correct syntax of the CREATE TABLE statement from the beginning of the article is like this: 1 CREATE TABLE dbo.Employees 2 (guid uniqueidentifier CONSTRAINT Guid_Default DEFAULT NEWSEQUENTIALID() ROWGUIDCOL, 3 Employee_Name varchar(60) 4 CONSTRAINT Guid_PK PRIMARY KEY (guid) ); That is practically everything you should know about BNF. I encourage you to study the syntax definitions for various statements and commands in Books Online, you can find really interesting things hidden there. Technorati Tags: SQL Server,t-sql,BNF,syntax   (1) No, my answer usually is a question – ‘What error message? What does it say?’. You’d be surprised to know how many people think I can go through time and space and look at their screen at the moment they received the error.

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