Search Results

Search found 18475 results on 739 pages for 'non exist'.

Page 516/739 | < Previous Page | 512 513 514 515 516 517 518 519 520 521 522 523  | Next Page >

  • Video stutter when using external drive

    - by psion
    When using boxee to play video files off of an external western digital 1TB drive formatted NTFS, I notice a slight stutter in the video every 5-10 seconds. When using mplayer, it doesn't stutter as often, but it still stutters occasionally. If I play the video off of the local sata drive, it plays fine even in boxee. I use this computer as my HTPC and I just switched from windows to linux on it. In windows, I never had any sort of stutter playing movies from the drive. I am using the latest intel graphics drivers (for the intel GMA 950) root@eee-htpc:/home/htpc# grep wd /etc/mtab /dev/sdb1 /mnt/wd2 fuseblk rw,nosuid,nodev,allow_other,blksize=512 0 0 I notice that despite trying to use ntfs or ntfs-3g, ubuntu uses ntfs-fuse which I've heard is slower. /dev/sdb1: Timing buffered disk reads: 80 MB in 3.07 seconds = 26.08 MB/sec root@eee-htpc:/mnt/wd2# dd if=/dev/zero of=./120mb bs=1024 count=120000 root@eee-htpc:/mnt/wd2# time mv ./120mb /home/htpc real 0m2.095s user 0m0.016s sys 0m0.736s Even though fuse has a reputation for being slow, it should easily be fast enough for playing standard definition video files. So why the video stutter? edit: The issue seems to be overhead cpu usage from either playing off of a usb device or ntfs/fuse. Watching CPU usage with top, local files use 10-40% CPU. Watching the same video on the external formatted ntfs, it spikes to 170% (over 100% because of hyperthreading). To me it seems like it must be overhead from the fuse driver, though I don't know if it has more or less overhead than ntfs-3g. It's a EEEBox B202 that has an atom 270, so not exactly the most powerful out there. edit2: I believe the solution would be to use non-fuse drivers or different fuse drivers. so far I have not been able to. edit3: I've probably edited this more times than I should, but as an update I have upgraded ntfs drivers to ntfs-3g 2010.8.8 external FUSE 28 - Third Generation NTFS Driver using the following PPA - ppa:x3lectric/team-iquik-releases. When first opening a video file in boxee that's on ntfs there's still the same amount of lag. After a few minutes of video, the lag seems to go away and the cpu usage comes down to 10-40%. Every so often though, it begins to stutter again. Also, if I skip ahead/back in the file, it begins to stutter a lot.

    Read the article

  • Repository/Updating/Upgrading Issue

    - by Jakob
    The other day I was asked to upgrade from 13.04 to 13.10, at the time I was busy and hit no. I can not upgrade/update at this point, I get (error -11) or a 404 in terminal. In the software updater I get 'failed to download repository information.' I have tried changing my "Download From" setting to "Best" to "Main" and even a few other countries. And in "Other Software" I have tried disabling packages, but doesn't seem to help what so ever. I have tried several of the other commands to try and fix it, such as -fix missing or sudo apt-get update clean. P.S. This has also affected my thunderbird client, I cannot send/receive emails. Here is my error log when trying to upgrade: jakob@Skeletor:~$ sudo update-manager -d gpg: /tmp/tmpvejqvl/trustdb.gpg: trustdb created gpg: /tmp/tmpnayby6/trustdb.gpg: trustdb created Traceback (most recent call last): File "/usr/lib/python3/dist-packages/defer/__init__.py", line 483, in _inline_callbacks result = gen.throw(excep) File "/usr/lib/python3/dist-packages/UpdateManager/backend/InstallBackendAptdaemon.py", line 86, in commit True, close_on_done) File "/usr/lib/python3/dist-packages/defer/__init__.py", line 483, in _inline_callbacks result = gen.throw(excep) File "/usr/lib/python3/dist-packages/UpdateManager/backend/InstallBackendAptdaemon.py", line 158, in _run_in_dialog yield trans.run() aptdaemon.errors.TransactionFailed: Transaction failed: Package does not exist Package linux-headers-3.8.0-33 isn't available gpg: /tmp/tmp3kw_hl/trustdb.gpg: trustdb created. And let me throw in my sudo apt-get update too. Which this has been working variably too, but I don't know what to change my repositories to, and disabling does not effect: E: Some index files failed to download. They have been ignored, or old ones used instead. This is the short version, but looks exactly like this fairly consistently. Sometimes it downloads, sometimes it doesn't. Sometimes it tells me I have an update, and doesn't do anything. If it helps, I have recently had issues trying to install Samba as well, and connecting to the office's NAS Drive. Which works now, but I had to edit /etc/fstab/ and a few other things trying to get that to work as well. I understand it could also be a DNS problem, but this has been going on for a few days, as well as I've already tried changing my DNS server via my computer, however I am not allowed to alter the DNS on our company's router.

    Read the article

  • Attunity Oracle CDC Solution for SSIS - Beta

    We in no way work for Attunity but we were asked to test drive a beta version of their Oracle CDC solution for SSIS.  Everybody should know that moving more data than you need to takes too much time and uses resources that may better be employed doing something else.  Change data Capture is a technology that is designed to help you identify only the data that has had something done to it and you can therefore move only what is needed.  Microsoft have implemented this exact functionality into SQL server 2008 and I really like it there.  Attunity though are doing it on Oracle. DISCLAIMER: This is a BETA release and some of the parts are a bit ugly/difficult to work with.  The idea though is definitely right and the product once working does exactly what it says on the tin.  They have always been helpful to me when I have had a problem with the product and if that continues then beta testing pain should be eased somewhat. In due course I am going to be doing some videos around me using the product.  If you use Oracle and SSIS then give it a go. Here is their product description.   Attunity is a Microsoft SQL Server technology partner and the creator of the Microsoft Connectors for Oracle and Teradata, currently available in SQL Server 2008 Enterprise Edition. Attunity released a beta version of the Attunity Oracle-CDC for SSIS, a product that integrates continually changing Oracle data into SSIS, efficiently and in real-time. Attunity designed the product and integrated it into SSIS to create the simple creation of change data capture (CDC) solutions, accelerate implementation time, and reduce resources and costs. They also utilize log-based CDC so the solution has minimal impact on the Oracle source system. You can use the product to implement enterprise-class data replication, synchronization, and real-time business intelligence (BI) and data warehousing projects, quickly and efficiently, leveraging their existing SQL Server investments and resource skills. Attunity architected the product specifically for the Microsoft SSIS developer community and the product is available for both SQL Server 2005 and SQL Server 2008. It offers the following key capabilities: · Log-based, non-intrusive Oracle CDC · Full integration into SSIS and the Business Intelligence Developer Studio · Automatic generation of SSIS packages for CDC as well as full-loads of Oracle data · Filtering of Oracle tables and columns at the source · Monitoring and control of CDC processing Click to learn more and download the beta.

    Read the article

  • How to sort a ListView control by a column in Visual C#

    - by bconlon
    Microsoft provide an article of the same name (previously published as Q319401) and it shows a nice class 'ListViewColumnSorter ' for sorting a standard ListView when the user clicks the column header. This is very useful for String values, however for Numeric or DateTime data it gives odd results. E.g. 100 would come before 99 in an ascending sort as the string compare sees 1 < 9. So my challenge was to allow other types to be sorted. This turned out to be fairly simple as I just needed to create an inner class in ListViewColumnSorter which extends the .Net CaseInsensitiveComparer class, and then use this as the ObjectCompare member's type. Note: Ideally we would be able to use IComparer as the member's type, but the Compare method is not virtual in CaseInsensitiveComparer , so we have to create an exact type: public class ListViewColumnSorter : IComparer {     private CaseInsensitiveComparer ObjectCompare;     private MyComparer ObjectCompare;     ... rest of Microsofts class implementation... } Here is my private inner comparer class, note the 'new int Compare' as Compare is not virtual, and also note we pass the values to the base compare as the correct type (e.g. Decimal, DateTime) so they compare correctly: private class MyComparer : CaseInsensitiveComparer {     public new int Compare(object x, object y)     {         try         {             string s1 = x.ToString();             string s2 = y.ToString();               // check for a numeric column             decimal n1, n2 = 0;             if (Decimal.TryParse(s1, out n1) && Decimal.TryParse(s2, out n2))                 return base.Compare(n1, n2);             else             {                 // check for a date column                 DateTime d1, d2;                 if (DateTime.TryParse(s1, out d1) && DateTime.TryParse(s2, out d2))                     return base.Compare(d1, d2);             }         }         catch (ArgumentException) { }           // just use base string compare         return base.Compare(x, y);     } } You could extend this for other types, even custom classes as long as they support ICompare. Microsoft also have another article How to: Sort a GridView Column When a Header Is Clicked that shows this for WPF, which looks conceptually very similar. I need to test it out to see if it handles non-string types. #

    Read the article

  • Tellago releases a RESTful API for BizTalk Server business rules

    - by Charles Young
    Jesus Rodriguez has blogged recently on Tellago Devlabs' release of an open source RESTful API for BizTalk Server Business Rules.   This is an excellent addition to the BizTalk ecosystem and I congratulate Tellago on their work.   See http://weblogs.asp.net/gsusx/archive/2011/02/08/tellago-devlabs-a-restful-api-for-biztalk-server-business-rules.aspx   The Microsoft BRE was originally designed to be used as an embedded library in .NET applications. This is reflected in the implementation of the Rules Engine Update (REU) Service which is a TCP/IP service that is hosted by a Windows service running locally on each BizTalk box. The job of the REU is to distribute rules, managed and held in a central database repository, across the various servers in a BizTalk group.   The engine is therefore distributed on each box, rather than exploited behind a central rules service.   This model is all very well, but proves quite restrictive in enterprise environments. The problem is that the BRE can only run legally on licensed BizTalk boxes. Increasingly we need to deliver rules capabilities across a more widely distributed environment. For example, in the project I am working on currently, we need to surface decisioning capabilities for use within WF workflow services running under AppFabric on non-BTS boxes. The BRE does not, currently, offer any centralised rule service facilities out of the box, and hence you have to roll your own (and then run your rules services on BTS boxes which has raised a few eyebrows on my current project, as all other WCF services run on a dedicated server farm ).   Tellago's API addresses this by providing a RESTful API for querying the rules repository and executing rule sets against XML passed in the request payload. As Jesus points out in his post, using a RESTful approach hugely increases the reach of BRE-based decisioning, allowing simple invocation from code written in dynamic languages, mobile devices, etc.   We developed our own SOAP-based general-purpose rules service to handle scenarios such as the one we face on my current project. SOAP is arguably better suited to enterprise service bus environments (please don't 'flame' me - I refuse to engage in the RESTFul vs. SOAP war). For example, on my current project we use claims based authorisation across the entire service bus and use WIF and WS-Federation for this purpose.   We have extended this to the rules service. I can't release the code for commercial reasons :-( but this approach allows us to legally extend the reach of BRE far beyond the confines of the BizTalk boxes on which it runs and to provide general purpose decisioning capabilities on the bus.   So, well done Tellago.   I haven't had a chance to play with the API yet, but am looking forward to doing so.

    Read the article

  • Mixed Solaris 10 and 11 versions in logical domains on the same server

    - by jsavit
    One question that comes up frequently is whether you can mix Solaris 10 and Solaris 11 in different logical domains under Oracle VM Server for SPARC. The answer is yes depending only on the system software requirements for the underlying hardware platform. Different versions of Solaris 10 and 11 can exist side-by-side on the same server and can act as control, service, I/O or guest domains subject only to the minimum software levels documented in the System Requirements section of the Oracle VM Server for SPARC Release Notes. Here's an example just taken from a running system. First, here's the control domain, which is running Solaris 10. I've highlighted a guest running Solaris 11. # uname -a SunOS atl-sewr-24 5.10 Generic_147440-01 sun4v sparc SUNW,SPARC-Enterprise-T5220 # ldm -V Logical Domains Manager (v 2.1) Hypervisor control protocol v 1.7 Using Hypervisor MD v 1.3 System PROM: Hypervisor v. 1.10.0 @(#)Hypervisor 1.10.0 2011/04/27 16:19\015 # ldm list NAME STATE FLAGS CONS VCPU MEMORY UTIL UPTIME primary active -n-cv- SP 16 4G 1.6% 120d 17h atl-sewr-pool-148 active -n---- 5001 8 2G 0.1% 119d 21h atl-sewr-pool-152 active -n---- 5000 8 4G 0.2% 112d 19h atl-sewr-pool-154 active -n---- 5002 8 2G 0.1% 120d 15h atl-sewr-pool-155 active -n---- 5003 16 2G 0.0% 26d 14h 30m This system is running Oracle VM Server 2.1 with a Solaris 10 control domain. Hmm, I should update this machine to 2.2 when I get a few free moments. Upgrading is very straightforward. Here's a display logging into the highlighted guest: Last login: Mon May 21 10:18:16 2012 from dhcp-adc-twvpn- Oracle Corporation SunOS 5.11 11.0 November 2011 sewr@atl-sewr-pool-152:~$ uname -a SunOS atl-sewr-pool-152 5.11 11.0 sun4v sparc SUNW,SPARC-Enterprise-T5220 sewr@atl-sewr-pool-152:~$ cat /etc/release Oracle Solaris 11 11/11 SPARC Copyright (c) 1983, 2011, Oracle and/or its affiliates. All rights reserved. Assembled 18 October 2011 sewr@atl-sewr-pool-152:~$ sudo virtinfo -ct Password: Domain role: LDoms guest Control domain: atl-sewr-24 sewr@atl-sewr-pool-152:~$ That's running the GA version of Solaris 11, so I probably should update that some time too. Note the use of the virtinfo -ct command that lets the guest get information about the hosting environment. Summary You can mix and match versions of Solaris in logical domains. All the different combinations work: Solaris 10 and/or Solaris 11 control and service domains with Solaris 10 and/or Solaris 11 guests. Mixing different guest OS levels on the same server is one of the traditional reasons for using virtual machines in the first place since virtual machines were invented some 40 years ago, used to run production and test systems in parallel while upgrading OS levels. This can easily be done with Oracle VM Server for SPARC (Logical Domains).

    Read the article

  • What changes were made to a document

    - by Daniel Moth
    Part of my job is writing functional specs. Due to the inevitable iterative and incremental nature of software design/development, these specs need to be updated with additions/deletions/changes over a period of time. When the time comes for a developer to implement features or update their design document (or a tester to test the feature or update their test specs) they need to be doing that against the latest spec. The problem is that if they have reviewed this document already, they need a quick way to find the delta from the last time they reviewed it to see what changes exist and how their existing plans may be affected (instead of having to read the entire document again). Doing that is very easy assuming your Word documents are hosted on SharePoint. 1. Every time you review a document note the SharePoint version and/or date (if it is a printed copy, make sure your printout includes the date in the footer – all my specs do) 2. When you need to see what changed, open the document (make sure you are not using a cached or local offline copy) and on the ribbon go to the "Review" tab and then  click on the "Compare" button. 3. Click on the "Specific Version…" option. In the dialog that pops up pick the last version you reviewed and click the "Compare" button. [TIP for authors: before checkin of your document, always compare against the "Last Version" on the SharePoint so you can add appropriate more complete check in comments] 4. What you see now is that in addition to the document you have open, two other documents just opened up. One is in the background (flashing on your task bar) – close that one as it is the old version. 5. The other document is in the foreground and contains all the changes between the old version and the latest one. Be sure not to make edits to this document, use it only for reading the changes. To find all the changes, on the ribbon under the "Review" tab, click on the "Reviewing Pane" to open the reviewing pane on the left. You can now click on each pink change to see what it is. 6. When you are done reviewing changes close the document and don't save any changes (remember if you want to make edits/additions/comments make them in the original document which is still open). And now I have a URL to point to people that keep asking about this – enjoy  :-) Comments about this post welcome at the original blog.

    Read the article

  • Configurable Objects - Introduction

    - by Anthony Shorten
    One of the interesting facilities in the framework is Configurable Object functionality (it is also known as Task Optimization and also known as Cool Tools). The idea is that any implementation can create their own views of the base product objects and services and implement functionality against those new views. For example, in Oracle Utilities Customer Care and Billing, there is a Person object. That object is used to store and manage information about individuals as well as companies. In the base product you would use the Person Maintenance screen and fill in some of the screen when you wanted to register or maintain and individual as well and fill out other parts of the screen when you wanted to register or maintain a company. This can be somewhat confusing to some customers. Using Configurable Objects this can be simplified. A business object can be created that is a view of the any object. For example, you could create a Human business object which would cover the aspects of the Person object pertaining to an individual and a Company business object to cover the aspects unique to a company. Even the tag names (i.e. Field Names) in the object can be changed to be more what the implementation is familiar with. The object can also restructure the object. For example, a common identifier for an individual in the USA is the Social Security number, this value is a Person Identifier (as this varies in each country). In the new Human object you can remap the Person Identifier as a Social Security number. To define a Business Object you use a schema editor built into the browser user interface and use a mapping language to setup the business objects. An example of the language is shown below in an extract of the schema for the Human business object. As you can see there are mapping as well as formatting and other tags. This information can be built manually or using a wizard which generates the base structure for you to alter. This is all stored as meta data when saved. Once a Business object is built it can be used as basis for code, other business objects (we support inheritance), called by a screen (called a UI Map) or even as a Web Service. This is just a start with Configurable Objects as you can also create views of base services called Business Services, Service Scripts used for non-object or complex object processing (as well as other things), UI Maps used for screens and Data Areas to reuse definitions across multiple objects. Configurable Objects are powerful and I only really touched on them here. Over the next few months I hope to add lots more entries about them.

    Read the article

  • Win7 is not a tablet OS, no matter what the boys in Redmond think.

    - by John Conwell
    Despite what execs at Microsoft think, Windows 7 is NOT a tablet OS.  Just because you can install some software (or OS) on a device, doesn't mean that device is meant to run that software.  This seems to be the step that the non-engineer execs at Microsoft have seem to not understood.  In order to seamlessly work with a device, the software needs to be designed with that device in mind.  That has been the problem with the Windows PDA platform, the Windows Mobil platform, and now with trying to force fit Windows 7 on a tablet.  Its just not designed for that style of interaction.   Windows is designed to be interacted with via a mouse and keyboard.  In fact, it is brilliant at that.  But, It is NOT designed to be interacted with by your fingers.  And that is why the Windows tablet failed 10 years ago, and why it will fail today.  Its not the hardware's fault like Microsoft claimed 10 years ago.  Its the User Interaction design that failed. And this is why the iPhone and Android OS's work wonderfully on a tablet.  The user interaction was designed for small screens, navigated by big fat fingers.  I love these OS's and how I interact with them.  And when I play with a touch screen Windows 7 device, I am feel like I'm playing with a brittle wana-be.  And its not the hardware's fault.  The touchscreen is very responsive.  I actually like the hardware.  But the OS and the software are just not designed to be interacted with, with my big fat fingers.  In order to be successful, Microsoft needs to start from scratch, and build a platform AND SOFTWARE specifically for use by fingers.  Thats why everyone was so excited when they though Microsoft was going to release the Courier tablet.  Because it looked like a totally different platform.  Something that might actually work.  But Windows 7...I hate to burst your bubble, but you are not a touch platform.

    Read the article

  • Create USB installer from the command line?

    - by j-g-faustus
    I'm trying to create a bootable USB image to install Ubuntu on a new computer. I have done this before following the "create USB drive" instructions for Ubuntu desktop, but I don't have an Ubuntu desktop available. How can I do the same using only the command line? Things I've tried: Create bootable USB on Mac OS X following the ubuntu.com "create USB drive" instructions for Mac: Doesn't boot. usb-creator: According to apt-cache search usb-creator and Wikipedia usb-creator only exists as a graphical tool. "Create manually" instructions at help.ubuntu.com: None of the files and directories described (e.g. casper, filesystem.manifest, menu.lst) exist in the ISO image, and I don't know what has replaced them. unetbootin scripting: Requires X server (graphics support) to run, even when fully scripted. (The command sudo unetbootin lang=en method=diskimage isofile=~/ubuntu-10.10-server-amd64.iso installtype=USB targetdrive=/dev/sdg1 autoinstall=yes gives an error message unetbootin: cannot connect to X server.) Update Also tried GRUB fiddling: Merging information from pendrivelinux.com a related question on the Linux Stackexchange and a grub configuration example I was able to get halfway there - it booted from USB, displayed the grub menu and started the installation, but installation did not complete. For reference, this is the closest I got: sudo su # mount USB pen mount /dev/sd[X]1 /media/usb # install GRUB grub-install --force --no-floppy --root-directory=/media/usb /dev/sd[X] # copy ISO image to USB cp ~/ubuntu-10.10-server-amd64.iso /media/usb # mount ISO image, copy existing grub.cfg mount ~/ubuntu-10.10-server-amd64.iso /media/iso/ -o loop cp /media/iso/boot/grub/grub.cfg /media/usb/boot/grub/ I then edited /media/usb/boot/grub.cfg to add an .iso loopback, example grub entry: menuentry "Install Ubuntu Server" { set gfxpayload=keep loopback loop /ubuntu-10.10-server-amd64.iso linux (loop)/install/vmlinuz file=(loop)/preseed/ubuntu-server.seed iso-scan/filename=/ubuntu-10.10-server-amd64.iso quiet -- initrd (loop)/install/initrd.gz } When booting from USB, this would give me the Grub boot menu and start the installer, but the installer gave up after a couple of screens complaining that it couldn't find the CD-ROM drive. (Naturally, as the box I'm installing on doesn't have an optical drive.) I resolved this particular issue by giving up and doing the "create USB drive" routine using the Ubuntu Live desktop CD (on a computer that does have an optical drive), then the USB install works. But I expect that there is some way to do this from the command line of an Ubuntu system without X server and without an optical drive, so the question still stands. Does anyone know how?

    Read the article

  • How much freedom should a programmer have in choosing a language and framework?

    - by Spencer
    I started working at a company that is primarily a C# oriented. We have a few people who like Java and JRuby, but a majority of programmers here like C#. I was hired because I have a lot of experience building web applications and because I lean towards newer technologies like JRuby on Rails or nodejs. I have recently started on a project building a web application with a focus on getting a lot of stuff done in a short amount of time. The software lead has dictated that I use mvc4 instead of rails. That might be OK, except I don't know mvc4, I don't know C# and I am the only one responsible for creating the web application server and front-end UI. Wouldn't it make sense to use a framework that I already know extremely well (Rails) instead of using mvc4? The two reasons behind the decision was that the tech lead doesn't know Jruby/rails and there would be no way to reuse the code. Counter arguments: He won't be contributing to the code and is frankly, not needed on this project. So, it doesn't really matter if he knows JRuby/rails or not. We actually can reuse the code since we have a lot of java apps that JRuby can pull code from and vice-versa. In fact, he has dedicated some resources to convert a Java library to C#, instead of just running the Java library on the JRuby on Rails app. All because he doesn't like Java or JRuby I have built many web applications, but using something unfamiliar is causing some spin-up and I am unable to build an awesome application in as short of a time that I'm used to. This would be fine, learning new technologies is important in this field. The problem is, for this project, we need to get a lot done in a short period of time. At what point should a developer be allowed to choose his tools? Is this dependent on the company? Does my company suck or is this considered normal? Do greener pastures exist? Am I looking at this the wrong way? Bonus: Should I just keep my head down and move along at a snails pace, or defy orders and go with what I know in order to make this project more successful? Edit: I had actually created a fully function rails application (on my own time) and showed it to the team and it did not seem to matter. I am currently porting it to mvc4 (slowly).

    Read the article

  • Tuxedo Load Balancing

    - by Todd Little
    A question I often receive is how does Tuxedo perform load balancing.  This is often asked by customers that see an imbalance in the number of requests handled by servers offering a specific service. First of all let me say that Tuxedo really does load or request optimization instead of load balancing.  What I mean by that is that Tuxedo doesn't attempt to ensure that all servers offering a specific service get the same number of requests, but instead attempts to ensure that requests are processed in the least amount of time.   Simple round robin "load balancing" can be employed to ensure that all servers for a particular service are given the same number of requests.  But the question I ask is, "to what benefit"?  Instead Tuxedo scans the queues (which may or may not correspond to servers based upon SSSQ - Single Server Single Queue or MSSQ - Multiple Server Single Queue) to determine on which queue a request should be placed.  The scan is always performed in the same order and during the scan if a queue is empty the request is immediately placed on that queue and request routing is done.  However, should all the queues be busy, meaning that requests are currently being processed, Tuxedo chooses the queue with the least amount of "work" queued to it where work is the sum of all the requests queued weighted by their "load" value as defined in the UBBCONFIG file.  What this means is that under light loads, only the first few queues (servers) process all the requests as an empty queue is often found before reaching the end of the scan.  Thus the first few servers in the queue handle most of the requests.  While this sounds non-optimal, in fact it capitalizes on the underlying operating systems and hardware behavior to produce the best possible performance.  Round Robin scheduling would spread the requests across all the available servers and thus require all of them to be in memory, and likely not share much in the way of hardware or memory caches.  Tuxedo's system maximizes the various caches and thus optimizes overall performance.  Hopefully this makes sense and now explains why you may see a few servers handling most of the requests.  Under heavy load, meaning enough load to keep all servers that can handle a request busy, you should see a relatively equal number of requests processed.  Next post I'll try and cover how this applies to servers in a clustered (MP) environment because the load balancing there is a little more complicated. Regards,Todd LittleOracle Tuxedo Chief Architect

    Read the article

  • Why no more macro languages?

    - by Muhammad Alkarouri
    In this answer to a previous question of mine about scripting languages suitability as shells, DigitalRoss identifies the difference between the macro languages and the "parsed typed" languages in terms of string treatment as the main reason that scripting languages are not suitable for shell purposes. Macro languages include nroff and m4 for example. What are the design decisions (or compromises) needed to create a macro programming language? And why are most of the mainstream languages parsed rather than macro? This very similar question (and the accepted answer) covers fairly well why the parsed typed languages, take C for example, suffer from the use of macros. I believe my question here covers different grounds: Macro languages or those working on a textual level are not wholly failures. Arguably, they include bash, Tcl and other shell languages. And they work in a specific niche such as shells as explained in my links above. Even m4 had a fairly long time of success, and some of the web template languages can be regarded as macro languages. It is quite possible that macros and parsed typing do not go well together and that is why macros "break" common languages. In the answer to the linked question, a macro like #define TWO 1+1 would have been covered by the common rules of the language rather than conflicting with those of the host language. And issues like "macros are not typed" and "code doesn't compile" are not relevant in the context of a language designed as untyped and interpreted with little concern for efficiency. The question about the design decisions needed to create a macro language pertain to a hobby project which I am currently working on on designing a new shell. Taking the previous question in context would clarify the difference between adding macros to a parsed language and my objective. I hope the clarification shows that the question linked doesn't cover this question, which is two parts: If I want to create a macro language (for a shell or a web template, for example), what limitations and compromises (and guidelines, if exist) need to be done? (Probably answerable by a link or reference) Why have no macro languages succeed in becoming mainstream except in particular niches? What makes typed languages successful in large programming, while "stringly-typed" languages succeed in shells and one-liner like environments?

    Read the article

  • Looking for tips on managing complexity with SCM repositories

    - by Philip Regan
    I am a solo developer in my department and I have a lot of individual projects, all created and managed by me. I started using SVN at ProjectLocker via Versions on the Mac a couple years ago when the variety of projects started getting unwieldy. Scenario 1: Now I have a process that is of reasonable complexity it can be broken up into multiple smaller applications and they all share files. In one phase, there is a single shared file—a constants file—that is shared between a Cocoa app and an iPhone app framework. In the second phase, the iPhone app framework will be used to create individual apps of the same ilk—controller classes and what not will all be the same—but with different content in each. The problem that I am running across is that the file in the first phase is in one repository with the application that started it, and the app framework is in a second, separate repository. Scenario 2: I have another application framework that partially relies on code from an open source project. This is all internal, non-commerical work, but again, the application framework is going to be used to create a variety of unique products and processes. So, now I have an internally managed repository and an externally managed one out of my control. I make little changes to the open source code to meet the needs of my framework when there is an update I download, but I never commit back into the external repository (though, now that I think about it, I don't think I'm committing it to mine either. Oops). The Problem I have all of this set up on my production Mac quite nicely, but duplicating and subsequently maintaining that environment on my laptop has been challenging. For Scenario 1, I've thought of merging these two projects together into the same repository because they are, for all intents and purposes inextricably linked. But, Scenario 2, I think I'm stuck just managing files as best I can. The Question I'm wondering if anyone has any tips on how to manage either of these situations, as well as other complex SCM scenarios when it comes to linking various files from various repositories together. My familiarity with SVN only comes from my work with Versions. It's been great, but I'm a little out of my depth here.

    Read the article

  • Enterprise 2.0 Conference recap

    - by kellsey.ruppel
    We had a great week in Boston attending the Enterprise 2.0 Conference. We learned a lot from industry thought leaders and had a chance to speak with a lot of different folks about social and collaboration technologies and trends.  Of all the conferences we attend, this one definitely has a different “feel”. It seems like the attendees are younger, they dress hipper, and there is much more livelihood all around. A few of the sessions addressed this, as the "millenials" or Generation Y, have been using Web 2.0 tools, such as Facebook and Twitter for many years now, and as they are entering the workforce they are expecting similar tools to be a part of how they accomplish their job tasks. It's important to note that it's not just Millenials that are expecting these technologies, as workers young and old alike benefit from social and collaboration tools. I’ve highlighted some of the takeaways I had, as well as a reaction from John Brunswick, who helped us in staffing the booth. Giving your employees choices is empowering, but if there is no course of action or plan, it’s useless. There is no such thing as collaboration without a goal. In a few years, social will become a feature in the “platform”, a component of collaboration. Social will become part of the norm – just like email is expected when you start a job at a company, Social will be too. 1 in 3 of your employees are using tools your company doesn't sanction (how scary is this?!) 25,000 pieces of content are created every second. Context is king. Social tools help us navigate and manage the complexities we face with information overload. We need to design products for the way people work. Consumerization of the enterprise - bringing social tools like Facebook to the organization. From John Brunswick: "The conference had solid attendance, standing as a testament to organizations making a concerted effort to understand what social tools exist to support their businesses.  Many vendors were narrowly focused and people we pleasantly surprised at the breadth of capability provided by Oracle WebCenter.  People seemed to feel that it just made sense that social technology provides the most benefit when presented in the context of key business data." Did you attend the conference? What were some of your key takeaways?

    Read the article

  • Using the jQuery UI Library in a MVC 3 Application to Build a Dialog Form

    - by ChrisD
    Using a simulated dialog window is a nice way to handle inline data editing. The jQuery UI has a UI widget for a dialog window that makes it easy to get up and running with it in your application. With the release of ASP.NET MVC 3, Microsoft included the jQuery UI scripts and files in the MVC 3 project templates for Visual Studio. With the release of the MVC 3 Tools Update, Microsoft implemented the inclusion of those with NuGet as packages. That means we can get up and running using the latest version of the jQuery UI with minimal effort. To the code! Another that might interested you about JQuery Mobile and ASP.NET MVC 3 with C#. If you are starting with a new MVC 3 application and have the Tools Update then you are a NuGet update and a <link> and <script> tag away from adding the jQuery UI to your project. If you are using an existing MVC project you can still get the jQuery UI library added to your project via NuGet and then add the link and script tags. Assuming that you have pulled down the latest version (at the time of this publish it was 1.8.13) you can add the following link and script tags to your <head> tag: < link href = "@Url.Content(" ~ / Content / themes / base / jquery . ui . all . css ")" rel = "Stylesheet" type = "text/css" /> < script src = "@Url.Content(" ~ / Scripts / jquery-ui-1 . 8 . 13 . min . js ")" type = "text/javascript" ></ script > The jQuery UI library relies upon the CSS scripts and some image files to handle rendering of its widgets (you can choose a different theme or role your own if you like). Adding these to the stock _Layout.cshtml file results in the following markup: <!DOCTYPE html> < html > < head >     < meta charset = "utf-8" />     < title > @ViewBag.Title </ title >     < link href = "@Url.Content(" ~ / Content / Site . css ")" rel = "stylesheet" type = "text/css" />     <link href="@Url.Content("~/Content/themes/base/jquery.ui.all.css")" rel="Stylesheet" type="text/css" />     <script src="@Url.Content("~/Scripts/jquery-1.5.1.min.js")" type="text/javascript"></script>     <script src="@Url.Content("~/Scripts/modernizr-1.7.min . js ")" type = "text/javascript" ></ script >     < script src = "@Url.Content(" ~ / Scripts / jquery-ui-1 . 8 . 13 . min . js ")" type = "text/javascript" ></ script > </ head > < body >     @RenderBody() </ body > </ html > Our example will involve building a list of notes with an id, title and description. Each note can be edited and new notes can be added. The user will never have to leave the single page of notes to manage the note data. The add and edit forms will be delivered in a jQuery UI dialog widget and the note list content will get reloaded via an AJAX call after each change to the list. To begin, we need to craft a model and a data management class. We will do this so we can simulate data storage and get a feel for the workflow of the user experience. The first class named Note will have properties to represent our data model. namespace Website . Models {     public class Note     {         public int Id { get ; set ; }         public string Title { get ; set ; }         public string Body { get ; set ; }     } } The second class named NoteManager will be used to set up our simulated data storage and provide methods for querying and updating the data. We will take a look at the class content as a whole and then walk through each method after. using System . Collections . ObjectModel ; using System . Linq ; using System . Web ; namespace Website . Models {     public class NoteManager     {         public Collection < Note > Notes         {             get             {                 if ( HttpRuntime . Cache [ "Notes" ] == null )                     this . loadInitialData ();                 return ( Collection < Note >) HttpRuntime . Cache [ "Notes" ];             }         }         private void loadInitialData ()         {             var notes = new Collection < Note >();             notes . Add ( new Note                           {                               Id = 1 ,                               Title = "Set DVR for Sunday" ,                               Body = "Don't forget to record Game of Thrones!"                           });             notes . Add ( new Note                           {                               Id = 2 ,                               Title = "Read MVC article" ,                               Body = "Check out the new iwantmymvc.com post"                           });             notes . Add ( new Note                           {                               Id = 3 ,                               Title = "Pick up kid" ,                               Body = "Daughter out of school at 1:30pm on Thursday. Don't forget!"                           });             notes . Add ( new Note                           {                               Id = 4 ,                               Title = "Paint" ,                               Body = "Finish the 2nd coat in the bathroom"                           });             HttpRuntime . Cache [ "Notes" ] = notes ;         }         public Collection < Note > GetAll ()         {             return Notes ;         }         public Note GetById ( int id )         {             return Notes . Where ( i => i . Id == id ). FirstOrDefault ();         }         public int Save ( Note item )         {             if ( item . Id <= 0 )                 return saveAsNew ( item );             var existingNote = Notes . Where ( i => i . Id == item . Id ). FirstOrDefault ();             existingNote . Title = item . Title ;             existingNote . Body = item . Body ;             return existingNote . Id ;         }         private int saveAsNew ( Note item )         {             item . Id = Notes . Count + 1 ;             Notes . Add ( item );             return item . Id ;         }     } } The class has a property named Notes that is read only and handles instantiating a collection of Note objects in the runtime cache if it doesn't exist, and then returns the collection from the cache. This property is there to give us a simulated storage so that we didn't have to add a full blown database (beyond the scope of this post). The private method loadInitialData handles pre-filling the collection of Note objects with some initial data and stuffs them into the cache. Both of these chunks of code would be refactored out with a move to a real means of data storage. The GetAll and GetById methods access our simulated data storage to return all of our notes or a specific note by id. The Save method takes in a Note object, checks to see if it has an Id less than or equal to zero (we assume that an Id that is not greater than zero represents a note that is new) and if so, calls the private method saveAsNew . If the Note item sent in has an Id , the code finds that Note in the simulated storage, updates the Title and Description , and returns the Id value. The saveAsNew method sets the Id , adds it to the simulated storage, and returns the Id value. The increment of the Id is simulated here by getting the current count of the note collection and adding 1 to it. The setting of the Id is the only other chunk of code that would be refactored out when moving to a different data storage approach. With our model and data manager code in place we can turn our attention to the controller and views. We can do all of our work in a single controller. If we use a HomeController , we can add an action method named Index that will return our main view. An action method named List will get all of our Note objects from our manager and return a partial view. We will use some jQuery to make an AJAX call to that action method and update our main view with the partial view content returned. Since the jQuery AJAX call will cache the call to the content in Internet Explorer by default (a setting in jQuery), we will decorate the List, Create and Edit action methods with the OutputCache attribute and a duration of 0. This will send the no-cache flag back in the header of the content to the browser and jQuery will pick that up and not cache the AJAX call. The Create action method instantiates a new Note model object and returns a partial view, specifying the NoteForm.cshtml view file and passing in the model. The NoteForm view is used for the add and edit functionality. The Edit action method takes in the Id of the note to be edited, loads the Note model object based on that Id , and does the same return of the partial view as the Create method. The Save method takes in the posted Note object and sends it to the manager to save. It is decorated with the HttpPost attribute to ensure that it will only be available via a POST. It returns a Json object with a property named Success that can be used by the UX to verify everything went well (we won't use that in our example). Both the add and edit actions in the UX will post to the Save action method, allowing us to reduce the amount of unique jQuery we need to write in our view. The contents of the HomeController.cs file: using System . Web . Mvc ; using Website . Models ; namespace Website . Controllers {     public class HomeController : Controller     {         public ActionResult Index ()         {             return View ();         }         [ OutputCache ( Duration = 0 )]         public ActionResult List ()         {             var manager = new NoteManager ();             var model = manager . GetAll ();             return PartialView ( model );         }         [ OutputCache ( Duration = 0 )]         public ActionResult Create ()         {             var model = new Note ();             return PartialView ( "NoteForm" , model );         }         [ OutputCache ( Duration = 0 )]         public ActionResult Edit ( int id )         {             var manager = new NoteManager ();             var model = manager . GetById ( id );             return PartialView ( "NoteForm" , model );         }         [ HttpPost ]         public JsonResult Save ( Note note )         {             var manager = new NoteManager ();             var noteId = manager . Save ( note );             return Json ( new { Success = noteId > 0 });         }     } } The view for the note form, NoteForm.cshtml , looks like so: @model Website . Models . Note @using ( Html . BeginForm ( "Save" , "Home" , FormMethod . Post , new { id = "NoteForm" })) { @Html . Hidden ( "Id" ) < label class = "Title" >     < span > Title < /span><br / >     @Html . TextBox ( "Title" ) < /label> <label class="Body">     <span>Body</ span >< br />     @Html . TextArea ( "Body" ) < /label> } It is a strongly typed view for our Note model class. We give the <form> element an id attribute so that we can reference it via jQuery. The <label> and <span> tags give our UX some structure that we can style with some CSS. The List.cshtml view is used to render out a <ul> element with all of our notes. @model IEnumerable < Website . Models . Note > < ul class = "NotesList" >     @foreach ( var note in Model )     {     < li >         @note . Title < br />         @note . Body < br />         < span class = "EditLink ButtonLink" noteid = "@note.Id" > Edit < /span>     </ li >     } < /ul> This view is strongly typed as well. It includes a <span> tag that we will use as an edit button. We add a custom attribute named noteid to the <span> tag that we can use in our jQuery to identify the Id of the note object we want to edit. The view, Index.cshtml , contains a bit of html block structure and all of our jQuery logic code. @ {     ViewBag . Title = "Index" ; } < h2 > Notes < /h2> <div id="NoteListBlock"></ div > < span class = "AddLink ButtonLink" > Add New Note < /span> <div id="NoteDialog" title="" class="Hidden"></ div > < script type = "text/javascript" >     $ ( function () {         $ ( "#NoteDialog" ). dialog ({             autoOpen : false , width : 400 , height : 330 , modal : true ,             buttons : {                 "Save" : function () {                     $ . post ( "/Home/Save" ,                         $ ( "#NoteForm" ). serialize (),                         function () {                             $ ( "#NoteDialog" ). dialog ( "close" );                             LoadList ();                         });                 },                 Cancel : function () { $ ( this ). dialog ( "close" ); }             }         });         $ ( ".EditLink" ). live ( "click" , function () {             var id = $ ( this ). attr ( "noteid" );             $ ( "#NoteDialog" ). html ( "" )                 . dialog ( "option" , "title" , "Edit Note" )                 . load ( "/Home/Edit/" + id , function () { $ ( "#NoteDialog" ). dialog ( "open" ); });         });         $ ( ".AddLink" ). click ( function () {             $ ( "#NoteDialog" ). html ( "" )                 . dialog ( "option" , "title" , "Add Note" )                 . load ( "/Home/Create" , function () { $ ( "#NoteDialog" ). dialog ( "open" ); });         });         LoadList ();     });     function LoadList () {         $ ( "#NoteListBlock" ). load ( "/Home/List" );     } < /script> The <div> tag with the id attribute of "NoteListBlock" is used as a container target for the load of the partial view content of our List action method. It starts out empty and will get loaded with content via jQuery once the DOM is loaded. The <div> tag with the id attribute of "NoteDialog" is the element for our dialog widget. The jQuery UI library will use the title attribute for the text in the dialog widget top header bar. We start out with it empty here and will dynamically change the text via jQuery based on the request to either add or edit a note. This <div> tag is given a CSS class named "Hidden" that will set the display:none style on the element. Since our call to the jQuery UI method to make the element a dialog widget will occur in the jQuery document ready code block, the end user will see the <div> element rendered in their browser as the page renders and then it will hide after that jQuery call. Adding the display:hidden to the <div> element via CSS will ensure that it is never rendered until the user triggers the request to open the dialog. The jQuery document load block contains the setup for the dialog node, click event bindings for the edit and add links, and a call to a JavaScript function called LoadList that handles the AJAX call to the List action method. The .dialog() method is called on the "NoteDialog" <div> element and the options are set for the dialog widget. The buttons option defines 2 buttons and their click actions. The first is the "Save" button (the text in quotations is used as the text for the button) that will do an AJAX post to our Save action method and send the serialized form data from the note form (targeted with the id attribute "NoteForm"). Upon completion it will close the dialog widget and call the LoadList to update the UX without a redirect. The "Cancel" button simply closes the dialog widget. The .live() method handles binding a function to the "click" event on all elements with the CSS class named EditLink . We use the .live() method because it will catch and bind our function to elements even as the DOM changes. Since we will be constantly changing the note list as we add and edit we want to ensure that the edit links get wired up with click events. The function for the click event on the edit links gets the noteid attribute and stores it in a local variable. Then it clears out the HTML in the dialog element (to ensure a fresh start), calls the .dialog() method and sets the "title" option (this sets the title attribute value), and then calls the .load() AJAX method to hit our Edit action method and inject the returned content into the "NoteDialog" <div> element. Once the .load() method is complete it opens the dialog widget. The click event binding for the add link is similar to the edit, only we don't need to get the id value and we load the Create action method. This binding is done via the .click() method because it will only be bound on the initial load of the page. The add button will always exist. Finally, we toss in some CSS in the Content/Site.css file to style our form and the add/edit links. . ButtonLink { color : Blue ; cursor : pointer ; } . ButtonLink : hover { text - decoration : underline ; } . Hidden { display : none ; } #NoteForm label { display:block; margin-bottom:6px; } #NoteForm label > span { font-weight:bold; } #NoteForm input[type=text] { width:350px; } #NoteForm textarea { width:350px; height:80px; } With all of our code in place we can do an F5 and see our list of notes: If we click on an edit link we will get the dialog widget with the correct note data loaded: And if we click on the add new note link we will get the dialog widget with the empty form: The end result of our solution tree for our sample:

    Read the article

  • SQL SERVER – A Brief Note on SET TEXTSIZE

    - by pinaldave
    Here is a small conversation I received. I thought though an old topic, indeed a thought provoking for the moment. Question: Is there any difference between LEFT function and SET TEXTSIZE? I really like this small but interesting question. The question does not specify the difference between usage or performance. Anyway we will quickly take a look at how TEXTSIZE works. You can run the following script to see how LEFT and SET TEXTSIZE works. USE TempDB GO -- Create TestTable CREATE TABLE MyTable (ID INT, MyText VARCHAR(MAX)) GO INSERT MyTable (ID, MyText) VALUES(1, REPLICATE('1234567890', 100)) GO -- Select Data SELECT ID, MyText FROM MyTable GO -- Using Left SELECT ID, LEFT(MyText, 10) MyText FROM MyTable GO -- Set TextSize SET TEXTSIZE 10; SELECT ID, MyText FROM MyTable; SET TEXTSIZE 2147483647 GO -- Clean up DROP TABLE MyTable GO Now let us see the usage result which we receive from both of the example. If you are going to ask what you should do – I really do not know. I can tell you where I will use either of the same. LEFT seems to be easy to use but again if you like to do extra work related to SET TEXTSIZE go for it. Here is how I will use SET TEXTSIZE. If I am selecting data from in my SSMS for testing or any other non production related work from a large table which has lots of columns with varchar data, I will consider using this statement to reduce the amount of the data which is retrieved in the result set. In simple word, for testing purpose I will use it. On the production server, there should be a specific reason to use the same. Here is my candid opinion – I do not think they can be directly comparable even though both of them give the exact same result. LEFT is applicable only on the column of a single SELECT statement. where it is used but it SET TEXTSIZE applies to all the columns in the SELECT and follow up SELECT statements till the SET TEXTSIZE is not modified again in the session. Uncomparable! I hope this sample example gives you idea how to use SET TEXTSIZE in your daily use. I would like to know your opinion about how and when do you use this feature. Please leave a comment. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

    Read the article

  • Development-led security vs administration-led security in a software product?

    - by haylem
    There are cases where you have the opportunity, as a developer, to enforce stricter security features and protections on a software, though they could very well be managed at an environmental level (ie, the operating system would take care of it). Where would you say you draw the line, and what elements do you factor in your decision? Concrete Examples User Management is the OS's responsibility Not exactly meant as a security feature, but in a similar case Google Chrome used to not allow separate profiles. The invoked reason (though it now supports multiple profiles for a same OS user) used to be that user management was the operating system's responsibility. Disabling Web-Form Fields A recurrent request I see addressed online is to have auto-completion be disabled on form fields. Auto-completion didn't exist in old browsers, and was a welcome feature at the time it was introduced for people who needed to fill in forms often. But it also brought in some security concerns, and so some browsers started to implement, on top of the (obviously needed) setting in their own preference/customization panel, an autocomplete attribute for form or input fields. And this has now been introduced into the upcoming HTML5 standard. For browsers that do not listen to this attribute, strange hacks* are offered, like generating unique IDs and names for fields to avoid them from being suggested in future forms (which comes with another herd of issues, like polluting your local auto-fill cache and not preventing a password from being stored in it, but instead probably duplicating its occurences). In this particular case, and others, I'd argue that this is a user setting and that it's the user's desire and the user's responsibility to enable or disable auto-fill (by disabling the feature altogether). And if it is based on an internal policy and security requirement in a corporate environment, then substitute the user for the administrator in the above. I assume it could be counter-argued that the user may want to access non-critical applications (or sites) with this handy feature enabled, and critical applications with this feature disabled. But then I'd think that's what security zones are for (in some browsers), or the sign that you need a more secure (and dedicated) environment / account to use these applications. * I obviously don't deny the ingeniosity of the people who were forced to find workarounds, just the necessity of said workarounds. Questions That was a tad long-winded, so I guess my questions are: Would you in general consider it to be the application's (hence, the developer's) responsiblity? Where do you draw the line, if not in the "general" case?

    Read the article

  • Design pattern for an ASP.NET project using Entity Framework

    - by MPelletier
    I'm building a website in ASP.NET (Web Forms) on top of an engine with business rules (which basically resides in a separate DLL), connected to a database mapped with Entity Framework (in a 3rd, separate project). I designed the Engine first, which has an Entity Framework context, and then went on to work on the website, which presents various reports. I believe I made a terrible design mistake in that the website has its own context (which sounded normal at first). I present this mockup of the engine and a report page's code behind: Engine (in separate DLL): public Engine { DatabaseEntities _engineContext; public Engine() { // Connection string and procedure managed in DB layer _engineContext = DatabaseEntities.Connect(); } public ChangeSomeEntity(SomeEntity someEntity, int newValue) { //Suppose there's some validation too, non trivial stuff SomeEntity.Value = newValue; _engineContext.SaveChanges(); } } And report: public partial class MyReport : Page { Engine _engine; DatabaseEntities _webpageContext; public MyReport() { _engine = new Engine(); _databaseContext = DatabaseEntities.Connect(); } public void ChangeSomeEntityButton_Clicked(object sender, EventArgs e) { SomeEntity someEntity; //Wrong way: //Get the entity from the webpage context someEntity = _webpageContext.SomeEntities.Single(s => s.Id == SomeEntityId); //Send the entity from _webpageContext to the engine _engine.ChangeSomeEntity(someEntity, SomeEntityNewValue); // <- oops, conflict of context //Right(?) way: //Get the entity from the engine context someEntity = _engine.GetSomeEntity(SomeEntityId); //undefined above //Send the entity from the engine's context to the engine _engine.ChangeSomeEntity(someEntity, SomeEntityNewValue); // <- oops, conflict of context } } Because the webpage has its own context, giving the Engine an entity from a different context will cause an error. I happen to know not to do that, to only give the Engine entities from its own context. But this is a very error-prone design. I see the error of my ways now. I just don't know the right path. I'm considering: Creating the connection in the Engine and passing it off to the webpage. Always instantiate an Engine, make its context accessible from a property, sharing it. Possible problems: other conflicts? Slow? Concurrency issues if I want to expand to AJAX? Creating the connection from the webpage and passing it off to the Engine (I believe that's dependency injection?) Only talking through ID's. Creates redundancy, not always practical, sounds archaic. But at the same time, I already recuperate stuff from the page as ID's that I need to fetch anyways. What would be best compromise here for safety, ease-of-use and understanding, stability, and speed?

    Read the article

  • How to implement a simple bullet trajectory

    - by AirieFenix
    I searched and searched and although it's a fair simple question, I don't find the proper answer but general ideas (which I already have). I have a top-down game and I want to implement a gun which shoots bullets that follow a simple path (no physics nor change of trajectory, just go from A to B thing). a: vector of the position of the gun/player. b: vector of the mouse position (cross-hair). w: the vector of the bullet's trajectory. So, w=b-a. And the position of the bullet = [x=x0+speed*time*normalized w.x , y=y0+speed*time * normalized w.y]. I have the constructor: public Shot(int shipX, int shipY, int mouseX, int mouseY) { //I get mouse with Gdx.input.getX()/getY() ... this.shotTime = TimeUtils.millis(); this.posX = shipX; this.posY = shipY; //I used aVector = aVector.nor() here before but for some reason didn't work float tmp = (float) (Math.pow(mouseX-shipX, 2) + Math.pow(mouseY-shipY, 2)); tmp = (float) Math.sqrt(Math.abs(tmp)); this.vecX = (mouseX-shipX)/tmp; this.vecY = (mouseY-shipY)/tmp; } And here I update the position and draw the shot: public void drawShot(SpriteBatch batch) { this.lifeTime = TimeUtils.millis() - this.shotTime; //position = positionBefore + v*t this.posX = this.posX + this.vecX*this.lifeTime*speed*Gdx.graphics.getDeltaTime(); this.posY = this.posY + this.vecY*this.lifeTime*speed*Gdx.graphics.getDeltaTime(); ... } Now, the behavior of the bullet seems very awkward, not going exactly where my mouse is (it's like the mouse is 30px off) and with a random speed. I know I probably need to open the old algebra book from college but I'd like somebody says if I'm in the right direction (or points me to it); if it's a calculation problem, a code problem or both. Also, is it possible that Gdx.input.getX() gives me non-precise position? Because when I draw the cross-hair it also draws off the cursor position. Sorry for the long post and sorry if it's a very basic question. Thanks!

    Read the article

  • What source code organization approach helps improve modularity and API/Implementation separation?

    - by Berin Loritsch
    Few languages are as restrictive as Java with file naming standards and project structure. In that language, the file name must match the public class declared in the file, and the file must live in a directory structure matching the class package. I have mixed feelings about that approach. While I never have to guess where a file lives, there's still a lot of empty directories and artificial constraints. There's several languages that define everything about a class in one file, at least by convention. C#, Python (I think), Ruby, Erlang, etc. The commonality in most these languages is that they are object oriented, although that statement can probably be rebuffed (there is one non-OO language in the list already). Finally, there's quite a few languages mostly in the C family that have a separate header and implementation file. For C I think this makes sense, because it is one of the few ways to separate the API interface from implementations. With C it seems that feature is used to promote modularity. Yet, with C++ the way header and implementation files are split seems rather forced. You don't get the same clean API separation that you do with C, and you are forced to include some private details in the header you would rather keep only in the implementation. There's quite a few languages that have a concept that overlaps with interfaces like Java, C#, Go, etc. Some languages use what feels like a hack to provide the same concept like C# using pure virtual abstract classes. Still others don't really have an interface concept and rely on "duck" typing--for example Ruby. Ruby has modules, but those are more along the lines of mixing in behaviors to a class than they are for defining how to interact with a class. In OO terms, interfaces are a powerful way to provide separation between an API client and an API implementation. So to hurry up and ask the question, from a personal experience point of view: Does separation of header and implementation help you write more modular code, or does it get in the way? (it helps to specify the language you are referring to) Does the strict file name to class name scheme of Java help maintainability, or is it unnecessary structure for structure's sake? What would you propose to promote good API/Implementation separation and project maintenance, how would you prefer to do it?

    Read the article

  • Dynamic character animation - Using the physics engine or not

    - by Lex Webb
    I'm planning on building a dynamic reactant animation engine for the characters in my 2D Game. I have already built templates for a skeleton based animation system using key frames and interpolation to specify a limbs position at any given moment in time. I am using Farseer physics (an extension of Box2D) in Monogame/XNA in C# My real question lies in how i go about tying this character animation into the physics engine. I have two options: Moving limbs using physics engine - applying a interpolated force to each limb (dynamic body) in order to attempt to get it to its position as donated by the skeleton animation. Moving limbs by simply changing the position of a fixed body - Updating the new position of each limb manually, attempting to take into account physics collisions. Then stepping the physics after the animation to allow for environment interaction. Each of these methods have their distinct advantages and disadvantages. Physics based movement Advantages: Possibly more natural/realistic movement Better interaction with game objects as force applying to objects colliding with characters would be calculated for me. No need to convert to dynamic bodies when reacting to projectiles/death/fighting. Disadvantages: Possible difficulty in calculating correct amount of force to move a limb a certain distance at a constant rate. Underlying character balance system would need to be created that would need to be robust enough to prevent characters falling over at the touch of a feather. Added code complexity and processing time for the above. Static Object movement Advantages: Easy to interpolate movement of limbs between game steps Moving limbs is as simple as applying a rotation to the skeleton bone. Greater control over limbs, wont need to worry about characters falling over as all animation would be pre-defined. Disadvantages: Possible unnatural movement (Depends entirely on my animation skills!) Bad physics collision reactions with physics engine (Dynamic bodies simply slide out of the way of static objects) Need to calculate collisions with physics objects and my limbs myself and apply directional forces to them. Hard to account for slopes/stairs/non standard planes when animating walking/running animations. Need to convert objects to dynamic when reacting to projectile/fighting/death physics objects. The Question! As you can see, i have thought about this extensively, i have also had Google into physics based animation and have found mostly dissertation papers! Which is filling me with sense that it may a lot more advanced than my mathematics skills. My question is mostly subjective based on my findings above/any experience you may have: Which of the above methods should i use when creating my game? I am willing to spend the time to get a physics solution working if you think it would be possible. In the end i want to provide the most satisfying experience for the gamer, as well as a robust and dynamic system i can use to animate pretty much anything i need.

    Read the article

  • What are the tradeoffs for using 'partial view models'?

    - by Kenny Evitt
    I've become aware of an itch due to some non-DRY code pertaining to view model classes in an (ASP.NET) MVC web application and I'm thinking of scratching my itch by organizing code in various 'partial view model' classes. By partial-view-model, I'm referring to a class like a view model class in an analogous way to how partial views are like views, i.e. a way to encapsulate common info and behavior. To strengthen the 'analogy', and to aid in visually organizing the code in my IDE, I was thinking of naming the partial-view-model classes with a _ prefix, e.g. _ParentItemViewModel. As a slightly more concrete example of why I'm thinking along these lines, imagine that I have a domain-model-entity class ParentItem and the user-friendly descriptive text that identifies these items to users is complex enough that I'd like to encapsulate that code in a method in a _ParentItemViewModel class, for which I can then include an object or a collection of objects of that class in all the view model classes for all the views that need to include a reference to a parent item, e.g. ChildItemViewModel can have a ParentItem property of the _ParentItemViewModel class type, so that in my ChildItemView view, I can use @Model.ParentItem.UserFriendlyDescription as desired, like breadcrumbs, links, etc. Edited 2014-02-06 09:56 -05 As a second example, imagine that I have entity classes SomeKindOfBatch, SomeKindOfBatchDetail, and SomeKindOfBatchDetailEvent, and a view model class and at least one view for each of those entities. Also, the example application covers a lot more than just some-kind-of-batches, so that it wouldn't really be useful or sensible to include info about a specific some-kind-of-batch in all of the project view model classes. But, like the above example, I have some code, say for generating a string for identifying a some-kind-of-batch in a user-friendly way, and I'd like to be able to use that in several views, say as breadcrumb text or text for a link. As a third example, I'll describe another pattern I'm currently using. I have a Contact entity class, but it's a fat class, with dozens of properties, and at least a dozen references to other fat classes. However, a lot of view model classes need properties for referencing a specific contact and most of those need other properties for collections of contacts, e.g. possible contacts to be referenced for some kind of relationship. Most of these view model classes only need a small fraction of all of the available contact info, basically just an ID and some kind of user-friendly description (i.e. a friendly name). It seems to be pretty useful to have a 'partial view model' class for contacts that all of these other view model classes can use. Maybe I'm just misunderstanding 'view model class' – I understand a view model class as always corresponding to a view. But maybe I'm assuming too much.

    Read the article

  • Is throwing an error in unpredictable subclass-specific circumstances a violation of LSP?

    - by Motti Strom
    Say, I wanted to create a Java List<String> (see spec) implementation that uses a complex subsystem, such as a database or file system, for its store so that it becomes a simple persistent collection rather than an basic in-memory one. (We're limiting it specifically to a List of Strings for the purposes of discussion, but it could extended to automatically de-/serialise any object, with some help. We can also provide persistent Sets, Maps and so on in this way too.) So here's a skeleton implementation: class DbBackedList implements List<String> { private DbBackedList() {} /** Returns a list, possibly non-empty */ public static getList() { return new DbBackedList(); } public String get(int index) { return Db.getTable().getRow(i).asString(); // may throw DbExceptions! } // add(String), add(int, String), etc. ... } My problem lies with the fact that the underlying DB API may encounter connection errors that are not specified in the List interface that it should throw. My problem is whether this violates Liskov's Substitution Principle (LSP). Bob Martin actually gives an example of a PersistentSet in his paper on LSP that violates LSP. The difference is that his newly-specified Exception there is determined by the inserted value and so is strengthening the precondition. In my case the connection/read error is unpredictable and due to external factors and so is not technically a new precondition, merely an error of circumstance, perhaps like OutOfMemoryError which can occur even when unspecified. In normal circumstances, the new Error/Exception might never be thrown. (The caller could catch if it is aware of the possibility, just as a memory-restricted Java program might specifically catch OOME.) Is this therefore a valid argument for throwing an extra error and can I still claim to be a valid java.util.List (or pick your SDK/language/collection in general) and not in violation of LSP? If this does indeed violate LSP and thus not practically usable, I have provided two less-palatable alternative solutions as answers that you can comment on, see below. Footnote: Use Cases In the simplest case, the goal is to provide a familiar interface for cases when (say) a database is just being used as a persistent list, and allow regular List operations such as search, subList and iteration. Another, more adventurous, use-case is as a slot-in replacement for libraries that work with basic Lists, e.g if we have a third-party task queue that usually works with a plain List: new TaskWorkQueue(new ArrayList<String>()).start() which is susceptible to losing all it's queue in event of a crash, if we just replace this with: new TaskWorkQueue(new DbBackedList()).start() we get a instant persistence and the ability to share the tasks amongst more than one machine. In either case, we could either handle connection/read exceptions that are thrown, perhaps retrying the connection/read first, or allow them to throw and crash the program (e.g. if we can't change the TaskWorkQueue code).

    Read the article

  • StreamInsight 1.0 Released

    - by Roman Schindlauer
    One piece in the set of products offered in SQL Server 2008 R2 that has generated a lot of buzz and interest during its CTP phase is StreamInsight, Microsoft’s platform for Complex Event Processing. Microsoft’s information platform vision provides enterprises with a “complete approach” to managing information assets, enabling all businesses to gain strategic value from information from the desktop to the datacenter to the cloud. And StreamInsight V1 is one essential piece in this spectrum. After more than a year of blood, sweat, tears, and insane amounts of coffee we are proud to release the first version of our Complex Event Processing Framework.   Those of you who have been following our Community Technology Previews (CTPs) throughout last year have already had the possibility to familiarize themselves with the product. Early feedback was not only incredibly positive, but also very constructive and strongly influenced the final feature set. Four notable increments over our last public CTP are: Count windows Non-occurrence detection (Anti-Join) Dynamic query composition at runtime Synchronize time across input streams Additionally, many smaller issues and bugs were addressed. A few APIs slightly changed with respect to the November CTP, but porting your application to RTM should not require a lot of effort.   Here are the (english) bits - choosing the evaluation license during setup lets you already play with this version. Before you install, make sure to uninstall any previous CTP version:   StreamInsight X86StreamInsight X64   Within a few days, we will update our product page and add download links and instructions there as well.   The StreamInsight documentation is provided through a help file as part of the installation as well as through Books Online on MSDN. We also invite you to visit the StreamInsight Blog and the StreamInsight Forum, which is a great place to discuss questions and issues with the community and the development team.   Regards,Roman Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

    Read the article

< Previous Page | 512 513 514 515 516 517 518 519 520 521 522 523  | Next Page >