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  • How do I mount my External HDD with filesystem type errors?

    - by Snuggie
    I am a relatively new Ubuntu user and I am having some difficulty mounting my external 2TB HDD. When I first installed Linux my external HDD was working just fine, however, it has stopped working and I have a lot of important files on there that I need. Before my HDD would automatically mount and no worries. Now, however, it doesn't automatically mount and when I try to manually mount it I keep running into filesystem type errors that I can't seem to get past. Below are images that depict my step by step process of how I am trying to mount my HDD along with the errors I am receiving. If anybody has any idea what I am doing wrong or how to correct the issue I would greatly appreciate it. Step 1) Ensure the computer recognizes my external HDD. pj@PJ:~$ dmesg ... [ 5790.367910] scsi 7:0:0:0: Direct-Access WD My Passport 0748 1022 PQ: 0 ANSI: 6 [ 5790.368278] scsi 7:0:0:1: Enclosure WD SES Device 1022 PQ: 0 ANSI: 6 [ 5790.370122] sd 7:0:0:0: Attached scsi generic sg2 type 0 [ 5790.370310] ses 7:0:0:1: Attached Enclosure device [ 5790.370462] ses 7:0:0:1: Attached scsi generic sg3 type 13 [ 5792.971601] sd 7:0:0:0: [sdb] 3906963456 512-byte logical blocks: (2.00 TB/1.81 TiB) [ 5792.972148] sd 7:0:0:0: [sdb] Write Protect is off [ 5792.972162] sd 7:0:0:0: [sdb] Mode Sense: 47 00 10 08 [ 5792.972591] sd 7:0:0:0: [sdb] No Caching mode page found [ 5792.972605] sd 7:0:0:0: [sdb] Assuming drive cache: write through [ 5792.975235] sd 7:0:0:0: [sdb] No Caching mode page found [ 5792.975249] sd 7:0:0:0: [sdb] Assuming drive cache: write through [ 5792.987504] sdb: sdb1 [ 5792.988900] sd 7:0:0:0: [sdb] No Caching mode page found [ 5792.988911] sd 7:0:0:0: [sdb] Assuming drive cache: write through [ 5792.988920] sd 7:0:0:0: [sdb] Attached SCSI disk Step 2) Check if it mounted properly (it does not) pj@PJ:~$ df -ah Filesystem Size Used Avail Use% Mounted on /dev/sda1 682G 3.9G 644G 1% / proc 0 0 0 - /proc sysfs 0 0 0 - /sys none 0 0 0 - /sys/fs/fuse/connections none 0 0 0 - /sys/kernel/debug none 0 0 0 - /sys/kernel/security udev 2.9G 4.0K 2.9G 1% /dev devpts 0 0 0 - /dev/pts tmpfs 1.2G 928K 1.2G 1% /run none 5.0M 0 5.0M 0% /run/lock none 2.9G 156K 2.9G 1% /run/shm gvfs-fuse-daemon 0 0 0 - /home/pj/.gvfs Step 3) Try mounting manually using NTFS and VFAT (both as SDB and SDB1) pj@PJ:~$ sudo mount /dev/sdb /media/Passport/ NTFS signature is missing. Failed to mount '/dev/sdb': Invalid argument The device '/dev/sdb' doesn't seem to have a valid NTFS. Maybe the wrong device is used? Or the whole disk instead of a partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around? pj@PJ:~$ sudo mount /dev/sdb1 /media/Passport/ NTFS signature is missing. Failed to mount '/dev/sdb1': Invalid argument The device '/dev/sdb1' doesn't seem to have a valid NTFS. Maybe the wrong device is used? Or the whole disk instead of a partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around? pj@PJ:~$ sudo mount -t ntfs /dev/sdb /media/Passport/ NTFS signature is missing. Failed to mount '/dev/sdb': Invalid argument The device '/dev/sdb' doesn't seem to have a valid NTFS. Maybe the wrong device is used? Or the whole disk instead of a partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around? pj@PJ:~$ sudo mount -t vfat /dev/sdb /media/Passport/ mount: wrong fs type, bad option, bad superblock on /dev/sdb, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so pj@PJ:~$ sudo mount -t ntfs /dev/sdb1 /media/Passport/ NTFS signature is missing. Failed to mount '/dev/sdb1': Invalid argument The device '/dev/sdb1' doesn't seem to have a valid NTFS. Maybe the wrong device is used? Or the whole disk instead of a partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around? pj@PJ:~$ sudo mount -t vfat /dev/sdb1 /media/Passport/ mount: wrong fs type, bad option, bad superblock on /dev/sdb1, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so

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  • HTML5 Canvas Game Timer

    - by zghyh
    How to create good timer for HTML5 Canvas games? I am using RequestAnimationFrame( http://paulirish.com/2011/requestanimationframe-for-smart-animating/ ) But object's move too fast. Something like my code is: http://pastebin.com/bSHCTMmq But if I press UP_ARROW player don't move one pixel, but move 5, 8, or 10 or more or less pixels. How to do if I press UP_ARROW player move 1 pixel? Thanks for help.

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  • Where can I hire local programmers with very specific skillsets?

    - by Lostsoul
    I have been browsing the site and haven't found a exact fit to this question so I'll post it but if its already answered(since I'm sure its a common problem, then let me know). I have a business and want to create a totally different product in a different industry than I'm currently in, so I learned how to program and created a working prototype. I have a bit of savings and am getting some cash flow from my current business so I can go out and hire a developer(in the future hopefully it can be permenant but right now I just need a person willing to work on contract and code on weekends or their spare time and I just want to pay in cash instead of equity or future promises). At first I wasn't sure what kind of developer to hire but this question helped me understand I should target specific skills I need as opposed to general programmers. This poses a problem for me since general programmers are everywhere but if I want specific skills I'm unsure how to get them. I thought about a list of approaches but it doesn't feel complete or effective since it seems to be assuming good developers are actively looking. If it helps I want someone local(since this is my first developer hire) and looking for skills like cuda, hadoop, hbase, java and c. Any suggestions? As a FYI, I have been thinking of approaching it as: Go to meet ups for one or more skills I need. Use LinkedIn to find people with the skills I need Search for job postings that contain skills I need and then use linkedIn to reach out to that firms employees since many profiles on linkedin are not very updated or detailed but job postings generally are. Send postings to universities and maybe find a student who loves technology so much they learned these tools on their own. Post on job board. Not sure how successful it will be to post to monster. Use Craigslist, not sure if a highly skilled developer would go here for work. What am I missing? I could be wrong but it seems like good/smart/able developers aren't hunting for work non-stop(especially in this tech job market). Plus most successful people I know have work/life balance so I'm not sure if the best ones really care about code after work. Lastly, most of the skills I need aren't used in big corporations so not sure how aggressively smart developers at small shops look for work. I don’t really know any developers personally, so but should I be using the above plan or if they live balanced lives should I be looking outside of the regular resources(and instead focus on asking around my gym or my accountant or something)? Sorry, I'm making huge assumptions here, I guess because developers are a total mystery to me. I kind of wish Jane Goodall wrote a book on understanding developers social behaviour better :-p

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  • Guiding Management to the Correct Decision

    - by Blumer
    My supervisor (also a developer) and I have a running joke about writing a book called "Managing From Beneath: Subversively Guiding Management to the Right Decision" and including a number of "techniques" we've developed for helping those who make the decisions to make the right ones. So far, we've got (cynicism warning!): BIC It! BIC stands for "Bury In Committee." When a bad idea comes up that someone wants to champion, we try to get it deferred to a committee for input. Typically it will either get killed outright (especially if other members of the committee are competing for you as a resource), or it will be hung up long enough that the proponent forgets about it. Smart, Stupid, or Expensive? When someone gets a visionary idea, offer them three ways to do it: a smart way, a stupid way, and an expensive way. The hope is that you've at least got a 2/3 shot of not having to do it the way that makes a piece of your soul die. All-Pro. It's a preemptive pro/con list in which you get into the mind of the (pr)opponent and think what would be cons against doing it your way. Twist them into pros and present them in your pro list before they have a chance to present them as cons. Dependicitis. Link pending decisions together, ideally with the proponent's pet project as the final link in the chain. Use this leverage to force action on those that have been put off. Preemptive Acceptance. Sometimes it's clear that management is going to go a particular direction regardless of advice to the contrary, and it's time to make the best of it. Take the opportunity to get something else you need, though. Approach the sponsor out of the blue and take the first step: "You know, I've been thinking about it, and while it's not the route I would advise, as long as we can get the schedule and budget for Project Awesome loosened up, I can work some magic to make your project fly." So ... what techniques have you come up with to try to head off the problem projects or make the best of what may come?

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  • Why are textures always square powers of two? What if they aren't?

    - by Keavon
    Why are the resolution of textures in games always a power of two (128x128, 256x256, 512x512, 1024x1024, etc.)? Wouldn't it be smart to save on the game's file size and make the texture exactly fit the UV unwrapped model? What would happen if there was a texture that was not a power of two? Would it be incorrect to have a texture be something like 256x512, or 512x1024? Or would this cause the problems that non-power-of-two textures may cause?

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  • JavaFX Developer Preview for ARM

    - by sasa
    ARM?Linux??JavaFX (JDK 7) Developer Preview?????????????????????JavaFX??????????????????????? ????????????BeagleBoard xM (Rev. C)?????????????????????????3M M2256PW?Chalkboard Electronics?1024x600 LCD????????????????????????????????????????????????? X?????X11???????????EGL???OpenGL ES 2.0??????????????????????????????Linux??????????????????????????Angstrom 2011.03????????????????????????????????????????Stopwatch(????????)?BouncingBalls(????????)?Calculator(???)?BrickBreaker(??????)?????????????? JavaOne?????????????????Raspberry Pi?Panda Board????????????? CON6094 - JavaFX on Smart Embedded Devices CON5348 - Do You Like Coffee with Your Dessert? Java and the Raspberry Pi CON4538 - Java Embedded Goes Modular: How to Build Your Custom Embedded Java Runtime

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  • Do I need to create my own or use a commercial server for the features and matchmaking options I want my game to support?

    - by baptzmoffire
    So I'm developing an indie turn-based game for iOS and, in coding up a Game Center matchmaking class, I'm starting to question whether Game Center is even the best choice for what I want this game to do. I need to figure out whether I need to create my own server, invest in a preexisting client or server service, or if I even need to use a server at all. If I do need to use a ready-made service other than Game Center, which server would accomodate my game's needs best? I have limited resources and funds. Here is the list of features I want my game to support, ideally: Turn-based gameplay (a la "with Friends" and "with Buddies" games) Smart matchmaking (matching users up with other players of comparable skill/achievements) Random matchmaking Facebook matchmaking Specific username matchmaking Contact list matchmaking A way to select what "type" of match you want to challenge an opponent to. (In random, smart, and Facebook matchmaking, there will be different "wagers" the player can make. [e.g. "I wanna play a random opponent for 1000 points. Now, I wanna play my Facebook buddy for 1,000,000 points."] There will be a predetermined range of amounts you can play for. It won't be customizable.) Buddies list capability (Game-buddies, as opposed to contacts and Facebook) A higher concurrent game cap than Game Center offers (which I still can't really find a straight answer on) Scalability (it should support 2 or 20,000,000 players) Objective-C compatibility Flexibility (for all the stuff I haven't thought of yet) Am I dreaming, here? Is there even a service that can handle all of these features? Do I need to invest months in learning a networking language to build my own? If so, how much would I need to spend on hardware? I've been looking around all morning and, so far, the only seemingly viable option is SmartFox. Under "Everything and the kitchen sink" section here, it says they support "virtual world with Zones, Rooms and RoomGroups, create complex game challenges, send invitations, manage buddy lists, create custom permission profiles, oversee the security aspects and tons more." http://www.smartfoxserver.com/overview/platform Is there an option that Im just overlooking? Thanks for any help anyone can provide. Sorry for the long poast. One last question: Does anyone know which server Dice with Buddies uses? I was experimenting with how many concurrent games I could get going and my ADHD kicked in at about 80 games. 80 concurrent games would be great for my game, but again, I need the other features I mentioned too. Thanks again.

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  • SQLServerCentral.com Users Survey 2012

    We want to make sure we're covering the things that are relevant to you, so we're asking for some feedback on what you use on SSC, where we need to improve, and what you'd like to see. It should only take a few minutes, and three randomly-selected people will win a $100 Amazon gift card for their efforts. Get smart with SQL Backup ProGet faster, smaller backups with integrated verification.Quickly and easily DBCC CHECKDB your backups. Learn more.

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  • Social media measurement tools [on hold]

    - by user29187
    I work for a non-profit and we are currently trying to develop a system to measure and evaluate our social media platforms (Facebook and Twitter). We would liek to tarck a variety of social metrics, including, but not limited to: Twitter: # of followers, # of mentions, # of retweets Facebook: # of likes, # people talking about, # of page views We are currently using a paid platform for this. I wondered if there is a way to configure Google Analytics to do this or if there are any other free/clever or smart ways to track social engagement with our brand?

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  • Implementing Foreach Looping Logic in SSIS

    With SSIS, it is possible to implement looping logic into SSIS's control flow in order to define a repeating workflow in a package for each member of a collection of objects. Rob Sheldon explains how to use this valuable feature of SSIS. Get smart with SQL Backup ProGet faster, smaller backups with integrated verification.Quickly and easily DBCC CHECKDB your backups. Learn more.

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  • How can I install Ubuntu on a Compaq DC7900?

    - by lemba
    I have an HP Compaq dc7900 Convertible Minitower from 2006: 80GB (3.5”) SATA 3.0GB/s with NCQ and Smart IV Intel Core 2 Duo E8500 I can install Ubuntu on it from a USB stick and everything seems to work fine, but when I finish and reboot the pc, grub will be shown but When I continue I get just a black screen with a blinking cursor I tried Linux Mint and OpenSuse as well but it seems there is something forbidden in the Bios. Installing Windows 8 works fine.

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  • A Small Blog About Huge Pages

    - by rickramsey
    Video Interview: What Are Linux Huge Pages?, by Ed Whalen, Oracle ACE Blog: There's Been a Change In How Huge Pages Are Allocated, by Tanel Poder, Oracle ACE Director Blog: Performance Issues with Transparent Huge Pages (thank you, Bjoern Rost!) Web: About the Car, by Smart Ridez LLC, of Woodland Hills, California - Rick Follow me on: Blog | Facebook | Twitter | Personal Twitter | YouTube | The Great Peruvian Novel

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  • Learn How to Create High-Converting Landing Pages - Part 4

    Once you have placed call to action through your pay per click ads on the landing pages, you have to make sure that as part of your SEO plan, you must include paid keyword several times in your landing pages which will lead to well optimized pages under your search engine marketing efforts. As a smart SEO expert, it is important for you to include the keywords in a manner that it cannot be skipped by your readers because if it is missed, it will affect your PPC campaign management and search engine optimization results.

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  • 7 Preventable Backup Errors

    The loss of a company's data is often enough to put the company out of business; and yet backup errors are generally avoidable with the application of common sense rather than deep technical knowledge. Grant digs into memories of his long experience of giving forum advice, to come up with the most easily preventable backup errors. Get Smart with SQL Backup Pro Powerful centralised management, encryption and more.SQL Backup Pro was the smartest kid at school Discover why.

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  • Building a Scale Out SSRS 2008 R2 Farm using Windows NLB Part 4

    Delivering reports is becoming more critical due to the increasing demand for business intelligence solutions. And while there are a lot of guides that walk us through building a highly available database engine, you’ll rarely see one for SQL Server Reporting Services. How do I go about building a scale-out SQL Server 2008 R2 Reporting Services running on Windows Server 2008 R2? Get smart with SQL Backup ProPowerful centralised management, encryption and more.SQL Backup Pro was the smartest kid at school. Discover why.

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  • SQL Server stored procedure to generate random passwords

    SQL Server is used to support many applications and one such feature of most applications is the storage of passwords. Sometimes there is a need to reset a password using a temporary password or generate a random password for a new user. In this tip I cover a simple stored procedure to generate random passwords that can be incorporated into your applications. Get Smart with SQL Backup Pro Powerful centralised management, encryption and more.SQL Backup Pro was the smartest kid at school Discover why.

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  • Red Gate SQL Prompt Verses Microsoft Intellisense

    In this economy, IT professionals have to make smart choices when it comes to spending money on developer tools. Does the new Intellisense feature of SQL Server 2008 Management Studio make third party intelligent code completion tools like Red Gate SQL Prompt obsolete?

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  • BIDS Helper 1.6 Beta Release (now with SQL 2012 support!)

    - by Darren Gosbell
    The beta for BIDS Helper 1.6 was just released. We have not updated the version notification just yet as we would like to get some feedback on people's experiences with the SQL 2012 version. So if you are using SQL 2012, go grab it and let us know how you go (you can post a comment on this blog post or on the BIDS Helper site itself). This is the first release that supports SQL 2012 and consequently also the first release that runs in Visual Studio 2010. A big thanks to Greg Galloway for doing the bulk of the work on this release. Please note that if you are doing an xcopy deploy that you will need to unblock the files you download or you will get a cryptic error message. This appears to be caused by a security update to either Visual Studio or the .Net framework – the xcopy deploy instructions have been updated to show you how to do this. Below are the notes from the release page. ====== This beta release is the first to support SQL Server 2012 (in addition to SQL Server 2005, 2008, and 2008 R2). Since it is marked as a beta release, we are looking for bug reports in the next few months as you use BIDS Helper on real projects. In addition to getting all existing BIDS Helper functionality working appropriately in SQL Server 2012 (SSDT), the following features are new... Analysis Services Tabular Smart Diff Tabular Actions Editor Tabular HideMemberIf Tabular Pre-Build Fixes and Updates The Unused Datasets feature for Reporting Services now accounts for new features in Reporting Services 2008 R2 like Lookups and new features in Reporting Services 2012. SSIS: emit an informational message when a variable has an expression defined and EvaluateAsExpression = False SSAS: roles reports points to wrong server SSIS - Variable Copy / Move broken in v1.5 "Unused DataSets Report" not showing up in Context menu on VS2005 if Solution Folders used SSAS Tabular: Create a UI for managing actions SSAS Tabular: Smart Diff improvements for new schema and Tabular models SSIS: Copy/Move Variable Erroring due to custom Control Flow item Icon SSIS Performance Visualization Index out of range fixing bugs in AggManager when aggregation design IDs don't match names The exe downloads are a self extracting installer, the zip downloads allow for an xcopy deploy. Make sure to note the updated xcopy deploy instructions for SQL Server 2012.

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  • Lenovo W520 back usb port not working

    - by jaudette
    The usb port in the back of my laptop (on the right side when viewed from using perspective) is not working. Does anybody know if we can get this port working, and what the port number is. Here is my lsusb, if it can help. % lsusb Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 003 Device 002: ID 046d:c01e Logitech, Inc. MX518 Optical Mouse Bus 003 Device 003: ID 046d:c318 Logitech, Inc. Illuminated Keyboard Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 003: ID 0765:5001 X-Rite, Inc. Huey PRO Colorimeter Bus 001 Device 004: ID 147e:2016 Upek Biometric Touchchip/Touchstrip Fingerprint Sensor Bus 001 Device 005: ID 0a5c:217f Broadcom Corp. Bluetooth Controller Bus 001 Device 006: ID 04f2:b217 Chicony Electronics Co., Ltd Lenovo Integrated Camera (0.3MP) Bus 002 Device 003: ID 17ef:1003 Lenovo Integrated Smart Card Reader I am running 12.10, upgraded from 12.04 but it did not work either in 12.04. The two usb ports on the left work just fine. EDIT: I just updated my bios from 1.32 to 1.39, no change in behaviour. The port does not even power up my devices. EDIT 2: Booted up windows, and the port is working. I went into the device manager and looked at the USB settings. I found my USB drive on Port 2, Hub 3, i just don't know how that relates to the Bus and Device numbers of linux. In windows, Smart card reader was on USB hub located at port 1 hub 2, fingerprint and bluetooth were on USB hub located at port 1 hub 1 EDIT 3: Went and looked at this SO post. Tried to look at my kern.log file with tail -f /var/log/kern.log. Got some activity when plugging/removing devices in other ports, but nothing happens when connecting a device into that port. It really looks disabled. Looked at my usb1-4 sys/bus/usb/devices/usb1/power/control and they are all set on auto. As expected, usb4 have version 3.00, the others (usb1-usb3) are 2.00.

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  • Oracle Turkey Applications Strategy Update Event

    - by [email protected]
    Oracle Turkey gathered its wide range of customers and associates in "Oracle Applications Strategy Update" event in Istanbul at 17 March of 2010 as a part of worldwide Global Applications Smart Strategies Tour.  The program discussed, the new technologies and, with real-world examples, presented strategies for  leveraging technology to succeed in today's challenging business environment.    

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  • EPM 11.1.2.1 - Smartview client and HFM office provider

    - by user809526
    If your connection to the smartview provider is very slow, because the login part takes a long time (user directory slowness, ...), consider adding on the desktop side a Windows parameter: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\InternetSettings\ ReceiveTimeout 300000 to avoid being prompted over and over again for username/password This is an addition to the support doc id: "Smart View 11.1.2.1 Keeps Prompting For Username And Password For Financial Management Provider [ID 1353294.1]"

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  • Resource Governor

    If you suffer from runaway queries, if you have several database applications with unpredictable fluctuation in workload, or if you need to ensure that workloads get the memory or CPU they need according to certain priorities, then you need Resource Governer, and you need Roy Ernest's clear explanation of the technology. Get Smart with SQL Backup Pro Powerful centralised management, encryption and more.SQL Backup Pro was the smartest kid at school Discover why.

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  • Implementing a Custom Coherence PartitionAssignmentStrategy

    - by jpurdy
    A recent A-Team engagement required the development of a custom PartitionAssignmentStrategy (PAS). By way of background, a PAS is an implementation of a Java interface that controls how a Coherence partitioned cache service assigns partitions (primary and backup copies) across the available set of storage-enabled members. While seemingly straightforward, this is actually a very difficult problem to solve. Traditionally, Coherence used a distributed algorithm spread across the cache servers (and as of Coherence 3.7, this is still the default implementation). With the introduction of the PAS interface, the model of operation was changed so that the logic would run solely in the cache service senior member. Obviously, this makes the development of a custom PAS vastly less complex, and in practice does not introduce a significant single point of failure/bottleneck. Note that Coherence ships with a default PAS implementation but it is not used by default. Further, custom PAS implementations are uncommon (this engagement was the first custom implementation that we know of). The particular implementation mentioned above also faced challenges related to managing multiple backup copies but that won't be discussed here. There were a few challenges that arose during design and implementation: Naive algorithms had an unreasonable upper bound of computational cost. There was significant complexity associated with configurations where the member count varied significantly between physical machines. Most of the complexity of a PAS is related to rebalancing, not initial assignment (which is usually fairly simple). A custom PAS may need to solve several problems simultaneously, such as: Ensuring that each member has a similar number of primary and backup partitions (e.g. each member has the same number of primary and backup partitions) Ensuring that each member carries similar responsibility (e.g. the most heavily loaded member has no more than one partition more than the least loaded). Ensuring that each partition is on the same member as a corresponding local resource (e.g. for applications that use partitioning across message queues, to ensure that each partition is collocated with its corresponding message queue). Ensuring that a given member holds no more than a given number of partitions (e.g. no member has more than 10 partitions) Ensuring that backups are placed far enough away from the primaries (e.g. on a different physical machine or a different blade enclosure) Achieving the above goals while ensuring that partition movement is minimized. These objectives can be even more complicated when the topology of the cluster is irregular. For example, if multiple cluster members may exist on each physical machine, then clearly the possibility exists that at certain points (e.g. following a member failure), the number of members on each machine may vary, in certain cases significantly so. Consider the case where there are three physical machines, with 3, 3 and 9 members each (respectively). This introduces complexity since the backups for the 9 members on the the largest machine must be spread across the other 6 members (to ensure placement on different physical machines), preventing an even distribution. For any given problem like this, there are usually reasonable compromises available, but the key point is that objectives may conflict under extreme (but not at all unlikely) circumstances. The most obvious general purpose partition assignment algorithm (possibly the only general purpose one) is to define a scoring function for a given mapping of partitions to members, and then apply that function to each possible permutation, selecting the most optimal permutation. This would result in N! (factorial) evaluations of the scoring function. This is clearly impractical for all but the smallest values of N (e.g. a partition count in the single digits). It's difficult to prove that more efficient general purpose algorithms don't exist, but the key take away from this is that algorithms will tend to either have exorbitant worst case performance or may fail to find optimal solutions (or both) -- it is very important to be able to show that worst case performance is acceptable. This quickly leads to the conclusion that the problem must be further constrained, perhaps by limiting functionality or by using domain-specific optimizations. Unfortunately, it can be very difficult to design these more focused algorithms. In the specific case mentioned, we constrained the solution space to very small clusters (in terms of machine count) with small partition counts and supported exactly two backup copies, and accepted the fact that partition movement could potentially be significant (preferring to solve that issue through brute force). We then used the out-of-the-box PAS implementation as a fallback, delegating to it for configurations that were not supported by our algorithm. Our experience was that the PAS interface is quite usable, but there are intrinsic challenges to designing PAS implementations that should be very carefully evaluated before committing to that approach.

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  • Loose Coupling and UX Patterns for Applications Integrations

    - by ultan o'broin
    I love that software architecture phrase loose coupling. There’s even a whole book about it. And, if you’re involved in enterprise methodology you’ll know just know important loose coupling is to the smart development of applications integrations too. Whether you are integrating offerings from the Oracle partner ecosystem with Fusion apps or applications coexistence scenarios, loose coupling enables the development of scalable, reliable, flexible solutions, with no second-guessing of technology. Another great book Enterprise Integration Patterns: Designing, Building, and Deploying Messaging Solutions tells us about loose coupling benefits of reducing the assumptions that integration parties (components, applications, services, programs, users) make about each other when they exchange information. Eliminating assumptions applies to UI development too. The days of assuming it’s enough to hard code a UI with linking libraries called code on a desktop PC for an office worker are over. The book predates PaaS development and SaaS deployments, and was written when web services and APIs were emerging. Yet it calls out how using middleware as an assumptions-dissolving technology “glue" is central to applications integration. Realizing integration design through a set of middleware messaging patterns (messaging in the sense of asynchronously communicating data) that enable developers to meet the typical business requirements of enterprises requiring integrated functionality is very Fusion-like. User experience developers can benefit from the loose coupling approach too. User expectations and work styles change all the time, and development is now about integrating SaaS through PaaS. Cloud computing offers a virtual pivot where a single source of truth (customer or employee data, for example) can be experienced through different UIs (desktop, simplified, or mobile), each optimized for the context of the user’s world of work and task completion. Smart enterprise applications developers, partners, and customers use design patterns for user experience integration benefits too. The Oracle Applications UX design patterns (and supporting guidelines) enable loose coupling of the optimized UI requirements from code. Developers can get on with the job of creating integrations through web services, APIs and SOA without having to figure out design problems about how UIs should work. Adding the already user proven UX design patterns (and supporting guidelines to your toolkit means ADF and other developers can easily offer much more than just functionality and be super productive too. Great looking application integration touchpoints can be built with our design patterns and guidelines too for a seamless applications UX. One of Oracle’s partners, Innowave Technologies used loose coupling architecture and our UX design patterns to create an integration for a customer that was scalable, cost effective, fast to develop and kept users productive while paving a roadmap for customers to keep pace with the latest UX designs over time. Innowave CEO Basheer Khan, a Fusion User Experience Advocate explains how to do it on the Usable Apps blog.

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