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  • Geez &ndash; do you even do basic testing?

    - by Shawn Cicoria
    You’d think that a “real” commercial software vendor would at least run a barrage of tests validating updates – ANY updates – before pushing out those updates. Well, McAfee has done it again.  This one, well it just shuts you down…  False positives on a core Windows file. https://kc.mcafee.com/corporate/index?page=content&id=KB68780 http://support.microsoft.com/kb/2025695 Usually, if I get a PC with McAfee offered for “free” usually, I either wipe or uninstall.  That product is the work of the devil.  I can’t understand how these guys are still in business.

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  • Better name of Social Networking ! quora.com

    - by Anirudha
    Originally posted on: http://geekswithblogs.net/anirugu/archive/2013/07/23/better-name-of-social-networking--quora.com.aspxAfter writing my recent post Facebook allow you to abuse in Non-English words ? I am looking for better social networking site. I found Facebook is not more then time wasting time. People share links and posts. Nowadays Facebook is marketing tool. Twitter is not useful too when you can’t say anything in less then 140 words. Now look at quora.com it’s very good site compare to other two. You can read a lot of discussion their. Too many discussion that you want to listen about. I am happy to use Quora.com no need of Facebook and Twitter. Both are dying already

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  • Is it possible to do freelancing with 3dsmax?

    - by Mirror51
    I am learning 3dsmax architecture for building models of houses. Is it possible to do freelancing with house modelling thing? For various reasons I have to stay at home. So I was wondering if I can earn some money by making some house models for someone. I really don't know how this works but may be someone can give some ideas. Would I need to go to construction or real estate companies and ask them if they want something like this?

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  • SATA errors reported during boot: exception Emask 0x40 SAct 0x0 SErr 0x80800 action 0x0

    - by digby280
    I have noticed some error during the Linux boot. They seem to continue to occur after the boot adding lines to the log every few seconds. Once booted this normally does not appear to be causing any problems. However, around 1 in 10 boots results in a kernel panic and the computer has on two or three occasions suddenly rebooted after being powered on for a number of hours. I presume the cause of the reboot is a kernel panic as well. I am running Ubuntu 11.10 and I have had Ubuntu installed on the computer for around a year. I have googled around and not found anything useful. I have provided the kernel log lines and the output of smartctl. Can anyone explain exactly what these errors mean, or better still how to resolve them? Apr 2 16:51:27 dell580 kernel: [ 19.831140] EXT4-fs (sdb2): re-mounted. Opts: errors=remount-ro,user_xattr,commit=0 Apr 2 16:51:27 dell580 kernel: [ 19.934194] tg3 0000:03:00.0: eth0: Link is down Apr 2 16:51:28 dell580 kernel: [ 20.929468] tg3 0000:03:00.0: eth0: Link is up at 100 Mbps, full duplex Apr 2 16:51:28 dell580 kernel: [ 20.929471] tg3 0000:03:00.0: eth0: Flow control is on for TX and on for RX Apr 2 16:51:28 dell580 kernel: [ 20.929727] ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready Apr 2 16:51:29 dell580 kernel: [ 21.609381] EXT4-fs (sdb2): re-mounted. Opts: errors=remount-ro,user_xattr,commit=0 Apr 2 16:51:29 dell580 kernel: [ 21.616515] ata2.01: exception Emask 0x40 SAct 0x0 SErr 0x80800 action 0x0 Apr 2 16:51:29 dell580 kernel: [ 21.616519] ata2.01: SError: { HostInt 10B8B } Apr 2 16:51:29 dell580 kernel: [ 21.616525] ata2.00: hard resetting link Apr 2 16:51:29 dell580 kernel: [ 21.934036] ata2.01: hard resetting link Apr 2 16:51:29 dell580 kernel: [ 22.408890] ata2.00: SATA link up 1.5 Gbps (SStatus 113 SControl 300) Apr 2 16:51:29 dell580 kernel: [ 22.408907] ata2.01: SATA link up 3.0 Gbps (SStatus 123 SControl 300) Apr 2 16:51:29 dell580 kernel: [ 22.440934] ata2.00: configured for UDMA/100 Apr 2 16:51:29 dell580 kernel: [ 22.449040] ata2.01: configured for UDMA/133 Apr 2 16:51:29 dell580 kernel: [ 22.449818] ata2: EH complete Apr 2 16:51:33 dell580 kernel: [ 26.122664] ata2.01: exception Emask 0x40 SAct 0x0 SErr 0x80800 action 0x0 Apr 2 16:51:33 dell580 kernel: [ 26.122670] ata2.01: SError: { HostInt 10B8B } Apr 2 16:51:33 dell580 kernel: [ 26.122677] ata2.00: hard resetting link Apr 2 16:51:33 dell580 kernel: [ 26.442684] ata2.01: hard resetting link Apr 2 16:51:34 dell580 kernel: [ 26.925545] ata2.00: SATA link up 1.5 Gbps (SStatus 113 SControl 300) Apr 2 16:51:34 dell580 kernel: [ 26.925561] ata2.01: SATA link up 3.0 Gbps (SStatus 123 SControl 300) Apr 2 16:51:34 dell580 kernel: [ 26.961542] ata2.00: configured for UDMA/100 Apr 2 16:51:34 dell580 kernel: [ 26.969616] ata2.01: configured for UDMA/133 Apr 2 16:51:34 dell580 kernel: [ 26.970400] ata2: EH complete Apr 2 16:51:35 dell580 kernel: [ 28.111180] ata2.01: exception Emask 0x40 SAct 0x0 SErr 0x80800 action 0x0 Apr 2 16:51:35 dell580 kernel: [ 28.111184] ata2.01: SError: { HostInt 10B8B } Apr 2 16:51:35 dell580 kernel: [ 28.111191] ata2.00: hard resetting link Apr 2 16:51:35 dell580 kernel: [ 28.429674] ata2.01: hard resetting link Apr 2 16:51:36 dell580 kernel: [ 28.904557] ata2.00: SATA link up 1.5 Gbps (SStatus 113 SControl 300) Apr 2 16:51:36 dell580 kernel: [ 28.904572] ata2.01: SATA link up 3.0 Gbps (SStatus 123 SControl 300) Apr 2 16:51:36 dell580 kernel: [ 28.936609] ata2.00: configured for UDMA/100 Apr 2 16:51:36 dell580 kernel: [ 28.944692] ata2.01: configured for UDMA/133 Apr 2 16:51:36 dell580 kernel: [ 28.945464] ata2: EH complete Apr 2 16:51:38 dell580 kernel: [ 31.581756] eth0: no IPv6 routers present Apr 2 16:51:38 dell580 kernel: [ 32.103066] ata2.01: exception Emask 0x40 SAct 0x0 SErr 0x80800 action 0x0 Apr 2 16:51:38 dell580 kernel: [ 32.103074] ata2.01: SError: { HostInt 10B8B } Apr 2 16:51:38 dell580 kernel: [ 32.103085] ata2.00: hard resetting link Apr 2 16:51:38 dell580 kernel: [ 32.419669] ata2.01: hard resetting link Apr 2 16:51:39 dell580 kernel: [ 32.894518] ata2.00: SATA link up 1.5 Gbps (SStatus 113 SControl 300) Apr 2 16:51:39 dell580 kernel: [ 32.894533] ata2.01: SATA link up 3.0 Gbps (SStatus 123 SControl 300) Apr 2 16:51:39 dell580 kernel: [ 32.926536] ata2.00: configured for UDMA/100 Apr 2 16:51:39 dell580 kernel: [ 32.934715] ata2.01: configured for UDMA/133 Apr 2 16:51:39 dell580 kernel: [ 32.935578] ata2: EH complete Here's the output of smartctl for the drive. smartctl 5.41 2011-06-09 r3365 [x86_64-linux-3.0.0-17-generic] (local build) Copyright (C) 2002-11 by Bruce Allen, http://smartmontools.sourceforge.net === START OF INFORMATION SECTION === Model Family: SAMSUNG SpinPoint F1 DT Device Model: SAMSUNG HD103UJ Serial Number: S13PJ90QC19706 LU WWN Device Id: 5 0000f0 00b1c7960 Firmware Version: 1AA01113 User Capacity: 1,000,204,886,016 bytes [1.00 TB] Sector Size: 512 bytes logical/physical Device is: In smartctl database [for details use: -P show] ATA Version is: 8 ATA Standard is: ATA-8-ACS revision 3b Local Time is: Mon Apr 2 17:13:48 2012 BST SMART support is: Available - device has SMART capability. SMART support is: Enabled === START OF READ SMART DATA SECTION === SMART overall-health self-assessment test result: PASSED General SMART Values: Offline data collection status: (0x00) Offline data collection activity was never started. Auto Offline Data Collection: Disabled. Self-test execution status: ( 41) The self-test routine was interrupted by the host with a hard or soft reset. Total time to complete Offline data collection: (11772) seconds. Offline data collection capabilities: (0x7b) SMART execute Offline immediate. Auto Offline data collection on/off support. Suspend Offline collection upon new command. Offline surface scan supported. Self-test supported. Conveyance Self-test supported. Selective Self-test supported. SMART capabilities: (0x0003) Saves SMART data before entering power-saving mode. Supports SMART auto save timer. Error logging capability: (0x01) Error logging supported. General Purpose Logging supported. Short self-test routine recommended polling time: ( 2) minutes. Extended self-test routine recommended polling time: ( 197) minutes. Conveyance self-test routine recommended polling time: ( 21) minutes. SCT capabilities: (0x003f) SCT Status supported. SCT Error Recovery Control supported. SCT Feature Control supported. SCT Data Table supported. SMART Attributes Data Structure revision number: 16 Vendor Specific SMART Attributes with Thresholds: ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE 1 Raw_Read_Error_Rate 0x000f 100 100 051 Pre-fail Always - 0 3 Spin_Up_Time 0x0007 076 076 011 Pre-fail Always - 7940 4 Start_Stop_Count 0x0032 099 099 000 Old_age Always - 521 5 Reallocated_Sector_Ct 0x0033 100 100 010 Pre-fail Always - 0 7 Seek_Error_Rate 0x000f 253 253 051 Pre-fail Always - 0 8 Seek_Time_Performance 0x0025 100 100 015 Pre-fail Offline - 0 9 Power_On_Hours 0x0032 100 100 000 Old_age Always - 642 10 Spin_Retry_Count 0x0033 100 100 051 Pre-fail Always - 0 11 Calibration_Retry_Count 0x0012 100 100 000 Old_age Always - 0 12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 482 13 Read_Soft_Error_Rate 0x000e 100 100 000 Old_age Always - 0 183 Runtime_Bad_Block 0x0032 100 100 000 Old_age Always - 759 184 End-to-End_Error 0x0033 100 100 000 Pre-fail Always - 0 187 Reported_Uncorrect 0x0032 100 100 000 Old_age Always - 0 188 Command_Timeout 0x0032 100 100 000 Old_age Always - 0 190 Airflow_Temperature_Cel 0x0022 073 069 000 Old_age Always - 27 (Min/Max 16/27) 194 Temperature_Celsius 0x0022 073 067 000 Old_age Always - 27 (Min/Max 16/28) 195 Hardware_ECC_Recovered 0x001a 100 100 000 Old_age Always - 320028 196 Reallocated_Event_Count 0x0032 100 100 000 Old_age Always - 0 197 Current_Pending_Sector 0x0012 100 100 000 Old_age Always - 0 198 Offline_Uncorrectable 0x0030 100 100 000 Old_age Offline - 0 199 UDMA_CRC_Error_Count 0x003e 099 099 000 Old_age Always - 1494 200 Multi_Zone_Error_Rate 0x000a 100 100 000 Old_age Always - 0 201 Soft_Read_Error_Rate 0x000a 253 253 000 Old_age Always - 0 SMART Error Log Version: 1 ATA Error Count: 211 (device log contains only the most recent five errors) CR = Command Register [HEX] FR = Features Register [HEX] SC = Sector Count Register [HEX] SN = Sector Number Register [HEX] CL = Cylinder Low Register [HEX] CH = Cylinder High Register [HEX] DH = Device/Head Register [HEX] DC = Device Command Register [HEX] ER = Error register [HEX] ST = Status register [HEX] Powered_Up_Time is measured from power on, and printed as DDd+hh:mm:SS.sss where DD=days, hh=hours, mm=minutes, SS=sec, and sss=millisec. It "wraps" after 49.710 days. Error 211 occurred at disk power-on lifetime: 0 hours (0 days + 0 hours) When the command that caused the error occurred, the device was active or idle. After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 84 51 0f 31 63 8f e1 Error: ICRC, ABRT 15 sectors at LBA = 0x018f6331 = 26174257 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- c8 00 00 40 62 8f e1 08 00:01:00.460 READ DMA c8 00 20 00 7c 30 e0 08 00:01:00.450 READ DMA c8 00 00 10 49 8f e1 08 00:01:00.440 READ DMA c8 00 e0 20 d0 30 e0 08 00:01:00.420 READ DMA c8 00 00 c0 59 90 e1 08 00:01:00.400 READ DMA Error 210 occurred at disk power-on lifetime: 0 hours (0 days + 0 hours) When the command that caused the error occurred, the device was active or idle. After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 84 51 cf e9 cf 66 e0 Error: ICRC, ABRT 207 sectors at LBA = 0x0066cfe9 = 6737897 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- c8 00 00 b8 cf 66 e0 08 00:08:29.780 READ DMA c8 00 60 60 c9 18 e0 08 00:08:29.770 READ DMA c8 00 40 20 c9 18 e0 08 00:08:29.770 READ DMA c8 00 20 00 c9 18 e0 08 00:08:29.760 READ DMA c8 00 20 98 cf 66 e0 08 00:08:29.750 READ DMA Error 209 occurred at disk power-on lifetime: 0 hours (0 days + 0 hours) When the command that caused the error occurred, the device was active or idle. After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 84 51 2f d1 74 e0 e0 Error: ICRC, ABRT 47 sectors at LBA = 0x00e074d1 = 14709969 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- c8 00 00 00 74 e0 e0 08 00:00:30.940 READ DMA c8 00 20 18 36 de e0 08 00:00:30.930 READ DMA c8 00 08 48 f1 dd e0 08 00:00:30.930 READ DMA c8 00 08 a8 f0 dd e0 08 00:00:30.930 READ DMA c8 00 08 90 f0 dd e0 08 00:00:30.930 READ DMA Error 208 occurred at disk power-on lifetime: 0 hours (0 days + 0 hours) When the command that caused the error occurred, the device was active or idle. After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 84 51 7f 21 88 9d e0 Error: ICRC, ABRT 127 sectors at LBA = 0x009d8821 = 10324001 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- c8 00 a0 00 88 9d e0 08 00:00:27.610 READ DMA c8 00 58 a8 e7 9c e0 08 00:00:27.610 READ DMA c8 00 00 28 e6 9c e0 08 00:00:27.610 READ DMA c8 00 00 e0 e4 9c e0 08 00:00:27.610 READ DMA c8 00 00 90 e0 9c e0 08 00:00:27.600 READ DMA Error 207 occurred at disk power-on lifetime: 0 hours (0 days + 0 hours) When the command that caused the error occurred, the device was active or idle. After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 04 51 26 6a 6a c3 e0 Error: ABRT at LBA = 0x00c36a6a = 12806762 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- ca 00 00 90 69 c3 e0 08 00:29:39.350 WRITE DMA ca 00 40 90 68 c3 e0 08 00:29:39.350 WRITE DMA ca 00 40 50 65 c3 e0 08 00:29:39.350 WRITE DMA ca 00 40 d0 64 c3 e0 08 00:29:39.350 WRITE DMA ca 00 40 90 63 c3 e0 08 00:29:39.350 WRITE DMA SMART Self-test log structure revision number 1 Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error # 1 Short offline Interrupted (host reset) 90% 638 - # 2 Short offline Interrupted (host reset) 90% 638 - # 3 Extended offline Interrupted (host reset) 90% 638 - # 4 Short offline Interrupted (host reset) 90% 638 - # 5 Extended offline Interrupted (host reset) 90% 638 - SMART Selective self-test log data structure revision number 1 SPAN MIN_LBA MAX_LBA CURRENT_TEST_STATUS 1 0 0 Not_testing 2 0 0 Not_testing 3 0 0 Not_testing 4 0 0 Not_testing 5 0 0 Not_testing Selective self-test flags (0x0): After scanning selected spans, do NOT read-scan remainder of disk. If Selective self-test is pending on power-up, resume after 0 minute delay.

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  • Floppy Autoloader Automatically Archives Thousands of Floppies

    - by Jason Fitzpatrick
    The thought of hand loading 5,000 floppy disks is more than enough to drive an inventive geek to create a better alternative–like this automated floppy disk archiver. DwellerTunes has several crates of floppy disks that contain old Amiga software and related material, personal programming projects, personal documents, and more. Realistically there’s no way he could devout time to hand loading and archiving thousands upon thousands of floppy disks so he built a automatic loader that accepts stacks of several hundred floppy disks at time. The loader not only loads and archives the floppy disks, but it photographs the label of each disk so that each archive includes a picture of the original label. Watch the video above to see it in action and then hit up the link below for more information. Converting All My Amiga Disks [DwellerTunes via Make] How to Own Your Own Website (Even If You Can’t Build One) Pt 2 How to Own Your Own Website (Even If You Can’t Build One) Pt 1 What’s the Difference Between Sleep and Hibernate in Windows?

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  • Friendly URLs: is there a max length for search engines?

    - by Olivier Pons
    People from stackoverflow have been working closely with google team to help them make the panda algorithm more efficient, so I guess they've learned a lot from the google team. Thus they may have done very clever friendly URLs to maximize the page rank. I've seen from time to time very long URLs (can't find where) in stackoverflow, but after a certain "amount" of character there were only numbers, kind of "ok passed this length, SEOs will ignore this so let's put only numbers". I've done a huge work on my framework to make very friendly URLs, and my website can come up with URLs like: http://www.mysite.fr/recherche/region/provence-alpes-cote-d-azur/departement/bouches-du-rhone/categorie-de-metiers/paramedical/ It's very long and I'm wondering if the previous URL won't be mixed with, say, this one: http://www.mysite.fr/recherche/region/provence-alpes-cote-d-azur/departement/bouches-du-rhone/categorie-de-metiers/art/

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  • How can I merge two SubVersion branches to one working copy without committing?

    - by Eric Belair
    My current SubVersion workflow is like so: The trunk is used to make small content changes and bug fixes to the main source code. Branches are used for adding/editing enhancements and projects. So, trunk changes are made, tested, committed and deployed pretty quickly. Whereas, enhancements and projects need additional user testing and approval. At time, I have two branches that need testing and approval at the same time. I don't want to merge to the trunk and commit until the changes are fully tested and approved. What I need to do is merge both branches to one working copy without any commits. I am using Tortoise SVN, and when I try to merge the second branch, I get an error message: Cannot merge into a working copy that has local modifications Is there a way that I can do this without committing either merge?

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  • Recursion VS memory allocation

    - by Vladimir Kishlaly
    Which approach is most popular in real-world examples: recursion or iteration? For example, simple tree preorder traversal with recursion: void preorderTraversal( Node root ){ if( root == null ) return; root.printValue(); preorderTraversal( root.getLeft() ); preorderTraversal( root.getRight() ); } and with iteration (using stack): Push the root node on the stack While the stack is not empty Pop a node Print its value If right child exists, push the node's right child If left child exists, push the node's left child In the first example we have recursive method calls, but in the second - new ancillary data structure. Complexity is similar in both cases - O(n). So, the main question is memory footprint requirement?

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  • Wecam not detected

    - by Richard
    after much research ang googling, my web cam is still not recognized. In the time of Ubuntu 11.04 it was working fine. I did a fresh install of 11.10 and not more web cam. All the cheese and camera monotor and V4L tests and all failes with "cannot connect to /dev/video0" or equivalent. The output of 'lsusb' shows the webcam Bus 001 Device 002: ID 05a9:2640 OmniVision Technologies, Inc. OV2640 Webcam What I noticed is that neither /dev/v4l nor /dev/video* exists. If I re-install the v4l package all the /dev/video* are created, but no /dev/v4l If I reboot the /dev/video* are NOT created. I think the trouble is that the device are not created at boot time. I have a DELL Inspiron 1525 and until this fresh install the web cam worked fine. Can somebody help ? Thanks a lot Richard

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  • Upgrade 11g szeminárium

    - by Lajos Sárecz
    Június 9-én az Oracle Database 11g Upgrade-rol szóló szemináriumot tartunk Mike Dietrich közremuködésével Budapesten! Ha valaki nem ismerné még Mike-ot és Oracle Database upgrade-et tervez, akkor épp itt az ideje hogy megismerje. Erre pedig kiváló alkalom a rendezvény június 9-én, Mike ugyanis az Oracle legfobb upgrade szakértoje. Számos upgrade szemináriumot tart, és nem utolsó sorban van egy kiváló blogja errol a témáról: http://blogs.oracle.com/UPGRADE/ Az esemény fókuszában az upgrade tippek&trükkök bemutatása, valamint az upgrade közben felmerülo buktatók elkerülésének ismertetése lesz. A szeminárium során áttekintést adunk az Oracle Database 11gR2 upgrade folyamatáról és a szükséges elokészíto lépésekrol. A nap során tárgyalni fogjuk a minimális állásidovel végrehajtható upgrade stratégiákat, és kiemelten foglalkozunk majd a teljesítmény hangolás módjával, felhasználva az SQL Plan Management-et és a Real Application Testing két funkcióját: az SQL Performance Analyzer-t, illetve a Database Replay-t. Befejezésként néhány ügyfél tapasztalatait fogjuk megosztani Önökkel. Helyszín a Ramada Plaza Budapest lesz, ahol minden kedves ügyfelünket és partnerünket sok szeretettel várunk. Regisztrálni a rendezvény weboldalán lehetséges.

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  • Swept AABB vs Line Segment 2D

    - by Larolaro
    I've really exhausted as much as Google has to give, I've spent a solid week googling every combination of words for an "AABBvsLine sweep", downloaded countless collision demos, dissected SAT intersection examples and an AABBvsAABB sweep trying to figure out how to approach this. I've not found a single thing covering this specific pairing. Can anyone shed any light on how to get the hit time of a swept AABB vs a Line segment in 2D? I'm still getting familiar with the SAT but I do know how to implement it to a degree, I'm just not sure how to extract the hit time from the velocity in the non axis aligned separating axes for the sweep. I really would appreciate anything at the moment, some code or even some helpful links, I'm at my wits end!

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  • Why Does Ejabberd Start Fail?

    - by Andrew
    I am trying to install ejabberd 2.1.10-2 on my Ubuntu 12.04.1 server. This is a fresh install, and ejabberd is never successfully installed. The Install Every time, apt-get hangs on this: Setting up ejabberd (2.1.10-2ubuntu1) ... Generating SSL certificate /etc/ejabberd/ejabberd.pem... Creating config file /etc/ejabberd/ejabberd.cfg with new version Starting jabber server: ejabberd............................................................ failed. The dots just go forever until it times out or I 'killall' beam, beam.smp, epmd, and ejabberd processes. I've turned off all firewall restrictions. Here's the output of epmd -names while the install is hung: epmd: up and running on port 4369 with data: name ejabberdctl at port 42108 name ejabberd at port 39621 And after it fails: epmd: up and running on port 4369 with data: name ejabberd at port 39621 At the same time (during and after), the output of both netstat -atnp | grep 5222 and netstat -atnp | grep 5280 is empty. The Crash File A crash dump file is create at /var/log/ejabber/erl_crash.dump. The slogan (i.e. reason for the crash) is: Slogan: Kernel pid terminated (application_controller) ({application_start_failure,kernel,{shutdown,{kernel,start,[normal,[]]}}}) It's alive? Whenever I try to relaunch ejabberd with service ejabberd start, the same thing happens - even if I've killed all processes before doing so. However, when I killall the processes listed above again, and run su - ejabberd -c /usr/sbin/ejabberd, this is the output I get: Erlang R14B04 (erts-5.8.5) [source] [64-bit] [rq:1] [async-threads:0] [kernel-poll:false] Eshell V5.8.5 (abort with ^G) (ejabberd@ns1)1> =INFO REPORT==== 15-Oct-2012::12:26:13 === I(<0.478.0>:ejabberd_listener:166) : Reusing listening port for 5222 =INFO REPORT==== 15-Oct-2012::12:26:13 === I(<0.479.0>:ejabberd_listener:166) : Reusing listening port for 5269 =INFO REPORT==== 15-Oct-2012::12:26:13 === I(<0.480.0>:ejabberd_listener:166) : Reusing listening port for 5280 =INFO REPORT==== 15-Oct-2012::12:26:13 === I(<0.40.0>:ejabberd_app:72) : ejabberd 2.1.10 is started in the node ejabberd@ns1 Then, the server appears to be running. I get a login prompt when I access http://mydomain.com:5280/admin/. Of course I can't login unless I create an account. At this time, the output of netstat -atnp | grep 5222 and netstat -atnp | grep 5280 is as follows: tcp 0 0 0.0.0.0:5222 0.0.0.0:* LISTEN 19347/beam tcp 0 0 0.0.0.0:5280 0.0.0.0:* LISTEN 19347/beam ejabberdctl Even when it appears ejabberd is running, trying to do anything with ejabberdctl fails. For example: trying to register a user: root@ns1:~# ejabberdctl register myusername mydomain.com mypassword Failed RPC connection to the node ejabberd@ns1: nodedown I have no idea what I'm doing wrong. This happens on two different servers I have with identical software installed (really not much of anything). Please help. Thanks.

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  • ORACLE RIGHTNOW DYNAMIC AGENT DESKTOP CLOUD SERVICE - Putting the Dynamite into Dynamic Agent Desktop

    - by Andreea Vaduva
    Untitled Document There’s a mountain of evidence to prove that a great contact centre experience results in happy, profitable and loyal customers. The very best Contact Centres are those with high first contact resolution, customer satisfaction and agent productivity. But how many companies really believe they are the best? And how many believe that they can be? We know that with the right tools, companies can aspire to greatness – and achieve it. Core to this is ensuring their agents have the best tools that give them the right information at the right time, so they can focus on the customer and provide a personalised, professional and efficient service. Today there are multiple channels through which customers can communicate with you; phone, web, chat, social to name a few but regardless of how they communicate, customers expect a seamless, quality experience. Most contact centre agents need to switch between lots of different systems to locate the right information. This hampers their productivity, frustrates both the agent and the customer and increases call handling times. With this in mind, Oracle RightNow has designed and refined a suite of add-ins to optimize the Agent Desktop. Each is designed to simplify and adapt the agent experience for any given situation and unify the customer experience across your media channels. Let’s take a brief look at some of the most useful tools available and see how they make a difference. Contextual Workspaces: The screen where agents do their job. Agents don’t want to be slowed down by busy screens, scrolling through endless tabs or links to find what they’re looking for. They want quick, accurate and easy. Contextual Workspaces are fully configurable and through workspace rules apply if, then, else logic to display only the information the agent needs for the issue at hand . Assigned at the Profile level, different levels of agent, from a novice to the most experienced, get a screen that is relevant to their role and responsibilities and ensures their job is done quickly and efficiently the first time round. Agent Scripting: Sometimes, agents need to deliver difficult or sensitive messages while maximising the opportunity to cross-sell and up-sell. After all, contact centres are now increasingly viewed as revenue generators. Containing sophisticated branching logic, scripting helps agents to capture the right level of information and guides the agent step by step, ensuring no mistakes, inconsistencies or missed opportunities. Guided Assistance: This is typically used to solve common troubleshooting issues, displaying a series of question and answer sets in a decision-tree structure. This means agents avoid having to bookmark favourites or rely on written notes. Agents find particular value in these guides - to quickly craft chat and email responses. What’s more, by publishing guides in answers on support pages customers, can resolve issues themselves, without needing to contact your agents. And b ecause it can also accelerate agent ramp-up time, it ensures that even novice agents can solve customer problems like an expert. Desktop Workflow: Take a step back and look at the full customer interaction of your agents. It probably spans multiple systems and multiple tasks. With Desktop Workflows you control the design workflows that span the full customer interaction from start to finish. As sequences of decisions and actions, workflows are unique in that they can create or modify different records and provide automation behind the scenes. This means your agents can save time and provide better quality of service by having the tools they need and the relevant information as required. And doing this boosts satisfaction among your customers, your agents and you – so win, win, win! I have highlighted above some of the tools which can be used to optimise the desktop; however, this is by no means an exhaustive list. In approaching your design, it’s important to understand why and how your customers contact you in the first place. Once you have this list of “whys” and “hows”, you can design effective policies and procedures to handle each category of problem, and then implement the right agent desktop user interface to support them. This will avoid duplication and wasted effort. Five Top Tips to take away: Start by working out “why” and “how” customers are contacting you. Implement a clean and relevant agent desktop to support your agents. If your workspaces are getting complicated consider using Desktop Workflow to streamline the interaction. Enhance your Knowledgebase with Guides. Agents can access them proactively and can be published on your web pages for customers to help themselves. Script any complex, critical or sensitive interactions to ensure consistency and accuracy. Desktop optimization is an ongoing process so continue to monitor and incorporate feedback from your agents and your customers to keep your Contact Centre successful.   Want to learn more? Having attending the 3-day Oracle RightNow Customer Service Administration class your next step is to attend the Oracle RightNow Customer Portal Design and 2-day Dynamic Agent Desktop Administration class. Here you’ll learn not only how to leverage the Agent Desktop tools but also how to optimise your self-service pages to enhance your customers’ web experience.   Useful resources: Review the Best Practice Guide Review the tune-up guide   About the Author: Angela Chandler joined Oracle University as a Senior Instructor through the RightNow Customer Experience Acquisition. Her other areas of expertise include Business Intelligence and Knowledge Management.  She currently delivers the following Oracle RightNow courses in the classroom and as a Live Virtual Class: RightNow Customer Service Administration (3 days) RightNow Customer Portal Design and Dynamic Agent Desktop Administration (2 days) RightNow Analytics (2 days) Rightnow Chat Cloud Service Administration (2 days)

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  • What can I do with dynamic typing that I can not do with static typing

    - by Justin984
    I've been using python for a few days now and I think I understand the difference between dynamic and static typing. What I don't understand is why it's useful. I keep hearing about its "flexibility" but it seems like it just moves a bunch of compile time checks to runtime, which means more unit tests. This seems like an awfully big tradeoff to make for small advantages like readability and "flexibility". Can someone provide me with a real world example where dynamic typing allows me to do something I can't do with static typing?

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  • Is GParted safe?

    - by Olivier Pons
    I want to resize my partitions: I have 3 partitions: Ubuntu 10.04 Windows Seven Ubuntu 11.10 It's booting with the boot installed by the Ubuntu 11.10 version. I want to expand (only expand) all the 3 partitions. My HD is 1,8 Tb so it's big and I have no possibility to save before expanding. So my question is: if you tell me GParted work 99,99 % of the time, I'm willing to take the risk. If you tell me GParted work 90 % of the time, I won't take that risk.

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  • T-SQL Tuesday #4: I/O, You Know

    - by Kalen Delaney
    It's time for the fourth T-SQL Tuesday , managed this time by Mike Walsh . I almost missed this deadline completely, since I didn't see the announcement at all. I wrote to Adam to ask if there even was an event this month, since I wasn't able to get into my own blog site ( www.SQLBlog.com ) for a week, and he pointed me to Mike's site. I'm wondering if it's this hit and miss for everyone. There is no single location where those people interested in T-SQL Tuesday can find out about it. Do you just...(read more)

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  • NightHacking demo: Java in the Internet of Things

    - by terrencebarr
    The NightHacking session with Steven Chin was good fun. Check out the video on “Java in the Internet of Things” and a live demo of the Smart Solar Tracking System with Java ME Embedded 3.2. Real hardware and demo flakiness included See here. While you are at, have a look at some of the other NightHacking sessions and a number of other videos on the YouTube Java Channel. Cheers, – Terrence Filed under: Mobile & Embedded Tagged: "Oracle Java ME Embedded", demo, embedded, iot, Java Embedded, nighthacking, video, webcast

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  • NightHacking demo: Java in the Internet of Things

    - by terrencebarr
    The NightHacking session with Steven Chin was good fun. Check out the video on “Java in the Internet of Things” and a live demo of the Smart Solar Tracking System with Java ME Embedded 3.2. Real hardware and demo flakiness included See here. While you are at, have a look at some of the other NightHacking sessions and a number of other videos on the YouTube Java Channel. Cheers, – Terrence Filed under: Mobile & Embedded Tagged: "Oracle Java ME Embedded", demo, embedded, iot, Java Embedded, nighthacking, video, webcast

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  • Is Python worth learning? Is it a useful tool? [closed]

    - by Kenneth
    I recently had a discussion with a professor of mine on the topic of web development. I had recently decided I would learn python to increase my arsenal of web tools which I mentioned to him at that time. He almost immediately asked why I would waste my time on that. I'm not certain but I think he recently started in on researching and studying web development so he could pick up the web development classes that haven't been taught for a while after the previous professor who taught those classes left. I've heard a lot about python and thought maybe he was mistaken about its usefulness. Is python a useful tool to have? What applications can it be used for? Is it better than other similar alternatives? Does it have useful applications outside of web development as well?

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  • Learn All About MySQL Cluster

    - by Antoinette O'Sullivan
    Just released - the all new MySQL Cluster training course. This MySQL Cluster training teaches you how to install and configure a real-time database cluster at the core of your application. Expert instructors will teach you how to design and maintain your clusters for high availability and scalability by using MySQL Cluster's open-source and enterprise components. This 4-day training course is a must for those who want to learn about MySQL Cluster as you will not only learn about the concepts and features but you will get extensive hands-on experience. You can follow this training course from your own desk via a live-virtual training or by traveling to an education center to follow this course. Be the first to influence the schedule for this newly released course by registering your interest on the Oracle University portal. For more information about the authentic MySQL curriculum, go to http://education.oracle.com/mysql

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  • Problem installing Ubuntu 10.04 64 bit side by side with Vista by using a bootable USB drive. What n

    - by Adam Siddhi
    What happened I decided to install Ubuntu 10.04 64 bit side by side with Vista Home Premium (I guess on another partition) with a USB stick. I found instructions on how to do this here: https://help.ubuntu.com/community/Installation/FromUSBStick To create the bootable USB drive I had to download a program called Unetbootin. That process was simple enough. All I had to do was just choose the disk image option, select the ubuntu-10.04-desktop-amd64.iso image, make sure it recognizes my USB drive and then press OK. It takes only like a few minutes to create a working bootable USB drive. Then I have to restart my computer, enter the BIOS, select my USB drive as the first boot drive, save options and continue with booting up. After this Ubuntu actually loads up. I think this is known as the Live version of Ubuntu so you can try it out before fully installing it. Any ways, on the Ubuntu 10.04 desktop I saw an installer. I click it and begin the installation process. Just so you know, I tried installing it 2 times. I will explain what happened each time: The first time I tried installing Ubuntu 10.04 I got stuck at step 4 of 7. I remember selecting the last option in the window which was Specify Partitions Manually (Advanced) I made my partition for Ubuntu like 52 gigs. I clicked forward and a little pop up window appeared saying Please Wait. So the installation process stalled on this window so I closed out of it and quit the installation process. So at this point I was worried because I had already selected the partition size and assumed it started making it. Since it stalled I had to quit out though. Anyways, once again I reached step 4 of 7 a decided to select the first option which is Install them side by side choosing between them each startup. I figured this was the safe way to go. I did that and the pop up window saying Please Wait popped up again but lasted only like 10 seconds. Then I got to I guess step 6 where it asks you to enter your desired name and password. Did that and clicked forward. The Ubuntu 10.04 installation load screen appeared and the loading bar at the bottom started filling up. So I got to 83% and stalled during the Importing other profile information (I think it was called this. I had the option to do this during I think step 6) process. So at this point I decided to get stop the installation process. I was getting very nervous. I tried to restart the computer but all that happened was that Ubuntu restarted. I finally got the computer to restart. I was pretty sure I had screwed something up big time by this point. As my computer was restarting I entered BIOS again and switched back to it booting from my main hard drive containing Vista. Saved it and continued the boot process. My worst fears were confirmed as Vista would not boot up. I mean I saw the little Microsoft Windows choppy animated green loading bar at the bottom of the screen and then boom! It decided to restart. When it restarted I had the option to run a memory test check to see if there was anything that needed to be repaired. That took like 20 minutes and at the end I saw that I did indeed have to repair something. I had to go through 2 repair processes. After each I had to restart the computer. The 2nd time it went through the repair process it said that it could not fully repair the damage. I was scared and restarted but Vista did load up. I got to my desktop and saw a message saying something like Repairs have been made, Please restart for changes to take effect I noticed that some Notification icons were missing and I could not hear volume in a video. Things were a bit funky. So I did restart and here I am. Now what?! So since I got back into Vista and thankfully have a working Internet connection I am trying to find answers to my problem (that is why I am writing this post). I am scared that I have partioned my hard drive 2 times after researching Installing Ubuntu 10.04 and seeing this post http://techie-buzz.com/foss/ubuntu-10-04-lts-installation-guide.html The author shows screen shots of installing Ubuntu 10.04. He shows the image of step 4 of 7 with a caption at the bottom. I will recreate it below: Select a partitioning option. Unless you want to format all the hard drive and install Ubuntu afresh, select the last option and proceed. Questions If I have indeed partitioned my HD 2 times (which I am sure it is), how do I get to a point where I can see all my bad, unfinished Ubuntu partitions and get rid of them? How do I clean this big mess up? & How can I ensure that this mess will not happen next time I try installing Ubuntu 10.04? Thank you Adam

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  • PTLQueue : a scalable bounded-capacity MPMC queue

    - by Dave
    Title: Fast concurrent MPMC queue -- I've used the following concurrent queue algorithm enough that it warrants a blog entry. I'll sketch out the design of a fast and scalable multiple-producer multiple-consumer (MPSC) concurrent queue called PTLQueue. The queue has bounded capacity and is implemented via a circular array. Bounded capacity can be a useful property if there's a mismatch between producer rates and consumer rates where an unbounded queue might otherwise result in excessive memory consumption by virtue of the container nodes that -- in some queue implementations -- are used to hold values. A bounded-capacity queue can provide flow control between components. Beware, however, that bounded collections can also result in resource deadlock if abused. The put() and take() operators are partial and wait for the collection to become non-full or non-empty, respectively. Put() and take() do not allocate memory, and are not vulnerable to the ABA pathologies. The PTLQueue algorithm can be implemented equally well in C/C++ and Java. Partial operators are often more convenient than total methods. In many use cases if the preconditions aren't met, there's nothing else useful the thread can do, so it may as well wait via a partial method. An exception is in the case of work-stealing queues where a thief might scan a set of queues from which it could potentially steal. Total methods return ASAP with a success-failure indication. (It's tempting to describe a queue or API as blocking or non-blocking instead of partial or total, but non-blocking is already an overloaded concurrency term. Perhaps waiting/non-waiting or patient/impatient might be better terms). It's also trivial to construct partial operators by busy-waiting via total operators, but such constructs may be less efficient than an operator explicitly and intentionally designed to wait. A PTLQueue instance contains an array of slots, where each slot has volatile Turn and MailBox fields. The array has power-of-two length allowing mod/div operations to be replaced by masking. We assume sensible padding and alignment to reduce the impact of false sharing. (On x86 I recommend 128-byte alignment and padding because of the adjacent-sector prefetch facility). Each queue also has PutCursor and TakeCursor cursor variables, each of which should be sequestered as the sole occupant of a cache line or sector. You can opt to use 64-bit integers if concerned about wrap-around aliasing in the cursor variables. Put(null) is considered illegal, but the caller or implementation can easily check for and convert null to a distinguished non-null proxy value if null happens to be a value you'd like to pass. Take() will accordingly convert the proxy value back to null. An advantage of PTLQueue is that you can use atomic fetch-and-increment for the partial methods. We initialize each slot at index I with (Turn=I, MailBox=null). Both cursors are initially 0. All shared variables are considered "volatile" and atomics such as CAS and AtomicFetchAndIncrement are presumed to have bidirectional fence semantics. Finally T is the templated type. I've sketched out a total tryTake() method below that allows the caller to poll the queue. tryPut() has an analogous construction. Zebra stripping : alternating row colors for nice-looking code listings. See also google code "prettify" : https://code.google.com/p/google-code-prettify/ Prettify is a javascript module that yields the HTML/CSS/JS equivalent of pretty-print. -- pre:nth-child(odd) { background-color:#ff0000; } pre:nth-child(even) { background-color:#0000ff; } border-left: 11px solid #ccc; margin: 1.7em 0 1.7em 0.3em; background-color:#BFB; font-size:12px; line-height:65%; " // PTLQueue : Put(v) : // producer : partial method - waits as necessary assert v != null assert Mask = 1 && (Mask & (Mask+1)) == 0 // Document invariants // doorway step // Obtain a sequence number -- ticket // As a practical concern the ticket value is temporally unique // The ticket also identifies and selects a slot auto tkt = AtomicFetchIncrement (&PutCursor, 1) slot * s = &Slots[tkt & Mask] // waiting phase : // wait for slot's generation to match the tkt value assigned to this put() invocation. // The "generation" is implicitly encoded as the upper bits in the cursor // above those used to specify the index : tkt div (Mask+1) // The generation serves as an epoch number to identify a cohort of threads // accessing disjoint slots while s-Turn != tkt : Pause assert s-MailBox == null s-MailBox = v // deposit and pass message Take() : // consumer : partial method - waits as necessary auto tkt = AtomicFetchIncrement (&TakeCursor,1) slot * s = &Slots[tkt & Mask] // 2-stage waiting : // First wait for turn for our generation // Acquire exclusive "take" access to slot's MailBox field // Then wait for the slot to become occupied while s-Turn != tkt : Pause // Concurrency in this section of code is now reduced to just 1 producer thread // vs 1 consumer thread. // For a given queue and slot, there will be most one Take() operation running // in this section. // Consumer waits for producer to arrive and make slot non-empty // Extract message; clear mailbox; advance Turn indicator // We have an obvious happens-before relation : // Put(m) happens-before corresponding Take() that returns that same "m" for T v = s-MailBox if v != null : s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 // unlock slot to admit next producer and consumer return v Pause tryTake() : // total method - returns ASAP with failure indication for auto tkt = TakeCursor slot * s = &Slots[tkt & Mask] if s-Turn != tkt : return null T v = s-MailBox // presumptive return value if v == null : return null // ratify tkt and v values and commit by advancing cursor if CAS (&TakeCursor, tkt, tkt+1) != tkt : continue s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 return v The basic idea derives from the Partitioned Ticket Lock "PTL" (US20120240126-A1) and the MultiLane Concurrent Bag (US8689237). The latter is essentially a circular ring-buffer where the elements themselves are queues or concurrent collections. You can think of the PTLQueue as a partitioned ticket lock "PTL" augmented to pass values from lock to unlock via the slots. Alternatively, you could conceptualize of PTLQueue as a degenerate MultiLane bag where each slot or "lane" consists of a simple single-word MailBox instead of a general queue. Each lane in PTLQueue also has a private Turn field which acts like the Turn (Grant) variables found in PTL. Turn enforces strict FIFO ordering and restricts concurrency on the slot mailbox field to at most one simultaneous put() and take() operation. PTL uses a single "ticket" variable and per-slot Turn (grant) fields while MultiLane has distinct PutCursor and TakeCursor cursors and abstract per-slot sub-queues. Both PTL and MultiLane advance their cursor and ticket variables with atomic fetch-and-increment. PTLQueue borrows from both PTL and MultiLane and has distinct put and take cursors and per-slot Turn fields. Instead of a per-slot queues, PTLQueue uses a simple single-word MailBox field. PutCursor and TakeCursor act like a pair of ticket locks, conferring "put" and "take" access to a given slot. PutCursor, for instance, assigns an incoming put() request to a slot and serves as a PTL "Ticket" to acquire "put" permission to that slot's MailBox field. To better explain the operation of PTLQueue we deconstruct the operation of put() and take() as follows. Put() first increments PutCursor obtaining a new unique ticket. That ticket value also identifies a slot. Put() next waits for that slot's Turn field to match that ticket value. This is tantamount to using a PTL to acquire "put" permission on the slot's MailBox field. Finally, having obtained exclusive "put" permission on the slot, put() stores the message value into the slot's MailBox. Take() similarly advances TakeCursor, identifying a slot, and then acquires and secures "take" permission on a slot by waiting for Turn. Take() then waits for the slot's MailBox to become non-empty, extracts the message, and clears MailBox. Finally, take() advances the slot's Turn field, which releases both "put" and "take" access to the slot's MailBox. Note the asymmetry : put() acquires "put" access to the slot, but take() releases that lock. At any given time, for a given slot in a PTLQueue, at most one thread has "put" access and at most one thread has "take" access. This restricts concurrency from general MPMC to 1-vs-1. We have 2 ticket locks -- one for put() and one for take() -- each with its own "ticket" variable in the form of the corresponding cursor, but they share a single "Grant" egress variable in the form of the slot's Turn variable. Advancing the PutCursor, for instance, serves two purposes. First, we obtain a unique ticket which identifies a slot. Second, incrementing the cursor is the doorway protocol step to acquire the per-slot mutual exclusion "put" lock. The cursors and operations to increment those cursors serve double-duty : slot-selection and ticket assignment for locking the slot's MailBox field. At any given time a slot MailBox field can be in one of the following states: empty with no pending operations -- neutral state; empty with one or more waiting take() operations pending -- deficit; occupied with no pending operations; occupied with one or more waiting put() operations -- surplus; empty with a pending put() or pending put() and take() operations -- transitional; or occupied with a pending take() or pending put() and take() operations -- transitional. The partial put() and take() operators can be implemented with an atomic fetch-and-increment operation, which may confer a performance advantage over a CAS-based loop. In addition we have independent PutCursor and TakeCursor cursors. Critically, a put() operation modifies PutCursor but does not access the TakeCursor and a take() operation modifies the TakeCursor cursor but does not access the PutCursor. This acts to reduce coherence traffic relative to some other queue designs. It's worth noting that slow threads or obstruction in one slot (or "lane") does not impede or obstruct operations in other slots -- this gives us some degree of obstruction isolation. PTLQueue is not lock-free, however. The implementation above is expressed with polite busy-waiting (Pause) but it's trivial to implement per-slot parking and unparking to deschedule waiting threads. It's also easy to convert the queue to a more general deque by replacing the PutCursor and TakeCursor cursors with Left/Front and Right/Back cursors that can move either direction. Specifically, to push and pop from the "left" side of the deque we would decrement and increment the Left cursor, respectively, and to push and pop from the "right" side of the deque we would increment and decrement the Right cursor, respectively. We used a variation of PTLQueue for message passing in our recent OPODIS 2013 paper. ul { list-style:none; padding-left:0; padding:0; margin:0; margin-left:0; } ul#myTagID { padding: 0px; margin: 0px; list-style:none; margin-left:0;} -- -- There's quite a bit of related literature in this area. I'll call out a few relevant references: Wilson's NYU Courant Institute UltraComputer dissertation from 1988 is classic and the canonical starting point : Operating System Data Structures for Shared-Memory MIMD Machines with Fetch-and-Add. Regarding provenance and priority, I think PTLQueue or queues effectively equivalent to PTLQueue have been independently rediscovered a number of times. See CB-Queue and BNPBV, below, for instance. But Wilson's dissertation anticipates the basic idea and seems to predate all the others. Gottlieb et al : Basic Techniques for the Efficient Coordination of Very Large Numbers of Cooperating Sequential Processors Orozco et al : CB-Queue in Toward high-throughput algorithms on many-core architectures which appeared in TACO 2012. Meneghin et al : BNPVB family in Performance evaluation of inter-thread communication mechanisms on multicore/multithreaded architecture Dmitry Vyukov : bounded MPMC queue (highly recommended) Alex Otenko : US8607249 (highly related). John Mellor-Crummey : Concurrent queues: Practical fetch-and-phi algorithms. Technical Report 229, Department of Computer Science, University of Rochester Thomasson : FIFO Distributed Bakery Algorithm (very similar to PTLQueue). Scott and Scherer : Dual Data Structures I'll propose an optimization left as an exercise for the reader. Say we wanted to reduce memory usage by eliminating inter-slot padding. Such padding is usually "dark" memory and otherwise unused and wasted. But eliminating the padding leaves us at risk of increased false sharing. Furthermore lets say it was usually the case that the PutCursor and TakeCursor were numerically close to each other. (That's true in some use cases). We might still reduce false sharing by incrementing the cursors by some value other than 1 that is not trivially small and is coprime with the number of slots. Alternatively, we might increment the cursor by one and mask as usual, resulting in a logical index. We then use that logical index value to index into a permutation table, yielding an effective index for use in the slot array. The permutation table would be constructed so that nearby logical indices would map to more distant effective indices. (Open question: what should that permutation look like? Possibly some perversion of a Gray code or De Bruijn sequence might be suitable). As an aside, say we need to busy-wait for some condition as follows : "while C == 0 : Pause". Lets say that C is usually non-zero, so we typically don't wait. But when C happens to be 0 we'll have to spin for some period, possibly brief. We can arrange for the code to be more machine-friendly with respect to the branch predictors by transforming the loop into : "if C == 0 : for { Pause; if C != 0 : break; }". Critically, we want to restructure the loop so there's one branch that controls entry and another that controls loop exit. A concern is that your compiler or JIT might be clever enough to transform this back to "while C == 0 : Pause". You can sometimes avoid this by inserting a call to a some type of very cheap "opaque" method that the compiler can't elide or reorder. On Solaris, for instance, you could use :"if C == 0 : { gethrtime(); for { Pause; if C != 0 : break; }}". It's worth noting the obvious duality between locks and queues. If you have strict FIFO lock implementation with local spinning and succession by direct handoff such as MCS or CLH,then you can usually transform that lock into a queue. Hidden commentary and annotations - invisible : * And of course there's a well-known duality between queues and locks, but I'll leave that topic for another blog post. * Compare and contrast : PTLQ vs PTL and MultiLane * Equivalent : Turn; seq; sequence; pos; position; ticket * Put = Lock; Deposit Take = identify and reserve slot; wait; extract & clear; unlock * conceptualize : Distinct PutLock and TakeLock implemented as ticket lock or PTL Distinct arrival cursors but share per-slot "Turn" variable provides exclusive role-based access to slot's mailbox field put() acquires exclusive access to a slot for purposes of "deposit" assigns slot round-robin and then acquires deposit access rights/perms to that slot take() acquires exclusive access to slot for purposes of "withdrawal" assigns slot round-robin and then acquires withdrawal access rights/perms to that slot At any given time, only one thread can have withdrawal access to a slot at any given time, only one thread can have deposit access to a slot Permissible for T1 to have deposit access and T2 to simultaneously have withdrawal access * round-robin for the purposes of; role-based; access mode; access role mailslot; mailbox; allocate/assign/identify slot rights; permission; license; access permission; * PTL/Ticket hybrid Asymmetric usage ; owner oblivious lock-unlock pairing K-exclusion add Grant cursor pass message m from lock to unlock via Slots[] array Cursor performs 2 functions : + PTL ticket + Assigns request to slot in round-robin fashion Deconstruct protocol : explication put() : allocate slot in round-robin fashion acquire PTL for "put" access store message into slot associated with PTL index take() : Acquire PTL for "take" access // doorway step seq = fetchAdd (&Grant, 1) s = &Slots[seq & Mask] // waiting phase while s-Turn != seq : pause Extract : wait for s-mailbox to be full v = s-mailbox s-mailbox = null Release PTL for both "put" and "take" access s-Turn = seq + Mask + 1 * Slot round-robin assignment and lock "doorway" protocol leverage the same cursor and FetchAdd operation on that cursor FetchAdd (&Cursor,1) + round-robin slot assignment and dispersal + PTL/ticket lock "doorway" step waiting phase is via "Turn" field in slot * PTLQueue uses 2 cursors -- put and take. Acquire "put" access to slot via PTL-like lock Acquire "take" access to slot via PTL-like lock 2 locks : put and take -- at most one thread can access slot's mailbox Both locks use same "turn" field Like multilane : 2 cursors : put and take slot is simple 1-capacity mailbox instead of queue Borrow per-slot turn/grant from PTL Provides strict FIFO Lock slot : put-vs-put take-vs-take at most one put accesses slot at any one time at most one put accesses take at any one time reduction to 1-vs-1 instead of N-vs-M concurrency Per slot locks for put/take Release put/take by advancing turn * is instrumental in ... * P-V Semaphore vs lock vs K-exclusion * See also : FastQueues-excerpt.java dice-etc/queue-mpmc-bounded-blocking-circular-xadd/ * PTLQueue is the same as PTLQB - identical * Expedient return; ASAP; prompt; immediately * Lamport's Bakery algorithm : doorway step then waiting phase Threads arriving at doorway obtain a unique ticket number Threads enter in ticket order * In the terminology of Reed and Kanodia a ticket lock corresponds to the busy-wait implementation of a semaphore using an eventcount and a sequencer It can also be thought of as an optimization of Lamport's bakery lock was designed for fault-tolerance rather than performance Instead of spinning on the release counter, processors using a bakery lock repeatedly examine the tickets of their peers --

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  • High CPU load - Ubuntu 14.04

    - by watt
    I noticed that sometimes when browsing (with other processes in the background), I get very high CPU load for the browser process (over 100%) and the computer becomes really slow. I tried switching from Firefox (with just a few extensions) to Chromium, but same thing happens without me visiting graphics-intense sites, flash sites or anything like that. I also noticed python or node (when running "make") produce the same high CPU load from time to time so this is not necessarily browser-related. When I only have a browser open, it doesn't seem to happen and everything is fine in Windows 7. I switched from unity to gnome3 with no effect. Specs: lenovo w510 (4gb RAM, i7 q820 @ 1.73) + up to date Ubuntu 14.04 64bit. Printscreen: http://imgur.com/8MZJNKC Do you guys have any idea why this might happen? Please let me know if there's other info you need. Thanks!

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  • Oracle on Oracle: Is that all?

    - by Darin Pendergraft
    On October 17th, I posted a short blog and a podcast interview with Chirag Andani, talking about how Oracle IT uses its own IDM products. Blog link here. In response, I received a comment from reader Jaime Cardoso ([email protected]) who posted: “- You could have talked about how by deploying Oracle's Open standards base technology you were able to integrate any new system in your infrastructure in days. - You could have talked about how by deploying federation you were enabling the business side to keep all their options open in terms of companies to buy and sell while maintaining perfect employee and customer's single view. - You could have talked about how you are now able to cut response times to your audit and security teams into 1/10th of your former times Instead you spent 6 minutes talking about single sign on and self provisioning? If I didn't knew your IDM offer so well I would now be wondering what its differences from Microsoft's offer was. Sorry for not giving a positive comment here but, please your IDM suite is very good and, you simply aren't promoting it well enough” So I decided to send Jaime a note asking him about his experience, and to get his perspective on what makes the Oracle products great. What I found out is that Jaime is a very experienced IDM Architect with several major projects under his belt. Darin Pendergraft: Can you tell me a bit about your experience? How long have you worked in IT, and what is your IDM experience? Jaime Cardoso: I started working in "serious" IT in 1998 when I became Netscape's technical specialist in Portugal. Netscape Portugal didn't exist so, I was working for their VAR here. Most of my work at the time was with Netscape's mail server and LDAP server. Since that time I've been bouncing between the system's side like Sun resellers, Solaris stuff and even worked with Sun's Engineering in the making of an Hierarchical Storage Product (Sun CIS if you know it) and the application's side, mostly in LDAP and IDM. Over the years I've been doing support, service delivery and pre-sales / architecture design of IDM solutions in most big customers in Portugal, to name a few projects: - The first European deployment of Sun Access Manager (SAPO – Portugal Telecom) - The identity repository of 5/5 of the Biggest Portuguese banks - The Portuguese government federation of services project DP: OK, in your blog response, you mentioned 3 topics: 1. Using Oracle's standards based architecture; (you) were able to integrate any new system in days: can you give an example? What systems, how long did it take, number of apps/users/accounts/roles etc. JC: It's relatively easy to design a user management strategy for a static environment, or if you simply assume that you're an <insert vendor here> shop and all your systems will bow to that vendor's will. We've all seen that path, the use of proprietary technologies in interoperability solutions but, then reality kicks in. As an ISP I recall that I made the technical decision to use Active Directory as a central authentication system for the entire IT infrastructure. Clients, systems, apps, everything was there. As a good part of the systems and apps were running on UNIX, then a connector became needed in order to have UNIX boxes to authenticate against AD. And, that strategy worked but, each new machine required the component to be installed, monitoring had to be made for that component and each new app had to be independently certified. A self care user portal was an ongoing project, AD access assumes the client is inside the domain, something the ISP's customers (and UNIX boxes) weren't nor had any intention of ever being. When the Windows 2008 rollout was done, Microsoft changed the Active Directory interface. The Windows administrators didn't have enough know-how about directories and the way systems outside the MS world behaved so, on the go live, things weren't properly tested and a general outage followed. Several hours and 1 roll back later, everything was back working. But, the ISP still had to change all of its applications to work with the new access methods and reset the effort spent on the self service user portal. To keep with the same strategy, they would also have to trust Microsoft not to change interfaces again. Simply by putting up an Oracle LDAP server in the middle and replicating the user info from the AD into LDAP, most of the problems went away. Even systems for which no AD connector existed had PAM in them so, integration was made at the OS level, fully supported by the OS supplier. Sun Identity Manager already had a self care portal, combined with a user workflow so, all the clearances had to be given before the account was created or updated. Adding a new system as a client for these authentication services was simply a new checkbox in the OS installer and, even True64 systems were, for the first time integrated also with a 5 minute work of a junior system admin. True, all the windows clients and MS apps still went to the AD for their authentication needs so, from the start everybody knew that they weren't 100% free of migration pains but, now they had a single point of problems to look at. If you're looking for numbers: - 500K directory entries (users) - 2-300 systems After the initial setup, I personally integrated about 20 systems / apps against LDAP in 1 day while being watched by the different IT teams. The internal IT staff did the rest. DP: 2. Using Federation allows the business to keep options open for buying and selling companies, and yet maintain a single view for both employee and customer. What do you mean by this? Can you give an example? JC: The market is dynamic. The company that's being bought today tomorrow will be sold again. Companies that spread on different markets may see the regulator forcing a sale of part of a company due to monopoly reasons and companies that are in multiple countries have to comply with different legislations. Our job, as IT architects, while addressing the customers and employees authentication services, is quite hard and, quite contrary. On one hand, we need to give access to all of our employees to the relevant systems, apps and resources and, we already have marketing talking with us trying to find out who's a customer of the bough company but not from ours to address. On the other hand, we have to do that and keep in mind we may have to break up all that effort and that different countries legislation may became a problem with a full integration plan. That's a job for user Federation. you don't want to be the one who's telling your President that he will sell that business unit without it's customer's database (making the deal worth a lot less) or that the buyer will take with him a copy of your entire customer's database. Federation enables you to start controlling permissions to users outside of your traditional authentication realm. So what if the people of that company you just bought are keeping their old logins? Do you want, because of that, to have a dedicated system for their expenses reports? And do you want to keep their sales (and pre-sales) people out of the loop in terms of your group's path? Control the information flow, establish a Federation trust circle and give access to your apps to users that haven't (yet?) been brought into your internal login systems. You can still see your users in a unified view, you obviously control if a user has access to any particular application, either that user is in your local database or stored in a directory on the other side of the world. DP: 3. Cut response times of audit and security teams to 1/10. Is this a real number? Can you give an example? JC: No, I don't have any backing for this number. One of the companies I did system Administration for has a SOX compliance policy in place (I remind you that I live in Portugal so, this definition of SOX may be somewhat different from what you're used to) and, every time the audit team says they'll do another audit, we have to negotiate with them the size of the sample and we spend about 15 man/days gathering all the required info they ask. I did some work with Sun's Identity auditor and, from what I've been seeing, Oracle's product is even better and, I've seen that most of the information they ask would have been provided in a few hours with the help of this tool. I do stand by what I said here but, to be honest, someone from Identity Auditor team would do a much better job than me explaining this time savings. Jaime is right: the Oracle IDM products have a lot of business value, and Oracle IT is using them for a lot more than I was able to cover in the short podcast that I posted. I want to thank Jaime for his comments and perspective. We want these blog posts to be informative and honest – so if you have feedback for the Oracle IDM team on any topic discussed here, please post your comments below.

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