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  • Which is Better? The Start Screen in Windows 8 or the Old Start Menu? [Analysis]

    - by Asian Angel
    There has been quite a bit of controversy surrounding Microsoft’s emphasis on the new Metro UI Start Screen in Windows 8, but when it comes down to it which is really better? The Start Screen in Windows 8 or the old Start Menu? Tech blog 7 Tutorials has done a quick analysis to see which one actually works better (and faster) when launching applications and doing searches. Images courtesy of 7 Tutorials. You can view the results and a comparison table by visiting the blog post linked below. Windows 8 Analysis: Is the Start Screen an Improvement vs. the Start Menu? [7 Tutorials] How to Stress Test the Hard Drives in Your PC or Server How To Customize Your Android Lock Screen with WidgetLocker The Best Free Portable Apps for Your Flash Drive Toolkit

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  • Managing Database Clusters - A Whole Lot Simpler

    - by mat.keep(at)oracle.com
    Clustered computing brings with it many benefits: high performance, high availability, scalable infrastructure, etc.  But it also brings with it more complexity.Why ?  Well, by its very nature, there are more "moving parts" to monitor and manage (from physical, virtual and logical hosts) to fault detection and failover software to redundant networking components - the list goes on.  And a cluster that isn't effectively provisioned and managed will cause more downtime than the standalone systems it is designed to improve upon.  Not so great....When it comes to the database industry, analysts already estimate that 50% of a typical database's Total Cost of Ownership is attributable to staffing and downtime costs.  These costs will only increase if a database cluster is to hard to properly administer.Over the past 9 months, monitoring and management has been a major focus in the development of the MySQL Cluster database, and on Tuesday 12th January, the product team will be presenting the output of that development in a new webinar.Even if you can't make the date, it is still worth registering so you will receive automatic notification when the on-demand replay is availableIn the webinar, the team will cover:    * NDBINFO: released with MySQL Cluster 7.1, NDBINFO presents real-time status and usage statistics, providing developers and DBAs with a simple means of pro-actively monitoring and optimizing database performance and availability.    * MySQL Cluster Manager (MCM): available as part of the commercial MySQL Cluster Carrier Grade Edition, MCM simplifies the creation and management of MySQL Cluster by automating common management tasks, delivering higher administration productivity and enhancing cluster agility. Tasks that used to take 46 commands can be reduced to just one!    * MySQL Cluster Advisors & Graphs: part of the MySQL Enterprise Monitor and available in the commercial MySQL Cluster Carrier Grade Edition, the Enterprise Advisor includes automated best practice rules that alert on key performance and availability metrics from MySQL Cluster data nodes.You'll also learn how you can get started evaluating and using all of these tools to simplify MySQL Cluster management.This session will last round an hour and will include interactive Q&A throughout. You can learn more about MySQL Cluster Manager from this whitepaper and on-line demonstration.  You can also download the packages from eDelivery (just select "MySQL Database" as the product pack, select your platform, click "Go" and then scroll down to get the software).While managing clusters will never be easy, the webinar will show hou how it just got a whole lot simpler !

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  • The Beginner’s Guide to Managing Users and Groups in Linux

    - by Zainul Franciscus
    Ubuntu Linux uses groups to help you manage users, set permissions on those users, and even monitor how much time they are spending in front of the PC. Here’s a beginner’s guide to how it all works Latest Features How-To Geek ETC The How-To Geek Holiday Gift Guide (Geeky Stuff We Like) LCD? LED? Plasma? The How-To Geek Guide to HDTV Technology The How-To Geek Guide to Learning Photoshop, Part 8: Filters Improve Digital Photography by Calibrating Your Monitor Our Favorite Tech: What We’re Thankful For at How-To Geek The How-To Geek Guide to Learning Photoshop, Part 7: Design and Typography Happy Snow Bears Theme for Chrome and Iron [Holiday] Download Full Command and Conquer: Tiberian Sun Game for Free Scorched Cometary Planet Wallpaper Quick Fix: Add the RSS Button Back to the Firefox Awesome Bar Dropbox Desktop Client 1.0.0 RC for Windows, Linux, and Mac Released Hang in There Scrat! – Ice Age Wallpaper

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  • External USB drive is failing

    - by dma_k
    I have an external USB 2.0 drive WD My Book Mirror Edition, running in RAID 1 (mirroring) mode. A while ago the hard drive started to fail: it stops responding (directories are not listed returning an error after a big timeout). Sometimes it works for weeks before a failure, sometimes – few hours. Small write operations (like removing few files or editing a small file) do not harm, but when copying large files to the drive over the network, or creating the archive locally, the kernel dumps. Also interesting to note that once kernel has failed, Linux does not want to reboot normally (reboot hangs); when Linux box is shutdown with power button, WD drive does not go to sleep mode (as it usually does): leds continue to run, pressing and holding the "shutdown" button on drive's back panel does not do anything; only unplugging the power cord helps. Here goes the boot log: Aug 16 00:32:21 kernel: [ 1.514106] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver Aug 16 00:32:21 kernel: [ 1.657738] ehci_hcd 0000:00:1d.7: PCI INT A -> GSI 23 (level, low) -> IRQ 23 Aug 16 00:32:21 kernel: [ 1.673747] ehci_hcd 0000:00:1d.7: setting latency timer to 64 Aug 16 00:32:21 kernel: [ 1.673751] ehci_hcd 0000:00:1d.7: EHCI Host Controller Aug 16 00:32:21 kernel: [ 1.725224] ehci_hcd 0000:00:1d.7: new USB bus registered, assigned bus number 1 Aug 16 00:32:21 kernel: [ 1.741647] ehci_hcd 0000:00:1d.7: using broken periodic workaround Aug 16 00:32:21 kernel: [ 1.761790] ehci_hcd 0000:00:1d.7: cache line size of 32 is not supported Aug 16 00:32:21 kernel: [ 1.761873] ehci_hcd 0000:00:1d.7: irq 23, io mem 0xfdfff000 Aug 16 00:32:21 kernel: [ 1.796043] ehci_hcd 0000:00:1d.7: USB 2.0 started, EHCI 1.00 Aug 16 00:32:21 kernel: [ 1.879069] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002 Aug 16 00:32:21 kernel: [ 1.895446] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1 Aug 16 00:32:21 kernel: [ 1.911796] usb usb1: Product: EHCI Host Controller Aug 16 00:32:21 kernel: [ 1.928015] usb usb1: Manufacturer: Linux 2.6.32-5-686 ehci_hcd Aug 16 00:32:21 kernel: [ 1.944331] usb usb1: SerialNumber: 0000:00:1d.7 Aug 16 00:32:21 kernel: [ 1.961285] usb usb1: configuration #1 chosen from 1 choice Aug 16 00:32:21 kernel: [ 1.994412] hub 1-0:1.0: USB hub found Aug 16 00:32:21 kernel: [ 2.010864] hub 1-0:1.0: 8 ports detected Aug 16 00:32:21 kernel: [ 2.085939] uhci_hcd: USB Universal Host Controller Interface driver Aug 16 00:32:21 kernel: [ 2.191945] uhci_hcd 0000:00:1d.0: PCI INT A -> GSI 23 (level, low) -> IRQ 23 Aug 16 00:32:21 kernel: [ 2.226029] uhci_hcd 0000:00:1d.0: setting latency timer to 64 Aug 16 00:32:21 kernel: [ 2.226034] uhci_hcd 0000:00:1d.0: UHCI Host Controller Aug 16 00:32:21 kernel: [ 2.243237] uhci_hcd 0000:00:1d.0: new USB bus registered, assigned bus number 2 Aug 16 00:32:21 kernel: [ 2.260390] uhci_hcd 0000:00:1d.0: irq 23, io base 0x0000fe00 Aug 16 00:32:21 kernel: [ 2.277517] usb usb2: New USB device found, idVendor=1d6b, idProduct=0001 Aug 16 00:32:21 kernel: [ 2.294815] usb usb2: New USB device strings: Mfr=3, Product=2, SerialNumber=1 Aug 16 00:32:21 kernel: [ 2.312173] usb usb2: Product: UHCI Host Controller Aug 16 00:32:21 kernel: [ 2.329534] usb usb2: Manufacturer: Linux 2.6.32-5-686 uhci_hcd Aug 16 00:32:21 kernel: [ 2.346828] usb usb2: SerialNumber: 0000:00:1d.0 Aug 16 00:32:21 kernel: [ 2.412989] usb usb2: configuration #1 chosen from 1 choice Aug 16 00:32:21 kernel: [ 2.430651] usb 1-2: new high speed USB device using ehci_hcd and address 2 Aug 16 00:32:21 kernel: [ 2.449046] hub 2-0:1.0: USB hub found Aug 16 00:32:21 kernel: [ 2.466514] hub 2-0:1.0: 2 ports detected Aug 16 00:32:21 kernel: [ 2.484639] uhci_hcd 0000:00:1d.1: PCI INT B -> GSI 19 (level, low) -> IRQ 19 Aug 16 00:32:21 kernel: [ 2.537750] uhci_hcd 0000:00:1d.1: setting latency timer to 64 Aug 16 00:32:21 kernel: [ 2.537756] uhci_hcd 0000:00:1d.1: UHCI Host Controller Aug 16 00:32:21 kernel: [ 2.555085] uhci_hcd 0000:00:1d.1: new USB bus registered, assigned bus number 3 Aug 16 00:32:21 kernel: [ 2.572231] uhci_hcd 0000:00:1d.1: irq 19, io base 0x0000fd00 Aug 16 00:32:21 kernel: [ 2.589593] usb usb3: New USB device found, idVendor=1d6b, idProduct=0001 Aug 16 00:32:21 kernel: [ 2.606869] usb usb3: New USB device strings: Mfr=3, Product=2, SerialNumber=1 Aug 16 00:32:21 kernel: [ 2.624134] usb usb3: Product: UHCI Host Controller Aug 16 00:32:21 kernel: [ 2.641329] usb usb3: Manufacturer: Linux 2.6.32-5-686 uhci_hcd Aug 16 00:32:21 kernel: [ 2.658505] usb usb3: SerialNumber: 0000:00:1d.1 Aug 16 00:32:21 kernel: [ 2.675843] usb usb3: configuration #1 chosen from 1 choice Aug 16 00:32:21 kernel: [ 2.692864] hub 3-0:1.0: USB hub found Aug 16 00:32:21 kernel: [ 2.709651] hub 3-0:1.0: 2 ports detected Aug 16 00:32:21 kernel: [ 2.727378] uhci_hcd 0000:00:1d.2: PCI INT C -> GSI 18 (level, low) -> IRQ 18 Aug 16 00:32:21 kernel: [ 2.768252] uhci_hcd 0000:00:1d.2: setting latency timer to 64 Aug 16 00:32:21 kernel: [ 2.768258] uhci_hcd 0000:00:1d.2: UHCI Host Controller Aug 16 00:32:21 kernel: [ 2.806679] uhci_hcd 0000:00:1d.2: new USB bus registered, assigned bus number 4 Aug 16 00:32:21 kernel: [ 2.824117] uhci_hcd 0000:00:1d.2: irq 18, io base 0x0000fc00 Aug 16 00:32:21 kernel: [ 2.841405] usb 1-2: New USB device found, idVendor=1058, idProduct=1104 Aug 16 00:32:21 kernel: [ 2.858448] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 Aug 16 00:32:21 kernel: [ 2.875347] usb 1-2: Product: My Book Aug 16 00:32:21 kernel: [ 2.892113] usb 1-2: Manufacturer: Western Digital Aug 16 00:32:21 kernel: [ 2.908915] usb 1-2: SerialNumber: 575532553130303530353538 Aug 16 00:32:21 kernel: [ 2.943242] usb usb4: New USB device found, idVendor=1d6b, idProduct=0001 Aug 16 00:32:21 kernel: [ 2.960405] usb usb4: New USB device strings: Mfr=3, Product=2, SerialNumber=1 Aug 16 00:32:21 kernel: [ 2.977615] usb usb4: Product: UHCI Host Controller Aug 16 00:32:21 kernel: [ 2.994687] usb usb4: Manufacturer: Linux 2.6.32-5-686 uhci_hcd Aug 16 00:32:21 kernel: [ 3.011711] usb usb4: SerialNumber: 0000:00:1d.2 Aug 16 00:32:21 kernel: [ 3.029589] usb usb4: configuration #1 chosen from 1 choice Aug 16 00:32:21 kernel: [ 3.082027] sd 2:0:0:0: [sda] Attached SCSI disk Aug 16 00:32:21 kernel: [ 3.103953] usb 1-2: configuration #1 chosen from 1 choice Aug 16 00:32:21 kernel: [ 3.122625] hub 4-0:1.0: USB hub found Aug 16 00:32:21 kernel: [ 3.140484] hub 4-0:1.0: 2 ports detected Aug 16 00:32:21 kernel: [ 3.161680] uhci_hcd 0000:00:1d.3: PCI INT D -> GSI 16 (level, low) -> IRQ 16 Aug 16 00:32:21 kernel: [ 3.181257] uhci_hcd 0000:00:1d.3: setting latency timer to 64 Aug 16 00:32:21 kernel: [ 3.181263] uhci_hcd 0000:00:1d.3: UHCI Host Controller Aug 16 00:32:21 kernel: [ 3.198614] uhci_hcd 0000:00:1d.3: new USB bus registered, assigned bus number 5 Aug 16 00:32:21 kernel: [ 3.216012] uhci_hcd 0000:00:1d.3: irq 16, io base 0x0000fb00 Aug 16 00:32:21 kernel: [ 3.249877] Uniform CD-ROM driver Revision: 3.20 Aug 16 00:32:21 kernel: [ 3.267765] usb usb5: New USB device found, idVendor=1d6b, idProduct=0001 Aug 16 00:32:21 kernel: [ 3.284947] usb usb5: New USB device strings: Mfr=3, Product=2, SerialNumber=1 Aug 16 00:32:21 kernel: [ 3.302023] usb usb5: Product: UHCI Host Controller Aug 16 00:32:21 kernel: [ 3.319215] usb usb5: Manufacturer: Linux 2.6.32-5-686 uhci_hcd Aug 16 00:32:21 kernel: [ 3.336298] usb usb5: SerialNumber: 0000:00:1d.3 Aug 16 00:32:21 kernel: [ 3.368377] Initializing USB Mass Storage driver... Aug 16 00:32:21 kernel: [ 3.390652] usbcore: registered new interface driver hiddev Aug 16 00:32:21 kernel: [ 3.408109] scsi4 : SCSI emulation for USB Mass Storage devices Aug 16 00:32:21 kernel: [ 3.425281] sr 0:0:1:0: Attached scsi CD-ROM sr0 Aug 16 00:32:21 kernel: [ 3.438978] sr 0:0:1:0: Attached scsi generic sg0 type 5 Aug 16 00:32:21 kernel: [ 3.456328] usbcore: registered new interface driver usb-storage Aug 16 00:32:21 kernel: [ 3.474564] usb-storage: device found at 2 Aug 16 00:32:21 kernel: [ 3.474567] usb-storage: waiting for device to settle before scanning Aug 16 00:32:21 kernel: [ 3.475320] sd 2:0:0:0: Attached scsi generic sg1 type 0 Aug 16 00:32:21 kernel: [ 3.492587] USB Mass Storage support registered. Aug 16 00:32:21 kernel: [ 3.510930] usb usb5: configuration #1 chosen from 1 choice Aug 16 00:32:21 kernel: [ 3.531076] hub 5-0:1.0: USB hub found Aug 16 00:32:21 kernel: [ 3.548399] hub 5-0:1.0: 2 ports detected Aug 16 00:32:21 kernel: [ 3.591743] input: Western Digital My Book as /devices/pci0000:00/0000:00:1d.7/usb1/1-2/1-2:1.1/input/input2 Aug 16 00:32:21 kernel: [ 3.609515] generic-usb 0003:1058:1104.0001: input,hidraw0: USB HID v1.11 Device [Western Digital My Book] on usb-0000:00:1d.7-2/input1 Aug 16 00:32:21 kernel: [ 3.627466] usbcore: registered new interface driver usbhid Aug 16 00:32:21 kernel: [ 8.581664] usb-storage: device scan complete Aug 16 00:32:21 kernel: [ 8.624270] scsi 4:0:0:0: Direct-Access WD My Book 1008 PQ: 0 ANSI: 4 Aug 16 00:32:21 kernel: [ 8.655135] scsi 4:0:0:1: Enclosure WD My Book Device 1008 PQ: 0 ANSI: 4 Aug 16 00:32:21 kernel: [ 8.675393] sd 4:0:0:0: Attached scsi generic sg2 type 0 Aug 16 00:32:21 kernel: [ 8.698669] scsi 4:0:0:1: Attached scsi generic sg3 type 13 Aug 16 00:32:21 kernel: [ 8.723370] sd 4:0:0:0: [sdb] 1953513472 512-byte logical blocks: (1.00 TB/931 GiB) Aug 16 00:32:21 kernel: [ 8.750477] sd 4:0:0:0: [sdb] Write Protect is off Aug 16 00:32:21 kernel: [ 8.769411] sd 4:0:0:0: [sdb] Mode Sense: 10 00 00 00 Aug 16 00:32:21 kernel: [ 8.769414] sd 4:0:0:0: [sdb] Assuming drive cache: write through Aug 16 00:32:21 kernel: [ 8.822971] sd 4:0:0:0: [sdb] Assuming drive cache: write through Aug 16 00:32:21 kernel: [ 8.841978] sdb: sdb1 Aug 16 00:32:21 kernel: [ 8.905580] sd 4:0:0:0: [sdb] Assuming drive cache: write through Aug 16 00:32:21 kernel: [ 8.924173] sd 4:0:0:0: [sdb] Attached SCSI disk Aug 16 00:32:21 kernel: [ 11.600492] XFS mounting filesystem sdb1 Aug 16 00:32:21 kernel: [ 12.222948] Ending clean XFS mount for filesystem: sdb1 After a while the following appears in a log: Aug 16 09:30:56 kernel: [32359.112029] usb 1-2: reset high speed USB device using ehci_hcd and address 2 Aug 16 09:31:59 kernel: [32422.112035] usb 1-2: reset high speed USB device using ehci_hcd and address 2 Aug 16 09:33:00 kernel: [32483.112029] usb 1-2: reset high speed USB device using ehci_hcd and address 2 And then it is followed by few kernel dumps, which I think, are not good: Aug 16 09:33:40 kernel: [32520.428027] INFO: task xfssyncd:1002 blocked for more than 120 seconds. Aug 16 09:33:40 kernel: [32520.462689] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Aug 16 09:33:40 kernel: [32520.497422] xfssyncd D c3d84a60 0 1002 2 0x00000000 Aug 16 09:33:40 kernel: [32520.532117] f6c9aa80 00000046 c1132742 c3d84a60 00000286 c1418100 c1418100 00000000 Aug 16 09:33:40 kernel: [32520.566867] f6c9ac3c c2808100 00000000 f653b18b 00001d76 00000001 f6c9aa80 c3c3f0e0 Aug 16 09:33:40 kernel: [32520.601343] 08e59242 f6c9ac3c 2e41392b 00000000 08e59242 00000000 c3f7fb48 0067385a Aug 16 09:33:40 kernel: [32520.635533] Call Trace: Aug 16 09:33:40 kernel: [32520.668991] [<c1132742>] ? cfq_set_request+0x0/0x290 Aug 16 09:33:40 kernel: [32520.702804] [<c126b532>] ? io_schedule+0x5f/0x98 Aug 16 09:33:40 kernel: [32520.736555] [<c1128be0>] ? get_request_wait+0xcb/0x146 Aug 16 09:33:40 kernel: [32520.770360] [<c10437ba>] ? autoremove_wake_function+0x0/0x2d Aug 16 09:33:40 kernel: [32520.804110] [<c112907c>] ? __make_request+0x2cc/0x3d9 Aug 16 09:33:40 kernel: [32520.837713] [<c1128230>] ? blk_peek_request+0x135/0x143 Aug 16 09:33:40 kernel: [32520.871265] [<f8582987>] ? scsi_dispatch_cmd+0x185/0x1e5 [scsi_mod] Aug 16 09:33:40 kernel: [32520.904407] [<c1127cf1>] ? generic_make_request+0x266/0x2b4 Aug 16 09:33:40 kernel: [32520.937007] [<c10cf821>] ? bvec_alloc_bs+0x95/0xaf Aug 16 09:33:40 kernel: [32520.969033] [<c1127dfb>] ? submit_bio+0xbc/0xd6 Aug 16 09:33:40 kernel: [32521.000485] [<c10cffd1>] ? bio_add_page+0x28/0x2e Aug 16 09:33:40 kernel: [32521.031403] [<f8918d38>] ? _xfs_buf_ioapply+0x206/0x22b [xfs] Aug 16 09:33:40 kernel: [32521.061888] [<f89197bd>] ? xfs_buf_iorequest+0x38/0x60 [xfs] Aug 16 09:33:40 kernel: [32521.091845] [<f8907230>] ? xlog_bdstrat_cb+0x16/0x3d [xfs] Aug 16 09:33:40 kernel: [32521.121222] [<f8905781>] ? XFS_bwrite+0x32/0x64 [xfs] Aug 16 09:33:40 kernel: [32521.150007] [<f89059be>] ? xlog_sync+0x20b/0x311 [xfs] Aug 16 09:33:40 kernel: [32521.178214] [<f89112fc>] ? xfs_trans_ail_tail+0x12/0x27 [xfs] Aug 16 09:33:40 kernel: [32521.205914] [<f8906261>] ? xlog_state_sync_all+0xa2/0x141 [xfs] Aug 16 09:33:40 kernel: [32521.233074] [<f8906611>] ? _xfs_log_force+0x51/0x68 [xfs] Aug 16 09:33:40 kernel: [32521.259664] [<c103abaf>] ? process_timeout+0x0/0x5 Aug 16 09:33:40 kernel: [32521.285662] [<f8906636>] ? xfs_log_force+0xe/0x27 [xfs] Aug 16 09:33:40 kernel: [32521.311171] [<f89202df>] ? xfs_sync_worker+0x17/0x5c [xfs] Aug 16 09:33:40 kernel: [32521.336117] [<f891fbb7>] ? xfssyncd+0x134/0x17d [xfs] Aug 16 09:33:40 kernel: [32521.360498] [<f891fa83>] ? xfssyncd+0x0/0x17d [xfs] Aug 16 09:33:40 kernel: [32521.384211] [<c1043588>] ? kthread+0x61/0x66 Aug 16 09:33:40 kernel: [32521.407890] [<c1043527>] ? kthread+0x0/0x66 Aug 16 09:33:40 kernel: [32521.430876] [<c1003d47>] ? kernel_thread_helper+0x7/0x10 Aug 16 09:33:40 kernel: [32521.453394] INFO: task flush-8:16:12945 blocked for more than 120 seconds. Aug 16 09:33:40 kernel: [32521.476116] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Aug 16 09:33:40 kernel: [32521.498579] flush-8:16 D 00000000 0 12945 2 0x00000000 Aug 16 09:33:40 kernel: [32521.520649] f4e4d540 00000046 e412e940 00000000 00000002 c1418100 c1418100 c14136ac Aug 16 09:33:40 kernel: [32521.542426] f4e4d6fc c2808100 00000000 00000000 000008b4 00000001 f4e4d540 c3c3f0e0 Aug 16 09:33:40 kernel: [32521.563745] 02e905a8 f4e4d6fc 007a5399 00000000 02e905a8 00000000 f4e2db48 00670b98 Aug 16 09:33:40 kernel: [32521.585077] Call Trace: Aug 16 09:33:40 kernel: [32521.605790] [<c126b532>] ? io_schedule+0x5f/0x98 Aug 16 09:33:40 kernel: [32521.626184] [<c1128be0>] ? get_request_wait+0xcb/0x146 Aug 16 09:33:40 kernel: [32521.646133] [<c10437ba>] ? autoremove_wake_function+0x0/0x2d Aug 16 09:33:40 kernel: [32521.665659] [<c112907c>] ? __make_request+0x2cc/0x3d9 Aug 16 09:33:40 kernel: [32521.684716] [<f891796e>] ? xfs_convert_page+0x30a/0x331 [xfs] Aug 16 09:33:40 kernel: [32521.703366] [<c1127cf1>] ? generic_make_request+0x266/0x2b4 Aug 16 09:33:40 kernel: [32521.721644] [<c10cf821>] ? bvec_alloc_bs+0x95/0xaf Aug 16 09:33:40 kernel: [32521.739465] [<c1127dfb>] ? submit_bio+0xbc/0xd6 Aug 16 09:33:40 kernel: [32521.756896] [<c10cfa45>] ? bio_alloc_bioset+0x7b/0xba Aug 16 09:33:40 kernel: [32521.774046] [<f8917af0>] ? xfs_submit_ioend_bio+0x3b/0x44 [xfs] Aug 16 09:33:40 kernel: [32521.790694] [<f8917ba3>] ? xfs_submit_ioend+0xaa/0xc4 [xfs] Aug 16 09:33:40 kernel: [32521.806736] [<f891817d>] ? xfs_page_state_convert+0x5c0/0x61c [xfs] Aug 16 09:33:40 kernel: [32521.822859] [<c113705b>] ? __lookup_tag+0x8e/0xee Aug 16 09:33:40 kernel: [32521.838958] [<f891840d>] ? xfs_vm_writepage+0x91/0xc4 [xfs] Aug 16 09:33:40 kernel: [32521.855039] [<c108bbcc>] ? __writepage+0x8/0x22 Aug 16 09:33:40 kernel: [32521.871067] [<c108c17b>] ? write_cache_pages+0x1af/0x29f Aug 16 09:33:40 kernel: [32521.886616] [<c108bbc4>] ? __writepage+0x0/0x22 Aug 16 09:33:40 kernel: [32521.901593] [<c108c285>] ? generic_writepages+0x1a/0x21 Aug 16 09:33:40 kernel: [32521.916455] [<f8918338>] ? xfs_vm_writepages+0x0/0x38 [xfs] Aug 16 09:33:40 kernel: [32521.931484] [<c108c2a5>] ? do_writepages+0x19/0x25 Aug 16 09:33:40 kernel: [32521.946648] [<c10c80d9>] ? writeback_single_inode+0xc7/0x273 Aug 16 09:33:40 kernel: [32521.961675] [<c10c8c44>] ? writeback_inodes_wb+0x3dd/0x49c Aug 16 09:33:40 kernel: [32521.976831] [<c10c8e18>] ? wb_writeback+0x115/0x178 Aug 16 09:33:40 kernel: [32521.991778] [<c10c901f>] ? wb_do_writeback+0x121/0x131 Aug 16 09:33:40 kernel: [32522.006538] [<c103abaf>] ? process_timeout+0x0/0x5 Aug 16 09:33:40 kernel: [32522.021091] [<c10c9050>] ? bdi_writeback_task+0x21/0x89 Aug 16 09:33:40 kernel: [32522.035493] [<c10979e5>] ? bdi_start_fn+0x59/0xa4 Aug 16 09:33:40 kernel: [32522.049765] [<c109798c>] ? bdi_start_fn+0x0/0xa4 Aug 16 09:33:40 kernel: [32522.063792] [<c1043588>] ? kthread+0x61/0x66 Aug 16 09:33:40 kernel: [32522.077612] [<c1043527>] ? kthread+0x0/0x66 Aug 16 09:33:40 kernel: [32522.091260] [<c1003d47>] ? kernel_thread_helper+0x7/0x10 Aug 16 09:33:40 kernel: [32522.104966] INFO: task smartctl:13098 blocked for more than 120 seconds. Aug 16 09:33:40 kernel: [32522.118883] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Aug 16 09:33:40 kernel: [32522.133012] smartctl D 00000020 0 13098 13097 0x00000000 Aug 16 09:33:40 kernel: [32522.147221] e50b9540 00000086 c11d28a8 00000020 00000770 c1418100 c1418100 c14136ac Aug 16 09:33:40 kernel: [32522.161720] e50b96fc c2808100 00000000 e53e8800 00000000 00000020 c3cec000 c13886c0 Aug 16 09:33:40 kernel: [32522.176217] f99dab68 e50b96fc 007a4f1e 00000001 c4082f24 c4082ed8 00000001 c3c3f0e0 Aug 16 09:33:40 kernel: [32522.190737] Call Trace: Aug 16 09:33:40 kernel: [32522.205038] [<c11d28a8>] ? __netdev_alloc_skb+0x14/0x2d Aug 16 09:33:40 kernel: [32522.219605] [<c126b799>] ? schedule_timeout+0x20/0xb0 Aug 16 09:33:40 kernel: [32522.234144] [<c112820d>] ? blk_peek_request+0x112/0x143 Aug 16 09:33:40 kernel: [32522.248649] [<f85873b6>] ? scsi_request_fn+0x3c1/0x47a [scsi_mod] Aug 16 09:33:40 kernel: [32522.263233] [<c103aba8>] ? del_timer+0x55/0x5c Aug 16 09:33:40 kernel: [32522.277773] [<c126b6a2>] ? wait_for_common+0xa4/0x100 Aug 16 09:33:40 kernel: [32522.292342] [<c102cd8d>] ? default_wake_function+0x0/0x8 Aug 16 09:33:40 kernel: [32522.306958] [<c112b3d1>] ? blk_execute_rq+0x8b/0xb2 Aug 16 09:33:40 kernel: [32522.321569] [<c112b2ac>] ? blk_end_sync_rq+0x0/0x23 Aug 16 09:33:40 kernel: [32522.336070] [<c112b58b>] ? blk_recount_segments+0x13/0x20 Aug 16 09:33:40 kernel: [32522.350583] [<c1127307>] ? blk_rq_bio_prep+0x44/0x74 Aug 16 09:33:40 kernel: [32522.365059] [<c112b0b2>] ? blk_rq_map_kern+0xc5/0xee Aug 16 09:33:40 kernel: [32522.379439] [<c112e2a5>] ? sg_scsi_ioctl+0x221/0x2aa Aug 16 09:33:40 kernel: [32522.393801] [<c112e672>] ? scsi_cmd_ioctl+0x344/0x39a Aug 16 09:33:40 kernel: [32522.408140] [<c1024c87>] ? update_curr+0x106/0x1b3 Aug 16 09:33:40 kernel: [32522.422566] [<c1024c87>] ? update_curr+0x106/0x1b3 Aug 16 09:33:40 kernel: [32522.436832] [<f87676aa>] ? sd_ioctl+0x90/0xb5 [sd_mod] Aug 16 09:33:40 kernel: [32522.451228] [<c112c35f>] ? __blkdev_driver_ioctl+0x53/0x63 Aug 16 09:33:40 kernel: [32522.465689] [<c112cbbf>] ? blkdev_ioctl+0x850/0x891 Aug 16 09:33:40 kernel: [32522.479982] [<c1020474>] ? __wake_up_common+0x34/0x59 Aug 16 09:33:40 kernel: [32522.494138] [<c10244cd>] ? complete+0x28/0x36 Aug 16 09:33:40 kernel: [32522.507986] [<c1086c64>] ? find_get_page+0x1f/0x81 Aug 16 09:33:40 kernel: [32522.521671] [<c10abed5>] ? add_partial+0xe/0x40 Aug 16 09:33:40 kernel: [32522.535285] [<c1086e68>] ? lock_page+0x8/0x1d Aug 16 09:33:40 kernel: [32522.548797] [<c1087432>] ? filemap_fault+0xb5/0x2e6 Aug 16 09:33:40 kernel: [32522.562141] [<c109941c>] ? __do_fault+0x381/0x3b1 Aug 16 09:33:40 kernel: [32522.575441] [<c10d0c30>] ? block_ioctl+0x27/0x2c Aug 16 09:33:40 kernel: [32522.588708] [<c10d0c09>] ? block_ioctl+0x0/0x2c Aug 16 09:33:40 kernel: [32522.601858] [<c10bcd78>] ? vfs_ioctl+0x1c/0x5f Aug 16 09:33:40 kernel: [32522.614917] [<c10bd30c>] ? do_vfs_ioctl+0x4aa/0x4e5 Aug 16 09:33:40 kernel: [32522.627961] [<c10350db>] ? __do_softirq+0x115/0x151 Aug 16 09:33:40 kernel: [32522.640901] [<c126e270>] ? do_page_fault+0x2f1/0x307 Aug 16 09:33:40 kernel: [32522.653803] [<c10bd388>] ? sys_ioctl+0x41/0x58 Aug 16 09:33:40 kernel: [32522.666674] [<c10030fb>] ? sysenter_do_call+0x12/0x28 Then again few messages reset high speed USB device using ehci_hcd and address 2. I have browsed and read similar error reports here and there and I tried: I have upgraded the kernel from v2.6.26-2 to 2.6.32-5, which has not solved the problem. They say, this might a cable problem. I have tried to replace the USB-to-miniUSB cable (that connects external drive with computer) with another one. No changes. Somebody suggests to try another USB port. I have only 4 external USB ports, tried another one with no success. They say to try uhci_hcd. I have unmounted the device, unloaded ehci_hcd and mounted again. The difference was that now in log I get reset full speed USB device using uhci_hcd and address 2 and similar kernel dumps after a while. They say to echo 128 > /sys/block/sdb/device/max_sectors. I tried it with ehci_hcd with no success (note: I have issued this command after the drive was mounted but before using it actively). I have lauched smartmond and checking periodically the output of smartctl: drive temperature is OK, number of bad sectors and uncorrectable errors is 0. Nothing suspicious is reported by S.M.A.R.T. except maybe the following: Aug 16 12:40:12 kernel: [43715.314566] program smartctl is using a deprecated SCSI ioctl, please convert it to SG_IO Aug 16 12:40:13 kernel: [43715.705622] program smartctl is using a deprecated SCSI ioctl, please convert it to SG_IO Of course, I have not tried all combinations of above. But unfortunately, I am run out of cardinal ideas. If anybody can advice something specific about the problem, you are very welcome.

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  • SAP lève le voile sur sa technologie « SAP in-memory », qui peut diviser par 1200 le temps de traitement de certains scénarios

    SAP lève le voile sur sa technologie SAP in-memory Qui peut diviser par 1200 le temps de traitement de certains scénarios SAP vient de lever le voile sur des détails techniques supplémentaires au sujet de son logiciel SAP High-Performance Analytic Appliance (SAP HANA), annoncé au SAP TechEd 2010 Bangalore. On savait déjà que la technologie SAP in-memory était au coeur de SAP HANA. Il s'agit d'une couche de base de données et de calcul permettant le traitement de volumes massifs de données en t...

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  • A Taxonomy of Numerical Methods v1

    - by JoshReuben
    Numerical Analysis – When, What, (but not how) Once you understand the Math & know C++, Numerical Methods are basically blocks of iterative & conditional math code. I found the real trick was seeing the forest for the trees – knowing which method to use for which situation. Its pretty easy to get lost in the details – so I’ve tried to organize these methods in a way that I can quickly look this up. I’ve included links to detailed explanations and to C++ code examples. I’ve tried to classify Numerical methods in the following broad categories: Solving Systems of Linear Equations Solving Non-Linear Equations Iteratively Interpolation Curve Fitting Optimization Numerical Differentiation & Integration Solving ODEs Boundary Problems Solving EigenValue problems Enjoy – I did ! Solving Systems of Linear Equations Overview Solve sets of algebraic equations with x unknowns The set is commonly in matrix form Gauss-Jordan Elimination http://en.wikipedia.org/wiki/Gauss%E2%80%93Jordan_elimination C++: http://www.codekeep.net/snippets/623f1923-e03c-4636-8c92-c9dc7aa0d3c0.aspx Produces solution of the equations & the coefficient matrix Efficient, stable 2 steps: · Forward Elimination – matrix decomposition: reduce set to triangular form (0s below the diagonal) or row echelon form. If degenerate, then there is no solution · Backward Elimination –write the original matrix as the product of ints inverse matrix & its reduced row-echelon matrix à reduce set to row canonical form & use back-substitution to find the solution to the set Elementary ops for matrix decomposition: · Row multiplication · Row switching · Add multiples of rows to other rows Use pivoting to ensure rows are ordered for achieving triangular form LU Decomposition http://en.wikipedia.org/wiki/LU_decomposition C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-lu-decomposition-for-solving.html Represent the matrix as a product of lower & upper triangular matrices A modified version of GJ Elimination Advantage – can easily apply forward & backward elimination to solve triangular matrices Techniques: · Doolittle Method – sets the L matrix diagonal to unity · Crout Method - sets the U matrix diagonal to unity Note: both the L & U matrices share the same unity diagonal & can be stored compactly in the same matrix Gauss-Seidel Iteration http://en.wikipedia.org/wiki/Gauss%E2%80%93Seidel_method C++: http://www.nr.com/forum/showthread.php?t=722 Transform the linear set of equations into a single equation & then use numerical integration (as integration formulas have Sums, it is implemented iteratively). an optimization of Gauss-Jacobi: 1.5 times faster, requires 0.25 iterations to achieve the same tolerance Solving Non-Linear Equations Iteratively find roots of polynomials – there may be 0, 1 or n solutions for an n order polynomial use iterative techniques Iterative methods · used when there are no known analytical techniques · Requires set functions to be continuous & differentiable · Requires an initial seed value – choice is critical to convergence à conduct multiple runs with different starting points & then select best result · Systematic - iterate until diminishing returns, tolerance or max iteration conditions are met · bracketing techniques will always yield convergent solutions, non-bracketing methods may fail to converge Incremental method if a nonlinear function has opposite signs at 2 ends of a small interval x1 & x2, then there is likely to be a solution in their interval – solutions are detected by evaluating a function over interval steps, for a change in sign, adjusting the step size dynamically. Limitations – can miss closely spaced solutions in large intervals, cannot detect degenerate (coinciding) solutions, limited to functions that cross the x-axis, gives false positives for singularities Fixed point method http://en.wikipedia.org/wiki/Fixed-point_iteration C++: http://books.google.co.il/books?id=weYj75E_t6MC&pg=PA79&lpg=PA79&dq=fixed+point+method++c%2B%2B&source=bl&ots=LQ-5P_taoC&sig=lENUUIYBK53tZtTwNfHLy5PEWDk&hl=en&sa=X&ei=wezDUPW1J5DptQaMsIHQCw&redir_esc=y#v=onepage&q=fixed%20point%20method%20%20c%2B%2B&f=false Algebraically rearrange a solution to isolate a variable then apply incremental method Bisection method http://en.wikipedia.org/wiki/Bisection_method C++: http://numericalcomputing.wordpress.com/category/algorithms/ Bracketed - Select an initial interval, keep bisecting it ad midpoint into sub-intervals and then apply incremental method on smaller & smaller intervals – zoom in Adv: unaffected by function gradient à reliable Disadv: slow convergence False Position Method http://en.wikipedia.org/wiki/False_position_method C++: http://www.dreamincode.net/forums/topic/126100-bisection-and-false-position-methods/ Bracketed - Select an initial interval , & use the relative value of function at interval end points to select next sub-intervals (estimate how far between the end points the solution might be & subdivide based on this) Newton-Raphson method http://en.wikipedia.org/wiki/Newton's_method C++: http://www-users.cselabs.umn.edu/classes/Summer-2012/csci1113/index.php?page=./newt3 Also known as Newton's method Convenient, efficient Not bracketed – only a single initial guess is required to start iteration – requires an analytical expression for the first derivative of the function as input. Evaluates the function & its derivative at each step. Can be extended to the Newton MutiRoot method for solving multiple roots Can be easily applied to an of n-coupled set of non-linear equations – conduct a Taylor Series expansion of a function, dropping terms of order n, rewrite as a Jacobian matrix of PDs & convert to simultaneous linear equations !!! Secant Method http://en.wikipedia.org/wiki/Secant_method C++: http://forum.vcoderz.com/showthread.php?p=205230 Unlike N-R, can estimate first derivative from an initial interval (does not require root to be bracketed) instead of inputting it Since derivative is approximated, may converge slower. Is fast in practice as it does not have to evaluate the derivative at each step. Similar implementation to False Positive method Birge-Vieta Method http://mat.iitm.ac.in/home/sryedida/public_html/caimna/transcendental/polynomial%20methods/bv%20method.html C++: http://books.google.co.il/books?id=cL1boM2uyQwC&pg=SA3-PA51&lpg=SA3-PA51&dq=Birge-Vieta+Method+c%2B%2B&source=bl&ots=QZmnDTK3rC&sig=BPNcHHbpR_DKVoZXrLi4nVXD-gg&hl=en&sa=X&ei=R-_DUK2iNIjzsgbE5ID4Dg&redir_esc=y#v=onepage&q=Birge-Vieta%20Method%20c%2B%2B&f=false combines Horner's method of polynomial evaluation (transforming into lesser degree polynomials that are more computationally efficient to process) with Newton-Raphson to provide a computational speed-up Interpolation Overview Construct new data points for as close as possible fit within range of a discrete set of known points (that were obtained via sampling, experimentation) Use Taylor Series Expansion of a function f(x) around a specific value for x Linear Interpolation http://en.wikipedia.org/wiki/Linear_interpolation C++: http://www.hamaluik.com/?p=289 Straight line between 2 points à concatenate interpolants between each pair of data points Bilinear Interpolation http://en.wikipedia.org/wiki/Bilinear_interpolation C++: http://supercomputingblog.com/graphics/coding-bilinear-interpolation/2/ Extension of the linear function for interpolating functions of 2 variables – perform linear interpolation first in 1 direction, then in another. Used in image processing – e.g. texture mapping filter. Uses 4 vertices to interpolate a value within a unit cell. Lagrange Interpolation http://en.wikipedia.org/wiki/Lagrange_polynomial C++: http://www.codecogs.com/code/maths/approximation/interpolation/lagrange.php For polynomials Requires recomputation for all terms for each distinct x value – can only be applied for small number of nodes Numerically unstable Barycentric Interpolation http://epubs.siam.org/doi/pdf/10.1137/S0036144502417715 C++: http://www.gamedev.net/topic/621445-barycentric-coordinates-c-code-check/ Rearrange the terms in the equation of the Legrange interpolation by defining weight functions that are independent of the interpolated value of x Newton Divided Difference Interpolation http://en.wikipedia.org/wiki/Newton_polynomial C++: http://jee-appy.blogspot.co.il/2011/12/newton-divided-difference-interpolation.html Hermite Divided Differences: Interpolation polynomial approximation for a given set of data points in the NR form - divided differences are used to approximately calculate the various differences. For a given set of 3 data points , fit a quadratic interpolant through the data Bracketed functions allow Newton divided differences to be calculated recursively Difference table Cubic Spline Interpolation http://en.wikipedia.org/wiki/Spline_interpolation C++: https://www.marcusbannerman.co.uk/index.php/home/latestarticles/42-articles/96-cubic-spline-class.html Spline is a piecewise polynomial Provides smoothness – for interpolations with significantly varying data Use weighted coefficients to bend the function to be smooth & its 1st & 2nd derivatives are continuous through the edge points in the interval Curve Fitting A generalization of interpolating whereby given data points may contain noise à the curve does not necessarily pass through all the points Least Squares Fit http://en.wikipedia.org/wiki/Least_squares C++: http://www.ccas.ru/mmes/educat/lab04k/02/least-squares.c Residual – difference between observed value & expected value Model function is often chosen as a linear combination of the specified functions Determines: A) The model instance in which the sum of squared residuals has the least value B) param values for which model best fits data Straight Line Fit Linear correlation between independent variable and dependent variable Linear Regression http://en.wikipedia.org/wiki/Linear_regression C++: http://www.oocities.org/david_swaim/cpp/linregc.htm Special case of statistically exact extrapolation Leverage least squares Given a basis function, the sum of the residuals is determined and the corresponding gradient equation is expressed as a set of normal linear equations in matrix form that can be solved (e.g. using LU Decomposition) Can be weighted - Drop the assumption that all errors have the same significance –-> confidence of accuracy is different for each data point. Fit the function closer to points with higher weights Polynomial Fit - use a polynomial basis function Moving Average http://en.wikipedia.org/wiki/Moving_average C++: http://www.codeproject.com/Articles/17860/A-Simple-Moving-Average-Algorithm Used for smoothing (cancel fluctuations to highlight longer-term trends & cycles), time series data analysis, signal processing filters Replace each data point with average of neighbors. Can be simple (SMA), weighted (WMA), exponential (EMA). Lags behind latest data points – extra weight can be given to more recent data points. Weights can decrease arithmetically or exponentially according to distance from point. Parameters: smoothing factor, period, weight basis Optimization Overview Given function with multiple variables, find Min (or max by minimizing –f(x)) Iterative approach Efficient, but not necessarily reliable Conditions: noisy data, constraints, non-linear models Detection via sign of first derivative - Derivative of saddle points will be 0 Local minima Bisection method Similar method for finding a root for a non-linear equation Start with an interval that contains a minimum Golden Search method http://en.wikipedia.org/wiki/Golden_section_search C++: http://www.codecogs.com/code/maths/optimization/golden.php Bisect intervals according to golden ratio 0.618.. Achieves reduction by evaluating a single function instead of 2 Newton-Raphson Method Brent method http://en.wikipedia.org/wiki/Brent's_method C++: http://people.sc.fsu.edu/~jburkardt/cpp_src/brent/brent.cpp Based on quadratic or parabolic interpolation – if the function is smooth & parabolic near to the minimum, then a parabola fitted through any 3 points should approximate the minima – fails when the 3 points are collinear , in which case the denominator is 0 Simplex Method http://en.wikipedia.org/wiki/Simplex_algorithm C++: http://www.codeguru.com/cpp/article.php/c17505/Simplex-Optimization-Algorithm-and-Implemetation-in-C-Programming.htm Find the global minima of any multi-variable function Direct search – no derivatives required At each step it maintains a non-degenerative simplex – a convex hull of n+1 vertices. Obtains the minimum for a function with n variables by evaluating the function at n-1 points, iteratively replacing the point of worst result with the point of best result, shrinking the multidimensional simplex around the best point. Point replacement involves expanding & contracting the simplex near the worst value point to determine a better replacement point Oscillation can be avoided by choosing the 2nd worst result Restart if it gets stuck Parameters: contraction & expansion factors Simulated Annealing http://en.wikipedia.org/wiki/Simulated_annealing C++: http://code.google.com/p/cppsimulatedannealing/ Analogy to heating & cooling metal to strengthen its structure Stochastic method – apply random permutation search for global minima - Avoid entrapment in local minima via hill climbing Heating schedule - Annealing schedule params: temperature, iterations at each temp, temperature delta Cooling schedule – can be linear, step-wise or exponential Differential Evolution http://en.wikipedia.org/wiki/Differential_evolution C++: http://www.amichel.com/de/doc/html/ More advanced stochastic methods analogous to biological processes: Genetic algorithms, evolution strategies Parallel direct search method against multiple discrete or continuous variables Initial population of variable vectors chosen randomly – if weighted difference vector of 2 vectors yields a lower objective function value then it replaces the comparison vector Many params: #parents, #variables, step size, crossover constant etc Convergence is slow – many more function evaluations than simulated annealing Numerical Differentiation Overview 2 approaches to finite difference methods: · A) approximate function via polynomial interpolation then differentiate · B) Taylor series approximation – additionally provides error estimate Finite Difference methods http://en.wikipedia.org/wiki/Finite_difference_method C++: http://www.wpi.edu/Pubs/ETD/Available/etd-051807-164436/unrestricted/EAMPADU.pdf Find differences between high order derivative values - Approximate differential equations by finite differences at evenly spaced data points Based on forward & backward Taylor series expansion of f(x) about x plus or minus multiples of delta h. Forward / backward difference - the sums of the series contains even derivatives and the difference of the series contains odd derivatives – coupled equations that can be solved. Provide an approximation of the derivative within a O(h^2) accuracy There is also central difference & extended central difference which has a O(h^4) accuracy Richardson Extrapolation http://en.wikipedia.org/wiki/Richardson_extrapolation C++: http://mathscoding.blogspot.co.il/2012/02/introduction-richardson-extrapolation.html A sequence acceleration method applied to finite differences Fast convergence, high accuracy O(h^4) Derivatives via Interpolation Cannot apply Finite Difference method to discrete data points at uneven intervals – so need to approximate the derivative of f(x) using the derivative of the interpolant via 3 point Lagrange Interpolation Note: the higher the order of the derivative, the lower the approximation precision Numerical Integration Estimate finite & infinite integrals of functions More accurate procedure than numerical differentiation Use when it is not possible to obtain an integral of a function analytically or when the function is not given, only the data points are Newton Cotes Methods http://en.wikipedia.org/wiki/Newton%E2%80%93Cotes_formulas C++: http://www.siafoo.net/snippet/324 For equally spaced data points Computationally easy – based on local interpolation of n rectangular strip areas that is piecewise fitted to a polynomial to get the sum total area Evaluate the integrand at n+1 evenly spaced points – approximate definite integral by Sum Weights are derived from Lagrange Basis polynomials Leverage Trapezoidal Rule for default 2nd formulas, Simpson 1/3 Rule for substituting 3 point formulas, Simpson 3/8 Rule for 4 point formulas. For 4 point formulas use Bodes Rule. Higher orders obtain more accurate results Trapezoidal Rule uses simple area, Simpsons Rule replaces the integrand f(x) with a quadratic polynomial p(x) that uses the same values as f(x) for its end points, but adds a midpoint Romberg Integration http://en.wikipedia.org/wiki/Romberg's_method C++: http://code.google.com/p/romberg-integration/downloads/detail?name=romberg.cpp&can=2&q= Combines trapezoidal rule with Richardson Extrapolation Evaluates the integrand at equally spaced points The integrand must have continuous derivatives Each R(n,m) extrapolation uses a higher order integrand polynomial replacement rule (zeroth starts with trapezoidal) à a lower triangular matrix set of equation coefficients where the bottom right term has the most accurate approximation. The process continues until the difference between 2 successive diagonal terms becomes sufficiently small. Gaussian Quadrature http://en.wikipedia.org/wiki/Gaussian_quadrature C++: http://www.alglib.net/integration/gaussianquadratures.php Data points are chosen to yield best possible accuracy – requires fewer evaluations Ability to handle singularities, functions that are difficult to evaluate The integrand can include a weighting function determined by a set of orthogonal polynomials. Points & weights are selected so that the integrand yields the exact integral if f(x) is a polynomial of degree <= 2n+1 Techniques (basically different weighting functions): · Gauss-Legendre Integration w(x)=1 · Gauss-Laguerre Integration w(x)=e^-x · Gauss-Hermite Integration w(x)=e^-x^2 · Gauss-Chebyshev Integration w(x)= 1 / Sqrt(1-x^2) Solving ODEs Use when high order differential equations cannot be solved analytically Evaluated under boundary conditions RK for systems – a high order differential equation can always be transformed into a coupled first order system of equations Euler method http://en.wikipedia.org/wiki/Euler_method C++: http://rosettacode.org/wiki/Euler_method First order Runge–Kutta method. Simple recursive method – given an initial value, calculate derivative deltas. Unstable & not very accurate (O(h) error) – not used in practice A first-order method - the local error (truncation error per step) is proportional to the square of the step size, and the global error (error at a given time) is proportional to the step size In evolving solution between data points xn & xn+1, only evaluates derivatives at beginning of interval xn à asymmetric at boundaries Higher order Runge Kutta http://en.wikipedia.org/wiki/Runge%E2%80%93Kutta_methods C++: http://www.dreamincode.net/code/snippet1441.htm 2nd & 4th order RK - Introduces parameterized midpoints for more symmetric solutions à accuracy at higher computational cost Adaptive RK – RK-Fehlberg – estimate the truncation at each integration step & automatically adjust the step size to keep error within prescribed limits. At each step 2 approximations are compared – if in disagreement to a specific accuracy, the step size is reduced Boundary Value Problems Where solution of differential equations are located at 2 different values of the independent variable x à more difficult, because cannot just start at point of initial value – there may not be enough starting conditions available at the end points to produce a unique solution An n-order equation will require n boundary conditions – need to determine the missing n-1 conditions which cause the given conditions at the other boundary to be satisfied Shooting Method http://en.wikipedia.org/wiki/Shooting_method C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-shooting-method-for-solving.html Iteratively guess the missing values for one end & integrate, then inspect the discrepancy with the boundary values of the other end to adjust the estimate Given the starting boundary values u1 & u2 which contain the root u, solve u given the false position method (solving the differential equation as an initial value problem via 4th order RK), then use u to solve the differential equations. Finite Difference Method For linear & non-linear systems Higher order derivatives require more computational steps – some combinations for boundary conditions may not work though Improve the accuracy by increasing the number of mesh points Solving EigenValue Problems An eigenvalue can substitute a matrix when doing matrix multiplication à convert matrix multiplication into a polynomial EigenValue For a given set of equations in matrix form, determine what are the solution eigenvalue & eigenvectors Similar Matrices - have same eigenvalues. Use orthogonal similarity transforms to reduce a matrix to diagonal form from which eigenvalue(s) & eigenvectors can be computed iteratively Jacobi method http://en.wikipedia.org/wiki/Jacobi_method C++: http://people.sc.fsu.edu/~jburkardt/classes/acs2_2008/openmp/jacobi/jacobi.html Robust but Computationally intense – use for small matrices < 10x10 Power Iteration http://en.wikipedia.org/wiki/Power_iteration For any given real symmetric matrix, generate the largest single eigenvalue & its eigenvectors Simplest method – does not compute matrix decomposition à suitable for large, sparse matrices Inverse Iteration Variation of power iteration method – generates the smallest eigenvalue from the inverse matrix Rayleigh Method http://en.wikipedia.org/wiki/Rayleigh's_method_of_dimensional_analysis Variation of power iteration method Rayleigh Quotient Method Variation of inverse iteration method Matrix Tri-diagonalization Method Use householder algorithm to reduce an NxN symmetric matrix to a tridiagonal real symmetric matrix vua N-2 orthogonal transforms     Whats Next Outside of Numerical Methods there are lots of different types of algorithms that I’ve learned over the decades: Data Mining – (I covered this briefly in a previous post: http://geekswithblogs.net/JoshReuben/archive/2007/12/31/ssas-dm-algorithms.aspx ) Search & Sort Routing Problem Solving Logical Theorem Proving Planning Probabilistic Reasoning Machine Learning Solvers (eg MIP) Bioinformatics (Sequence Alignment, Protein Folding) Quant Finance (I read Wilmott’s books – interesting) Sooner or later, I’ll cover the above topics as well.

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  • 15 Oracle customers are 'Winners' at Progressive Mfgs 100 Awards

    - by [email protected]
    This year, 15 Oracle customers will receive awards at the Managing Automation's PM100 Event  for their outstanding accomplishments in a number of supply chain applications innovation categories. The event will be held at the Breakers Hotel in Palm Beach Fl from May 3-6, 2010. Award winners include: Arvin Meritor, Ball Aerospace, US Dept. of Treasury/Engraving, Doosan Infracore, Freescale Semi, Ingersoll-Rand, JDS Uniphase, L&L Products, Masco Builders, Mercury Marine Sanmina-SCI, Siemens Water TEch, US Concrete, VirTex Assy Services. Details of the event and Oracle's sponsorship can be found at: http://www.managingautomation.com/awards/ or contact Stephen Slade at [email protected]      

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  • Test Drive Windows 7 Online with Virtual Labs

    - by Matthew Guay
    Did you miss out on the Windows 7 public beta and want to try it out before you actually make the leap and upgrade? Maybe you want to learn how to deploy new features in a business environment. Here’s how you can test drive Windows 7 directly from your browser. Whether you manage 10,000 desktops or simply manage your own laptop, it’s usually best to test out a new OS before installing it.  If you’re upgrading from Windows XP you may find many things unfamiliar.  Microsoft has setup a special Windows 7 Test Drive website with resources to help IT professionals test and deploy Windows 7 in their workplaces.  This is a great resource to try out Windows 7 from the comfort of your browser, and look at some of the new features without even installing it. Please note that the online version is not nearly as responsive as a full standard install of Windows 7.  It also does not run the full Aero interface or desktop effects, and may refresh slowly depending on your Internet connection.  So don’t judge Windows 7’s performance based on this virtual lab, but use it as a way to learn more about Windows 7 without installing it. Getting Started To test drive Windows 7, visit Microsoft’s Windows 7 Test Drive website (link below).  You will need to run the Windows 7 Test Drive in Internet Explorer, as it requires Active X support.  We received this error when attempting to run the Test Drive in Firefox: Now, click the “Take a Test Drive” link on the bottom left of the page. This site includes several test drives to demonstrate different features of Windows 7 and its related ecosystem of products including Windows Server 2008 R2, some of which, including the XP Mode test drive, are not yet ready.  For this test, we selected the MED-V Test drive, as this includes Office 2007 and 2010 so you can test them in Windows 7 as well.  Simply select the test drive you want, and click “Try it now!”   If you haven’t run a Windows test drive before, you will be asked to install an ActiveX control.  Click the link to install. Click the yellow bar at the top of the page in Internet Explorer, and select to Install the add-on.  You may have to approve a UAC prompt to finish the install. Once this is finished, click the link on the bottom of the page to return to your test drive.  The test drive page should automatically refresh; if it doesn’t, click refresh to reload it. Now the test drive will load the components.   Once its fully loaded, click the link to launch Windows 7 in a new window. You may see a prompt warning that the server may have been impersonated.  Simply click Yes to proceed. The test lab will give you some getting started directions; click Close Window when you’re ready to try out Windows 7. Here’s the default desktop in the Windows 7 test drive.  You can use it just like a normal Windows computer, but do note that it may function slowly depending on your internet connection.   This test drive includes both Office 2007 and Office 2010 Tech Preview, so you can try out both in Windows 7 as well. You can try out the new Windows 7 applications such as the reworked Paint with the Ribbon interface from Office. Or you can even test the newest version of Media Center, though it will warn you that it may not function good with the down-scaled graphics in the test drive.   Most importantly, you can try out the new features in Windows 7, such as Jumplists and even Aero Snap.  Once again, these features will not function the quickest, but it does let you test them out. While working with the Virtual Lab, there are different tasks it walks you through. You can also download a copy of the lab manual in PDF format to help you navigate through the various objectives. The test drive system is running Microsoft Forefront Security, the enterprise security solution from which Microsoft Security Essentials has adapted components from. Conclusion These virtual labs are great for tech students, or those of you who want to get a first-hand trial of the new features. Also, if you’re not sure on how to deploy something and want to practice in a virtual environment, these labs are quite valuable.While these labs are geared toward IT professionals, it’s a good way for anyone to try out Windows 7 features from the comfort of your current computer. Test Drive Windows 7 Similar Articles Productive Geek Tips Mount Multiple ISO Images Using Virtual CloneDriveHow To Delete a VHD in Windows 7Keyboard Shortcuts for VMware WorkstationMount an ISO image in Windows 7 or VistaHow To Turn a Physical Computer Into A Virtual Machine with Disk2vhd TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 If it were only this easy SyncToy syncs Files and Folders across Computers on a Network (or partitions on the same drive) Classic Cinema Online offers 100’s of OnDemand Movies OutSync will Sync Photos of your Friends on Facebook and Outlook Windows 7 Easter Theme YoWindoW, a real time weather screensaver

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  • C++ AMP Video Overview

    - by Daniel Moth
    I hope to be recording some C++ AMP screencasts for channel9 soon (you'll find them through my regular screencasts link on the left), and in all of them I will assume you have watched this short interview overview of C++ AMP.   Note: I think there were some technical problems with streaming so best to download the "High Quality WMV" or switch to progressive format. Comments about this post by Daniel Moth welcome at the original blog.

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  • Evolution of Apple: A Fan Spliced Mega Tribute to the Apple Product Lineup

    - by Jason Fitzpatrick
    Whether you’re an Apple fan or not, this 3.5 minute tribute to the evolution of Apple products is a neat look back at decades of computing history and iconic design. Put together by Apple fan August Brandels, the video splices together Apple commercials and promotional footage from the last 30 years (remixed against the catchy background tune Silhouettes by Avicii) into a mega tribute to the computer giant. If nothing else they should hire the guy to do motivational videos for annual employee meetings. [via Tech Crunch] HTG Explains: How Antivirus Software Works HTG Explains: Why Deleted Files Can Be Recovered and How You Can Prevent It HTG Explains: What Are the Sys Rq, Scroll Lock, and Pause/Break Keys on My Keyboard?

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  • SQLAuthority News – Pluralsight Course Review – Practices for Software Startups – Part 1 of 2

    - by pinaldave
    This is first part of the two part series of Practices for Software Startup Pluralsight Course. The course is written by Stephen Forte (Blog | Twitter). Stephen Forte is the Chief Strategy Officer of the venture backed company, Telerik, a leading vendor of developer and team productivity tools. Stephen is also a Certified Scrum Master, Certified Scrum Professional, PMP, and also speaks regularly at industry conferences around the world. He has written several books on application and database development.  Stephen is also a board member of the Scrum Alliance. Startups – Everybodies Dream Start-up companies are an important topic right now – everyone wants to start their own business.  It is also important to remember that all companies were a start up at one point – from your corner store to the giants like Microsoft and Apple.  Research proves that not every start-up succeeds, in fact, most will fail before their first year.  There are many reasons for this, and this could be due to the fact that there are many stages to a start-up company, and stumbling at any of these stages can lead to failure.  It is important to understand what makes a start-up company succeed at all its hurdles to become successful.  It is even important to define success.  For most start-ups this would mean becoming their own independently functioning company or to be bought out for a hefty profit by a larger company.  The idea of making a hefty profit by living your dream is extremely important, and you can even think of start-ups as the new craze.  That’s why studying them is so important – they are very popular, but things have changed a lot since their inception. Starting the Startups Beginning a start-up company used to be difficult, but now facilities and information is widely available, and it is much easier.  But that means it is much easier to fail, also.  Previously to start your own company, everything was planned and organized, resources were ensured and backed up before beginning; even the idea of starting your own business was a big thing.  Now anybody can do it, and the steps are simple and outlines everywhere – you can get online software and easily outsource , cloud source, or crowdsource a lot of your material.  But without the type of planning previously required, things can often go badly. New Products – New Ideas – New World There are so many fantastic new products, but they don’t reach success all the time.  I find start-up companies very interesting, and whenever I meet someone who is interested in the subject or already starting their own company, I always ask what they are doing, their plans, goals, market, etc.  I am sorry to say that in most cases, they cannot answer my questions.  It is true that many fantastic ideas fail because of bad decisions.  These bad decisions were not made intentionally, but people were simply unaware of what they should be doing.  This will always lead to failure.  But I am happy to say that all these issues can be gone because Pluralsight is now offering a course all about start-ups by Stephen Forte.  Stephen is a start up leader.  He has successfully started many companies and most are still going strong, or have gone on to even bigger and better things. Beginning Course on Startup I have always thought start-ups are a fascinating subject, and decided to take his course, but it is three hours long.  This would be hard to fit into my busy work day all at once, so I decided to do half of his course before my daughter wakes up, and the other half after she goes to sleep.  The course is divided into six modules, so this would be easy to do.  I began the first chapter early in the morning, at 5 am.  Stephen jumped right into the middle of the subject in the very first module – designing your business plan.  The first question you will have to answer to yourself, to others, and to investors is: What is your product and when will we be able to see it?  So a very important concept is a “minimal viable product.”  This means setting goals for yourself and your product.  We all have large dreams, but your minimal viable product doesn’t have to be your final vision at the very first.  For example: Apple is a giant company, but it is still evolving.  Steve Jobs didn’t envision the iPhone 6 at the very beginning.  He had to start at the first iPhone and do his market research, and the idea evolved into the technology you see now.  So for yourself, you should decide a beginning and stop point.  Do your market research.  Determine who you want to reach, what audience you want for your product.  You can have a great idea that simply will not work in the market, do need, bottlenecks, lack of resources, or competition.  There is a lot of research that needs to be done before you even write a business plan, and Stephen covers it in the very first chapter. The Team – Unique Key to Success After jumping right into the subject in the very first module, I wondered what Stephen could have in store for me for the rest of the course.  Chapter number two is building a team.  Having a team is important regardless of what your startup is.  You can be a true visionary with endless ideas and energy, but one person can still not do everything.  It is important to decide from the very beginning if you will have cofounders, team leaders, and how many employees you’ll need.  Even more important, you’ll need to decide what kind of team you want – what personalities, skills, and type of energy you want each of your employees to bring.  Do you want to have an A+ team with a B- idea, or do you have a B- idea that needs an A+ team to sell it?  Stephen asks all the hard questions!  I was especially impressed by his insight on developing.  You have to decide if you need developers, how many, and what their skills should be. I found this insight extremely useful for everyday usage, not just for start-up companies.  I would apply this kind of information in management at any position.  An amazing team will build an amazing product – and that doesn’t matter if you’re a start-up company or a small team working for a much larger business. Customer Development – The Ultimate Obective Chapter three was about customer development. According to Stephen, there are four different steps to develop a customer base.  The first question to ask yourself is if you are envisioning a large customer base buying a few products each, or a small, dedicated base that buys a lot of your product – quantity vs. Quality.  He also discusses how to earn, retain, and get more customers.  He also says that each customer should be placed in a different role – some will be like investors, who regularly spend with you and invest their money in your business.  It is then your job to take that investment and turn it into a better product in the future.  You need to deal with their money properly – think of it is as theirs as investors, not yours as profit.  At the end of this module I felt that only Stephen could provide this kind of insight, and then he listed all the resources he took his information from.  I have never seen a group of people so passionate about their customers. It was indeed a long day for me. In tomorrow’s part 2 we will discuss rest of the three module and also will see a quick video of the Practices for Software Startup Pluralsight Course. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Best Practices, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Seriously, It’s Time to Get Your Content Act Together

    - by Mike Stiles
    Branded content, content marketing, social content, brand journalism, we’re seeing those terms more and more. Why? The technology tools are coming together. We should know. We can gather big data, crunch it, listen to the public, moderate, respond, get to know the customer intimately, know what they like, know what they want, we can target, distribute, amplify, measure engagement and reaction, modify strategy and even automate a great deal of all that. An amazing machine, a sleek, smooth-running engine has been built such that all the parts can interact and work together to deliver peak performance and maximum output. But that engine isn’t going anywhere without any gas. Content is the gas. Yes, we curate other people’s content. We can siphon their gas. There’s tech to help with that too. But as for the creation of original, worthwhile content made for a specific audience, our audience, machines can’t do that…at least not yet. Curated content is great. But somebody has to originate the content for it to be curated and shared. And since the need for good, curated content is obviously large and the desire to share is there, it’s a winning proposition for a brand to be a consistent producer of original content. And yet, it feels like content is an issue we’re avoiding. There’s a reluctance to build a massive pipeline if you have no idea what you’re going to run through it. The C-suite often doesn’t know what content is, that it’s different from ads, where to get it, who makes it, how long it should be, what the point of it is if there’s no hard sell of the product, what it costs, how to use it, how to measure it, how to make sure it’s good, or how to make sure it will keep flowing. It could be the reason many brands aren’t pulling the trigger on socially enabling the enterprise. And that’s a shame, because there are a lot of creative, daring, experimental, uniquely talented entertainers and journalists chomping at the bit to execute content for brands. But for many corporate executives, content is “weird,” and the people who make it are even weirder. The content side of the equation is human. It’s art, but art that can be informed by data. The natural inclination is for brands to turn to their agencies for such creative endeavors. But agencies are falling into one of two categories. They’re failing to transition from ads to content. In “Content Era, What’s the Role of Agencies?” Alexander Jutkowitz says agencies were made for one-hit campaigns, not ongoing content. Or, they’re ready and capable but can’t get clients to do the right things. Agencies have to make money, even if it means continuing to do the wrong things because that’s all the client will agree to. So what we wind up with in the pipeline is advertising, marketing-heavy content, content that was obviously created or spearheaded by non-creative executives, random & inconsistent content, copy written for SEO bots, and other completely uninteresting nightmares. Frank Rose, author of “The Art of Immersion,” writes, “Content without story and excitement is noise pollution.” In the old days, you made an ad and inserted it into shows made by people who knew what they were doing. You could bask in that show’s success and leverage their audience. Now, you are tasked with attracting, amassing and holding your own audience. You may just want to make, advertise and sell your widgets. But now there’s a war on for a precious commodity, attention. People are busy. They have filters to keep uninteresting and irrelevant things out. They value their time and expect value back when they give it up. Joe Pulizzi, founder of the Content Marketing Institute, says, "Your customers don't care about you, your products, your services…they care about themselves, their wants and their needs." Is it worth getting serious about content and doing it right? 61% of consumers feel better about a company that delivers custom content (Custom Content Council). Interesting content is one of the top 3 reasons people follow brands on social (Content+). 78% of consumers think organizations that provide custom content want to build good relationships with them (TMG Custom Media). On the B2B side, 80% of business decision makers prefer to get company info in a series of articles vs. an ad. So what’s the hang-up? Cited barriers to content marketing are lack of human resources (42%) and lack of budget (35%). 54% of brands don’t have a single on-site, dedicated content creator. And only 38% of brands have a content marketing strategy. Tech has built the biggest, most incredible stage for brands that’s ever been built. Putting something on that stage is your responsibility. Do a bad show, or no show at all, and you’ll be the beautiful, talented actress that never got discovered. @mikestilesPhoto: Gabriella Fabbri, stock.xchng

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  • SQL SERVER – Quick Note of Database Mirroring

    - by pinaldave
    Just a day ago, I was invited at Round Table meeting at prestigious organization. They were planning to implement High Availability solution using Database Mirroring. During the meeting, I have made few notes of what was being discussed there. I just thought it would be interested for all of you know about it. Database Mirroring works [...]

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  • cdc-acm driver: This device cannot do calls on its own. It is not a modem

    - by Sorcrer
    I am using Beagleboard-xm with 3.12 Kernel and ubuntu rootfs from Robert Nelson's site. I use a Telit HE910 GPS+GSM modem along with my project .So as per the HW user guide i have to apply a logic high for 5s on the input of this modem for enabling it So when I does this by toggling the gpio pin for 5s using a script I'm getting some messages on the terminal I am sure this message comes from the driver in usb/class/cdc-acm.c but couldn't find the reason behind this? How can I solve this issue?? root@arm:~# ./modem_on.sh Turning on Telit modem ...... going to sleep and toggle [ 70.791381] cdc_acm 1-2:1.0: This device cannot do calls on its own. It is not a modem. [ 74.390258] cdc_acm 1-2:1.0: This device cannot do calls on its own. It is not a modem. [ 74.406890] cdc_acm 1-2:1.2: This device cannot do calls on its own. It is not a modem. [ 74.462188] cdc_acm 1-2:1.4: This device cannot do calls on its own. It is not a modem. [ 74.478363] cdc_acm 1-2:1.6: This device cannot do calls on its own. It is not a modem. [ 74.495269] cdc_acm 1-2:1.8: This device cannot do calls on its own. It is not a modem. [ 74.510040] cdc_acm 1-2:1.10: This device cannot do calls on its own. It is not a modem. [ 74.530090] cdc_acm 1-2:1.12: This device cannot do calls on its own. It is not a modem. [ 74.619720] cdc_acm 1-2:1.0: This device cannot do calls on its own. It is not a modem. [ 74.634429] cdc_acm 1-2:1.2: This device cannot do calls on its own. It is not a modem. [ 74.649475] cdc_acm 1-2:1.4: This device cannot do calls on its own. It is not a modem. [ 74.664459] cdc_acm 1-2:1.6: This device cannot do calls on its own. It is not a modem. [ 74.678741] cdc_acm 1-2:1.8: This device cannot do calls on its own. It is not a modem. [ 74.693389] cdc_acm 1-2:1.10: This device cannot do calls on its own. It is not a modem. [ 74.708099] cdc_acm 1-2:1.12: This device cannot do calls on its own. It is not a modem. Script complete .......... The realted necessary portion of dmesg is below [ 30.623107] init: plymouth-upstart-bridge main process ended, respawning [ 70.629943] usb 1-2: new high-speed USB device number 2 using ehci-omap [ 70.782501] usb 1-2: config 1 interface 0 altsetting 0 endpoint 0x81 has an invalid bInterval 255, changing to 11 [ 70.782592] usb 1-2: New USB device found, idVendor=058b, idProduct=0041 [ 70.782623] usb 1-2: New USB device strings: Mfr=0, Product=0, SerialNumber=0 [ 70.791381] cdc_acm 1-2:1.0: This device cannot do calls on its own. It is not a modem. [ 70.801483] cdc_acm 1-2:1.0: ttyACM0: USB ACM device [ 73.041625] usb 1-2: USB disconnect, device number 2 [ 74.209930] usb 1-2: new high-speed USB device number 3 using ehci-omap [ 74.369049] usb 1-2: New USB device found, idVendor=1bc7, idProduct=0021 [ 74.369110] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 74.369140] usb 1-2: Product: Telit Wireless Module [ 74.369171] usb 1-2: Manufacturer: Telit wireless solutions [ 74.369201] usb 1-2: SerialNumber: 357164042197668 [ 74.390258] cdc_acm 1-2:1.0: This device cannot do calls on its own. It is not a modem. [ 74.400207] cdc_acm 1-2:1.0: ttyACM0: USB ACM device [ 74.406890] cdc_acm 1-2:1.2: This device cannot do calls on its own. It is not a modem. [ 74.416900] cdc_acm 1-2:1.2: ttyACM1: USB ACM device [ 74.462188] cdc_acm 1-2:1.4: This device cannot do calls on its own. It is not a modem. [ 74.472259] cdc_acm 1-2:1.4: ttyACM2: USB ACM device [ 74.478363] cdc_acm 1-2:1.6: This device cannot do calls on its own. It is not a modem. [ 74.488372] cdc_acm 1-2:1.6: ttyACM3: USB ACM device [ 74.495269] cdc_acm 1-2:1.8: This device cannot do calls on its own. It is not a modem. [ 74.505279] cdc_acm 1-2:1.8: ttyACM4: USB ACM device [ 74.510040] cdc_acm 1-2:1.10: This device cannot do calls on its own. It is not a modem. [ 74.520141] cdc_acm 1-2:1.10: ttyACM5: USB ACM device [ 74.530090] cdc_acm 1-2:1.12: This device cannot do calls on its own. It is not a modem. [ 74.540283] cdc_acm 1-2:1.12: ttyACM6: USB ACM device [ 74.619720] cdc_acm 1-2:1.0: This device cannot do calls on its own. It is not a modem. [ 74.629455] cdc_acm 1-2:1.0: ttyACM0: USB ACM device [ 74.634429] cdc_acm 1-2:1.2: This device cannot do calls on its own. It is not a modem. [ 74.644042] cdc_acm 1-2:1.2: ttyACM1: USB ACM device [ 74.649475] cdc_acm 1-2:1.4: This device cannot do calls on its own. It is not a modem. [ 74.659027] cdc_acm 1-2:1.4: ttyACM2: USB ACM device [ 74.664459] cdc_acm 1-2:1.6: This device cannot do calls on its own. It is not a modem. [ 74.674133] cdc_acm 1-2:1.6: ttyACM3: USB ACM device [ 74.678741] cdc_acm 1-2:1.8: This device cannot do calls on its own. It is not a modem. [ 74.688415] cdc_acm 1-2:1.8: ttyACM4: USB ACM device [ 74.693389] cdc_acm 1-2:1.10: This device cannot do calls on its own. It is not a modem. [ 74.703186] cdc_acm 1-2:1.10: ttyACM5: USB ACM device [ 74.708099] cdc_acm 1-2:1.12: This device cannot do calls on its own. It is not a modem. [ 74.717895] cdc_acm 1-2:1.12: ttyACM6: USB ACM device `

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  • Best Practices for Building a Virtualized SPARC Computing Environment

    - by Scott Elvington
    Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Oracle just published Best Practices for Building a Virtualized SPARC Computing Environment, a white paper that provides guidance on the complete hardware and software stack for deploying and managing your physical and virtual SPARC infrastructure. The solution is based on Oracle SPARC T4 servers, Oracle Solaris 11 with Oracle VM for SPARC 2.2, Sun ZFS storage appliances, Sun 10GbE 72 port switches and Oracle Enterprise Manager Ops Center 12c. The paper emphasizes the value and importance of planning the resources (compute, network and storage) that will comprise the virtualized environment to achieve the desired capacity, performance and availability characteristics. The document also details numerous operational best practices that will help you deliver on those characteristics with unique capabilities provided by Enterprise Manager Ops Center including policy-based guest placement, pool resource balancing and automated guest recovery in the event of server failure. Plenty of references to supplementary documentation are included to help point you to additional resources. Whether you’re building the first stages of your private cloud or a general-purpose virtualized SPARC computing environment, these documented best practices will help ensure success. Please join Phil Bullinger and Steve Wilson from Oracle to learn more about breakthrough efficiency in private cloud infrastructure and how SPARC based virtualization can help you get started on your cloud journey. Stay Connected: Twitter |  Face book |  You Tube |  Linked in |  Newsletter

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  • Java(standard, non standard) or Non Java based Web developement [closed]

    - by LivingThing
    I am new to web development. Initially i thought i would be learning LAMP or WAMP to acquire web developement skills but recently i came across Standard Java based (JSP, servlets) and Non standard Java based (GWT). My question is related to if and how LAMP can be compared with Java (standarad or non stadard) technologies. Is LAMP even comparable to Java based tech or it does something else or something more or less ? what requirement for a web developement projects require the choice that which of these 'technologies' should be choosen ? Thank YOu

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  • SQLAuthority News – Meeting with Allen Bailochan Tuladhar – An Unlimited Experience

    - by pinaldave
    Allen  Tuladhar I recently came back from my 9-day trip in Nepal and I must say that this is one of the best trips I had in my lifetime. Allen Bailochan Tuladhar is a wonderful person and an extreme enthusiast for Microsoft Technology. Allen is the Chief Executive Officer of Unlimited Technologies Pvt Ltd., Country Manager of Microsoft MDP Nepal, the Member Secretary of Nepali Language in Information Technology, and member of the Steering Committee of the Government of Nepal. He is the person who keeps the Nepal’s Tech Community constantly motivating and taking it to the next level. I have met Allen for many times before, but this was the first time I was with him in Kathmandu, Nepal. I was very impressed with the amount of the work he does in the community. During my 9 days of stay, every single day was a new lesson for me. I was amazed and overwhelmed with the many things he does every single day. Not only he does he work closely with Government of Nepal ministry, but he is also the most known person in the Student Community. His expertise in the technical subject matter is not limited to one technology; rather, I have seen him actively engaging himself in  discussions of various tech topics. Allen presending at TechMela Kathmandu, Nepal Allen is currently active in working out to localize Windows and Office and incorporate it using the Nepali language. I was able to witness and experience how the localization works, as well as the procedure on how to do such. If you know the whole localization process, you must have realized how big and daunting of a process it is. I was glad that I became a part of it. Prominent Personality of Nepal on Panel Discussion Another great opportunity I had when I was at Allen’s office is that I have learned how the radio technology talk show works. Nepali Radio station has the weekly program in their local language, in which MS technology is discussed and industry leaders are invited to talk about their experience with the technology. I found the program so interesting because it has so much variety in terms of technology subjects. Well, my understanding of Nepali language is limited but I did understand quite a bit. Ravi, Nutan, Pinal, Gandip I got the chance to meet lots of Database Professionals as well. People in Nepal are very polite even though they are very strong in their technology fundamentals. I had in-depth discussion regarding High Availability scenarios, as well Query Tuning. Database professionals from the leading financial sectors of Nepal wanted me to visit their Data Center and help them out with a few advances. In no time, Allen organized a visit for me. He sent me a Nepali-speaking expert from his own organization to accompany me in overcoming any difficulties while I was on my way helping this financial district. Pinal (SQLAuthority) and Deependra (Unlimited) When I was going to Nepal, I was really not sure if I would be able to stay busy for 9 days straight in Community-related activity. However, on the 9th day I realize that I can still stay here for more than 9 days because in every single day, I feel enthusiastic enough to do something new. Allen Bailochan Tuladhar Even though I was working  very hard every day, I hardly had the chance to work with and talk to him one-on-one for the first few days. One of the evenings, Allen invited me to his home and we discussed about his future ideas. I was really surprised to see how much a man can do for his technical community and for his country. When I asked Allen’s wife and daughter if they ever think it’s getting too much with regards to Allen putting tough efforts to the community, their answer was something I did not expect. I found out that Allen’s wife manages all the back office and logistics of the community events and his daughter manages the websites. I felt that they do not have any complain,  and instead, their whole family is in this activity as deeply as it can get, which I thought is a very good thing. Pinal and Allen I want to end this post with an interesting story that happened during our lunch hour at one of the Nepali restaurants. While we were having our lunch and having some chitchat, Allen suddenly stood up and called several people walking along the pavement. He introduced them all to me as Microsoft Student Partners. He asked all of them to order their favorite dish and called the waiter to inform that he will pick up their tab. Figuring out the question written on my face, he just said one sentence: “They are all future technology professionals who are going to make all of us proud.” I guess I have a lot of things to learn. Hats off to Allen! Pinal and Allen at Microsoft MDP Unlimited Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: MVP, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, T SQL, Technology

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  • Slides and Code from my Silverlight MVVM Talk at DevConnections

    - by dwahlin
    I had a great time at the DevConnections conference in Las Vegas this year where Visual Studio 2010 and Silverlight 4 were launched. While at the conference I had the opportunity to give a full-day Silverlight workshop as well as 4 different talks and met a lot of people developing applications in Silverlight. I also had a chance to appear on a live broadcast of Channel 9 with John Papa, Ward Bell and Shawn Wildermuth, record a video with Rick Strahl covering jQuery versus Silverlight and record a few podcasts on Silverlight and ASP.NET MVC 2.  It was a really busy 4 days but I had a lot of fun chatting with people and hearing about different business problems they were solving with ASP.NET and/or Silverlight. Thanks to everyone who attended my sessions and took the time to ask questions and stop by to talk one-on-one. One of the talks I gave covered the Model-View-ViewModel pattern and how it can be used to build architecturally sound applications. Topics covered in the talk included: Understanding the MVVM pattern Benefits of the MVVM pattern Creating a ViewModel class Implementing INotifyPropertyChanged in a ViewModelBase class Binding a ViewModel declaratively in XAML Binding a ViewModel with code ICommand and ButtonBase commanding support in Silverlight 4 Using InvokeCommandBehavior to handle additional commanding needs Working with ViewModels and Sample Data in Blend Messaging support with EventBus classes, EventAggregator and Messenger My personal take on code in a code-beside file (I’m all in favor of it when used appropriately for message boxes, child windows, animations, etc.) One of the samples I showed in the talk was intended to teach all of the concepts mentioned above while keeping things as simple as possible.  The sample demonstrates quite a few things you can do with Silverlight and the MVVM pattern so check it out and feel free to leave feedback about things you like, things you’d do differently or anything else. MVVM is simply a pattern, not a way of life so there are many different ways to implement it. If you’re new to the subject of MVVM check out the following resources. I wish this talk would’ve been recorded (especially since my live and canned demos all worked :-)) but these resources will help get you going quickly. Getting Started with the MVVM Pattern in Silverlight Applications Model-View-ViewModel (MVVM) Explained Laurent Bugnion’s Excellent Talk at MIX10     Download sample code and slides from my DevConnections talk     For more information about onsite, online and video training, mentoring and consulting solutions for .NET, SharePoint or Silverlight please visit http://www.thewahlingroup.com.

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  • How to increase screen resolution in Hyper-V

    - by Saad
    I am using Ubuntu 12.04 on Hyper-V in windows 8. I want to increase the resolution so that Ubuntu window can occupy my whole screen. Does anyone have any idea of how it can be done ? I found one solution http://nramkumar.org/tech/blog/2013/05/04/ubuntu-under-hyper-v-how-to-overcome-screen-resolution-issue/, I have installed OpenSSH server on Ubuntu and Xming and Putty on windows. I am not sure what hostname to use to connect to Ubuntu (running in Hyper-V), using [email protected] or username@localhost in the hostname field returns error "Network error:connection refused". Can someone help me figure out what i am doing wrong ?

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  • Interesting articles and blogs on SPARC T4

    - by mv
    Interesting articles and blogs on SPARC T4 processor   I have consolidated all the interesting information I could get on SPARC T4 processor and its hardware cryptographic capabilities.  Hope its useful. 1. Advantages of SPARC T4 processor  Most important points in this T4 announcement are : "The SPARC T4 processor was designed from the ground up for high speed security and has a cryptographic stream processing unit (SPU) integrated directly into each processor core. These accelerators support 16 industry standard security ciphers and enable high speed encryption at rates 3 to 5 times that of competing processors. By integrating encryption capabilities directly inside the instruction pipeline, the SPARC T4 processor eliminates the performance and cost barriers typically associated with secure computing and makes it possible to deliver high security levels without impacting the user experience." Data Sheet has more details on these  : "New on-chip Encryption Instruction Accelerators with direct non-privileged support for 16 industry-standard cryptographic algorithms plus random number generation in each of the eight cores: AES, Camellia, CRC32c, DES, 3DES, DH, DSA, ECC, Kasumi, MD5, RSA, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512" I ran "isainfo -v" command on Solaris 11 Sparc T4-1 system. It shows the new instructions as expected  : $ isainfo -v 64-bit sparcv9 applications crc32c cbcond pause mont mpmul sha512 sha256 sha1 md5 camellia kasumi des aes ima hpc vis3 fmaf asi_blk_init vis2 vis popc 32-bit sparc applications crc32c cbcond pause mont mpmul sha512 sha256 sha1 md5 camellia kasumi des aes ima hpc vis3 fmaf asi_blk_init vis2 vis popc v8plus div32 mul32  2.  Dan Anderson's Blog have some interesting points about how these can be used : "New T4 crypto instructions include: aes_kexpand0, aes_kexpand1, aes_kexpand2,         aes_eround01, aes_eround23, aes_eround01_l, aes_eround_23_l, aes_dround01, aes_dround23, aes_dround01_l, aes_dround_23_l.       Having SPARC T4 hardware crypto instructions is all well and good, but how do we access it ?      The software is available with Solaris 11 and is used automatically if you are running Solaris a SPARC T4.  It is used internally in the kernel through kernel crypto modules.  It is available in user space through the PKCS#11 library." 3.   Dans' Blog on Where's the Crypto Libraries? Although this was written in 2009 but still is very useful  "Here's a brief tour of the major crypto libraries shown in the digraph:   The libpkcs11 library contains the PKCS#11 API (C_\*() functions, such as C_Initialize()). That in turn calls library pkcs11_softtoken or pkcs11_kernel, for userland or kernel crypto providers. The latter is used mostly for hardware-assisted cryptography (such as n2cp for Niagara2 SPARC processors), as that is performed more efficiently in kernel space with the "kCF" module (Kernel Crypto Framework). Additionally, for Solaris 10, strong crypto algorithms were split off in separate libraries, pkcs11_softtoken_extra libcryptoutil contains low-level utility functions to help implement cryptography. libsoftcrypto (OpenSolaris and Solaris Nevada only) implements several symmetric-key crypto algorithms in software, such as AES, RC4, and DES3, and the bignum library (used for RSA). libmd implements MD5, SHA, and SHA2 message digest algorithms" 4. Difference in T3 and T4 Diagram in this blog is good and self explanatory. Jeff's blog also highlights the differences  "The T4 servers have improved crypto acceleration, described at https://blogs.oracle.com/DanX/entry/sparc_t4_openssl_engine. It is "just built in" so administrators no longer have to assign crypto accelerator units to domains - it "just happens". Every physical or virtual CPU on a SPARC-T4 has full access to hardware based crypto acceleration at all times. .... For completeness sake, it's worth noting that the T4 adds more crypto algorithms, and accelerates Camelia, CRC32c, and more SHA-x." 5. About performance counters In this blog, performance counters are explained : "Note that unlike T3 and before, T4 crypto doesn't require kernel modules like ncp or n2cp, there is no visibility of crypto hardware with kstats or cryptoadm. T4 does provide hardware counters for crypto operations.  You can see these using cpustat: cpustat -c pic0=Instr_FGU_crypto 5 You can check the general crypto support of the hardware and OS with the command "isainfo -v". Since T4 crypto's implementation now allows direct userland access, there are no "crypto units" visible to cryptoadm.  " For more details refer Martin's blog as well. 6. How to turn off  SPARC T4 or Intel AES-NI crypto acceleration  I found this interesting blog from Darren about how to turn off  SPARC T4 or Intel AES-NI crypto acceleration. "One of the new Solaris 11 features of the linker/loader is the ability to have a single ELF object that has multiple different implementations of the same functions that are selected at runtime based on the capabilities of the machine.   The alternate to this is having the application coded to call getisax(2) system call and make the choice itself.  We use this functionality of the linker/loader when we build the userland libraries for the Solaris Cryptographic Framework (specifically libmd.so and libsoftcrypto.so) The Solaris linker/loader allows control of a lot of its functionality via environment variables, we can use that to control the version of the cryptographic functions we run.  To do this we simply export the LD_HWCAP environment variable with values that tell ld.so.1 to not select the HWCAP section matching certain features even if isainfo says they are present.  This will work for consumers of the Solaris Cryptographic Framework that use the Solaris PKCS#11 libraries or use libmd.so interfaces directly.  For SPARC T4 : export LD_HWCAP="-aes -des -md5 -sha256 -sha512 -mont -mpul" .. For Intel systems with AES-NI support: export LD_HWCAP="-aes"" Note that LD_HWCAP is explained in  http://docs.oracle.com/cd/E23823_01/html/816-5165/ld.so.1-1.html "LD_HWCAP, LD_HWCAP_32, and LD_HWCAP_64 -  Identifies an alternative hardware capabilities value... A “-” prefix results in the capabilities that follow being removed from the alternative capabilities." 7. Whitepaper on SPARC T4 Servers—Optimized for End-to-End Data Center Computing This Whitepaper on SPARC T4 Servers—Optimized for End-to-End Data Center Computing explains more details.  It has DTrace scripts which may come in handy : "To ensure the hardware-assisted cryptographic acceleration is configured to use and working with the security scenarios, it is recommended to use the following Solaris DTrace script. #!/usr/sbin/dtrace -s pid$1:libsoftcrypto:yf*:entry, pid$target:libsoftcrypto:rsa*:entry, pid$1:libmd:yf*:entry { @[probefunc] = count(); } tick-1sec { printa(@ops); trunc(@ops); }" Note that I have slightly modified the D Script to have RSA "libsoftcrypto:rsa*:entry" as well as per recommendations from Chi-Chang Lin. 8. References http://www.oracle.com/us/corporate/features/sparc-t4-announcement-494846.html http://www.oracle.com/us/products/servers-storage/servers/sparc-enterprise/t-series/sparc-t4-1-ds-487858.pdf https://blogs.oracle.com/DanX/entry/sparc_t4_openssl_engine https://blogs.oracle.com/DanX/entry/where_s_the_crypto_libraries https://blogs.oracle.com/darren/entry/howto_turn_off_sparc_t4 http://docs.oracle.com/cd/E23823_01/html/816-5165/ld.so.1-1.html   https://blogs.oracle.com/hardware/entry/unleash_the_power_of_cryptography https://blogs.oracle.com/cmt/entry/t4_crypto_cheat_sheet https://blogs.oracle.com/martinm/entry/t4_performance_counters_explained  https://blogs.oracle.com/jsavit/entry/no_mau_required_on_a http://www.oracle.com/us/products/servers-storage/servers/sparc-enterprise/t-series/sparc-t4-business-wp-524472.pdf

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  • BULL nous parle de Cloud Maker, offre de cloud computing s'appuyant sur l'hyperviseur de Microsoft

    BULL nous parle de Cloud Maker, offre de cloud computing s'appuyant sur l'hyperviseur de Microsoft Lors des Tech Days 2010, organisés par Microsoft, Bull avait annoncé la signature d'un accord de coopération stratégique dans le domaine de l'interopérabilité avec la firme de Redmond. De ce fait, les équipes de Bull et de Microsoft collaboreront dans plusieurs domaines pour renforcer les synergies et l'interopérabilité entre les environnements logiciels Microsoft et les solutions tierces, notamment les solutions Open Source et Unix, dont Bull est un des contributeurs et intégrateurs majeurs en Europe. Les deux entreprises travaillent en partenariat depuis de nombreuses années, même si elles sont également concurrentes...

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