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  • What Counts For a DBA – Depth

    - by Louis Davidson
    SQL Server offers very simple interfaces to many of its features. Most people could open up SSMS, connect to a server, write a simple query and see the results. Even several of the core DBA tasks are deceptively straightforward. It doesn’t take a rocket scientist to perform a basic database backup or run a trace (even using the newfangled Extended Events!). However, appearances can be deceptive, and often times it is really important that a DBA understands not just the basics of how to perform a task, but why we do a task, and how that task works. As an analogy, consider a child walking into a darkened room. Most would know that they need to turn on the light, and how to do it, so they flick the switch. But what happens if light fails to shine forth. Most would immediately tell you that you need to consider changing the light bulb. So you hop in the car and take them to the local home store and instruct them to buy a replacement. Confronted with a 40 foot display of light bulbs, how will they decide which of the hundreds of types of bulbs, of different types, fittings, shapes, colors, power and efficiency ratings, is the right choice? Obviously the main lesson the child is going to learn this day is how to use their cell phone as a flashlight so they don’t have to ask for help the next time. Likewise, when the metaphorical toddlers who use your database server have issues, they will instinctively know something is wrong, and may even have some idea what caused it, but will have no depth of knowledge to figure out the right solution. That is where the DBA comes in and attempts to save the day. However, when one looks beneath the shiny UI, SQL Server has its own “40 foot display of light bulbs”, in the form of the tremendous number of tools and the often-bewildering amount of information they can present to the DBA, to help us find issues. Unfortunately, resorting to guesswork, to trying different “bulbs” over and over, hoping to stumble on the answer. This is where the right depth of knowledge goes a long way. If we need to write a SELECT statement, then knowing the syntax and where to find the data is not enough. Knowledge of indexes and query plans is essential. Without it, we might hit on a query that “works”, but we are basically still a user, not a programmer, because we have no real control over our platform. Is that level of knowledge deep enough? Probably not, since knowledge of the underlying metadata and structures would be very useful in helping us make sense of any query plan. Understanding the structure of an index makes the “key lookup” operator not sound like what you do when someone tapes your car key to the ceiling. So is even this level of understanding deep enough? Do we need to understand the memory architecture used to process the query? It might be a comforting level of knowledge, and will doubtless come in handy at some point, but is not strictly necessary in most cases. Beyond that lies (more or less) full knowledge of SQL language and the intricacies of every step the SQL Server engine takes to process our query. My personal theory is that, as a professional, our knowledge of a given task should extend, at a minimum, one level deeper than is strictly necessary to perform the task. Anything deeper can be left to the ridiculously smart, or obsessive, or both. As an example. tasked with storing an integer value between 0 and 99999999, it’s essential that I know that choosing an Integer over Decimal(8,0) will likely offer performance benefits. It is then useful that I also understand the value of adding a CHECK constraint, to make sure the values are valid to the desired range; and comforting that I know a little about the underlying processors, registers and computer math. Anything further, I leave to the likes of Joe Chang, whose recent blog post on the topic offers depth by the bucketful!  

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  • Using WKA in Large Coherence Clusters (Disabling Multicast)

    - by jpurdy
    Disabling hardware multicast (by configuring well-known addresses aka WKA) will place significant stress on the network. For messages that must be sent to multiple servers, rather than having a server send a single packet to the switch and having the switch broadcast that packet to the rest of the cluster, the server must send a packet to each of the other servers. While hardware varies significantly, consider that a server with a single gigabit connection can send at most ~70,000 packets per second. To continue with some concrete numbers, in a cluster with 500 members, that means that each server can send at most 140 cluster-wide messages per second. And if there are 10 cluster members on each physical machine, that number shrinks to 14 cluster-wide messages per second (or with only mild hyperbole, roughly zero). It is also important to keep in mind that network I/O is not only expensive in terms of the network itself, but also the consumption of CPU required to send (or receive) a message (due to things like copying the packet bytes, processing a interrupt, etc). Fortunately, Coherence is designed to rely primarily on point-to-point messages, but there are some features that are inherently one-to-many: Announcing the arrival or departure of a member Updating partition assignment maps across the cluster Creating or destroying a NamedCache Invalidating a cache entry from a large number of client-side near caches Distributing a filter-based request across the full set of cache servers (e.g. queries, aggregators and entry processors) Invoking clear() on a NamedCache The first few of these are operations that are primarily routed through a single senior member, and also occur infrequently, so they usually are not a primary consideration. There are cases, however, where the load from introducing new members can be substantial (to the point of destabilizing the cluster). Consider the case where cluster in the first paragraph grows from 500 members to 1000 members (holding the number of physical machines constant). During this period, there will be 500 new member introductions, each of which may consist of several cluster-wide operations (for the cluster membership itself as well as the partitioned cache services, replicated cache services, invocation services, management services, etc). Note that all of these introductions will route through that one senior member, which is sharing its network bandwidth with several other members (which will be communicating to a lesser degree with other members throughout this process). While each service may have a distinct senior member, there's a good chance during initial startup that a single member will be the senior for all services (if those services start on the senior before the second member joins the cluster). It's obvious that this could cause CPU and/or network starvation. In the current release of Coherence (3.7.1.3 as of this writing), the pure unicast code path also has less sophisticated flow-control for cluster-wide messages (compared to the multicast-enabled code path), which may also result in significant heap consumption on the senior member's JVM (from the message backlog). This is almost never a problem in practice, but with sufficient CPU or network starvation, it could become critical. For the non-operational concerns (near caches, queries, etc), the application itself will determine how much load is placed on the cluster. Applications intended for deployment in a pure unicast environment should be careful to avoid excessive dependence on these features. Even in an environment with multicast support, these operations may scale poorly since even with a constant request rate, the underlying workload will increase at roughly the same rate as the underlying resources are added. Unless there is an infrastructural requirement to the contrary, multicast should be enabled. If it can't be enabled, care should be taken to ensure the added overhead doesn't lead to performance or stability issues. This is particularly crucial in large clusters.

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  • XenServer 6.0.2 path to installation media contains non-ascii characters

    - by cmaduro
    XenServer 6.0.2 install fails no matter what I do. I have confirmed that the md5 checksum on my ISO file is good. I tried installing from a mounted ISO file (remotely via iKVM). I tried installing from physical media. I tried installing from a bootable USB stick (using syslinux + contents of the ISO) All attempts have yielded the same result: When verifying the installation media, at 0% initializing, the following is reported: "Some packages appeared to be damaged." followed by a list of pretty much all the gz2 and rpm packages. If I skip the media verification the installer proceeds and then gives me an error when it reaches "Installing from base pack" at 0% which states "An unrecoverable error has occurred. The error was: 'ascii' codec can't decode byte 0xff in position 20710: ordinal not in range(128) Please refer to your user guide, or contact a Technical Support Representative, for further details" there is one option left which is to reboot. Apparently at some point during the processing of the repositories on the installation media non-ascii characters are found, which causes the installer to quit. How do I fix this? Here are my specs TYAN S8236 motherboard 2 AMD Opteron 6234 processors LSI2008 card connected to 2 1TB Seagate Constellation drives SATA, 1 500GB Corsair m4 SSD SATA and 1 Corsair Forse 3 - 64GB SSD SATA Onboard SATA connected to a slim DVD-+RW. Onboard SAS connected to 2 IBM ESX 70GB 10K SAS drives (for XenServer) 256GB memory ================================================================================= Comments: According to pylonsbook.com "chances are you have run into a problem with character sets, encodings, and Unicode" – cmaduro 10 hours ago A clue is provided by "vmware.com/support/vsphere5/doc/…; Data migration fails if the path to the vCenter Server installation media contains non-ASCII characters When this problem occurs, an error message similar to: 'ascii' codec can't decode byte 0xd0 in position 30: ordinal not in range(128) appears, and the installer quits unexpectedly during the data migration process. – cmaduro 10 hours ago This is an error that python throws. And guess what, the .py extention of the file you have to edit in this link community.spiceworks.com/how_to/show/1168 means the installer is written in python. Python is interpreted, so now to find the install file responsible for this error. – cmaduro 6 hours ago The file that generates the error upon verification is /opt/xensource/installer/tui/repo.py. The error message appears around line 359. – cmaduro 2 hours ago I am fairly sure that the install error is generated somewhere in repository.py as the backend.py file throws errors while methods in that file are being called. Perhaps all errors can be traced back to this file. – cmaduro 1 hour ago

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  • How to calculate CPU % based on raw CPU ticks in SNMP

    - by bjeanes
    According to http://net-snmp.sourceforge.net/docs/mibs/ucdavis.html#scalar_notcurrent ssCpuUser, ssCpuSystem, ssCpuIdle, etc are deprecated in favor of the raw variants (ssCpuRawUser, etc). The former values (which don't cover things like nice, wait, kernel, interrupt, etc) returned a percentage value: The percentage of CPU time spent processing user-level code, calculated over the last minute. This object has been deprecated in favour of 'ssCpuRawUser(50)', which can be used to calculate the same metric, but over any desired time period. The raw values return the "raw" number of ticks the CPU spent: The number of 'ticks' (typically 1/100s) spent processing user-level code. On a multi-processor system, the 'ssCpuRaw*' counters are cumulative over all CPUs, so their sum will typically be N*100 (for N processors). My question is: how do you turn the number of ticks into percentage? That is, how do you know how many ticks per second (it's typically — which implies not always — 1/100s, which either means 1 every 100 seconds or that a tick represents 1/100th of a second). I imagine you also need to know how many CPUs there are or you need to fetch all the CPU values to add them all together. I can't seem to find a MIB that gives you an integer value for # of CPUs which makes the former route awkward. The latter route seems unreliable because some of the numbers overlap (sometimes). For example, ssCpuRawWait has the following warning: This object will not be implemented on hosts where the underlying operating system does not measure this particular CPU metric. This time may also be included within the 'ssCpuRawSystem(52)' counter. Some help would be appreciated. Everywhere seems to just say that % is deprecated because it can be derived, but I haven't found anywhere that shows the official standard way to perform this derivation. The second component is that these "ticks" seem to be cumulative instead of over some time period. How do I sample values over some time period? The ultimate information I want is: % of user, system, idle, nice (and ideally steal, though there doesn't seem to be a standard MIB for this) "currently" (over the last 1-60s would probably be sufficient, with a preference for smaller time spans).

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  • OSX 10.6.6 SSH md5 break-in check

    - by Alex
    Information Recently one of the linux servers that I access was compromised to steal passwords and ssh keys using a modified ssh binary. This lead me to question if the attacker had compromised my OSX Laptop which had ssh access turned on. A sophos virus scan turned up nothing, and I did not have rkhunter installed before the attack, so I could not compare hashes of the system binaries to be sure. However because OSX is relatively standard for each of their major releases, I asked fiends for md5 hashes md5 /usr/bin/ssh and md5 /usr/sbin/sshd as a basic first check to see if there was anything different about my machine. A few emails later I have found the following data: Version (Arch) [N] MD5 (/usr/bin/ssh) MD5 (/usr/sbin/sshd) OSX 10.5.8 (PPC) [3] 1e9fd483eef23464ec61c815f7984d61 9d32a36294565368728c18de466e69f1 OSX 10.5.8 (intel) [5] 1e9fd483eef23464ec61c815f7984d61 9d32a36294565368728c18de466e69f1 OSX 10.6.x (intel) [7] 591fbe723011c17b6ce41c537353b059 e781fad4fc86cf652f6df22106e0bf0e OSX 10.6.x (intel) [4] 58be068ad5e575c303ec348a1c71d48b 33dafd419194b04a558c8404b484f650 Mine 10.6.6 (intel) df344cc00a294c91230c65e8b7332a79 b5094ccf4cd074aaf573d4f5df75906a where N is the number of machines with with that MD5, and the last row is my laptop. The sample is relatively heterogeneous spaning a few years of different makes and models of Apples, and different versions of 10.6.x. The different hash for my system made me worried that these binaries might have been compromised. So I made sure that my backup for the week was good, and dived into formatting my system and reinstalling OSX. After reinstalling OSX from the manufacturer DVD, I found that the MD5 hash did not change for either ssh, or sshd. Goal Make sure that my system is does not have any malicious software. Should I be worried that this base install of OSX (with no other software installed) has been compromised? I have also updated my system to 10.6.6 and found no change as well. Other Information I am not sure if this is helpful information, but my laptop is a i7 15 inch MacBook Pro bought in Nov 2010, and here is some output from system_profiler: System Software Overview: System Version: Mac OS X 10.6.6 (10J567) Kernel Version: Darwin 10.6.0 64-bit Kernel and Extensions: No Time since boot: 1:37 Hardware: Hardware Overview: Model Name: MacBook Model Identifier: MacBook6,2 Processor Name: Intel Core i7 Processor Speed: 2.66 GHz Number Of Processors: 1 Total Number Of Cores: 2 L2 Cache (per core): 256 KB L3 Cache: 4 MB Memory: 4 GB Processor Interconnect Speed: 4.8 GT/s Boot ROM Version: MBP61.0057.B0C SMC Version (system): 1.58f16 Sudden Motion Sensor: State: Enabled On the laptop, I find: $ codesign -vvv /usr/bin/ssh /usr/bin/ssh: valid on disk /usr/bin/ssh: satisfies its Designated Requirement $ codesign -vvv /usr/sbin/sshd /usr/sbin/sshd: valid on disk /usr/sbin/sshd: satisfies its Designated Requirement $ ls -la /usr/bin/ssh -rwxr-xr-x 1 root wheel 1001520 Feb 11 2010 /usr/bin/ssh $ ls -la /usr/sbin/sshd -rwxr-xr-x 1 root wheel 1304800 Feb 11 2010 /usr/sbin/sshd $ ls -la /sbin/md5 -r-xr-xr-x 1 root wheel 65232 May 18 2009 /sbin/md5 Update So far I have not gotten an answer about this question, but if you could help by increasing the number of hashes that I can compare against, that would be great. To get hashes, and version numbers, run the following on osx: md5 /usr/bin/ssh md5 /usr/sbin/sshd ssh -V sw_vers

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  • Automating the choice between JPEG and PNG with a script

    - by MHC
    Choosing the right format to save your images in is crucial for preserving image quality and reducing artifacts. Different formats follow different compression methods and come with their own set of advantages and disadvantages. JPG, for instance is suited for real life photographs that are rich in color gradients. The lossless PNG, on the other hand, is far superior when it comes to schematic figures: Picking the right format can be a chore when working with a large number of files. That's why I would love to find a way to automate it. A little bit of background on my particular use case: I am working on a number of handouts for a series of lectures at my unversity. The handouts are rich in figures, which I have to extract from PDF-formatted slides. Extracting these images gives me lossless PNGs, which are needlessly large at times. Converting these particular files to JPEG can reduce their size to up to less than 20% of their original file size, while maintaining the same quality. This is important as working with hundreds of large images in word processors is pretty crash-prone. Batch converting all extracted PNGs to JPEGs is not an option I am willing to follow, as many if not most images are better suited to be formatted as PNGs. Converting these would result in insignificant size reductions and sometimes even increases in filesize - that's at least what my test runs showed. What we can take from this is that file size after compression can serve as an indicator on what format is suited best for a particular image. It's not a particularly accurate predictor, but works well enough. So why not use it in form of a script: I included inotifywait because I would prefer for the script be executed automatically as soon as I drag an extracted image into a folder. This is a simpler version of the script that I've been using for the last couple of weeks: #!/bin/bash inotifywait -m --format "%w%f" --exclude '.jpg' -r -e create -e moved_to --fromfile '/home/MHC/.scripts/Workflow/Conversion/include_inotifywait' | while read file; do mogrify -format jpg -quality 92 "$file" done The advanced version of the script would have to be able to handle spaces in file names and directory names preserve the original file names flatten PNG images if an alpha value is set compare the file size between the temporary converted image and its original determine if the difference is greater than a given precentage act accordingly The actual conversion could be done with imagemagick tools: convert -quality 92 -flatten -background white file.png file.jpg Unfortunately, my bash skills aren't even close to advanced enough to convert the scheme above into an actual script, but I am sure many of you can. My reputation points on here are pretty low, but I will gladly award the most helpful answer with the highest bounty I can set. References: http://www.formortals.com/introducing-cnb-imageguide/, http://www.turnkeylinux.org/blog/png-vs-jpg Edit: Also see my comments below for some more information on why I think this script would be the best solution to the problem I am facing.

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  • Windows 7 Bluescreen: IRQ_NOT_LESS_OR_EQUAL | athrxusb.sys

    - by wretrOvian
    I'd left my system on last night, and found the bluescreen in the morning. This has been happening occasionally, over the past few days. Details: ================================================== Dump File : 022710-18236-01.dmp Crash Time : 2/27/2010 8:46:44 AM Bug Check String : DRIVER_IRQL_NOT_LESS_OR_EQUAL Bug Check Code : 0x000000d1 Parameter 1 : 00000000`00001001 Parameter 2 : 00000000`00000002 Parameter 3 : 00000000`00000000 Parameter 4 : fffff880`06b5c0e1 Caused By Driver : athrxusb.sys Caused By Address : athrxusb.sys+760e1 File Description : Product Name : Company : File Version : Processor : x64 Computer Name : Full Path : C:\Windows\minidump\022710-18236-01.dmp Processors Count : 2 Major Version : 15 Minor Version : 7600 ================================================== HiJackThis ("[...]" indicates removed text; full log [posted to pastebin][1]): Logfile of Trend Micro HijackThis v2.0.2 Scan saved at 8:49:15 AM, on 2/27/2010 Platform: Unknown Windows (WinNT 6.01.3504) MSInternet Explorer: Internet Explorer v8.00 (8.00.7600.16385) Boot mode: Normal Running processes: C:\Windows\DAODx.exe C:\Program Files (x86)\Asus\EPU\EPU.exe C:\Program Files\Asus\TurboV\TurboV.exe C:\Program Files (x86)\PowerISO\PWRISOVM.EXE C:\Program Files (x86)\OpenOffice.org 3\program\soffice.exe C:\Program Files (x86)\OpenOffice.org 3\program\soffice.bin D:\Downloads\HijackThis.exe C:\Program Files (x86)\uTorrent\uTorrent.exe R1 - HKCU\Software\Microsoft\Internet Explorer\[...] [...] O2 - BHO: Java(tm) Plug-In 2 SSV Helper - {DBC80044-A445-435b-BC74-9C25C1C588A9} - C:\Program Files (x86)\Java\jre6\bin\jp2ssv.dll O4 - HKLM\..\Run: [HDAudDeck] C:\Program Files (x86)\VIA\VIAudioi\VDeck\VDeck.exe -r O4 - HKLM\..\Run: [StartCCC] "C:\Program Files (x86)\ATI Technologies\ATI.ACE\Core-Static\CLIStart.exe" MSRun O4 - HKLM\..\Run: [TurboV] "C:\Program Files\Asus\TurboV\TurboV.exe" O4 - HKLM\..\Run: [PWRISOVM.EXE] C:\Program Files (x86)\PowerISO\PWRISOVM.EXE O4 - HKLM\..\Run: [googletalk] C:\Program Files (x86)\Google\Google Talk\googletalk.exe /autostart O4 - HKLM\..\Run: [AdobeCS4ServiceManager] "C:\Program Files (x86)\Common Files\Adobe\CS4ServiceManager\CS4ServiceManager.exe" -launchedbylogin O4 - HKCU\..\Run: [uTorrent] "C:\Program Files (x86)\uTorrent\uTorrent.exe" O4 - HKUS\S-1-5-19\..\Run: [Sidebar] %ProgramFiles%\Windows Sidebar\Sidebar.exe /autoRun (User 'LOCAL SERVICE') O4 - HKUS\S-1-5-19\..\RunOnce: [mctadmin] C:\Windows\System32\mctadmin.exe (User 'LOCAL SERVICE') O4 - HKUS\S-1-5-20\..\Run: [Sidebar] %ProgramFiles%\Windows Sidebar\Sidebar.exe /autoRun (User 'NETWORK SERVICE') O4 - HKUS\S-1-5-20\..\RunOnce: [mctadmin] C:\Windows\System32\mctadmin.exe (User 'NETWORK SERVICE') O4 - Startup: OpenOffice.org 3.1.lnk = C:\Program Files (x86)\OpenOffice.org 3\program\quickstart.exe O13 - Gopher Prefix: O23 - Service: @%SystemRoot%\system32\Alg.exe,-112 (ALG) - Unknown owner - C:\Windows\System32\alg.exe (file missing) O23 - Service: AMD External Events Utility - Unknown owner - C:\Windows\system32\atiesrxx.exe (file missing) O23 - Service: Asus System Control Service (AsSysCtrlService) - Unknown owner - C:\Program Files (x86)\Asus\AsSysCtrlService\1.00.02\AsSysCtrlService.exe O23 - Service: DeviceVM Meta Data Export Service (DvmMDES) - DeviceVM - C:\Asus.SYS\config\DVMExportService.exe O23 - Service: @%SystemRoot%\system32\efssvc.dll,-100 (EFS) - Unknown owner - C:\Windows\System32\lsass.exe (file missing) O23 - Service: ESET HTTP Server (EhttpSrv) - ESET - C:\Program Files\ESET\ESET NOD32 Antivirus\EHttpSrv.exe O23 - Service: ESET Service (ekrn) - ESET - C:\Program Files\ESET\ESET NOD32 Antivirus\x86\ekrn.exe O23 - Service: @%systemroot%\system32\fxsresm.dll,-118 (Fax) - Unknown owner - C:\Windows\system32\fxssvc.exe (file missing) O23 - Service: FLEXnet Licens

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  • Logitech Optical Mouse Frozen In Middle of Windows XP Pro Screen

    - by Code Sherpa
    I have a Logitech Optical Mouse/Keyboard. I have been using them just fine with the system drivers for almost a year now. I recently updated my Kaspersky software and rebooted. Now the mouse is frozen in the middle of my screen. I am not able to login to the Windows XP Pro box that has the frozen mouse (because i can't work the mouse) but am able to remote desktop to this computer. Things I know / have tried: When I boot on the problem computer, I am able to use the keyboard, but not the mouse. I have installed the latest version of Logitech's SetPoint (with the updated drivers) on the problem computer (via remote desktop) and that didn't seem to matter. I bought new batteries for the mouse and that didn't matter. I have tried the mouse/keyboard on another computer and the mouse works just fine there. My suspicion is that the Kaspersky install has overwritten a driver of some sort. Things I have not done (and would appreciate detailed steps if you feel this is the way to go): 1) Uninstalled all the mouse drivers on the machine and reboot. Then, reinstall. Note: When I get to the Device Manager I don't see an option for Human Interface Devices (where the mouse device is). Here are my options: Computer, Disk Drives, DVD/CD-Rom drives, Floppy controllers, IDE ATA/ATAPI, Imaging devices, Network Adapters, Other devices, Ports, Processors, Sound, video, and gaming, System devices, USB controllers. Also, I should point out that Video Controller is the only thing under Other devices and it has a yellow exclamation mark. The same is true for all the items under Universal Serial Bus controllers. I think this means I have to update my BIOS but, since my mouse was working just fine without doing that, I don't think that is my problem. So, how do I get to my Mouse Device? 2) Update my BIOS. Note: As pointed out above, I don't think this matters as my mouse was working just fine under my computer's current BIOS version. Thanks for your help.

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  • Best Processor for MediaSmart Server?

    - by Kent Boogaart
    I'm trying to figure out what the best possible processor is that I can stick in my HP MediaSmart server. I'm clueless when it comes to correlating CPUs to motherboards. I suspect it's the socket type I care about, but I worry that there's more to it. CPU-Z gives me (excerpt): Processors Information ------------------------------------------------------------------------- Processor 1 ID = 0 Number of cores 1 (max 1) Number of threads 1 (max 1) Name AMD Sempron LE-1150 Codename Sparta Specification AMD Sempron(tm) Processor LE-1150 Package Socket AM2 (940) CPUID F.F.1 Extended CPUID F.7F Brand ID 1 Core Stepping DH-G1 Technology 65 nm Core Speed 1000.0 MHz Multiplier x FSB 5.0 x 200.0 MHz HT Link speed 800.0 MHz Stock frequency 2000 MHz Instructions sets MMX (+), 3DNow! (+), SSE, SSE2, SSE3, x86-64 L1 Data cache 64 KBytes, 2-way set associative, 64-byte line size L1 Instruction cache 64 KBytes, 2-way set associative, 64-byte line size L2 cache 256 KBytes, 16-way set associative, 64-byte line size FID/VID Control yes Max FID 10.0x Max VID 1.350 V P-State FID 0x2 - VID 0x12 (5.0x - 1.100 V) P-State FID 0xA - VID 0x0C (9.0x - 1.250 V) P-State FID 0xC - VID 0x0A (10.0x - 1.300 V) K8 Thermal sensor yes K8 Revision ID 6.0 Attached device PCI device at bus 0, device 24, function 0 Attached device PCI device at bus 0, device 24, function 1 Attached device PCI device at bus 0, device 24, function 2 Attached device PCI device at bus 0, device 24, function 3 Chipset ------------------------------------------------------------------------- Northbridge SiS 761GX rev. 02 Southbridge SiS 966 rev. 59 Graphic Interface AGP AGP Revision 3.0 AGP Transfer Rate 8x AGP SBA supported, enabled Memory Type DDR2 Memory Size 2048 MBytes Channels Single Memory Frequency 200.0 MHz (CPU/5) CAS# latency (CL) 5.0 RAS# to CAS# delay (tRCD) 5 RAS# Precharge (tRP) 5 Cycle Time (tRAS) 15 Bank Cycle Time (tRC) 21 Command Rate (CR) 1T DMI ------------------------------------------------------------------------- DMI BIOS vendor Phoenix Technologies, LTD version R03 date 05/08/2008 DMI System Information manufacturer HP product MediaSmart Server version unknown serial CN68330DGH UUID A482007B-B0CC7593-DD11736A-407B7067 DMI Baseboard vendor Wistron model SJD4 revision A.0 serial unknown DMI System Enclosure manufacturer HP chassis type Desktop chassis serial unknown DMI Processor manufacturer AMD model AMD Sempron(tm) Processor LE-1150 clock speed 2000.0 MHz FSB speed 200.0 MHz multiplier 10.0x DMI Memory Controller correction 64-bit ECC Max module size 4096 MBytes DMI Memory Module designation A0 size 2048 MBytes (double bank) DMI Memory Module designation A1 DMI Memory Module designation A2 DMI Memory Module designation A3 DMI Port Connector designation PS/2 Mouse (internal) port type Mouse Port connector PS/2 connector PS/2 DMI Port Connector designation USB0 (external) port type USB DMI Physical Memory Array location Motherboard usage System Memory correction None max capacity 16384 MBytes max# of devices 4 DMI Memory Device designation A0 format DIMM type unknown total width 64 bits data width 64 bits size 2048 MBytes DMI Memory Device designation A1 format DIMM type unknown total width 64 bits data width 64 bits DMI Memory Device designation A2 format DIMM type unknown total width 64 bits data width 64 bits DMI Memory Device designation A3 format DIMM type unknown total width 64 bits data width 64 bits How do I figure out what options I have for an upgrade?

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  • HP UX can not boot from Ignite Tape

    - by Spirit
    We have hp rp2470 server running hp-ux 11.00, with LVM mirroring. As for redundancy we have second rp2470 same hw (same two processors, same ram, same two hdd’s, same number of lan cards). I want to clone first one to the second. For that purpose I am making ignite tape with the following command: make_tape_recovery -x inc_entire=vg00 Ignite tape finishes without problems. When I boot second server from this ignate tape, server is starting to boot, and ignite restore finishes without any errors, only few notes, which are normal. However vmunix is not booting and when restore finishes, it boot to ISL prompt. From this I cannot boot /stand/vmunix. I tried to run recovery shell but no success. When recovery shell ask to do frecover to restore critical files, then I receive error: frecover(5405): unable to open /dev/rmt/0m At first I thought that the problem might be in the difference of the firmware version of the servers: fw version of production server is: Firmware Version 43.50 and fw version of backup server is: Firmware Version 42.19 So i did a fw upgrade of my backup server so that both servers are v43.50, and tried a recovery but again cant boot the system. Next I did another archive tape with -I (Interactive) flag: make_tape_recovery -I -x inc_entire=vg00 and tried recovery with it, again no good. I cannot find any error or warnings on ignite log, and I cannot boot hpux. I am only on ISL prompt. This is what i've noticed on the gsp logs: ************* SYSTEM ALERT ************** SYSTEM NAME: mcnfwim1 DATE: 07/27/2003 TIME: 10:18:49 ALERT LEVEL: 6 = Boot possible, pending failure - action required REASON FOR ALERT SOURCE: 8 = I/O SOURCE DETAIL: 6 = disk SOURCE ID: 0 PROBLEM DETAIL: 0 = no problem detail LEDs: RUN ATTENTION FAULT REMOTE POWER FLASH OFF ON ON ON LED State: Boot Failed. Running non-OS code. Check Chassis and Console Logs for error messages. 0x00000060860010B0 00000000 00000000 - type 0 = Data Field Unused 0x58000860860010B0 00006706 1B0A1231 - type 11 = Timestamp 07/27/2003 10:18:49 And another gsp log: Log Entry # 3 : SYSTEM NAME: mcnfwim1 DATE: 07/27/2003 TIME: 10:12:20 ALERT LEVEL: 6 = Boot possible, pending failure - action required SOURCE: 8 = I/O SOURCE DETAIL: 6 = disk SOURCE ID: 0 PROBLEM DETAIL: 0 = no problem detail CALLER ACTIVITY: 1 = test STATUS: 0 CALLER SUBACTIVITY: 0B = implementation dependent REPORTING ENTITY TYPE: 0 = system firmware REPORTING ENTITY ID: 00 0x00000060860010B0 00000000 00000000 type 0 = Data Field Unused 0x58000860860010B0 00006706 1B0A0C14 type 11 = Timestamp 07/27/2003 10:12:20 Type CR for next entry, - CR for previous entry, Q CR to quit. Please note that I can not change anything on the production server. I can only make changes to the backup server. Any help is appreciated.

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  • Linux per-process resource limits - a deep Red Hat Mystery

    - by BobBanana
    I have my own multithreaded C program which scales in speed smoothly with the number of CPU cores.. I can run it with 1, 2, 3, etc threads and get linear speedup.. up to about 5.5x speed on a 6-core CPU on a Ubuntu Linux box. I had an opportunity to run the program on a very high end Sunfire x4450 with 4 quad-core Xeon processors, running Red Hat Enterprise Linux. I was eagerly anticipating seeing how fast the 16 cores could run my program with 16 threads.. But it runs at the same speed as just TWO threads! Much hair-pulling and debugging later, I see that my program really is creating all the threads, they really are running simultaneously, but the threads themselves are slower than they should be. 2 threads runs about 1.7x faster than 1, but 3, 4, 8, 10, 16 threads all run at just net 1.9x! I can see all the threads are running (not stalled or sleeping), they're just slow. To check that the HARDWARE wasn't at fault, I ran SIXTEEN copies of my program independently, simultaneously. They all ran at full speed. There really are 16 cores and they really do run at full speed and there really is enough RAM (in fact this machine has 64GB, and I only use 1GB per process). So, my question is if there's some OPERATING SYSTEM explanation, perhaps some per-process resource limit which automatically scales back thread scheduling to keep one process from hogging the machine. Clues are: My program does not access the disk or network. It's CPU limited. Its speed scales linearly on a single CPU box in Ubuntu Linux with a hexacore i7 for 1-6 threads. 6 threads is effectively 6x speedup. My program never runs faster than 2x speedup on this 16 core Sunfire Xeon box, for any number of threads from 2-16. Running 16 copies of my program single threaded runs perfectly, all 16 running at once at full speed. top shows 1600% of CPUs allocated. /proc/cpuinfo shows all 16 cores running at full 2.9GHz speed (not low frequency idle speed of 1.6GHz) There's 48GB of RAM free, it is not swapping. What's happening? Is there some process CPU limit policy? How could I measure it if so? What else could explain this behavior? Thanks for your ideas to solve this, the Great Xeon Slowdown Mystery of 2010!

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  • Impact of the L3 cache on performance - worth a dual-processor system?

    - by Dan Nissenbaum
    I will be purchasing a new high-end system, and I would like to have a better sense of whether a dual-processor Xeon system (I am looking at the new, high-end Xeon E5-2687W) might, realistically, provide a noticeable performance improvement due to the doubling of the L3 cache (20 MB per CPU). (This is in addition to the occasional added advantage due to the doubling of cores and RAM.) My usage scenario is, roughly, that I have many background applications running at any time - 3 or 4 data compression/backup applications, a low-impact web server, one or two virtual machines at any given time (usually fairly idle), and perhaps 20 utility programs that utilize a noticeable (but small) portion of the CPU cores. In total, when I am not actively using the computer, about 25% of the total CPU power is utilized in my current i7-970 6-core (12 thread) system. When I am doing routine work, the CPU utilization often exceeds 50%, and occasionally hits 75%-80%. The Xeon E5-2687W is not only a second-generation i7 (so should improve performance for that reason), but also has 8 cores (16 threads), rather than 6 cores. For this reason, I expect to run into the 75% CPU range even less frequently. Nonetheless, the ability to double the cores and the RAM is a consideration. However, in the end, I believe this decision comes down to whether the doubling of the L3 cache will provide a noticeable improvement. There are many benchmarks, and a lot of discussion, regarding CPU power. However, I find very little discussion of L3 cache utilization, and how increases in the L3 cache (such as doubling it with dual processors) affect performance. For example: If there are only two processes running, but each benefits from a large L3 cache (such as might be the case for background processes that frequently scan the file system), perhaps the overall system performance might noticeably improve with dual CPU's - even if only a single core is active on each CPU - due to each process having double the effective L3 cache. I am hoping that someone has a sense of the benefits of increasing (or doubling) the L3 cache size. Note: the CPU I am considering (the Xeon E5-2687W) has 20 MB L3 cache, so a system with dual CPU's would have 40 MB L3 cache.

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  • How to temporary disable a mirror video driver in windows xp registry

    - by happy clicker
    Because its a lot of text, I will ask first my question and then explain what the base problem is. Perhaps someone can give me a solution to the base problem: Is there is a way to temporary disable mirror video drivers (through registry or so), without uninstalling the corresponding software. I tested changing the enumeration in LocalMachine\Hardware\DeviceMap\Video but after reboot always the old configuration is restored. Explanation of the base problem We are working on a wpf-project for a department of a big company. There we have the problem that WPF renders only in software mode, although the hardware they have, must support hardware rendering (Tier 2). After searching for a solution to the problem, we found out that direct 3d does not work properly and we think thats why WPF can only use SW-rendering. In dxdiag.exe the direct3d-acceleration is enabled, but if we start the test-routine it always fails saying that it has not enough memory (it says memory, not video memory!). I have seen there 3 different types of pc’s (they have some hundreds of each type) and every type shows the exactly same behavior. We tried to update all the drivers, also dx (Version 9.0c) and we searched a lot in the web but could not find a solution. All the pcs have Intel Dual-Core processors or better, one type has an Intel gma 9000 graphics card the other two types have actual ATI and NVidia graphic-cards with 256MB onboard memory. Also the system memory is at least 2GB. Windows is XPSP3. The pc’s are of two different manufacturers. Because we see the exactly same behavior on every computer of this three very different computer-types, we don’t think that this is a driver or a direct x problem. What we’ve found in other newsgroups is, that direct x could be disturbed through mirror-video drivers such as NetMeeting, VNC and other remote desktop-installations. In the registry, we see under LocalMachine\Hardware\DeviceMap\Video a lot of such mirror-entries and we find also the definitions in the CurrentControlSet\Control\Video-Section (However this drivers are not shown in the hardware panel of the os). We can have admin-rights to one of these computers to test if disabling these drivers would help, but we must not change the configuration so that some software does not work after the tests. Therefore I cannot uninstall any software because I have not the mediums, licenses or knowhow to reinstall those apps. The support of this company however will only begin to work, if I can tell them what the real problem is. Thats why we search for a way to disable these mirror-drivers (or a hint to solve the dx problem if we are on a false trace)

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  • Why did Intel drop the Itanium?

    - by Cole Johnson
    I was reading up on the history of the computer and I came along the IA-64 (Itanium) processors. They sounded really interesting and I was confused as to why Intel would decide to drop them. The ability to choose explicitly what 2 instructions you wanted to run in that cycle is a great idea, especially when writing your program in assembly, for example, a faster bootloader. The hundreds of registers should be convincing for any assembly programmer. You could essentially store all the functions variables in the registers if it doesn't call any other ones. The ability to do instructions like this: (qp) xor r1 = r2, r3 ; r1 = r2 XOR r3 (qp) xor r1 = (imm8), r3 ; r1 = (imm8) XOR r3 versus having to do: ; eax = r1 ; ebx = r2 ; ecx = r3 mov eax, ebx ; first put r2 into r1 xor eax, ecx ; then set r1 equivalent to r2 XOR r3 or ; SAME mov eax, (imm32) ; first put (imm32) into r1 xor eax, ecx ; then set r1 equivalent to (imm32) XOR r3 I heard it was because of no backwards x86 comparability, but couldn't thy be fixed by just adding the Pentium circuitry to it and just add a processor flag that would switch it to Itanium mode (like switching to Protected or Long mode) All the great things about it would have surly put them a giant leap ahead of AMD. Any ideas? Sadly this means you will need a very advanced compiler to do this. Or even one per specific model of the CPU. (E.g. a newer version of the Itanium with an extra feature would require different compiler). When I was working on a WinForms (target only had .NET 2.0) project in Visual Studio 2010, I had a compile target of IA-64. That means that there is a .NET runtime that was able to be compiled for IA-64 and a .NET runtime means Windows. Plus, Hamilton's answer mentions Windows NT. Having a full blown OS like Windows NT means that there is a compiler capable of generating IA-64 machine code.

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  • PHP-FPM performing worse than mod_php

    - by lordstyx
    Recently the website I maintain has been growing a lot and I saw the point coming where I'd want to switch from apache to nginx, because I kept on reading that it performs way better. Now I've done the switch, and I have to say, nginx is keeping up just fine. However, php-fpm is forming a problem. Where the php pages used to take 0.1 second to generate with the same load they now take around 3 seconds! Furthermore the error.log from nginx is being spammed with errors like: upstream timed out (110: Connection timed out) while connecting to upstream, client: ... I also tried using unix sockets instead, but those would complain about the following: connect() to unix:/tmp/php5-fpm.sock failed (11: Resource temporarily unavailable) while connecting to upstream I've fiddled with settings here and there but nothing seems to work. Changing the amount of pm.max_children doesn't seem to help a lot either, but with it's current amount at 350 it seems to be the lesser of all evil. The server that's being used has 3 GB RAM (not all of it is free due to a MySQL server also running) along with 2 dual-core processors (4 cores in total). Am I doing something majorly wrong with the settings here, or is the server simply not capable enough? EDIT: Here is the nginx server block server { listen 80; listen [::]:80 default ipv6only=on; root /var/www; index index.php index.html index.htm; server_name localhost; location / { try_files $uri $uri/ /index.html; } location /doc/ { alias /usr/share/doc/; autoindex on; allow 127.0.0.1; deny all; } location = /50x.html { root /usr/share/nginx/www; } location ~ \.php$ { fastcgi_split_path_info ^(.+\.php)(/.+)$; # NOTE: You should have "cgi.fix_pathinfo = 0;" in php.ini try_files $uri = 404; # With php5-cgi alone: fastcgi_pass 127.0.0.1:9000; # With php5-fpm: #fastcgi_pass unix:/tmp/php5-fpm.sock; fastcgi_index index.php; include fastcgi_params; } location ~ /\.ht { deny all; } } And the php-fpm pool: [www] user = www-data group = www-data listen = 127.0.0.1:9000 ;listen = /tmp/php5-fpm.sock listen.backlog = -1 pm = dynamic pm.max_children = 350 pm.start_servers = 200 pm.min_spare_servers = 10 pm.max_spare_servers = 350 pm.max_requests = 1536 rlimit_files = 65536 rlimit_core = unlimited chdir = /

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  • Logitech Optical Mouse Frozen In Middle of Windows XP Pro Screen

    - by Code Sherpa
    Hi. I have a Logitech Optical Mouse/Keyboard. I have been using them just fine with the system drivers for almost a year now. I recently updated my Kaspersky software and rebooted. Now the mouse is frozen in the middle of my screen. I am not able to login to the Windows XP Pro box that has the frozen mouse (because i can't work the mouse) but am able to remote desktop to this computer. Things I know / have tried: When I boot on the problem computer, I am able to use the keyboard, but not the mouse. I have installed the latest version of Logitech's SetPoint (with the updated drivers) on the problem computer (via remote desktop) and that didn't seem to matter. I bought new batteries for the mouse and that didn't matter. I have tried the mouse/keyboard on another computer and the mouse works just fine there. My suspicion is that the Kaspersky install has overwritten a driver of some sort. Things I have not done (and would appreciate detailed steps if you feel this is the way to go): 1) Uninstalled all the mouse drivers on the machine and reboot. Then, reinstall. Note: When I get to the Device Manager I don't see an option for Human Interface Devices (where the mouse device is). Here are my options: Computer, Disk Drives, DVD/CD-Rom drives, Floppy controllers, IDE ATA/ATAPI, Imaging devices, Network Adapters, Other devices, Ports, Processors, Sound, video, and gaming, System devices, USB controllers. Also, I should point out that Video Controller is the only thing under Other devices and it has a yellow exclamation mark. The same is true for all the items under Universal Serial Bus controllers. I think this means I have to update my BIOS but, since my mouse was working just fine without doing that, I don't think that is my problem. So, how do I get to my Mouse Device? 2) Update my BIOS. Note: As pointed out above, I don't think this matters as my mouse was working just fine under my computer's current BIOS version. Thanks for your help.

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  • Synergy 1.5 crash (OSX 10.6.8)

    - by Oliver
    THANKS FOR TAKING THE TIME TO READ THIS I recently installed Synergy 1.5 r2278 (for Mac OSX 10.6.8) and was using it fine for most of the day, then it decided to stop working (the only thing I changed systemwise was the screensaver - and then after it started crashing disabled it - to see if it would resolve). When I start Synergy (on the Mac - Client) it says: after about 5 seconds (and successfully connecting to the Server) "synergyc quit unexpectedly" Here is the crash log (w/ binery info removed - too long for post requirements) Process: synergyc [1026] Path: /Applications/Synergy.app/Contents/MacOS/synergyc Identifier: synergy Version: ??? (???) Code Type: X86 (Native) Parent Process: Synergy [1023] Date/Time: 2014-05-28 15:36:17.746 +0930 OS Version: Mac OS X 10.6.8 (10K549) Report Version: 6 Interval Since Last Report: 2144189 sec Crashes Since Last Report: 23 Per-App Interval Since Last Report: 10242 sec Per-App Crashes Since Last Report: 9 Anonymous UUID: 86D5A57C-13D4-470E-AC72-48ACDDDE5EB0 Exception Type: EXC_CRASH (SIGABRT) Exception Codes: 0x0000000000000000, 0x0000000000000000 Crashed Thread: 5 Application Specific Information: abort() called Thread 0: Dispatch queue: com.apple.main-thread 0 libSystem.B.dylib 0x95cf3afa mach_msg_trap + 10 1 libSystem.B.dylib 0x95cf4267 mach_msg + 68 2 com.apple.CoreFoundation 0x95af02df __CFRunLoopRun + 2079 3 com.apple.CoreFoundation 0x95aef3c4 CFRunLoopRunSpecific + 452 4 com.apple.CoreFoundation 0x95aef1f1 CFRunLoopRunInMode + 97 5 com.apple.HIToolbox 0x93654e04 RunCurrentEventLoopInMode + 392 6 com.apple.HIToolbox 0x93654bb9 ReceiveNextEventCommon + 354 7 com.apple.HIToolbox 0x937dd137 ReceiveNextEvent + 83 8 synergyc 0x000356d0 COSXEventQueueBuffer::waitForEvent(double) + 48 9 synergyc 0x00010dd5 CEventQueue::getEvent(CEvent&, double) + 325 10 synergyc 0x00011fb0 CEventQueue::loop() + 272 11 synergyc 0x00044eb6 CClientApp::mainLoop() + 134 12 synergyc 0x0005c509 standardStartupStatic(int, char**) + 41 13 synergyc 0x000448a9 CClientApp::runInner(int, char**, ILogOutputter*, int (*)(int, char**)) + 137 14 synergyc 0x0005c4b0 CAppUtilUnix::run(int, char**) + 64 15 synergyc 0x000427df CApp::run(int, char**) + 63 16 synergyc 0x00006e65 main + 117 17 synergyc 0x00006dd9 start + 53 Thread 1: 0 libSystem.B.dylib 0x95d607da __sigwait + 10 1 libSystem.B.dylib 0x95d607b6 sigwait$UNIX2003 + 71 2 synergyc 0x00009583 CArchMultithreadPosix::threadSignalHandler(void*) + 67 3 libSystem.B.dylib 0x95d21259 _pthread_start + 345 4 libSystem.B.dylib 0x95d210de thread_start + 34 Thread 2: 0 libSystem.B.dylib 0x95d21aa2 __semwait_signal + 10 1 libSystem.B.dylib 0x95d2175e _pthread_cond_wait + 1191 2 libSystem.B.dylib 0x95d212b1 pthread_cond_timedwait$UNIX2003 + 72 3 synergyc 0x00009476 CArchMultithreadPosix::waitCondVar(CArchCondImpl*, CArchMutexImpl*, double) + 150 4 synergyc 0x0002b18f CCondVarBase::wait(double) const + 63 5 synergyc 0x0002ce68 CSocketMultiplexer::serviceThread(void*) + 136 6 synergyc 0x0002d698 TMethodJob<CSocketMultiplexer>::run() + 40 7 synergyc 0x0002b8f4 CThread::threadFunc(void*) + 132 8 synergyc 0x00008f30 CArchMultithreadPosix::doThreadFunc(CArchThreadImpl*) + 80 9 synergyc 0x0000902a CArchMultithreadPosix::threadFunc(void*) + 74 10 libSystem.B.dylib 0x95d21259 _pthread_start + 345 11 libSystem.B.dylib 0x95d210de thread_start + 34 Thread 3: Dispatch queue: com.apple.libdispatch-manager 0 libSystem.B.dylib 0x95d1a382 kevent + 10 1 libSystem.B.dylib 0x95d1aa9c _dispatch_mgr_invoke + 215 2 libSystem.B.dylib 0x95d19f59 _dispatch_queue_invoke + 163 3 libSystem.B.dylib 0x95d19cfe _dispatch_worker_thread2 + 240 4 libSystem.B.dylib 0x95d19781 _pthread_wqthread + 390 5 libSystem.B.dylib 0x95d195c6 start_wqthread + 30 Thread 4: 0 libSystem.B.dylib 0x95d19412 __workq_kernreturn + 10 1 libSystem.B.dylib 0x95d199a8 _pthread_wqthread + 941 2 libSystem.B.dylib 0x95d195c6 start_wqthread + 30 Thread 5 Crashed: 0 libSystem.B.dylib 0x95d610ee __semwait_signal_nocancel + 10 1 libSystem.B.dylib 0x95d60fd2 nanosleep$NOCANCEL$UNIX2003 + 166 2 libSystem.B.dylib 0x95ddbfb2 usleep$NOCANCEL$UNIX2003 + 61 3 libSystem.B.dylib 0x95dfd6f0 abort + 105 4 libSystem.B.dylib 0x95d79b1b _Unwind_Resume + 59 5 synergyc 0x00008fd1 CArchMultithreadPosix::doThreadFunc(CArchThreadImpl*) + 241 6 synergyc 0x0000902a CArchMultithreadPosix::threadFunc(void*) + 74 7 libSystem.B.dylib 0x95d21259 _pthread_start + 345 8 libSystem.B.dylib 0x95d210de thread_start + 34 Thread 5 crashed with X86 Thread State (32-bit): eax: 0x0000003c ebx: 0x95d60f39 ecx: 0xb0288a7c edx: 0x95d610ee edi: 0x00521950 esi: 0xb0288ad8 ebp: 0xb0288ab8 esp: 0xb0288a7c ss: 0x0000001f efl: 0x00000247 eip: 0x95d610ee cs: 0x00000007 ds: 0x0000001f es: 0x0000001f fs: 0x0000001f gs: 0x00000037 cr2: 0x002fe000 Model: MacBook2,1, BootROM MB21.00A5.B07, 2 processors, Intel Core 2 Duo, 2.16 GHz, 2 GB

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  • Remote Debian System Preventing Logon

    - by choobablue
    I have a dozen or so single board computers on a network running Debian (squeeze) and access them via ssh (ssh server is dropbear). To give an idea of the hardware of these computers they're 1.2 GHz x86 processors, 1GB of RAM and 4GB flash drives formatted as ext2 (I avoided ext3 to prevent the added flash write stress from journaling), there is also a swap partition on the drive. Normally the setup I'm using works great and I can access all the computers. Every once in a while one will prevent access. What happens is I try to connect via ssh (putty) and it gives me the login prompt, I enter the username and password and it responds 'Access Denied' and it will also refuse any public key in ~/.ssh/authorized_keys. The credentials are correct as they worked previously. The computer responds to pings and putty recognizes the server public key, which implies to me the system is still running. Restarting the server fixes the problem and I can log in again. (I tried a temporary fix of putting shutdown -r now in the root crontab but this doesn't seem to reliably be run once the hang happens) Once I restart however there doesn't seem to be any information in any of the system logs to indicate what happened, the logs are simply empty for that time period, as if the system had crashed. There is some custom software running on the system which appears to stop working (which is why I wanted to ssh to begin with). I'm assuming that this program is the source of the problems but I'm unsure of how it would cause it and how to debug what is happening. The most likely explanation I can think of is that there is a memory leak in the other program that then prevents dropbear from spawning a new login shell (and crontab from executing shutdown) as there is not enough free memory. But looking at memory usage of the other (working) computers there doesn't seem to be any meaningful increase in memory to indicate a leak (unless it's a very big, fast acting and rare leak). I would think that when the OS ran out of memory it would restart the system or kill processes (the Linux kernel restarts right?). The other thing I wonder about is if the fact that they are running off a flash drive could have some effect, especially the swap partition (which I think I should remove to prevent wear of the flash), but the flash drives are young (~1 month) and I don't think that wear would be a factor yet. Does anybody have an idea of what could cause these symptoms, if it could be done by a memory leak, or something else I haven't thought of. And does anybody know of a method to try to debug the problem and find out more information about what's going wrong?

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  • OBIEE 11.1.1 - OBIEE 11g Full Sample App on VMware Player 4

    - by user809526
    The Full Sample App is designed to run on Virtual Box. Let's describe how to run it on VMware Player 4. Open Virtualization Format Tool http://communities.vmware.com/community/vmtn/server/vsphere/automationtools/ovf VMware Player Documentation https://www.vmware.com/support/pubs/player_pubs.html Full Sample App Deployment Guide sampleapp107-vbimage-deployguide-453583.pdf INSTALL VMplayer 4.0.0 as root LINUX # sh VMware-Player-4.0.0-471780.x86_64.bundle (A new VM is not needed and can be deleted later after that installation is completed. "I will install OS later" - blank hard disk Guest: linux, Red Hat Enterprise Linux 5-64bits => rename to RHEL target: eg /a/root/vmware/ Max disk size: 5 GB (will be deleted) Disk: Single file Dummy RHEL.vmk, RHEL.vmdk is generated. "Delete VM from Disk" in VM Player.) Copy Full Sample App files to target /a/root/vmware/ WARNING: Select a target eg /a/root/vmware/ with lots of free space, 95 GB. Check checksums (md5sum). Please do it! ff85c7eacf7fb8c382e98da875e879e1  Sampleapp_v107_GA-disk1.vmdk 973258cb3c7d64ab03ae853278cf2233  Sampleapp_v107_GA-disk2.vmdk e576be16e36d810479736bfb15d050f5  Sampleapp_v107_GA-disk3.vmdk 3455df77279e53e07d5fee6712f1597d  Sampleapp_v107_GA-disk4.vmdk OVF FILE   Sampleapp_v107_GA.ovf CONVERSION $ cd /a/root/vmware/ LINUX $ /usr/bin/ovftool -tt=ovf --compress=1 -dm=monolithicSparse Sampleapp_v107_GA.ovf .  [dot] Opening OVF source: Sampleapp_v107_GA.ovf Warning: No manifest file Opening OVF target: . Writing OVF package: Sampleapp_v107_GA/Sampleapp_v107_GA.ovf Disk Transfer Completed                   Completed successfully WINDOWS CYGWIN $ /cygdrive/c/VMwarePlayer/OVFTool/ovftool.exe -tt=ovf --compress=1 -dm=monolithicSparse Sampleapp_v107_GA.ovf .  [dot] Opening OVF source: Sampleapp_v107_GA.ovf Warning: No manifest file Opening OVF target: . Writing OVF package: Sampleapp_v107_GA\Sampleapp_v107_GA.ovf Disk Transfer Completed Completed successfully /a/root/vmware$ du -sk 49095328    .   [50 GB already occupied] IMPORT - First start of VM Player 4: /usr/bin/vmplayer "Open a Virtual Machine" Browse to /a/root/vmware/Sampleapp_v107_GA/Sampleapp_v107_GA.ovf [the new generated .ovf] "Import Virtual Machine" dialog Name: Sampleapp_v107_GA Location: /a/root/vmware/Sampleapp_v107_GA/storage [was /home/tdubois/vmware/Sampleapp_v107_GA] "Import" "The import failed because /a/root/vmware/Sampleapp_v107_GA/Sampleapp_v107_GA.ovf did not pass OVF specification conformance or virtual hardware compliance checks. Click Retry to relax OVF specification..." "Retry" ; Long import /a/root/vmware/Sampleapp_v107_GA/storage/Sampleapp_v107_GA.vmx and new .vmdk files are created. /a/root/vmware$ du -sk 95551384    .   [95 GB occupied] Full Sample App GUEST SETUP "Edit VM settings" min 3GB, 2+ processors, network bridged. For OBIEE + Essbase testing use 8 GB RAM hardware. At first time lauch of Full Sample App, leave OEL booting for several minutes undisturbed. Problem with X display server may occur [/usr/bin/Xorg ; man Xorg]. "Failed to start the X server.... Would you like to view the X server output to diagnose the problem?" "No" [tab key] "Would you like to try to configure the X server? Note that you will need the root password for this." "Yes" [oracle] X Display Settings 800x600 saved in /etc/X11/xorg.conf "Trying to restart the X server" Login as root/oracle in guest OEL. In guest OEL, Virtual Machine > Install VMware Tools... Extract archive VMwareTools-8.8.0-471268.tar.gz all files in writable local directory eg /root In Terminal run Perl script # cd /root/vmware-tools-distrib ; ./vmware-install.pl [keep all default answers] Set keyboard layout System > Preferences > Keyboard > Layouts Restart X server eg System > Log Out root... , relogin Modify X resolution System > Preferences > Screen Resolution Full Sample App OEL login: oracle/oracle ; root/oracle [default US keyboard layout] Credentials are described in the 'sampleapp107-vbimage-deployguide-453583.pdf' The large files in /a/root/vmware/ /a/root/vmware/Sampleapp_v107_GA/ may be removed. FAILURE REMARK: Adding the 4 original Sampleapp_v107_GA-disks[1234].vmdk to VM Player does NOT work as described below. "Edit VM settings" "Remove" "Hard Disk" "Edit VM settings" "Add" "Hard Disk" "Next" "Use an existing virtual disk" "Browse" "Finish" "Keep existing format" "Ok" for each 4 disks settings one by one. Start VM Player 4. "You do not have write access to a partition" Allow all Sampleapp_v107 OEL linux launches. OEL stalls silently after 'Checking filesystems'.

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  • Diagnose PC Hardware Problems with an Ubuntu Live CD

    - by Trevor Bekolay
    So your PC randomly shuts down or gives you the blue screen of death, but you can’t figure out what’s wrong. The problem could be bad memory or hardware related, and thankfully the Ubuntu Live CD has some tools to help you figure it out. Test your RAM with memtest86+ RAM problems are difficult to diagnose—they can range from annoying program crashes, or crippling reboot loops. Even if you’re not having problems, when you install new RAM it’s a good idea to thoroughly test it. The Ubuntu Live CD includes a tool called Memtest86+ that will do just that—test your computer’s RAM! Unlike many of the Live CD tools that we’ve looked at so far, Memtest86+ has to be run outside of a graphical Ubuntu session. Fortunately, it only takes a few keystrokes. Note: If you used UNetbootin to create an Ubuntu flash drive, then memtest86+ will not be available. We recommend using the Universal USB Installer from Pendrivelinux instead (persistence is possible with Universal USB Installer, but not mandatory). Boot up your computer with a Ubuntu Live CD or USB drive. You will be greeted with this screen: Use the down arrow key to select the Test memory option and hit Enter. Memtest86+ will immediately start testing your RAM. If you suspect that a certain part of memory is the problem, you can select certain portions of memory by pressing “c” and changing that option. You can also select specific tests to run. However, the default settings of Memtest86+ will exhaustively test your memory, so we recommend leaving the settings alone. Memtest86+ will run a variety of tests that can take some time to complete, so start it running before you go to bed to give it adequate time. Test your CPU with cpuburn Random shutdowns – especially when doing computationally intensive tasks – can be a sign of a faulty CPU, power supply, or cooling system. A utility called cpuburn can help you determine if one of these pieces of hardware is the problem. Note: cpuburn is designed to stress test your computer – it will run it fast and cause the CPU to heat up, which may exacerbate small problems that otherwise would be minor. It is a powerful diagnostic tool, but should be used with caution. Boot up your computer with a Ubuntu Live CD or USB drive, and choose to run Ubuntu from the CD or USB drive. When the desktop environment loads up, open the Synaptic Package Manager by clicking on the System menu in the top-left of the screen, then selecting Administration, and then Synaptic Package Manager. Cpuburn is in the universe repository. To enable the universe repository, click on Settings in the menu at the top, and then Repositories. Add a checkmark in the box labeled “Community-maintained Open Source software (universe)”. Click close. In the main Synaptic window, click the Reload button. After the package list has reloaded and the search index has been rebuilt, enter “cpuburn” in the Quick search text box. Click the checkbox in the left column, and select Mark for Installation. Click the Apply button near the top of the window. As cpuburn installs, it will caution you about the possible dangers of its use. Assuming you wish to take the risk (and if your computer is randomly restarting constantly, it’s probably worth it), open a terminal window by clicking on the Applications menu in the top-left of the screen and then selection Applications > Terminal. Cpuburn includes a number of tools to test different types of CPUs. If your CPU is more than six years old, see the full list; for modern AMD CPUs, use the terminal command burnK7 and for modern Intel processors, use the terminal command burnP6 Our processor is an Intel, so we ran burnP6. Once it started up, it immediately pushed the CPU up to 99.7% total usage, according to the Linux utility “top”. If your computer is having a CPU, power supply, or cooling problem, then your computer is likely to shutdown within ten or fifteen minutes. Because of the strain this program puts on your computer, we don’t recommend leaving it running overnight – if there’s a problem, it should crop up relatively quickly. Cpuburn’s tools, including burnP6, have no interface; once they start running, they will start driving your CPU until you stop them. To stop a program like burnP6, press Ctrl+C in the terminal window that is running the program. Conclusion The Ubuntu Live CD provides two great testing tools to diagnose a tricky computer problem, or to stress test a new computer. While they are advanced tools that should be used with caution, they’re extremely useful and easy enough that anyone can use them. Similar Articles Productive Geek Tips Reset Your Ubuntu Password Easily from the Live CDCreate a Persistent Bootable Ubuntu USB Flash DriveAdding extra Repositories on UbuntuHow to Share folders with your Ubuntu Virtual Machine (guest)Building a New Computer – Part 3: Setting it Up 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 Have Fun Editing Photo Editing with Citrify Outlook Connector Upgrade Error Gadfly is a cool Twitter/Silverlight app Enable DreamScene in Windows 7 Microsoft’s “How Do I ?” Videos Home Networks – How do they look like & the problems they cause

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  • Top 10 Tips & Tricks for Oracle SQL Developer

    - by thatjeffsmith
    Being a short week due to the holiday, and with everyone enjoying their Summer vacations (apologies Southern Hemispherians), I reckoned it was a great time to do one of those lazy recap-Top 10-Reader’s Digest type posts. I’ve been sharing 1-3 tips or ‘tricks’ a week since I started blogging about SQL Developer, and I have more than enough content to write a book. But since I’m lazy, I’m just going to compile a list of my favorite ‘must know’ tips instead. I always have to leave out a few tips when I do my presentations, so now I can refer back to this list to make sure I’m not forgetting anything. So without further ado… 1. Configure Your Preferences Yes, there are a LOT of options. But you don’t need to worry about all of them just yet. I do recommend you take a quick look at these ones in particular. Whether you’re new to the tool or have been using it for 5 years, don’t overlook these settings! 2. Disable Extensions You Aren’t Using If you’re not using Data Miner, or if you’re not working on a Migration – disable those extensions! SQL Developer will run leaner & meaner, plus the user interface will be a bit more simplified making the tool easier to navigate as well. 3. SQL Recall via Keyboard Access your history via the keyboard! Cycle through your recent SQL statements just using these magic key strokes! Ctrl+Up or Ctrl+Down. 4. Format Your Query Output Directly to CSV, XML, HTML, etc Have the query results pre-formatted in the format of your choice! Too lazy to run the Export wizard for your query result sets? Just add the SQL Developer output hints to your statement and have the output auto-magically formatted to the style of your choice! 5. Drag & Drop Multiple Tables to the Worksheet SQL Developer will auto-join the related objects. You can then toggle over to the Query Builder to toggle off the columns you don’t want to query. I guarantee this tip will save you time if you’re joining 3 or more tables! 6. Drag & Drop Multiple Tables to a Relational Model A pretty picture is worth a few dozen DDL scripts? SQL Developer does data modeling! If you ctrl-drag a table to a model, it will take that table and any related tables and reverse engineer them to a relational model! You can then print it out or export it to HTML, PDF, etc. 7. View Your PL/SQL Execution Output Automatically Function returns a refcursor? Procedure had 3 out parameters? When you run these programs via the Procedure Editor, we automatically capture the output and place them into one or more data grids for you to browse. 8. Disable Automatic Code Insight and Use It On-Demand Code Editor – Completion Insight – Enable Completion Auto-Popup (Keyword being Auto) Some folks really don’t like it when their IDEs or word-processors try to do ‘too much’ for them. Thankfully SQL Developer allows you to either increase the delay before it attempts to auto-complete your text OR to disable the automatic bit. Instead, you can invoke it on-demand. 9. Interactive Debugging – Change Your Variable Values as You Step Through Your PLSQL Watches aren’t just for watching. You can actually interact with your programs and ‘see what happens’ when X = 256 instead of 1. 10. Ditch the Tree View for the Schema Browser There’s nothing wrong with the Connection tree for browsing your database objects. But some folks just can’t seem to get comfortable with it. So, we built them a Schema Browser that uses a drop down control instead for changing up your schema and object types. Already Know This Stuff, Want More? Just check out my SQL Developer resource page, it’s one of the main links on the top of this page. Or if you can’t find something, just drop me a note in the form of a comment on this page and I’ll do my best to find it or write it for you.

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  • SQL SERVER – CXPACKET – Parallelism – Usual Solution – Wait Type – Day 6 of 28

    - by pinaldave
    CXPACKET has to be most popular one of all wait stats. I have commonly seen this wait stat as one of the top 5 wait stats in most of the systems with more than one CPU. Books On-Line: Occurs when trying to synchronize the query processor exchange iterator. You may consider lowering the degree of parallelism if contention on this wait type becomes a problem. CXPACKET Explanation: When a parallel operation is created for SQL Query, there are multiple threads for a single query. Each query deals with a different set of the data (or rows). Due to some reasons, one or more of the threads lag behind, creating the CXPACKET Wait Stat. There is an organizer/coordinator thread (thread 0), which takes waits for all the threads to complete and gathers result together to present on the client’s side. The organizer thread has to wait for the all the threads to finish before it can move ahead. The Wait by this organizer thread for slow threads to complete is called CXPACKET wait. Note that not all the CXPACKET wait types are bad. You might experience a case when it totally makes sense. There might also be cases when this is unavoidable. If you remove this particular wait type for any query, then that query may run slower because the parallel operations are disabled for the query. Reducing CXPACKET wait: We cannot discuss about reducing the CXPACKET wait without talking about the server workload type. OLTP: On Pure OLTP system, where the transactions are smaller and queries are not long but very quick usually, set the “Maximum Degree of Parallelism” to 1 (one). This way it makes sure that the query never goes for parallelism and does not incur more engine overhead. EXEC sys.sp_configure N'cost threshold for parallelism', N'1' GO RECONFIGURE WITH OVERRIDE GO Data-warehousing / Reporting server: As queries will be running for long time, it is advised to set the “Maximum Degree of Parallelism” to 0 (zero). This way most of the queries will utilize the parallel processor, and long running queries get a boost in their performance due to multiple processors. EXEC sys.sp_configure N'cost threshold for parallelism', N'0' GO RECONFIGURE WITH OVERRIDE GO Mixed System (OLTP & OLAP): Here is the challenge. The right balance has to be found. I have taken a very simple approach. I set the “Maximum Degree of Parallelism” to 2, which means the query still uses parallelism but only on 2 CPUs. However, I keep the “Cost Threshold for Parallelism” very high. This way, not all the queries will qualify for parallelism but only the query with higher cost will go for parallelism. I have found this to work best for a system that has OLTP queries and also where the reporting server is set up. Here, I am setting ‘Cost Threshold for Parallelism’ to 25 values (which is just for illustration); you can choose any value, and you can find it out by experimenting with the system only. In the following script, I am setting the ‘Max Degree of Parallelism’ to 2, which indicates that the query that will have a higher cost (here, more than 25) will qualify for parallel query to run on 2 CPUs. This implies that regardless of the number of CPUs, the query will select any two CPUs to execute itself. EXEC sys.sp_configure N'cost threshold for parallelism', N'25' GO EXEC sys.sp_configure N'max degree of parallelism', N'2' GO RECONFIGURE WITH OVERRIDE GO Read all the post in the Wait Types and Queue series. Additionally a must read comment of Jonathan Kehayias. Note: The information presented here is from my experience and I no way claim it to be accurate. I suggest you all to read the online book for further clarification. All the discussion of Wait Stats over here is generic and it varies from system to system. It is recommended that you test this on the development server before implementing on the production server. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: DMV, Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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  • SPARC M7 Chip - 32 cores - Mind Blowing performance

    - by Angelo-Oracle
    The M7 Chip Oracle just announced its Next Generation Processor at the HotChips HC26 conference. As the Tech Lead in our Systems Division's Partner group, I had a front row seat to the extraordinary price performance advantage of Oracle current T5 and M6 based systems. Partner after partner tested  these systems and were impressed with it performance. Just read some of the quotes to see what our partner has been saying about our hardware. We just announced our next generation processor, the M7. This has 32 cores (up from 16-cores in T5 and 12-cores in M6). With 20 nm technology  this is our most advanced processor. The processor has more cores than anything else in the industry today. After the Sun acquisition Oracle has released 5 processors in 4 years and this is the 6th.  The S4 core  The M7 is built using the foundation of the S4 core. This is the next generation core technology. Like its predecessor, the S4 has 8 dynamic threads. It increases the frequency while maintaining the Pipeline depth. Each core has its own fine grain power estimator that keeps the core within its power envelop in 250 nano-sec granularity. Each core also includes Software in Silicon features for Application Acceleration Support. Each core includes features to improve Application Data Integrity, with almost no performance loss. The core also allows using part of the Virtual Address to store meta-data.  User-Level Synchronization Instructions are also part of the S4 core. Each core has 16 KB Instruction and 16 KB Data L1 cache. The Core Clusters  The cores on the M7 chip are organized in sets of 4-core clusters. The core clusters share  L2 cache.  All four cores in the complex share 256 KB of 4 way set associative L2 Instruction Cache, with over 1/2 TB/s of throughput. Two cores share 256 KB of 8 way set associative L2 Data Cache, with over 1/2 TB/s of throughput. With this innovative Core Cluster architecture, the M7 doubles core execution bandwidth. to maximize per-thread performance.  The Chip  Each  M7 chip has 8 sets of these core-clusters. The chip has 64 MB on-chip L3 cache. This L3 caches is shared among all the cores and is partitioned into 8 x 8 MB chunks. Each chunk is  8-way set associative cache. The aggregate bandwidth for the L3 cache on the chip is over 1.6TB/s. Each chip has 4 DDR4 memory controllers and can support upto 16 DDR4 DIMMs, allowing for 2 TB of RAM/chip. The chip also includes 4 internal links of PCIe Gen3 I/O controllers.  Each chip has 7 coherence links, allowing for 8 of these chips to be connected together gluelessly. Also 32 of these chips can be connected in an SMP configuration. A potential system with 32 chips will have 1024 cores and 8192 threads and 64 TB of RAM.  Software in Silicon The M7 chip has many built in Application Accelerators in Silicon. These features will be exposed to our Software partners using the SPARC Accelerator Program.  The M7  has built-in logic to decompress data at the speed of memory access. This means that applications can directly work on compressed data in memory increasing the data access rates. The VA Masking feature allows the use of part of the virtual address to store meta-data.  Realtime Application Data Integrity The Realtime Application Data Integrity feature helps applications safeguard against invalid, stale memory reference and buffer overflows. The first 4-bits if the Pointer can be used to store a version number and this version number is also maintained in the memory & cache lines. When a pointer accesses memory the hardware checks to make sure the two versions match. A SEGV signal is raised when there is a mismatch. This feature can be used by the Database, applications and the OS.  M7 Database In-Memory Query Accelerator The M7 chip also includes a In-Silicon Query Engines.  These accelerate tasks that work on In-Memory Columnar Vectors. Oracle In-Memory options stores data in Column Format. The M7 Query Engine can speed up In-Memory Format Conversion, Value and Range Comparisons and Set Membership lookups. This engine can work on Compressed data - this means not only are we accelerating the query performance but also increasing the memory bandwidth for queries.  SPARC Accelerated Program  At the Hotchips conference we also introduced the SPARC Accelerated Program to provide our partners and third part developers access to all the goodness of the M7's SPARC Application Acceleration features. Please get in touch with us if you are interested in knowing more about this program. 

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  • Organization &amp; Architecture UNISA Studies &ndash; Chap 5

    - by MarkPearl
    Learning Outcomes Describe the operation of a memory cell Explain the difference between DRAM and SRAM Discuss the different types of ROM Explain the concepts of a hard failure and a soft error respectively Describe SDRAM organization Semiconductor Main Memory The two traditional forms of RAM used in computers are DRAM and SRAM DRAM (Dynamic RAM) Divided into two technologies… Dynamic Static Dynamic RAM is made with cells that store data as charge on capacitors. The presence or absence of charge in a capacitor is interpreted as a binary 1 or 0. Because capacitors have natural tendency to discharge, dynamic RAM requires periodic charge refreshing to maintain data storage. The term dynamic refers to the tendency of the stored charge to leak away, even with power continuously applied. Although the DRAM cell is used to store a single bit (0 or 1), it is essentially an analogue device. The capacitor can store any charge value within a range, a threshold value determines whether the charge is interpreted as a 1 or 0. SRAM (Static RAM) SRAM is a digital device that uses the same logic elements used in the processor. In SRAM, binary values are stored using traditional flip flop logic configurations. SRAM will hold its data as along as power is supplied to it. Unlike DRAM, no refresh is required to retain data. SRAM vs. DRAM DRAM is simpler and smaller than SRAM. Thus it is more dense and less expensive than SRAM. The cost of the refreshing circuitry for DRAM needs to be considered, but if the machine requires a large amount of memory, DRAM turns out to be cheaper than SRAM. SRAMS are somewhat faster than DRAM, thus SRAM is generally used for cache memory and DRAM is used for main memory. Types of ROM Read Only Memory (ROM) contains a permanent pattern of data that cannot be changed. ROM is non volatile meaning no power source is required to maintain the bit values in memory. While it is possible to read a ROM, it is not possible to write new data into it. An important application of ROM is microprogramming, other applications include library subroutines for frequently wanted functions, System programs, Function tables. A ROM is created like any other integrated circuit chip, with the data actually wired into the chip as part of the fabrication process. To reduce costs of fabrication, we have PROMS. PROMS are… Written only once Non-volatile Written after fabrication Another variation of ROM is the read-mostly memory, which is useful for applications in which read operations are far more frequent than write operations, but for which non volatile storage is required. There are three common forms of read-mostly memory, namely… EPROM EEPROM Flash memory Error Correction Semiconductor memory is subject to errors, which can be classed into two categories… Hard failure – Permanent physical defect so that the memory cell or cells cannot reliably store data Soft failure – Random error that alters the contents of one or more memory cells without damaging the memory (common cause includes power supply issues, etc.) Most modern main memory systems include logic for both detecting and correcting errors. Error detection works as follows… When data is to be read into memory, a calculation is performed on the data to produce a code Both the code and the data are stored When the previously stored word is read out, the code is used to detect and possibly correct errors The error checking provides one of 3 possible results… No errors are detected – the fetched data bits are sent out An error is detected, and it is possible to correct the error. The data bits plus error correction bits are fed into a corrector, which produces a corrected set of bits to be sent out An error is detected, but it is not possible to correct it. This condition is reported Hamming Code See wiki for detailed explanation. We will probably need to know how to do a hemming code – refer to the textbook (pg. 188 – 189) Advanced DRAM organization One of the most critical system bottlenecks when using high-performance processors is the interface to main memory. This interface is the most important pathway in the entire computer system. The basic building block of main memory remains the DRAM chip. In recent years a number of enhancements to the basic DRAM architecture have been explored, and some of these are now on the market including… SDRAM (Synchronous DRAM) DDR-DRAM RDRAM SDRAM (Synchronous DRAM) SDRAM exchanges data with the processor synchronized to an external clock signal and running at the full speed of the processor/memory bus without imposing wait states. SDRAM employs a burst mode to eliminate the address setup time and row and column line precharge time after the first access In burst mode a series of data bits can be clocked out rapidly after the first bit has been accessed SDRAM has a multiple bank internal architecture that improves opportunities for on chip parallelism SDRAM performs best when it is transferring large blocks of data serially There is now an enhanced version of SDRAM known as double data rate SDRAM or DDR-SDRAM that overcomes the once-per-cycle limitation of SDRAM

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  • JavaOne Latin America Opening Keynotes

    - by Tori Wieldt
    Originally published on blogs.oracle.com/javaone It was a great first day at JavaOne Brazil, which included the Java Strategy and Java Technical keynotes. Henrik Stahl, Senior Director, Product Management for Java opened the keynotes by saying that this is the third year for JavaOne Latin America. He explained, "You know what they say, the first time doesn't count, the second time is a habit and the third time it's a tradition!" He mentioned that he was thrilled that this is largest JavaOne in Brazil to date, and he wants next year to be larger. He said that Oracle knows Latin America is an important hub for development.  "We continually come back to Latin America because of the dedication the community has with driving the continued innovation for Java," he said. Stahl explained that Oracle and the Java community must continue to innovate and Make the Future Java together. The success of Java depends on three important factors: technological innovation, Oracle as a strong steward of Java, and community participation. "The Latin American Java Community (especially in Brazil) is a shining example of how to be positive contributor to Java," Stahl said. Next, George Saab, VP software dev, Java Platform Group at Oracle, discussed some of the recent and upcoming changes to Java. "In addition to the incremental improvements to Java 7, we have also increased the set of platforms supported by Oracle from Linux, Windows, and Solaris to now also include Mac OS X and Linux/ARM for ARM-based PCs such as the Raspberry Pi and emerging ARM based microservers."  Saab announced that EA builds for Linux ARM Hard Float ABI will be available by the end of the year.  Staffan Friberg, Product Manager, Java Platform Group, provided an overview of some of the language coming in Java 8, including Lambda, remove of PermGen, improved data and time APIs and improved security, Java 8 development is moving along. He reminded the audience that they can go to OpenJDK to see this development being done in real-time, and that there are weekly early access builds of OracleJDK 8 that developers can download and try today. Judson Althoff, Senior Vice President, Worldwide Alliances and Channels and Embedded Sales, was invited to the stage, and the audience was told that "even though he is wearing a suit, he is still pretty technical." Althoff started off with a bang: "The Internet of Things is on a collision course with big data and this is a huge opportunity for developers."  For example, Althoff said, today cars are more a data device than a mechanical device. A car embedded with sensors for fuel efficiency, temperature, tire pressure, etc. can generate a petabyte of data A DAY. There are similar examples in healthcare (patient monitoring and privacy requirements creates a complex data problem) and transportation management (sending a package around the world with sensors for humidity, temperature and light). Althoff then brought on stage representatives from three companies that are successful with Java today, first Axel Hansmann, VP Strategy & Marketing Communications, Cinterion. Mr. Hansmann explained that Cinterion, a market leader in Latin America, enables M2M services with Java. At JavaOne San Francisco, Cinterion launched the EHS5, the smallest 3g solderable module, with Java installed on it. This provides Original Equipment Manufacturers (OEMs) with a cost effective, flexible platform for bringing advanced M2M technology to market.Next, Steve Nelson, Director of Marketing for the Americas, at Freescale explained that Freescale is #1 in Embedded Processors in Wired and Wireless Communications, and #1 in Automotive Semiconductors in the Americas. He said that Java provides a mature, proven platform that is uniquely suited to meet the requirements of almost any type of embedded device. He encouraged University students to get involved in the Freescale Cup, a global competition where student teams build, program, and race a model car around a track for speed.Roberto Franco, SBTVD Forum President, SBTVD, talked about Ginga, a Java-based standard for television in Brazil. He said there are 4 million Ginga TV sets in Brazil, and they expect over 20 million TV sets to be sold by the end of 2014. Ginga is also being adopted in other 11 countries in Latin America. Ginga brings interactive services not only at TV set, but also on other devices such as tablets,  PCs or smartphones, as the main or second screen. "Interactive services is already a reality," he said, ' but in a near future, we foresee interactivity enhanced TV content, convergence with OTT services and a big participation from the audience,  all integrated on TV, tablets, smartphones and second screen devices."Before he left the stage, Nandini Ramani thanked Judson for being part of the Java community and invited him to the next Geek Bike Ride in Brazil. She presented him an official geek bike ride jersey.For the Technical Keynote, a "blue screen of death" appeared. With mock concern, Stephin Chin asked the rest of the presenters if they could go on without slides. What followed was a interesting collection of demos, including JavaFX on a tablet, a look at Project Easel in NetBeans, and even Simon Ritter controlling legos with his brainwaves! Stay tuned for more dispatches.

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