Search Results

Search found 11587 results on 464 pages for 'pseudo random numbers'.

Page 358/464 | < Previous Page | 354 355 356 357 358 359 360 361 362 363 364 365  | Next Page >

• How to diagnose storage system scaling problems?

  - by Unknown

  We are currently testing the maximum sequential read throughput of a storage system (48 disks total behind two HP P2000 arrays) connected to HP DL580 G7 running RHEL 5 with 128 GB of memory. Initial testing has been mainly done by running DD-commands like this: dd if=/dev/mapper/mpath1 of=/dev/null bs=1M count=3000 In parallel for each disk. However, we have been unable to scale the results from one array (maximum throughput of 1.3 GB/s) to two (almost the same throughput). Each array is connected to a dedicated host bust adapter, so they should not be the bottleneck. The disks are currently in JBOD configuration, so each disk can be addressed directly. I have two questions: Is running multiple DD commands in parallel really a good way to test maximum read throughput? We have noticed very high SWAPIN-% numbers in iotop, which I find hard to explain because the target is /dev/null How shoud we proceed in trying to find the reason for the scaling problem? Do you thing the server itself is the bottleneck here, or could there be some linux parameters that we have overlooked?

  Read the article

• Wireless keeps shutting off in Windows 7

  - by Nathan Adams

  I have Windows 7 Ultimate 32bit installed on a Dell Latitude XT Tablet and for the life of me I can't figure out this really weird problem. The symptom is that the Wireless will disconnect from the AP and if I tell it to scan again, it says there are no APs in the area. I do have another wireless card in the laptop and if I disable the first one and enable the second, I am able to get onto the wireless however if I want to use the first card again I have to restart. I tried enabling/disabling the device, nothing will kick start the wireless again in the first card without a restart. I even tried different drivers. So, it seems it is random but it does occur more often when there is increased network activity (ie downloading a large file). The laptop doesn't seem to be overheating. I have tried the following: Under "Change Advanced Power Settings" for the current power profile, I set the "Wireless Adapter settings" to "Maximum Performance". Under device manger, I went to the card in question, and went to the advanced tab and set the "Power Saving mode" to "MAX_PSP" Both cards I have seem to exhibit the behavior after awhile. Both models of those cards are: Dell Wireless 1505 Draft 802.11n WLAN Mini-Card Gigabyte GN-WS30N 802.11n mini WLAN Card Has anyone have any ideas or ran into this before?

  Read the article

• How to simulate Apache [END] flag on a redirect?

  - by Javier Méndez

  For business-specific reasons I created the following rewrite rule for Apache 2.2.22 (mod_rewrite): RewriteRule /site/(\d+)/([^/]+)\.html /site/$2/$1 [R=301,L] Which if given an URL like: http://www.mydomain.com/site/0999/document.html Is translated to: http://www.mydomain.com/site/document/0999.html That's the expected scenario. However, there are documents which name are only numbers. So consider the following case: http://www.mydomain.com/site/0055/0666.html Gets translated to: http://www.mydomain.com/site/0666/0055.html Which also matches my rewrite rule pattern, so I end up with "The web page resulted in too many redirects" errors from browsers. I have researched for a long time, and haven't found "good" solutions. Things I tried: Use the [END] flag. Unfortunately is not available on my Apache version nor it works with redirects. Use %{ENV:REDIRECT_STATUS} on a RewriteCond clause to end the rewrite process (L). For some reason %{ENV:REDIRECT_STATUS} is empty all the times I tried. Add a response header with the Header clause if my rule matches and then check for that header (see: here for details). Seems that a) REDIRECT_addHeader is empty b) headers are can't be set on the 301 response explicitly. There is another alternative. I could set a query parameter to the redirect URL which indicates it comes from a redirect, but I don't like that solution as it seems to hacky. Is there a way to do exactly what the [END] flag does but in older Apache versions? Such as mine 2.2.22. Thanks!

  Read the article

• Router reporting failed admin login attempts from home server

  - by jeffora

  I recently noticed in the logs of my home router that it relatively regularly lists the following entry: [admin login failure] from source 192.168.0.160, Monday, June 20,2011 18:13:25 192.168.0.160 is the internal address of my home server, running Windows Home Server 2011. Is there anyway I can find out what specifically is trying to login to the router? Or is there some explanation for this behaviour? (not sure if this belongs here or on superuser...) [Update] I've run both Wireshark and netmon for a while on my home server. Wireshark captured the traffic, but didn't really show anything useful (or nothing I could make use of). A simple HTTP GET request is sent from the server (192.168.0.160) to the router (192.168.0.1), from a seemingly random port (I've seen examples from 50068, 52883), and it appears to do it twice in quick succession (incrementing port by 1), about every hour. Running netstat around the time of the failure didn't show anything (probably too long after anyway). I tried using netmon as it categorises by process, so I thought it might show a corresponding process for the port. Unfortunately, this comes in under the 'unknown' category, meaning it's basically just a slower, less useful Wireshark. I know there's not much to go on here, but does this help in anyway?

  Read the article

• Limiting bandwith on an Windows 7 machine

  - by Mihai Damian

  I need to limit the bandwidth on my Windows 7 x64 machine. In the past (on XP) I've been able to use NetLimiter for similar tasks. However for some reason I can't get it to work anymore. For lower limits the bandwidth tests are able to exceed the limit by 10-50%; higher limits seem to be ignored completely and the bandwidth tests report download speeds of over 10 times the speed I set. I'm using speedtest.net and some similar service from my ISP for these tests. Anyway, I don't necessarily need a program as complex as NetLimiter since I only need to throttle my machine's bandwidth, not a specific program's. In case you are wondering why in the world I'd want to cripple my Internet speed, there is a funny story behind this. Long story short, my modem gets random disconnects. Tech support comes in, says my Internet speed is abnormally high and I must be using some tools to somehow make it go faster than it's supposed to and this messes up my modem. I check the connection with another computer and it seems that my PC is the only one in my network that gets abnormal speeds. I reinstall my OS, speed looks normal at first, after I install the batch of 50 or so updates, it goes back to abnormally high speeds and the disconnect problems are not solved. Now I don't have a clue if the explanation the tech team gave me was just a strategy to lay the blame on someone else, but I was trying to give them the benefit of the doubt and see what happens if I really reduce my speed to their specification. Any help appreciated.

  Read the article

• Hardware issue, bsod with windows xp irq and strange messages with ubuntu

  - by JP Hellemons

  I have an old Acer T160 and it used to run Windows XP. But I keep getting random BSOD's. I keep seeing IRQ conflicts. I tried to run ubuntu, which runs and keeps running. But sometimes is not responding. Also there are these popups at ubuntu 12.04 that my network cable (which is onboard) is unplugged. But I have no cable in it! and have an usb dongle for wifi. which also seems unstable. have to (auto)reconnect sometimes. So my question is: is it my mobo, power supply or something else? FYI: I had an dvd-rw station which did not open properly, so unplugged the ata and power, als removed the second harddrive. now only have sata harddrive. also removed the extra video card (ati sapphire x1600 pro) so use only onboard video now and still have these issues. EDIT Update: will try with a new PSU (power supply unit of 400watt) the old (factory) one was 300watt. and will use a usb drive which has 12.04 ubuntu on it (made with unetbootin) to format everything and re-install ubuntu. (so also delete mbr partition) will update the day after tomorrow.

  Read the article

• Nginx proxy to IIS Connection Timeout

  - by MitMaro

  I am having an issue with random timeouts with a Nginx proxy connecting to an IIS machine. I have been watching a packet capture between the two servers and it seems that the IIS machine is receiving a SYN packet but is not responding with what I think should be an ACK response. Before the timeout occurs there seems to be a slower response from the IIS server. There is no unusual memory or processor usage on the IIS or Nginx machine. Some information on the servers and setup: Nginx Machine: Ubuntu 10.04 64bit Nginx 0.7.65 Amazon EC2 Windows Machine: Windows Server 2008 IIS 7 ASP.net Application in Integrated Mode Nginx Error: 2011/01/10 17:57:40 [error] 8297#0: *30 connect() failed (110: Connection timed out) while connecting to upstream, client: 209.***.***.***, server: secure.example.com, request: "GET /a/path/deliver.aspx HTTP/1.1", upstream: "http://***.***.***.****:****//another/path/deliver.aspx", host: "secure.example.com" WireShark Packets 6521.449528 10.***.***.*** -> 174.***.***.*** TCP 38695 > us-cli [SYN] Seq=0 Win=5840 Len=0 MSS=1460 TSV=477422103 TSER=0 WS=7 6524.443239 10.***.***.*** -> 174.***.***.*** TCP 38695 > us-cli [SYN] Seq=0 Win=5840 Len=0 MSS=1460 TSV=477422403 TSER=0 WS=7 6530.443241 10.***.***.*** -> 174.***.***.*** TCP 38695 > us-cli [SYN] Seq=0 Win=5840 Len=0 MSS=1460 TSV=477423003 TSER=0 WS=7

  Read the article

• Replacing the LCD panel in a netbook (Asus Eee PC 1005)

  - by neilfein

  Yesterday, I was cleaning up and dropped my Asus Eee 1005PE. The screen is cracked inside (i.e., cracks are visible only when on), and no longer works properly. I booted up with another monitor attached, and the computer itself is fine, but needs a new screen. Best Buy wants at least $250 to repair it (that includes their $150 fee to breathe in the same room as the unit), and Asus was of no help at all. (They're incredibly cagey and won't provide any money numbers at all, not even the cost of the part.) If replacing the LCD is no more trouble than replacing memory or a hard drive, I can do that. It's within my means to buy the part (18G241010402, a TFT LCD), but I'd like to know more about the procedure involved. My question: How does one replace the screen in this unit? Do I simply open the case and swap out the unit, or do I need to disassemble anything else to get to the screen? I don't want to order the part and then end up in a situation like this. Is the case screwed shut, or is it like an iPod where they glue things closed? I know enough about my abilities with a soldering gun to not attempt to solder tiny wires, would any of that be involved?

  Read the article

• Difficult to point-and-click target with Apple Magic Trackpad?

  - by Andrew Swift

  My Magic Trackpad is great for most things involving dragging and gestures, but for simple point-and-click use it is starting to get really annoying. For example, my bank has a numeric code that I need to enter from a visual grid on the screen, by clicking on the six numbers in order. To do this is quite difficult with the Magic Trackpad. Idea 1: it is because when you start dragging on the touchpad, there is a brief delay before the mouse starts to move. The delay might be enough to screw up my anticipation of where the cursor is going to go. Idea 2: it may have to do with the cursor acceleration. If I move it a little, the cursor moves a little. If I move it a lot, it goes much faster. I have tried various settings in the preference pane, and although the cursor does move more or less quickly, it doesn't seem any more or less easy to hit a given target. As I am writing this post, I tried a brief experiment -- I chose a spot on the page (the bracket in the superuser logo) and tried to move the cursor there in one quick movement. It's extremely difficult, even though I've been using Macs and touchpads since 1999. There is something about the behavior of the trackpad that is making it impossible for me to learn how to accurately predict where the cursor will end up. Does anyone else have this problem?

  Read the article

• What's throttling the database?

  - by Troels Arvin

  Hardware: Intel x86_64 with 192GB of RAM. OS: CentOS 5.4 x86_64. DBMS: DB2 v. 9.7.1 64 bit. During certain special workloads (e.g. parallel REORGs/RUNSTATs), I've seen the server transporting 450MB/s with 25000IO/s (yes, there is probably some storage system caching happening here) while all CPU cores were happily working in an even mix of usermode/wait. And disk benchmark tools can also bring some very satisfying bandwith and IO/s numbers to the table. On the other hand, we also have another scenario: A single rather complex query with at least one large table scan. db2's "list applications" reports that the query is Executing (not locked). IO: At most 10MB/s, 500 IO/s; CPU: two cores in 99.9% wait state, all other cores 100% idle. The tables which the query reads from have been altered to have LOCKSIZE=TABLE, so I would think that lock list work is zero. What's going on in such a situation? What tools/snapshots/... can I use to gain better insight in such a case?

  Read the article

• jdbc4 CommunicationsException

  - by letronje

  I have a machine running a java app talking to a mysql instance running on the same instance. the app uses jdbc4 drivers from mysql. I keep getting com.mysql.jdbc.exceptions.jdbc4.CommunicationsException at random times. Here is the whole message. Could not open JDBC Connection for transaction; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet successfully received from the server was25899 milliseconds ago.The last packet sent successfully to the server was 25899 milliseconds ago, which is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem. For mysql, the value of global 'wait_timeout' and 'interactive_timeout' is set to 3600 seconds and 'connect_timeout' is set to 60 secs. the wait timeout value is much higher than the 26 secs(25899 msecs). mentioned in the exception trace. I use dbcp for connection pooling and here is spring bean config for the datasource. <bean id="dataSource" destroy-method="close" class="org.apache.commons.dbcp.BasicDataSource" > <property name="driverClassName" value="com.mysql.jdbc.Driver"/> <property name="url" value="jdbc:mysql://localhost:3306/db"/> <property name="username" value="xxx"/> <property name="password" value="xxx" /> <property name="poolPreparedStatements" value="false" /> <property name="maxActive" value="3" /> <property name="maxIdle" value="3" /> </bean> Any idea why this could be happening? Will using c3p0 solve the problem ?

  Read the article

• Recover badly recorded DVDs

  - by CesarGon

  A few years ago (2003-2005) I bought a Sony USB external DVD recorder for my Dell laptop and I used it to burn a lot of discs. Much later, when I tried to use one of these discs, I realised that I could not read it. The disc behaved as if it was scratched or dirty. I tried on a couple of different DVD drives but got the same effect. Sadly, all the discs that I burnt with that recorder suffer from the same problem. Edit. When I read one of these discs with ImgBurn, I get lots of unrecovered read errors in multiple sectors, even at 1x speed. The sectors that cause read errors seem to be quite random; it's not always the same one. I have no idea what could be wrong with the discs. I doubt that they are scratched or dirty; it would be too much of a coincidence that all the discs that I burnt with that recorder got damaged at the same time. Also, they don't show any physical defects. Is there any way to diagnose what the problem is and, hopefully, recover the contents of the discs? Many thanks.

  Read the article

• Max. Temp. on Intel Burn Test for Stock Dell Precision T3500

  - by HK1

  I'm troubleshooting an issue on a Dell Precision T3500. As part of my troubleshooting I've decided to try running a stress test using Intel Burn Test software. This machine is a stock configuration with 12GB of RAM and a Xeon W3670 processor (nothing overclocked). When I run IBT using the standard mode, SpeedFan reports a processor temperature in excess of 80C. I've seen numbers as high as 90C but even at that temperature the machine does not become unstable or crash. However, it seems way too high. This processor has a TCase of 67.9C according to Intel's website. I'm guessing that means I'm in the danger zone any time I go over that temperature. I've checked the cooling system and everything looks fine. I've even took out the heat sink and reinstalled it with new thermal compound. This did not appear to make the problem better or worse. Is there a discrepancy somewhere here in the way temperatures are measured or displayed? I've also tried using HWMonitor from CPUID and it reports the same temperatures. Should I just let the Standard Test go and disregard the temperature outputs?

  Read the article

• How can I remedy the always-on-top window problem?

  - by GateKiller

  Sorry for the vague title but this one is hard to explain so bear with me please. I'm using Windows Vista at work for web development and sometimes when I Click or Alt-Tab to background window, the window will get focus but it will not be brought to the front. In order to bring the window to the front, I have to click on the applications border (when the resize cursor appears) and the window will then jump to the front. I've had this problem for about a year now and it happens at least a dozen times a day, but it doesn't do this all the time - seems random. I hope I have explained the issue fully (and you've understood it) and would appreciate any constructive answers or comments to solve this problem. Example: If I Alt-Tab from Google Chrome to Notepad and this problem randomly occurs, Google Chrome will remain in front of Notepad, however, I will be able to type text into Notepad while the window is behind Google Chrome. Clicking on Notepad's content area will not bring it to the front but clicking it's window border will. Video Exampe http://vimeo.com/19388998 In this video, I clicked from Google Chome to UltraEdit and chrome stayed in font, but as you can see, I can still type in UltraEdit. I'm starting to believe that this could be a bug in Google Chrome so I'll continue to watch if this between other applications.

  Read the article

• Windows Server 2008 R2 Virtual Network Setup

  - by jpearl01

  Some background: I'm very much new to networking in general, and virtualization in particular. I'm trying to set up a series of VMs as we are transitioning to a thin client setup. I have been supplied a limited number of static ip addresses. The server is located in an offsite building which houses the network we use to connect to the internet, share folders etc. The setup I've been trying to go for is this: The host OS (Windows Server 2008 R2) is bound to one nic using one of the static ips (say, Nic1 and ip 10.255.6.61). I've set up another external virtual network attached to another physical nic , and a virtual private network attached to no nic. There is one VM running the same os (as the host). This VM is connected to both the external virtual network (and uses another static ip say Nic2 and ip 10.255.6.62) and also to the virtual private network (I gave it a static random ip 192.168.88.1 subnet mask 255.255.255.0). This virtual private network is connected to all the other VMs. I'd like to share the internet connection with all the other VMs on the private virtual network, and so I installed the RRAS role on the server connected to Nic2, and selected the option to share the internet over the vpn. I've run through the RRAS wizard a few times, trying different configurations, but none of them seem to be letting the other vms connect to the 'net. The vms seem to connect to the virtual private network fine, they are assigned an ip address and everything, but no internet, and no rest of the network either. The other problem is in general I connect to the vms with RDP. Will that be possible with a setup like this? i.e. will the vms show up as computers on the network? If not, what are my other options? Thanks! ~josh

  Read the article

• All network devices freezing when Airport Extreme Base Station is connected. Any ideas?

  - by Jon

  I've been troubleshooting this issue for a while, and through a series of events have it narrowed down to my airport extreme base station. I like this router, since I'm able to connect to IPV6 sites without any insane configuration (my alternate router is too old and doesn't support v6). My question is: Has anyone else had this issue, if so how is it resolved? If not, can you recommend a good IPv6 router? Here is how I came to the conclusion that it is the router: Devices: XBOX 360, HTC Incredible, Home-Built machine running FreeBSD, Home-Built machine running Ubuntu 10.04. 1.) Noticed freezing on Ubuntu Box. 2.) Noticed freezing on XBOX360 3.) Noticed freezing on HTC Incredible (only when connected to my network wirelessly). The above all happened at random times throughout the past few weeks. Over the last few days, I was playing XBOX and noticed that the XBOX and Ubuntu machines both froze. I picked up my phone, and it was also frozen. I reset all devices, power-cycled my router, and all was fine again. About two hours later, it happened again (I was playing Forza III, the XBOX froze; I went to the Ubuntu box and it was frozen; unfortunately, the HTC phone was not connected wirelessly, and the FreeBSD box was turned off). I can't even begin to imaging what a router could be doing to freeze devices with such differing hardware/software/OS, and I feel absurd for coming to this conclusion, but I have nothing else. I hooked up my archaic Netgear router, and have had no problems since. :(

  Read the article

• configure a Macbook Pro to use external monitor at boot (Debian Linux)

  - by Eric

  In the spirit of reuse, I've installed Debian (version 6.0.5 "squeeze") on my wife’s old Macbook Pro (circa 2009 or so), to repurpose it for various tasks. The catch is the display is flaky. It will last a random amount of time, between 2 minutes and 2 hours, before freezing and graying out. This is a known issue with that generation of MBP. Fortunately it’s no problem for me, as I plan to use it with an external monitor anyway. Which brings us to the problem: How do I configure this thing to output to the external display by default, and hopefully disable the built-in LCD? The ideal solution would be to modify a setting in the EFI (BIOS), but I’m not holding out much hope for that. Next best thing would be a kernel option I can pass to the NVIDIA driver. What won’t work is a solution that doesn’t give me a display until X starts. I need to have console access, especially given that the built-in LCD is dying, and any day now might give out completely. So far I haven’t been able to find anything online. lspci says I’ve got an NVIDIA GeForce 9400M Help is much appreciated! Eric PS if this question is better suited to the Unix & Linux area, pls advise and I will move it.

  Read the article

• Users getting 'flooded' with not read notifications (NRNs) for old emails and meeting requests

  - by Exile

  I'm being placed under quite a lot of pressure from senior management over a relatively trivial issue. Basically the vast majority of users are complaining that they receive not read notifications (NRNs) for old emails and meeting requests in large numbers multiple times a day. I know something strange is happening because some are delivered at silly times in the morning (i.e 3AM or 4AM). The problem I have is that these some of these NRNs are from meeting requests and messages that are 120 days old, so some users have deleted the original message so I don’t actually know if the NRN is from an email or meeting request. This is typical of what users receive as a NRN: From: Sender Sent: 23 March 2012 04:16 To: Recepient Subject: Not read: Accepted: Status update Your message To: Sender Subject: Accepted: Status update Sent: Wednesday, November 23, 2011 8:59:00 AM (UTC) Dublin, Edinburgh, Lisbon, London was deleted without being read on Friday, March 23, 2012 4:15:32 AM (UTC) Dublin, Edinburgh, Lisbon, London. ... From: Sender Sent: 18 March 2012 01:13 To: Recepient Subject: Not read: Gold delivery - Sourcing module Your message To: Sender Subject: Gold delivery - Sourcing module Sent: Friday, November 18, 2011 9:37:58 AM (UTC) Dublin, Edinburgh, Lisbon, London was deleted without being read on Sunday, March 18, 2012 1:12:37 AM (UTC) Dublin, Edinburgh, Lisbon, London. I have done a search and found the following: http://support.microsoft.com/kb/2544246 http://support.microsoft.com/kb/2471964 But we already installed 'Update Rollup 6 for Exchange Server 2010 Service Pack 1' back in December, so I am not sure what we can do to fix this?

  Read the article

• Possible disk IO issue

  - by Tim Meers

  I've been trying to really figure out what my IOPS are on my DB server array and see if it's just too much. The array is four 72.6gb 15k rpm drives in RAID 5. To calculate IOPS for RAID 5 the following formula is used: (reads + (4 * Writes)) / Number of disks = total IOPS. The formula is from MSDN. I also want to calculate the Avg Queue Length but I'm not sure where they are getting the formula from, but i think it reads on that page as avg que length/number of disks = actual queue. To populate that formula I used the perfmon to gather the needed information. I came up with this, under normal production load: (873.982 + (4 * 28.999)) / 4 = 247.495. Also the disk queue lengh of 14.454/4 = 3.614. So to the question, am I wrong in thinking this array has a very high disk IO? Edit I got the chance to review it again this morning under normal/high load. This time with even bigger numbers and IOPS in excess of 600 for about 5 minutes then it died down again. But I also took a look at the Avg sec/Transfer, %Disk Time, and %Idle Time. These number were taken when the reads/writes per sec were only 332.997/17.999 respectively. %Disk Time: 219.436 %Idle Time: 0.300 Avg Disk Queue Length: 2.194 Avg Disk sec/Transfer: 0.006 Pages/sec: 2927.802 % Processor Time: 21.877 Edit (again) Looks like I have that issue solved. Thanks for the help. Also for a pretty slick parser I found this: http://pal.codeplex.com/ It works pretty well for breaking down the data into something usable.

  Read the article

• Docking Station Sound Doesn't Work on Dell D830 with Windows 7

  - by cisellis

  EDIT: I can only mark one answer as the correct one but the actual solution was a combination of two comments (updating the BIOS to A15 AND installing the Sigmatel audio drivers). I have a Dell Latitude D830 laptop that is running Windows 7 Enterprise x64. I connect to a docking station during the day with multiple monitors, a keyboard and a mouse. Everything runs with no problems including most of the docking station ports (usb, monitors, etc.) However, the sound port from the docking station does not work since the upgrade to Windows-7. Even with the laptop plugged in, the sound always comes out of the laptop, not the headphones plugged into the docking station. Here's what I've tried: I've seen other issues like via Google this that seem to be mostly unanswered. I found one or two that referenced using the Vista x64 drivers, especially the Nvidia drivers. I do not have an Nvidia chipset but I've reinstalled the sound drivers and that has not helped. I don't have a support contract and considering the cost is usually high to call Dell, that's not an option. Dell's forums are pretty much a wasteland and I've found no help there. Since this is a docking station I thought I might need to try the SATA or Intel chipset drivers from the dell site instead, however I'm not really sure and I need to work on this laptop in the meantime. I can't really afford the downtime to experiment with random drivers all day in case they turn out to be incompatible (Dell still hasn't added Windows 7 to their support site as far as I can tell). Does anyone have any other ideas? Has anyone had this issue and solved it? If so, how? Thanks in advance for your help.

  Read the article

• To what extent is size a factor in SSD performance?

  - by artif

  To what extent is the size of an SSD a factor in its performance? In my mind, correct me if I'm wrong, a bigger SSD should be, everything else being equal, faster than a smaller one. A bigger SSD would have more erase blocks and thus more leeway for the FTL (flash translation layer) to do garbage collection optimization. Also there would be more time before TRIM became necessary. I see on Wikipedia that it remarks that "The performance of the SSD can scale with the number of parallel NAND flash chips used in the device" so it seems throughput also increases significantly. Also many SSDs contain internal caches of some sort and presumably those caches are larger for correspondingly large SSDs. But supposing this effect exists, I would like a quantitative analysis. Does throughput increase linearly? How much is garbage collection impacted, if at all? Does latency stay the same? And so on. Would the performance of a 8 GB SSD be significantly different from, for example, an 80 GB SSD assuming both used high quality chips, controllers, etc? Are there any resources (webpages, research papers, presentations, books, etc) that discuss correlations between SSD performance (4 KB random write speed, latency, maximum sequential throughput, etc) and size? I realize this does not really sound like a programming question but it is relevant for what I'm working on (using flash for caching hard drive data) which does involve programming. If there is a better place to ask this question, eg a more hardware oriented site, what would that be? Something like the equivalent of stack overflow (or perhaps a forum) for in-depth questions on hardware interfaces, internals, etc would be appreciated.

  Read the article

• Computer does not boot, often

  - by tam

  I've ran into a issue with my computer that it does no longer reach POST, but simply powers on for a fraction of a second and powers off. But this is not always, some times it boots just normally and it works as it should, no issues with not enough power or anything. But as soon as I turn it of, I can not turn it back on, but then again at some random point it just powers up again, and resumes normal operation. If I disconnect the 8pin ATX connector from the motherboard, it powers up, fans and disks spinning normally until I power it off again. So this problem only happens when ATX is connected, which seems odd, I normally always saw this kind of an error if ATX was not connected, but here it's the exact opposite. It also does not emit any sound on the buzzer, except the normal beep, when it powers up normally. I have already tried: Remove graphics card Remove one and/or all RAM sticks Disconnect everything non-essential, even hard drives Clear CMOS I have not yet tried to remove all components and tried to boot everything outside of the case, because I did not have the time to disassemble and bleed the water loop. However, I can confirm that nothing is stuck underneath the motherboard, not is any of those brass raisers touching the board where it should not. Specs: Gigabyte GA-970A-UD3 AMD FX6300 ATI HD7850 I think this should be enough for this issue.

  Read the article

• Why is my cron daemon is being killed every few minutes?

  - by user113215

  As of about a week ago, my cron daemon refuses to stay running. I'm using Debian 6 x64 on an OpenVZ virtual machine. Running something like pgrep cron shows that the daemon isn't running. I start the service with service cron start or /etc/init.d/cron start and it launches, but it disappears from the running process list after a few minutes (varying anywhere between 1 - 30 minutes before the process is killed again). Using strace -f service cron start, I can see that the process is being killed for some reason: nanosleep({60, 0}, <unfinished ...> +++ killed by SIGKILL +++ There's nothing relevant in /var/log/syslog, /var/log/messages, /var/log/auth.log, or /var/log/kern.log to explain why the the process is dying. The system has at least 800 MB of free memory, and cat /proc/loadavg returns 0.22 0.13 0.04 so resources shouldn't be the issue. With cron running, free -m reports: total used free shared buffers cached Mem: 1024 211 812 0 0 0 -/+ buffers/cache: 211 812 Swap: 0 0 0 I also tried removing and reinstalling the cron package using apt-get. Update: I initially thought the problem was a resource issues. I erased my entire VPS and started from a fresh Debian image. There is now nothing else running on the system, but even from a clean install my cron daemon is still being killed at random. What else should I check? How do I find out what's killing my crond?

  Read the article

• What Windows app can sort a huge XML file?

  - by Torben Gundtofte-Bruun

  I have some enormous XML-based configuration files, with 125000 lines in them. The problem is that they are auto-generated by the system I use, and "child" tags are in a random order within their respective parent tag. This means that a diff comparison is impossible. I want to recursively sort all tags within a parent tag by the value in name="". Some parent tags only appear once and don't have a name="" parameter; these should be sorted by the tag name itself. Once the files are sorted like this, they can be compared quite easily using normal tools. We are currently using ExamXML which can match unsorted XML files, but it fails because the files are too big. Is there an application that can do this? (Windows much preferred; Linux only as a last resort) I do not want to dive into development or XSLT jobs. I am thinking that someone must have made a simple sorting tool like this already - I just can't find it using Google. Update: With help from this site, I created a small package that I want to share: XML-Sorter_v0.3.zip Update: Follow-up question here.

  Read the article

• DSL Connection drops

  - by user60024

  Ok, I just moved so I had to switch from Cable to DSL. I know very little about computers or internet connections and such, so I had AT&T come out to the new house to set up their highest speed. When they got here, they told me that I needed to downgrade to 3.5mbps because I was too far away. Well we did and everything was going great for two days until I started experiencing random disconnects which have been happening now for about 2 to 3 weeks. I am using a N300 Wireless Dual Band ADSL2+ Modem Router and my ethernet cable is hooked directly into my computer from it. I recently started to notice that it disconnects around 5:30 and 8:30, which may be because a lot of people are on their computers(?) and that it works perfectly fine, almost, all the time if I'm not playing a game. During this time, when I try to load up World of Warcraft the Internet light disappears and the DSL light begins blinking. (So maybe it's too much for the modem and it resets?) Other than that it is amazing, but I'd like to try and fix some of these problems. If you need more information, let me know on how to get it for you and what to do. Thanks for the help!

  Read the article

< Previous Page | 354 355 356 357 358 359 360 361 362 363 364 365  | Next Page >