Search Results

Search found 6682 results on 268 pages for 'edge cases'.

Page 190/268 | < Previous Page | 186 187 188 189 190 191 192 193 194 195 196 197  | Next Page >

  • Gvim on Windows 7: ALT codes not working

    - by John Sonderson
    I would like to be able to enter ALT codes in Gvim on Windows 7 as documented on the following site: Alt Codes On Windows (Windows 7 in my case), to generate a character via an ALT code you make sure that the NumLock key on your keypad is toggled on, hold down the ALT key, enter the keycode on the numeric keypad, and then release the ALT key. However this does not work in Gvim on Windows (which ignores the fact that I am pressing the ALT key and just prints to entered keypad key directly onto the screen). How can I get these keystroke combinations to work in Gvim as well? Thanks. EDIT: As the answer below points out, the way to insert non-ASCII characters for which you do not have entries on your keyboard without changing the keyboard layout is as follows: Make sure you are in insert mode, and then type CTRL-V followed by the Unicode character code of interest, for instance: CTRL-V u00E0 (generates à) CTRL-V u00C8 (generates È) CTRL-V u00E8 (generates è) CTRL-V u00E9 (generates é) CTRL-V u00EC (generates ì) CTRL-V u00F2 (generates ò) etc... See for instance http://unicode-table.com/ for a full list of Unicode character codes. The following list of Unicode characters by language may also be useful: http://en.wikipedia.org/wiki/List_of_Unicode_characters In some cases such as this one, though, there might be an easier way to enter special characters (see :help digraphs and :digraphs). For example, while in insert mode you may be able to type the following: CTRL-K E! (yields É) CTRL-K a' (yields á) Note that as the following page shows: http://code.google.com/p/vim/source/browse/runtime/doc/digraph.txt Gvim 7.4 contains an even wider set of default digraphs than Gvim 7.3, thus providing convenience to an even broader set of languages. Regards.

    Read the article

  • Home Server: cpu virtualisation, what to choose?

    - by Huygens
    I'm looking for virtualisation solutions for storage and OS for a home server. A sort of private cloud where I manage the storage space independently of the VM one. This question focus on VM (or compute instance) management and what would best suit my needs. (I have another question related to the storage management). My use cases are: A backup server: rsync and other services running. A personal cloud server: a kind of owned dropbox system, à la ownCloud. " users foreseen. A media server: streaming videos and displaying photos. Here my environement and wishes: Server: HP Proliant MicroServer with 8 GB RAM (AMD Turion dual core with AMD-V technology) OS types: only Linux (perhaps a *BSD VM in the future) Linux distributions do not matter, I'm familiar with RHEL, Fedora, Suse, Ubuntu, but any other recommandation will be fine 2-3 VMs foreseen: backup server, owncloud server and media server (optional). Those are only servers, so no graphical console needed (I don't need VirtualBox) By VM I mean a virtualised environment like KVM, Xen, etc. or a compute instance like with OpenStack storage should be "virtualised/cloudified" see my other question. VM should be able to be migrated to another server in the future if performance cannot be fullfilled anymore by the current server It does not matter if installation of such setup is complicated as long as management tools allow for easy maintenance I don't have Windows at home, so solution should be Linux friendly and would be nice to be web based. But native apps are OK too. System should be easy to enhance: by adding a new server to migate some of the VMs to it. So it's really a kind of private cloud on which I could run some Linux OS. I would prefer free (libre, as in a free speach) and open source tools. But it does not have to be free as in a free beer. So Xen, KVM, VitualBox or OpenStack? What would you recommend?

    Read the article

  • Outlook error-'Can't open e-mail folders.You must connect to Exchange w/ current profile before you can sync folders w/ your Outlook data file'

    - by Emilio
    Note that the error message I put in the title of this question is abbreviated. The actual error message is below. I have an Exchange account and using Outlook 2010 as the client. I run in Cached Exchange Mode and have an .OST file locally. Recently I uninstalled and reinstalled office. I set up a new mail profile when prompted by Outlook 2010 upon first execution of the program. In my initial attempt, I pointed the data file at my existing OST file. In my second attempt, I had Outlook create a fresh empty file. In both cases I'm getting the error 'Cannot open your default e-mail folders. You must connect to Microsoft Exchange with the current profile before you can synchronize your folders with your Outlook data file (.ost).', also shown in this screenshot -- http://drop.io/4rc9v9o/asset/outlook-error-png. I don't know how to connect with the current profile - that's what I thought I did when I created a new .OST file? I've had this problem for several days so my OST file is now out of date. Once I get things running I obviously want my active mailbox to update the OST, not the other way around.

    Read the article

  • Changing Corosync/Heartbeat pair's active node based on MySQL/Galera cluster state

    - by Hace
    Background I'm planning on building a High Availability "cluster" for our Zabbix instance by placing two physical servers in one server room and two in another server room. In each server room one of the physical servers will run Zabbix on RHEL and the other will run Zabbix's MySQL database, also on RHEL. I'd prefer synchronous replication for the MySQL nodes so I'm planning on using Galera in a master-slave configuration. The Zabbix instances on the two Zabbix servers would be controlled by Heartbeat/Corosync (although Red Hat Cluster Suite is also an option...) If the Zabbix server in Server Room A goes down, the one in Server Room B becomes active (and vice versa). Ditto for the MySQL servers/instances. If either of those cases happen, however, the connection between the Zabbix server and the MySQL server becomes significantly slower as ti has to travel over WAN. Question Is it possible to configure the Heartbeat/CoroSync pair to instruct the MySQL/Galera cluster to change the master node to switch to (if available) the one that's in the server room as the active Heartbeat/Corosync -node and (more challengingly) is it possible to do the same in the other direction, i.e have the Galera cluster change the active Heartbeat/CoroSync server to be in the same room as the active MySQL master server in case of a failover in over to avoid unnecessary WAN transfers between the application and its DB? Theories Most likely I can get CoroSync to run something that'd log in to one of the DB nodes to change the MySQL/Galera master but I don't know if it's really possible to do anything similar in the other direction in Galera. Is it possible to define a "service" in CoroSync/Heartbeat so that both the service and its MySQL service would migrate as one if possible. Using the DB server that's behind WAN should still be a better option to DB downtime. Am I just using too many tools to solve a problem that'd be far simpler with something else?

    Read the article

  • Printing on Windows 8 with PDF viewer (Adobe Reader) from network

    - by Bongo
    i have a problem with the Adobe Reader 8, but the problem seems to be equally bad with other pdf viewers. Here is the configuration: My PDF viewer is located on network drive "Z:" which is the network adress \dgs-main\progs. I tried to start the adobe reader from here - \\dgs-main\progs\Adobe\Reader 8.0\Reader\AcroRd32.exe and open the PDF from here - C:\Users\ServiceDesk\AppData\Local\Temp\GeneratedPDF.pdf The problem is as follows, if i open the PDF with a local PDF viewer everything works fine and i can print the document. If i open the PDF with the Network PDF viewer then it opens, but printing is impossible. The error message states: "Unable to start print job. Is printer available?" As mentioned above, it works with a local pdf viewer. In both cases i use the same printer. The Printer is a network printer but even with a local printer it fails. The error occurs only on Windows 8 machines. On windows 7 it works fine. I Hope somebody can tell me what the problem is. Thanks in advance and have a fine day.

    Read the article

  • Corliss Expert Group Home Security: How to Secure Your Home without Spending Too Much?

    - by Mika Esmond
    HOME SECURITY: HOW TO SECURE YOUR HOME WITHOUT SPENDING TOO MUCH Imagine if there were no burglar or criminals who threaten the safety of our homes; we will be surprised how much savings we would have on several things we do to secure ourselves and our loved ones. We would not need fences, gates with locks, doors locks, window grills, CCTV cams, perimeter lighting, shotguns and baseball bats. The cost of maintaining these things can run up to the entire cost of building another room or, in some cases, a whole new house. The rationale for home security is the same for national security. A nation maintains an army whether it has enemies or not; so, whether burglars will come or not, we have to prepare for the eventuality. Hence, we end up spending for something we might never put into the actual use it was intended for. You buy a pistol and when a burglar breaks in you fire the gun either to scare or disable the intruder. We hope we will never have to use these things; but we still buy them for the peace of mind that comes from knowing we can secure or protect our family and home.

    Read the article

  • MAMP MySQL won't start

    - by Tony
    I uninstalled MAMP completely, downloaded fresh copy of MAMP 2 from the MAMP website, did a clean install. However, when I try to start mysql, I get the following error log 111120 21:37:49 mysqld_safe Starting mysqld daemon with databases from /Applications/MAMP/db/mysql 111120 21:37:50 [Warning] You have forced lower_case_table_names to 0 through a command-line option, even though your file system '/Applications/MAMP/db/mysql/' is case insensitive. This means that you can corrupt a MyISAM table by accessing it with different cases. You should consider changing lower_case_table_names to 1 or 2 111120 21:37:50 [Note] Plugin 'FEDERATED' is disabled. 111120 21:37:50 InnoDB: The InnoDB memory heap is disabled 111120 21:37:50 InnoDB: Mutexes and rw_locks use GCC atomic builtins 111120 21:37:50 InnoDB: Compressed tables use zlib 1.2.3 111120 21:37:50 InnoDB: Initializing buffer pool, size = 128.0M 111120 21:37:50 InnoDB: Completed initialization of buffer pool 111120 21:37:50 InnoDB: highest supported file format is Barracuda. 111120 21:37:50 InnoDB: Waiting for the background threads to start 111120 21:37:51 InnoDB: 1.1.5 started; log sequence number 1595675 111120 21:37:51 [ERROR] /Applications/MAMP/Library/bin/mysqld: unknown option '--skip-locking' 111120 21:37:51 [ERROR] Aborting 111120 21:37:51 InnoDB: Starting shutdown... 111120 21:37:51 InnoDB: Shutdown completed; log sequence number 1595675 111120 21:37:51 [Note] /Applications/MAMP/Library/bin/mysqld: Shutdown complete 111120 21:37:51 mysqld_safe mysqld from pid file /Applications/MAMP/tmp/mysql/mysql.pid ended I've no clue why this is happening. I googled around and made sure that no instance of MySQL is running. Nothing seems to help.

    Read the article

  • How to get an inactive RAID device working again?

    - by Jonik
    After booting, my RAID1 device (/dev/md_d0 *) sometimes goes in some funny state and I cannot mount it. * Originally I created /dev/md0 but it has somehow changed itself into /dev/md_d0. # mount /opt mount: wrong fs type, bad option, bad superblock on /dev/md_d0, missing codepage or helper program, or other error (could this be the IDE device where you in fact use ide-scsi so that sr0 or sda or so is needed?) In some cases useful info is found in syslog - try dmesg | tail or so The RAID device appears to be inactive somehow: # cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md_d0 : inactive sda4[0](S) 241095104 blocks # mdadm --detail /dev/md_d0 mdadm: md device /dev/md_d0 does not appear to be active. Question is, how to make active the device again (using mdmadm, I presume)? (Other times it's alright (active) after boot, and I can mount it manually without problems. But it still won't mount automatically even though I have it in /etc/fstab: /dev/md_d0 /opt ext4 defaults 0 0 So a bonus question: what should I do to make the RAID device automatically mount at /opt at boot time?) This is an Ubuntu 9.10 workstation. Background info about my RAID setup in this question.

    Read the article

  • Why does this loopback device creation malfunction?

    - by user50118
    The stackoverflow people thought this was more appropriate here, I put it there as it is part of a program but I can see their POV, so here it is: At the bottom of the code you can see it failing. In fact, I'll put it here at the start too because it is the problem I need to solve: [350591.924819] EXT4-fs (loop0): bad geometry: block count 9750806 exceeds size of device (9750168 blocks) I don't understand why the device is supposedly too small. I made this partition two days ago with normal fdisk, it was created and formatted with ext4 supplying no options other than the partition (/dev/sdb2) to format. The only explaination I can think of is that ext4 has the size of the partition wrong somehow but that seems very unlikely. What is wrong with my math? The offset is correct, you can see that with the file command, and the size should be correct too because End - Start comes to the same number of sectors minus 1, just like it should (A disk starting on sector 1 and ending on sector 2 would be 2 - 1 = 1 and have two sectors). # sfdisk -luS /dev/sdb Disk /dev/sdb: 9729 cylinders, 255 heads, 63 sectors/track Units = sectors of 512 bytes, counting from 0 Device Boot Start End #sectors Id System /dev/sdb2 78295040 156296384 78001345 83 Linux # losetup -r -f --show -o $((78295040 * 512)) --sizelimit $((78001345 * 512)) /dev/sdb /dev/loop0 # file -s /dev/loop0 /dev/loop0: Linux rev 1.0 ext4 filesystem data (needs journal recovery) (extents) (large files) (huge files) # mount -o ro -t ext4 /dev/loop0 /mnt mount: wrong fs type, bad option, bad superblock on /dev/loop0, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so # dmesg | tail -n 1 [350591.924819] EXT4-fs (loop0): bad geometry: block count 9750806 exceeds size of device (9750168 blocks)

    Read the article

  • "Security Warning" comes up when I run via another program

    - by Alexander Bird
    If I execute vmmap from the command line it works fine. However, if I call some other program and pass vmmap as a paramater for this other program to start the execution, then I get this "security error" popup -- which makes it hard to automate scripts. In other words, I want to wrap vmmap via another program. In my case, I want to wrap vmmap via another program because whenever vmmap runs, it will bring a window up momentarily and then disappear. So I try passing vmmap as an argument to another program which will start the program "headlessly". I tried this program and this program, and in both cases I get the same popup which defeats the purpose of automation. Why does this happen when the program isn't run directly? Does anyone know the internals of what this warning is? And, utlimately, is there a way to stop this from happening, but only for this instance? I don't want to disable this warning-system on my whole computer. EDIT: I am using Windows Server 2003, and I don't necessarily need solutions for other platforms, but I would like to know what they are if they are platform-dependent solutions.

    Read the article

  • (manually configured) kernel update leaves wireless in a mess

    - by Mala
    I recently upgraded my kernel from 2.6.31-gentoo-r6 to 2.6.32-gentoo-r7. In both cases, I configured everything manually. However, since the upgrade, my wireless card appears to be on the fritz. It will connect to networks just fine, and remain connected, but can only access the internet (and other hosts on the network) for about 3 seconds after connecting. Reconnecting to the network appears to fix the problem... for another 3 seconds or so. The problem is "solved" by booting into the older kernel. The relevant lspci entry is 02:00.0 Network controller: Intel Corporation PRO/Wireless 5300 AGN [Shiloh] Network Connection I'm pretty sure I have the correct drivers enabled in the kernel Device Drivers ---> Network device support ---> Wireless LAN (IEEE 802.11) ---> <*> Intel Wireless Wifi [*] Enable LED support in iwlagn and iwl3945 drivers [*] Enable Spectrum Measurement in iwlagn driver [*] Enable full debugging output in iwlagn and iwl3945 drivers <*> Intel Wireless WiFi Next Gen AGN (iwlagn) [*] Intel Wireless WiFi 4965AGN [*] Intel Wireless WiFi 5000AGN; Intel WiFi Link 1000, 6000, and 6050 Series I tried with the other intel drivers enabled as well (iwl3945) and no difference. Is there something stupid I'm missing? Is there something I have to recompile after upgrading the kernel (a la nvidia)? Thanks Mala

    Read the article

  • Debugging Windows PC freeze

    - by Violet Giraffe
    I have a problem with my computer, would appreciate any hints/ideas. It usually begins not immediately after booting Windows, but at some unpredictable point in time, which doesn't seem to correlate with any specific actions of mine. First sign of a problem is process System starting to consume 25% CPU time steadily. I have a quad-core CPU, so it might be one thread working non-stop. At this point micro-freezes start to occur - screen stops refreshing, but if I have, say, music player running - it continues playing. If I try to do something between the freezes, like open Start menu, it will freeze completely and forever. If I press reset button the PC will shut down and then start cold, as opposed to usual reset behavior (which doesn't include PC shutting down). I have noticed that full restart upon reset is usual for hardware problems, but I think this problem isn't related to at least motherboard-CPU-RAM-videoadapter. It certainly isn't caused by overheating. One very important not is that it seems to be related to Windows hosted WLAN network: I have USB Wi-Fi dongle and have configured a hosted network to share cable Internet connection with Wi-Fi devices. I am not 100% certain there's a strong connection, but in 9 or 10 cases when I enabled the network (by executing netsh wlan start hostednetwork), it did freeze eventually (sometimes within minutes of starting the network, sometimes within hours), and on at least 10 days when I didn't start the network it never froze, no matter how I used the computer). There are no critical/error entries in the events log that I can suspect as being related, only regular stuff like "driver not loaded". I have found no critical/error events that are being logged around the time of freeze occurring and are not logged during normal boot without starting the WLAN.

    Read the article

  • Problem routing between directly connected Subnets w/ ASA-5510

    - by Zephyr Pellerin
    This is an issue I've been struggling with for quite some time, with a seemingly simple answer (Aren't all IT problems?). And that is the problem of passing traffic between two directly connected subnets with an ASA While I'm aware that best practice is to have Internet - Firewall - Router, in many cases this isn't possible. For example, In have an ASA with two interfaces, named OutsideNetwork (10.19.200.3/24) and InternalNetwork (10.19.4.254/24). You'd expect Outside to be able to get to, say, 10.19.4.1, or at LEAST 10.19.4.254, but pinging the interface gives only bad news. Result of the command: "ping OutsideNetwork 10.19.4.254" Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.19.4.254, timeout is 2 seconds: ????? Success rate is 0 percent (0/5) Naturally, you'd assume that you could add a static route, to no avail. [ERROR] route Outsidenetwork 10.19.4.0 255.255.255.0 10.19.4.254 1 Cannot add route, connected route exists At this point, you might gander if its a NAT or Access list problem. access-list Outsidenetwork_access_in extended permit ip any any access-list Internalnetwork_access_in extended permit ip any any There is no dynamic nat (or static nat for that matter), and Unnatted traffic is permitted. When I try pinging the above address (10.19.4.254 from Outsidenetwork), I get this error message from level 0 logging (debugging). Routing failed to locate next hop for icmp from NP Identity Ifc:10.19.200.3/0 to Outsidenetwork:10.19.4.1/0 This led me to set same-security traffic permit, and assigned the same, lesser and greater security numbers between the two interfaces. Am I overlooking something obvious? Is there a command to set static routes that are classified higher than connected routes?

    Read the article

  • Is execution of sync(8) still required before shutting down linux?

    - by Amos Shapira
    I still see people recommend use of "sync; sync; sync; sleep 30; halt" incantations when talking about shutting down or rebooting Linux. I've been running Linux since its inception and although this was the recommended procedure in the BSD 4.2/4.3 and SunOS 4 days, I can't recall that I had to do that for at least the last ten years, during which I probably went through shutdown/reboot of Linux maybe thousands of times. I suspect that this is an anachronism since the days that the kernel couldn't unmount and sync the root filesystem and other critical filesystems required even during single-user mode (e.g. /tmp), and therefore it was necessary to tell it explicitly to flush as much data as it can to disk. These days, without finding the relevant code in the kernel source yet (digging through http://lxr.linux.no and google), I suspect that the kernel is smart enough to cleanly unmount even the root filesystem and the filesystem is smart enough to effectively do a sync(2) before unmounting itself during a normal "shutdown"/"reboot"/"poweorff". The "sync; sync; sync" is only necessary in extreme cases where the filesystem won't unmount cleanly (e.g. physical disk failure) or the system is in a state that only forcing a direct reboot(8) will get it out of its freeze (e.g. the load is too high to let it schedule the shutdown command). I also never do the "sync" procedure before unmounting removable devices, and never hit a problem. Another example - Xen allows the DomU to be sent a "shutdown" command from the Dom0, this is considered a "clean shutdown" without anyone having to login and type the magical "sync; sync; sync" first. Am I right or was I lucky for a few thousands of system shutdowns?

    Read the article

  • Running $ORIGIN linked binaries from setuid scripts on linux

    - by drscroogemcduck
    I'm using suidperl to run some programs that require root permissions. however, the runtime linker won't expand library paths which contain $ORIGIN entries so the programs i want to run (jstack from java) won't run. more info here There is one exception to the advice to make heavy use of $ORIGIN. The runtime linker will not expand tokens like $ORIGIN for secure (setuid) applications. This should not be a problem in the vast majority of cases. my program looks something like this: #!/usr/bin/perl $ENV{PATH} = "/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/java/jdk1.6.0_12/bin:/root/bin"; $ENV{JAVA_HOME} = "/usr/java/jdk1.6.0_12"; open(FILE, '/var/run/kil.pid'); $pid = <FILE>; close(FILE); chomp($pid); if ($pid =~ /^(\d+)/) { $pid = $1; } else { die 'nopid'; } system( "/usr/java/jdk1.6.0_12/bin/jstack", "$pid"); is there any way to fork off a child process in a way so that the linker will work correctly.

    Read the article

  • Is it possible to have a conditional formatting cell "visually cycle" through all the formats that evaluated true?

    - by Ben
    Like the title says, "In Excel, when a cell has multiple conditional formatting rules that evaluate true, is it possible to have the cell "visually cycle" through all the formats that evaluated true? If not, suggestions on what to do would be appreciated!" I'm creating an employee schedule for a business that has multiple job areas that need to have an employee assigned to cover. The schedule is currently set up with the date on the top row, employee list down the left column, and the employee's assigned "job area" cross-referencing with the date on the top row. Originally it was set up where if every required "job area" didn't have someone assigned to it, the date would (via conditional formatting) change to red. I've set it up now that if a condition isn't met, the date will change to the color of the "job area" that doesn't have an employee assigned to it. However, there are cases where multiple job areas don't have an employee assigned, but the date will only change color based on the first condition that isn't met. It'd be nice if there was some way for the date cell to cycle through the different colors that correspond to the job areas where no one is assigned. I have a hunch that's not possible though. If it is possible, I'd love to know how to do it. And if it isn't, if anyone has any suggestions on how I can modify the Excel sheet to make it easier to identify the job areas that don't have anyone assigned to them, I would appreciate it. FYI This schedule goes out months in advance.

    Read the article

  • What was SPX from the IPX/SPX stack ever used for?

    - by Kumba
    Been trying to learn about older networking protocols a bit, and figured that I would start with IPX/SPX. So I built two MS-DOS virtual machines in VirtualBox, and got IPX communications working (after much trial and error). The idea being to get several old DOS games to run, link up to a multiplayer match, interact with each game window, and capture the traffic using Wireshark from the host machine. From this, I got Quake, Masters of Orion 2, and MechWarrior 2 to communicate back and forth. Doom, Doom2, Duke3d, Warcraft, and several others either buggered up under the VM or just couldn't see the other VM on the IPX network. What did I discover? None of the working games used SPX. Not even Microsoft's NET DIAG used SPX. They all ran ONLY on top of IPX. I can't even find SPX examples or use-cases of SPX traffic running over IEEE 802.3 Ethernet II framing. I did find references that it was in abundant use on token ring, but that's it. Yet any IPX-aware application that I've hunted down so far usually advertises itself as "IPX/SPX", which seems to be a bit of a misnomer, since it doesn't seem to use SPX. So what was SPX used for? Any DOS applications out there that use it which will run under my VM setup? Edit: I am aware that IPX is to SPX as IP is to TCP (layer 3 to layer 4), so I expected to see an SPX layer underneath the IPX layer in Wireshark when I ran my tests.

    Read the article

  • Word 2010, Multiple Columns, Vertical center one column only

    - by Nancy N Jones
    I am creating a document with two columns in Microsoft Word 2010. I want the first column to be centered vertically. I want the second column to be on the same page and the vertical placement to be from the top. I highlight my text in the first column that I want centered vertically, then go to Page Layout Margins Custom Margins Layout, you can choose to center the vertical alignment. I have choosen the "Section Start" to be "Column" and also tried "Continuous." In all cases it always shifts all of my second column information to a new page. I don't want my second column text to be on a new page, I want it to be on the same page and vertically aligned from the top--not the center. Am I understanding the functionality of the Section Start on the Layout tab correctly? Maybe the page layout isn't the correct formatting to use. What I am really doing is formatting columns. I haven't found anywhere to format the columns for this. Am I missing some important column formatting features? I know that I can use the paragraph formatting and add space above the first line of text to make it look like it is centered vertically. However, this is a template for a master document and will be changed frequently. I really would like the first column text to be automatically formatted to be centered vertically without having to go in and manually change the space above the paragraph every time. Your assistance would be greatly appreciated.

    Read the article

  • What are the frequencies of current in computers' external peripheral cables and internal buses?

    - by Tim
    From Wikipedia, three different cases of current frequency are discussed along with the types of cables that are suitable for them: An Extra Ordinary electrical cables suffice to carry low frequency AC, such as mains power, which reverses direction 100 to 120 times per second (cycling 50 to 60 times per second). However, they cannot be used to carry currents in the radio frequency range or higher, which reverse direction millions to billions of times per second, because the energy tends to radiate off the cable as radio waves, causing power losses. Radio frequency currents also tend to reflect from discontinuities in the cable such as connectors, and travel back down the cable toward the source. These reflections act as bottlenecks, preventing the power from reaching the destination. Transmission lines use specialized construction such as precise conductor dimensions and spacing, and impedance matching, to carry electromagnetic signals with minimal reflections and power losses. Types of transmission line include ladder line, coaxial cable, dielectric slabs, stripline, optical fiber, and waveguides. The higher the frequency, the shorter are the waves in a transmission medium. Transmission lines must be used when the frequency is high enough that the wavelength of the waves begins to approach the length of the cable used. To conduct energy at frequencies above the radio range, such as millimeter waves, infrared, and light, the waves become much smaller than the dimensions of the structures used to guide them, so transmission line techniques become inadequate and the methods of optics are used. I wonder what the frequencies are for the currents in computers' external peripheral cables, such as Ethernet cable, USB cable, and in computers' internal buses? Are the cables also made specially for the frequencies? Thanks!

    Read the article

  • Laptop Randomly Turning On and Off

    - by Ian Mallett
    So, I have a pretty new laptop, and one of its quirks is that, at random times (though typically in the middle of the night), it seems to wake up from sleep mode, churn a bit, and then go back into sleep mode. I write "seems" because its fans are very loud, so it's obvious when it's not asleep, but during the time it is "on", I can't see anything on the screen. I have researched the problem somewhat, and could only find similar issues; nothing identical. In those cases, it appeared that certain devices could be responsible. Nothing is plugged into my computer during this behavior, but I nonetheless disabled every device's permission to wake the computer through the device manager. This included disabling the magic packet wake for the network (despite its only having a wireless connection). Using "powercfg /lastwake" gives an empty wake history. But, I also went through all the tasks and checked if they would wake the computer. None appeared to. The problem persisted, so, after some more research, I found this, and executed it for all power schemes on the computer. The problem persists. System: OS: Windows 7 Professional CPU: Intel 990X GPU: NVIDIA GeForce 580M/12GB RAM Motherboard: Clevo X7200 Model: NP7282-S1 (Sager-built laptop)

    Read the article

  • Why *do* windows print queues occasionally choke on a print job

    - by Ian
    Y'know they way windows print queues will occasionally stop working with a print job at the head of the queue which just won't print and which you can't delete? Anyone know whats going on when this happens? I've been seeing this since the NT4 days and it still happens on 2008. I'm talking about standard IP connected laser printers - nothing fancy. I support a lot of servers and loads of workstations and see this happen a few times a year. The user will call saying they can't print. When you examine the print queue, which in my case will generally be a server based queue shared out to the workstations, you find a print job which you cannot cancel. You also can't pause it, reinitialize it, nothing. Stopping the spooler is the usual trick and works sometimes. However I occasionally see cases which even this doesn't cure and which a reboot is the only solution. Pause the queue, reboot, when it comes back up the job can then be deleted. Once gone the printer happily goes back to its normal state. No action is ever necessary on the printer. I regard having to reboot as last resort and don't like it. What on earth can be going on when stopping the process (spooler) and restarting it doesn't clear a problem? Its not linked to any manufacturer either. I've seen this on HPs, lexmark, canon, ricoh, on lasers, on plotters.... can't say I ever saw this on dot matrix. Anyone got any ideas as to what may be going on. Ian

    Read the article

  • mysql thread count

    - by Ryan M.
    We have a web application that uses apache and mysql. Generally (according to Munin) our MySQL thread count sits between 2 and 4 at all times. The other day, our server almost came to a halt. HTTP requests were slow or wouldn't go through at all, SSH would work, but would take 30+ seconds to register keystrokes, etc.. So we pull up Munin and the only thing that's out of normal boundaries is the Mysql thread count. CPU usage was under 1%, load was under 1.0, plenty of available RAM. As mentioned before, the thread count floats around 2 to 4. At the time of our slow downs it had spiked to 14. So I start poking around the Internet and I see that in most cases, you'll start to see a higher thread count when you start running into slow queries. If I understand it correctly, the request comes in that takes a while to process, in the mean time other requests are coming in, so a new thread will be created to work on the request (yes?). But at the time of the slow down, we had 0 slow queries. My question is: What else can cause mysql to create additional threads. And would this sudden spike in threads possibly cause the server to slow down? To fix the issue, we restarted apache and everything went back to it's beautiful, normal self. Considering the the Server Vitals (CPU, RAM, Network, etc) were all ideal, and the thread count was the only thing out of place, this seems like the most logical thing to pursue as the possible cause. If it matters, we're on Mysql 5.1.40. Server is FreeBSD 7.2 and the server in question is inside a jail.

    Read the article

  • Is this "cache administrator" error my server's problem?

    - by Eoin
    Hey, I have a CentOS VPS running Apache with a phpBB installation. One specific user has received errors when posting a message or logging in to the forum. The following issue has arisen in parallel to installing nginx, which serves only the static files of my site. Not sure if this is only coincidence. Furthermore, my setup uses redirects (in some cases, double-redirects) to point the user to a different virtual folder. So, the forum is seen to be at /translation/ but the actual files are found in /phpbb/. I'm at a loss as to what may be the underlying issue. My server? The person's ISP? She has tested both at home and at work, with similar issues. While trying to process the request: GET /phpbb/index.php?sid=f62c927e7eb8f1d60a92dcc6fd918112 HTTP/1.1 Host: www.irishgaelictranslator.com User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: en-za Accept-Encoding: gzip,deflate Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7 Keep-Alive: 115 Connection: keep-alive Referer: http://www.irishgaelictranslator.com/phpbb/ucp.php?mode=login Cookie: phpbb3_cipi4_u=96645; phpbb3_cipi4_k=; phpbb3_cipi4_sid=f62c927e7eb8f1d60a92dcc6fd918112; __utma=153470688.1232378553.1294664234.1294664234.1294664234.1; __utmb=153470688.9.10.1294664234; __utmc=153470688; __utmz=153470688.1294664235.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); style_cookie=null The following error was encountered: Invalid Response The HTTP Response message received from the contacted server could not be understood or was otherwise malformed. Please contact the site operator. Your cache administrator may be able to provide you with more details about the exact nature of the problem if needed.

    Read the article

  • How to test/debug bad network wiring?

    - by Jack Lloyd
    I recently bought a place already wired with Cat 5E (8 ports, leading to a central closet). However attempting to get link, nothing works. On closer examination, it was obvious that the ends in the closet were wired backwards (brown on pin 1, etc). The jacks that I've pulled out of the wall do look to be correctly done. However, testing with a network cable tester shows zero link between any of the jacks and any of the ports in the closet - I had expected to just see a 1/8, 2/7, ... 8/1 mismatch, but instead get nothing at all. The runs are accessible and look neat, though they take some bends that seem quite sharp and are in some cases much longer than they need to be (the person who put this in was a professional electrician but I suspect this was the first time he ran network cabling). My best guess at this point is that he either bought bad cable, or put so much tension on it that he snapped wires. Though it seems surprising/unlikely that I wouldn't get at least one active wire on one of the 8 lines. So, my question: is there anything else I should try or test before I go ripping out everything and running new cable?

    Read the article

  • Windows Server 2012 Hyper-V very slow

    - by Matt Taylor
    I have been running several Hyper-V VMs on Windows Server 2008 R2 for the past couple of years and enjoying perfectly adequate performance for my testing/development/r&d environments. I'm a software developer so my hardware knowledge is basic however I built the rig using: •Gigabyte GA-X58A-UD3R Intel X58 (Socket 1366) DDR3 Motherboard •Intel Core i7 960 3.20GHz (Bloomfield) (Socket LGA1366) •24GB triple channel RAM The host OS is running on an OCZ SSD and all the VMs are running on a 2TB Marvell SATA3 RAID 0 array consisting of 2 Western Digital Caviar Black 7,200rpm drives. I have tested the speed of the 2TB drive and appear to be getting less than 3Mbs but it can adequately run a 4 VM farm including a DC, (SQL) database and IIS application servers. I recently upgraded the SSD on which the host runs to a 256GB OCZ Vertex 4 and took the opportunity to upgrade to Windows Server 2012 and installed the Hyper-V role. I tried importing one of my existing Windows Server 2008 R2 VMs (and converted it to .vhdx) plus I have tried creating a brand new Windows Server 2008 R2 VM but both are running extremely slowly and I can see nothing obvious using the host and guest Task Manager/Resource Monitor tools. In both cases the VM has 8GB RAM (fixed), 4 CPUs, fixed size HD (not expanding) and is using an external virtual network running on a separate NIC to the host. I have upgraded the BIOS to the latest available version and checked the virtualization settings. I have run out of "obvious" (to a developer) things to check/configure and my next option will be to re-install the host OS but before I do I would very much appreciate any advice from any experts out there. Thanks

    Read the article

< Previous Page | 186 187 188 189 190 191 192 193 194 195 196 197  | Next Page >