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  • SQLAuthority News – Windows Efficiency Tricks and Tips – Personal Technology Tip

    - by pinaldave
    This is the second post in my series about my favorite Technology Tips, and I wanted to focus on my favorite Microsoft product.  Choosing just one topic to cover was too hard, though.  There are so many interesting things I have to share that I am forced to turn this second installment into a five-part post.  My five favorite Windows tips and tricks. 1) You can open multiple applications using the task bar. With the new Windows 7 taskbar, you can start navigating with just one click.  For example, you can launch Word by clicking on the icon on your taskbar, and if you are using multiple different programs at the same time, you can simply click on the icon to return to Word.  However, what if you need to open another Word document, or begin a new one?  Clicking on the Word icon is just going to bring you back to your original program.  Just click on the Word icon again while holding down the shift key, and you’ll open up a new document. 2) Navigate the screen with the touch of a button – and not your mouse button. Yes, we live in a pampered age.  We have access to amazing technology, and it just gets better every year.  But have you ever found yourself wishing that right when you were in the middle of something, you didn’t have to interrupt your work flow be reaching for your mouse to navigate through the screen?  Yes, we have all been guilty of this pampered wish.  But Windows has delivered!  Now you can move your application window using your arrow keys. Lock the window to the left, right hand screen: Win+left Arrow and Win+right Arrow Maximize & minimize: Win+up arrow and Win+down arrow Minimize all items on screen: Win+M Return to your original folder, or browse through all open windows: Alt+up arrow, Alt+Left Arrow, or Alt+right arrow Close down or reopen all windows: win+home 3) Are you one of the few people who still uses Command Prompt? You know who you are, and you aren’t ashamed to still use this option that so many people have forgotten about it.  You can easily access it by holding down the shift key while RIGHT clicking on any folder. 4) Quickly select multiple files without using your mouse. We all know how to select multiple files or folders by Ctrl-clicking or Shift-clicking multiple items.  But all of us have tried this, and then accidentally released Ctrl, only to lose all our precious work.  Now there is a way to select only the files you want through a check box system.  First, go to Windows Explorer, click Organize, and then “Folder and Search Options.”  Go to the View tab, and under advanced settings, you can find a box that says “Use check boxes to select items.”  Once this has been selected, you will be able to hover your mouse over any file and a check box will appear.  This makes selecting multiple, random files quick and easy. 5) Make more out of remote access. If you work anywhere in the tech field, you are probably the go-to for computer help with friends and family, and you know the usefulness of remote access (ok, some of us use this extensively at work, as well, but we all have friends and family who rely on our skills!).  Often it is necessary to restart a computer, which is impossible in remote access as the computer will not show the shutdown menu.  To force the computer to do your wishes, we return to Command Prompt.  Open Command Prompt and type “shutdown /s” for shutdown, or “shutdown /r” for restart. I hope you will find above five tricks which I use in my daily use very important. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority News, T SQL, Technology Tagged: Personal Technology

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  • How do you install a USB CD Rom drive?

    - by Matt Allen
    Hello, I recently purchased a USB CD ROM drive, but I don't know how to get it to work with my computer which runs Ubuntu 10.04. http://www.amazon.com/gp/product/B00303H908/ref=oss_product When I issue the lsusb command, it shows up as: Bus 002 Device 016: ID 05e3:0701 Genesys Logic, Inc. USB 2.0 IDE Adapter The computer doesn't recognize it automatically. How can I get this drive to show up as an actual drive on my computer? If this particular drive can't handle Linux, can you recommended one which can and provide a link to it so I can purchase it? Thanks! Update: I was asked by Scaine to run a command and report back with the output: joe@joe-laptop:~$ tail -f /var/log/kern.log Dec 29 12:51:35 joe-laptop kernel: [103190.551437] sr 7:0:0:0: [sr1] Add. Sense: Illegal mode for this track Dec 29 12:51:35 joe-laptop kernel: [103190.551446] sr 7:0:0:0: [sr1] CDB: Read(10): 28 00 00 00 00 00 00 00 02 00 Dec 29 12:51:35 joe-laptop kernel: [103190.551463] end_request: I/O error, dev sr1, sector 0 Dec 29 12:51:35 joe-laptop kernel: [103190.877542] sr 7:0:0:0: [sr1] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE Dec 29 12:51:35 joe-laptop kernel: [103190.877551] sr 7:0:0:0: [sr1] Sense Key : Illegal Request [current] Dec 29 12:51:35 joe-laptop kernel: [103190.877559] Info fld=0x0, ILI Dec 29 12:51:35 joe-laptop kernel: [103190.877562] sr 7:0:0:0: [sr1] Add. Sense: Illegal mode for this track Dec 29 12:51:35 joe-laptop kernel: [103190.877572] sr 7:0:0:0: [sr1] CDB: Read(10): 28 00 00 00 00 00 00 00 02 00 Dec 29 12:51:35 joe-laptop kernel: [103190.877588] end_request: I/O error, dev sr1, sector 0 Dec 29 13:08:46 joe-laptop kernel: [104221.558911] usb 2-2.2: USB disconnect, address 16 Then when I plugged the drive back into the computer, I got: Dec 29 13:10:29 joe-laptop kernel: [104324.668320] usb 2-2.2: new high speed USB device using ehci_hcd and address 17 Dec 29 13:10:29 joe-laptop kernel: [104324.761702] usb 2-2.2: configuration #1 chosen from 1 choice Dec 29 13:10:29 joe-laptop kernel: [104324.762700] scsi8 : SCSI emulation for USB Mass Storage devices Dec 29 13:10:29 joe-laptop kernel: [104324.762935] usb-storage: device found at 17 Dec 29 13:10:29 joe-laptop kernel: [104324.762938] usb-storage: waiting for device to settle before scanning Dec 29 13:10:34 joe-laptop kernel: [104329.760521] usb-storage: device scan complete Dec 29 13:10:34 joe-laptop kernel: [104329.761344] scsi 8:0:0:0: CD-ROM TEAC CD-224E 1.7A PQ: 0 ANSI: 0 CCS Dec 29 13:10:34 joe-laptop kernel: [104329.767425] sr1: scsi3-mmc drive: 24x/24x cd/rw xa/form2 cdda tray Dec 29 13:10:34 joe-laptop kernel: [104329.767612] sr 8:0:0:0: Attached scsi CD-ROM sr1 Dec 29 13:10:34 joe-laptop kernel: [104329.767720] sr 8:0:0:0: Attached scsi generic sg2 type 5 Dec 29 13:10:34 joe-laptop kernel: [104330.141060] sr 8:0:0:0: [sr1] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE Dec 29 13:10:34 joe-laptop kernel: [104330.141069] sr 8:0:0:0: [sr1] Sense Key : Illegal Request [current] Dec 29 13:10:34 joe-laptop kernel: [104330.141077] Info fld=0x0, ILI Dec 29 13:10:34 joe-laptop kernel: [104330.141081] sr 8:0:0:0: [sr1] Add. Sense: Illegal mode for this track Dec 29 13:10:34 joe-laptop kernel: [104330.141090] sr 8:0:0:0: [sr1] CDB: Read(10): 28 00 00 00 00 00 00 00 02 00 Dec 29 13:10:34 joe-laptop kernel: [104330.141106] end_request: I/O error, dev sr1, sector 0 Dec 29 13:10:34 joe-laptop kernel: [104330.141113] __ratelimit: 18 callbacks suppressed There was more output than this (the number of lines started growing after the drive was plugged back in, and kept growing), but this is the first few lines.

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  • Read Mobi eBooks on Kindle for PC

    - by Matthew Guay
    Do you use your PC as a eBook reader?  Kindle for PC makes it easy to read thousands of books from the Kindle Store on your computer. What you may not know is that is also works with .mobi format too, so you can increase the amount of books you can read. Amazon has jumpstarted the eBook market with their popular Kindle device.  Last fall Amazon unveiled Kindle for PC, and we reviewed how you can Read Kindle Books On Your Computer with Kindle for PC.  Whether or not you own a Kindle or other eBook reader, this is a great way to take advantage of the thousands of eBooks available from the Kindle Store today. It supports azw, prc, and tpz format, which are sold from the Kindle store, but it also supports Mobipocket (.mobi) eBooks that are not DRM protected.  Here’s how you can add them to Kindle for PC so you can easily read them on your PC Getting Started: First, make sure you have Kindle for PC (link below) installed on your computer. Sign in with your Amazon account when you first run it. Kindle for PC lets you easily read eBooks downloaded from the Kindle Store, but it doesn’t have any way to add other eBooks directly from the program. To add eBooks, you can sometimes download and double-click on the books, and they will open in Kindle for PC and be automatically added to the library.  However, this does not always seem to work. So instead, browse to your Documents folder (simply click on the Documents link on your Start menu), and double-click on the My Kindle Content folder. This folder contains all the Kindle books you have downloaded.  If you have other eBooks you would like to add to Kindle for PC, simply drag-and-drop or copy and paste them into this folder.  Here we have a .mobi formatted book downloaded from the Gutenberg Project that we’re dragging into the folder. Now, close and reopen Kindle for PC.  It should now show your new eBook right beside the eBooks you have downloaded from the Kindle Store. These eBooks work just the same as the ones downloaded from the Kindle store, and you can change font size and add bookmarks just as with other eBooks. The eBooks downloaded this way may show up with either a Amazon logo or a mobile device icon.  You should only see the mobile device icon on .mobi files formatted for mobile devices; other ones should show up with the Amazon logo.  In this screen, Pilgrim’s Progress is a standard .mobi book, The Adventures of Sherlock Holmes is a mobipocket book, and the others are downloaded from the Kindle Store. Conclusion This is a great way to read eBooks from across the internet on Kindle for PC.  Wikipedia’s Kindle page has a list of websites that offer eBooks formatted for the Kindle, so be sure to check it out for more books. Links Download Kindle for PC List of websites that offer eBooks that will work on Kindle – via Wikipedia Similar Articles Productive Geek Tips Read Kindle Books On Your Computer with Kindle for PCInstall Adobe PDF Reader on Ubuntu EdgyHow to Access your Box.Net Account from Ubuntu the Easy Way 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 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 PCmover Professional New Stinger from McAfee Helps Remove ‘FakeAlert’ Threats Google Apps Marketplace: Tools & Services For Google Apps Users Get News Quick and Precise With Newser Scan for Viruses in Ubuntu using ClamAV Replace Your Windows Task Manager With System Explorer Create Talking Photos using Fotobabble

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  • Laptop screen blank after login when external monitor is not connected

    - by Ramon Suarez
    Ubuntu does not switch back automatically to only monitor present when booting after disconnecting external monitor. Here's a video showing what happens. I get to the login window and everything looks ok, then I type my password, the desktop image shows up and... everything goes blank. It does not happen when I just login as a guest. When possible I work with my laptop connected to an external screen via the VGA port. The problem comes when I boot the computer without that secondary screen connected: The login screen comes out ok. After login the screen goes black, but I can hear the login sound. If I hit ctr + alt + backwards-delete and login again sometimes it is fixed, but not all. If I log in as a different user everything is OK. Then I log in as my user and sometimes it works. To have a screen I have to plug a monitor. Although I have turned on the laptop display with that monitor on, if I reboot it goes blank again after login, even if I turn off the external monitor before turning off the computer. I've managed to get my screen back with my username after going into recovery mode, but only sometimes. Failsafe would not load after second screen asking me what I wanted to do (no mouse to click nor keyboard working). My computer is a LDLC Aurore BB1-i5 -8 -S1. Which is the configuration file that keeps the information about the monitors using Displays under lightgdm and where is it? I guess if I could edit it I may have a chance :) One of the things I tried following a solution in another post was removing my monitors.xml file, but it does not work and I don't know how to create a good one that I could use now. When doing DISPLAY=:0 xrandrI get: Screen 0: minimum 320 x 200, current 320 x 200, maximum 8192 x 8192 LVDS1 connected (normal left inverted right x axis y axis) 1366x768 60.0 + 1360x768 59.8 60.0 1024x768 60.0 800x600 60.3 56.2 640x480 59.9 VGA1 disconnected (normal left inverted right x axis y axis) HDMI1 disconnected (normal left inverted right x axis y axis) DP1 disconnected (normal left inverted right x axis y axis) This is the full dmesg after activating sudo xdiagnoseas Bryce sugested. (If you tell me the relevant parts I will paste them here) When conecting the external monitor, only the external will work, although I can see using Displays that the computer thinks that both are working. I've asked the question in Launchpad but have it keeps on expiring without any feedback. In my opinion Ubuntu should be able to detect automatically that there is no external monitor present and switch to the laptop monitor. There's a similar question here, but it does not apply to my case External monitor set as primary even when disconnected from laptop Update: For clarification, the problem happens only with my user and once I log in. I even get to see the screensaver for about a second, and then it goes blank. Tried Bryce's example (see his answer below), but it did not work. This is the info I get from tty1 with Display=:0 xrandr: – Ramon Suarez Jul 9 at 16:36 Screen 0: minimum 320 x 200, current 320 x 200, maximum 8192 x 8192 LVDS1 connected (normal left inverted right x axis y axis) 1366x768 60.0 + 1360x768 59.8 60.0 1024x768 60.0 800x600 60.3 56.2 640x480 59.9 VGA1 disconnected (normal left inverted right x axis y axis) HDMI1 disconnected (normal left inverted right x axis y axis) DP1 disconnected (normal left inverted right x axis y axis)

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  • Ubuntu 12.04 Bootloader failed to install

    - by Chris
    Sorry about the excessively long question, but I figured giving more information would be better. I recently bought a new desktop for myself, running Windows 7. It has two hard drives, and I wanted to install Ubuntu on a small partition on the second hard drive. I created 25GB "free space" in Windows and ran a LiveCD install. I wanted to select the install options myself but accidentally selected "Install alongside Windows 7," but it seemed to pick up the free space and installed itself there as I wanted it to. However, I was told that the bootloader installation had failed. I chose to "Cancel installation," leaving my computer unable to boot. I wiped my computer and reinstalled Windows. After that, I tried installing Ubuntu through Windows using WUBI, once using files from my LiveCD and once downloading everything again. Both times the install succeeded, but both times when I restarted and tried to load Ubuntu, it gave me an error - wubildr.mbr was corrupt or missing. I checked in Windows - it was indeed present on the C:\ drive. I went back to the LiveCD installation, this time going the custom options route. I assigned 16GB to an Ext4 journaling file system and 10GB to a swap file. I got the same bootloader error as before. Being prompted to select a different partition to install the bootloader to, I first tried the partition Ubuntu was installed on. A window came up saying that the install had succeeded, but a second window gave me the same error and choices as before. I went through every single option it gave me, including the Windows partition and the hard drives themselves (dev/sda, dev/sdb). Same result. I then chose to not install a bootloader. Windows still works fine, and I assume Ubuntu has installed but is unbootable. Knowing that my computer could potentially brick itself again - and, this time around, with a lot of data to lose and hassle to go through if I mess it up - I really don't want to do anything without some advice. So I'll ask this: a) Why did the bootloader fail to install? Can I fix the error and install Ubuntu fresh? b) Is there any way to get around the error, install the bootloader, and point it towards an existing installation of Ubuntu? c) Is there a quicker and easier solution I might have missed? EDIT: Thanks for the tip, AthloX. After testing the liveCD in Virtualbox with no installation problems, I looked around for some alternate bootloaders but had no success. I attempted another install, which installed the bootloader and Ubuntu just fine but bricked Windows 7. I wiped both hard disks clean, including some "System Reserved" partitions I hadn't noticed before, before re-installing Windows 7 on one hard drive and immediately afterwards installing Ubuntu on the other. Now the computer boots into Windows, but I can pop into the BIOS at startup to boot into Ubunbtu via it's bootloader, and I'm guessing it'll only take a bit of poking at the BIOS to swap the load order. Many thanks!

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  • Ubuntu 13.04 installation issues: unable to handle kernel paging request error

    - by user173944
    I wish I could say that I’ve done more for the Linux community as of recent but I am very VERY new to all of this and I feel very much in over my head. I figured I would install Ubuntu. on my computer and then I would learn and contribute to the community simultaneously. I will try to be as detailed as I can, please ask questions if you need clarification. I installed Ubuntu. 13.04 (64-bit) on my dell Inspiron 1501. This has an AMD Turion 64-bit TL-56 1.8 Ghz mobile processor. It is a dual core. It has an ATI Radeon Xpress 1150 chipset in it as well. As of right now I only have a total of 2Ghz ram, however I was planning on upgrading that in the near future so I opted for the 64-bit Ubuntu. 13.04. I first tried the live CD and everything seemed to be functioning correctly other than the wireless (but that's not the issue at hand, there are plenty of guides on the internet on how to get that functioning). The internet worked just fine when it was plugged in so no issues there. However, once I went from that to installing 13.04 (just 13.04, no dual partitioning... I want this computer to run strictly Ubuntu.) it did not work. It took me into a shell that I could not type anything into. In this shell it said Bug: unable to handle kernel paging and then it called a bunch of traces and froze up. I had to hard reset the laptop. I tried the boot-repair program multiple times with many different settings and typically after starting up the laptop would say something along the lines of recursive errors. will attempt to fix and then it would attempt to fix a couple of things, and then the computer would freeze up after the text said end trace... so I had to hard reset it again. I'm not an impatient person either, when I say it would freeze up it would be for a period of at least 15 minutes each time before I decided to hard reset. I attempted to install 12.10 on it instead and I got the same exact message, and when I ran boot-repair it did the same exact thing as before. I am currently in the process of running memtest64+ on the computer's memory, though I really don't believe that, nor any of the hardware is at fault due to the fact that it was still running windows vista perfectly when I had decided to switch over to Ubuntu. so far the memtest has came back just fine without any errors, but I’ve only been running it for approximately an hour. So this is the situation I’m in. I did notice when I was using the live disk that the video driver needed updated so I performed that, though I’m fairly certain that has nothing to do with this. I have also attempted (though I’m not certain that my attempt was successful in accomplishing what I had planned) to manually edit the grub settings by making acpi=0 along top of adding nomodeset to the boot commands. Like I said, I’m not sure I did that correctly though, but I’m fairly certain I did. If anyone needs any more information I will be more than happy to provide it, I will post back once I get the full results of the memtest. I very much appreciate any ideas anyone else has, I’ve been at this for a few days to no avail... thank you

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  • Slow Ubuntu 10.04 after long time unused

    - by Winston Ewert
    I'm at spring break so I'm back at my parent's house. I've turned my computer on which has been off since January and its unusably slow. This was not the case when I last used the computer in January. It is running 10.04, Memory: 875.5 MB CPU: AMD Athlon 64 X2 Dual Core Processor 4400+ Available Disk Space: 330.8 GB I'm not seeing a large usage of either memory or Disk I/O. If I look at my list of processes there is only a very small amount of CPU usage. However, if I hover over the CPU usage graph that I've on the top bar, I sometimes get really high readings like 100%. It took a long time to boot, to open firefox, to open a link in firefox. As far as I can tell everything that the computer tries to do is just massively slow. Right now, I'm apt-get dist-upgrading to install any updates that I will have missed since last time this computer was on. Any ideas as to what is going on here? UPDATE: I thought to check dmesg and it has a lot of entries like this: [ 1870.142201] ata3.00: exception Emask 0x0 SAct 0x7 SErr 0x0 action 0x0 [ 1870.142206] ata3.00: irq_stat 0x40000008 [ 1870.142210] ata3.00: failed command: READ FPDMA QUEUED [ 1870.142217] ata3.00: cmd 60/08:10:c0:4a:65/00:00:03:00:00/40 tag 2 ncq 4096 in [ 1870.142218] res 41/40:00:c5:4a:65/00:00:03:00:00/40 Emask 0x409 (media error) <F> [ 1870.142221] ata3.00: status: { DRDY ERR } [ 1870.142223] ata3.00: error: { UNC } [ 1870.143981] ata3.00: SB600 AHCI: limiting to 255 sectors per cmd [ 1870.146758] ata3.00: SB600 AHCI: limiting to 255 sectors per cmd [ 1870.146761] ata3.00: configured for UDMA/133 [ 1870.146777] ata3: EH complete [ 1872.092269] ata3.00: exception Emask 0x0 SAct 0x7 SErr 0x0 action 0x0 [ 1872.092274] ata3.00: irq_stat 0x40000008 [ 1872.092278] ata3.00: failed command: READ FPDMA QUEUED [ 1872.092285] ata3.00: cmd 60/08:00:c0:4a:65/00:00:03:00:00/40 tag 0 ncq 4096 in [ 1872.092287] res 41/40:00:c5:4a:65/00:00:03:00:00/40 Emask 0x409 (media error) <F> [ 1872.092289] ata3.00: status: { DRDY ERR } [ 1872.092292] ata3.00: error: { UNC } [ 1872.094050] ata3.00: SB600 AHCI: limiting to 255 sectors per cmd [ 1872.096795] ata3.00: SB600 AHCI: limiting to 255 sectors per cmd [ 1872.096798] ata3.00: configured for UDMA/133 [ 1872.096814] ata3: EH complete [ 1874.042279] ata3.00: exception Emask 0x0 SAct 0x7 SErr 0x0 action 0x0 [ 1874.042285] ata3.00: irq_stat 0x40000008 [ 1874.042289] ata3.00: failed command: READ FPDMA QUEUED [ 1874.042296] ata3.00: cmd 60/08:10:c0:4a:65/00:00:03:00:00/40 tag 2 ncq 4096 in [ 1874.042297] res 41/40:00:c5:4a:65/00:00:03:00:00/40 Emask 0x409 (media error) <F> [ 1874.042300] ata3.00: status: { DRDY ERR } [ 1874.042302] ata3.00: error: { UNC } [ 1874.044048] ata3.00: SB600 AHCI: limiting to 255 sectors per cmd [ 1874.046837] ata3.00: SB600 AHCI: limiting to 255 sectors per cmd [ 1874.046840] ata3.00: configured for UDMA/133 [ 1874.046861] sd 2:0:0:0: [sda] Unhandled sense code [ 1874.046863] sd 2:0:0:0: [sda] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [ 1874.046867] sd 2:0:0:0: [sda] Sense Key : Medium Error [current] [descriptor] [ 1874.046872] Descriptor sense data with sense descriptors (in hex): [ 1874.046874] 72 03 11 04 00 00 00 0c 00 0a 80 00 00 00 00 00 [ 1874.046883] 03 65 4a c5 [ 1874.046886] sd 2:0:0:0: [sda] Add. Sense: Unrecovered read error - auto reallocate failed [ 1874.046892] sd 2:0:0:0: [sda] CDB: Read(10): 28 00 03 65 4a c0 00 00 08 00 [ 1874.046900] end_request: I/O error, dev sda, sector 56969925 [ 1874.046920] ata3: EH complete I'm not certain, but that looks like my problem may be a failing hard drive. But the drive is less then a year old, it really shouldn't be failing now...

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  • Communication between state machines with hidden transitions

    - by slartibartfast
    The question emerged for me in embedded programming but I think it can be applied to quite a number of general networking situations e.g. when a communication partner fails. Assume we have an application logic (a program) running on a computer and a gadget connected to that computer via e.g. a serial interface like RS232. The gadget has a red/green/blue LED and a button which disables the LED. The LEDs color can be driven by software commands over the serial interface and the state (red/green/blue/off) is read back and causes a reaction in the application logic. Asynchronous behaviour of the application logic with regard to the LED color down to a certain delay (depending on the execution cycle of the application) is tolerated. What we essentially have is a resource (the LED) which can not be reserved and handled atomically by software because the (organic) user can at any time press the button to interfere/break the software attempt to switch the LED color. Stripping this example from its physical outfit I dare to say that we have two communicating state machines A (application logic) and G (gadget) where G executes state changes unbeknownst to A (and also the other way round, but this is not significant in our example) and only A can be modified at a reasonable price. A needs to see the reaction and state of G in one piece of information which may be (slightly) outdated but not inconsistent with respect to the short time window when this information was generated on the side of G. What I am looking for is a concise method to handle such a situation in embedded software (i.e. no layer/framework like CORBA etc. available). A programming technique which is able to map the complete behaviour of both participants on classical interfaces of a classical programming language (C in this case). To complicate matters (or rather, to generalize), a simple high frequency communication cycle of A to G and back (IOW: A is rapidly polling G) is out of focus because of technical restrictions (delay of serial com, A not always active, etc.). What I currently see as a general solution is: the application logic A as one thread of execution an adapter object (proxy) PG (presenting G inside the computer), together with the serial driver as another thread a communication object between the two (A and PG) which is transactionally safe to exchange The two execution contexts (threads) on the computer may be multi-core or just interrupt driven or tasks in an RTOS. The com object contains the following data: suspected state (written by A): effectively a member of the power set of states in G (in our case: red, green, blue, off, red_or_green, red_or_blue, red_or_off...etc.) command data (written by A): test_if_off, switch_to_red, switch_to_green, switch_to_blue operation status (written by PG): operation_pending, success, wrong_state, link_broken new state (written by PG): red, green, blue, off The idea of the com object is that A writes whichever (set of) state it thinks G is in, together with a command. (Example: suspected state="red_or_green", command: "switch_to_blue") Notice that the commands issued by A will not work if the user has switched off the LED and A needs to know this. PG will pick up such a com object and try to send the command to G, receive its answer (or a timeout) and set the operation status and new state accordingly. A will take back the oject once it is no longer at operation_pending and can react to the outcome. The com object could be separated of course (into two objects, one for each direction) but I think it is convenient in nearly all instances to have the command close to the result. I would like to have major flaws pointed out or hear an entirely different view on such a situation.

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  • Come up with a real-world problem in which only the best solution will do (a problem from Introduction to algorithms) [closed]

    - by Mike
    EDITED (I realized that the question certainly needs a context) The problem 1.1-5 in the book of Thomas Cormen et al Introduction to algorithms is: "Come up with a real-world problem in which only the best solution will do. Then come up with one in which a solution that is “approximately” the best is good enough." I'm interested in its first statement. And (from my understanding) it is asked to name a real-world problem where only the exact solution will work as opposed to a real-world problem where good-enough solution will be ok. So what is the difference between the exact and good enough solution. Consider some physics problem for example the simulation of the fulid flow in the permeable medium. To make this simulation happen some simplyfing assumptions have to be made when deriving a mathematical model. Otherwise the model becomes at least complex and unsolvable. Virtually any particle in the universe has its influence on the fluid flow. But not all particles are equal. Those that form the permeable medium are much more influental than the ones located light years away. Then when the mathematical model needs to be solved an exact solution can rarely be found unless the mathematical model is simple enough (wich probably means the model isn't close to reality). We take an approximate numerical method and after hours of coding and days of verification come up with the program or algorithm which is a solution. And if the model and an algorithm give results close to a real problem by some degree that is good enough soultion. Its worth noting the difference between exact solution algorithm and exact computation result. When considering real-world problems and real-world computation machines I believe all physical problems solutions where any calculations are taken can not be exact because universal physical constants are represented approximately in the computer. Any numbers are represented with the limited precision, at least limited by amount of memory available to computing machine. I can imagine plenty of problems where good-enough, good to some degree solution will work, like train scheduling, automated trading, satellite orbit calculation, health care expert systems. In that cases exact solutions can't be derived due to constraints on computation time, limitations in computer memory or due to the nature of problems. I googled this question and like what this guy suggests: there're kinds of mathematical problems that need exact solutions (little note here: because the question is taken from the book "Introduction to algorithms" the term "solution" means an algorithm or a program, which in this case gives exact answer on each input). But that's probably more of theoretical interest. So I would like to narrow down the question to: What are the real-world practical problems where only the best (exact) solution algorithm or program will do (but not the good-enough solution)? There are problems like breaking of cryptographic ciphers where only exact solution matters in practice and again in practice the process of deciphering without knowing a secret should take reasonable amount of time. Returning to the original question this is the problem where good-enough (fast-enough) solution will do there's no practical need in instant crack though it's desired. So the quality of "best" can be understood in any sense: exact, fastest, requiring least memory, having minimal possible network traffic etc. And still I want this question to be theoretical if possible. In a sense that there may be example of computer X that has limited resource R of amount Y where the best solution to problem P is the one that takes not more than available Y for inputs of size N*Y. But that's the problem of finding solution for P on computer X which is... well, good enough. My final thought that we live in a world where it is required from programming solutions to practical purposes to be good enough. In rare cases really very very good but still not the best ones. Isn't it? :) If it's not can you provide an example? Or can you name any such unsolved problem of practical interest?

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  • Desktop Notifications, aka Internal Alert System

    - by Refracted Paladin
    It has become apparent that where I work needs, internally, a "notification system". The issue being that we are very spread out throughout multiple buildings and the bulk of the work force regularly keeps there email closed for hours at a time. I need to create a simple way to be able to push out a message and have it "pop up" on everyones computer(or a single computer). My first thought was to write a windows service that calls a winform/wpf app that resides on each computer that simply pops up with the message. Not sure how viable an idea that is but this is just brain-storming. A different route, I thought, could be an app that resides in the systray on each computer that polls a db table and using the Query Notifications could pop up a message each time a new row is added. Then simply create an insanely basic app for writing a row to that table. So, what I am asking is if any one else has walked this path. If so, how? What things did you take into consideration? Are either of my ideas valid starting points or are "egg and my face in perfect alignment"? Is there a different way that is even simpler? Thanks

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  • running bash scripts in php

    - by HDawg
    I have two computers. On the first computer I have apache running with all my web code. On the second computer I have large amounts of data stored with a retrieval script (the script usually takes hours to run). I am essentially creating a web UI to access this data without any time delay. so I call: exec("bash initial.bash"); this is a driver script that is in my Apache folder. It calls the script on the other computer. calling: ssh otherMachine temp.bash& this script invokes the data retrieval script on the second computer. If I call initial.bash in the terminal, everything works smoothly and successfully, but if I call it in my PHP file, then all my commands in initial.bash run, with the exception of ssh otherMachine temp.bash&. I put the & at the end of that, so that temp.bash will run in the background, since it does take a few hours to complete. I am not sure why the nested script is not running when invoked by Apache. Is there a better alternative than using exec or shell_exec to call a script, which ultimately calls another script. The reason I don't call a script on the second machine directly is because of the time it takes the program to run. Shell_exec does not render the php page until the script is complete.

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  • can't properly shutdown ubuntu and sound problem on HP mini 311 netbook

    - by Viele
    hi, I recently bought a HP mini 311 netbook. I replaced its harddrive and installed ubuntu 10.04. Since then, I have encountered some very strange problem with its sound and shutdown/reboot. At times, when I start the computer, it will have no sound, on the GUI the sound is at max, but no sound is available. This sometimes also happen after after upgrades, hibernate, and toggling the wireless radio button. Strangely, when the sound is out the device will also refuse to be shutdown. If I shutdown the computer using the GUI, it will simply go back to the log in screen without actually shutting down. If I use "sudo shutdown 0", the computer will hang on the loading screen of the shut down process. I had to force the pc to shutdown by holding the power button down. usually (probably always) after I force a turn-off then start off again. the sound and shutdown become normal. I wonder if anyone have clues regarding to the cause of this problem. This the info about the computer: 1) installed ubuntu 10.04LTS RC, later upgraded to formal released version. 2) cat /proc/asound/version == "Advanced Linux Sound Architecture Driver Version 1.0.21." however, when doing 'alsaconf' the version displayed is 1.0.23 any help is appreciated. Thanks

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  • MacVim, Command-T: SEGV

    - by Ramon Tayag
    Details: OSX 10.7.4 I installed the latest MacVim via Homebrew: $ command-t brew install macvim ==> Downloading https://github.com/b4winckler/macvim/tarball/snapshot-64 Already downloaded: /Library/Caches/Homebrew/macvim-7.3-64.tgz ==> ./configure --with-features=huge --with-tlib=ncurses --enable-multibyte --with-macarchs=x86_64 --enable-perlinterp --enable-pythoninterp --enable-rubyinterp --enable-t ==> make getenvy ==> make ==> Caveats MacVim.app installed to: /usr/local/Cellar/macvim/7.3-64 To link the application to a normal Mac OS X location: brew linkapps or: ln -s /usr/local/Cellar/macvim/7.3-64/MacVim.app /Applications ==> Summary /usr/local/Cellar/macvim/7.3-64: 1733 files, 27M, built in 53 seconds $ command-t brew linkapps Linking /usr/local/Cellar/macvim/7.3-64/MacVim.app Finished linking. Find the links under ~/Applications. $ command-t ruby -v ruby 1.8.7 (2011-12-28 patchlevel 357) [universal-darwin11.0] $ command-t rvm list rvm rubies ree-1.8.7-2012.02 [ i686 ] ruby-1.8.7-p358 [ i686 ] ruby-1.9.2-p290 [ x86_64 ] ruby-1.9.2-p320 [ x86_64 ] ruby-1.9.3-p194 [ x86_64 ] # Default ruby not set. Try 'rvm alias create default <ruby>'. # => - current # =* - current && default # * - default $ command-t cd ~/.vim/bundle/vim-command-t/ruby/command-t ruby extconf.rb $ command-t ruby extconf.rb checking for ruby.h... yes creating Makefile $ command-t make cc -arch i386 -arch x86_64 -pipe -bundle -undefined dynamic_lookup -o ext.bundle ext.o match.o matcher.o -L. -L/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib -L. -arch i386 -arch x86_64 -lruby -lpthread -ldl -lobjc ld: warning: ignoring file ext.o, file was built for unsupported file format which is not the architecture being linked (i386) ld: warning: ignoring file match.o, file was built for unsupported file format which is not the architecture being linked (i386) ld: warning: ignoring file matcher.o, file was built for unsupported file format which is not the architecture being linked (i386) $ command-t mvim MacVim then opens here. But when I open Command-T, MacVim crashes and I see this in the command line: $ command-t dyld: lazy symbol binding failed: Symbol not found: _rb_intern2 Referenced from: /Users/ramon/.vim/bundle/vim-command-t/ruby/command-t/ext.bundle Expected in: flat namespace dyld: Symbol not found: _rb_intern2 Referenced from: /Users/ramon/.vim/bundle/vim-command-t/ruby/command-t/ext.bundle Expected in: flat namespace Vim: Caught deadly signal TRAP Vim: Finished. The problem I have is very similar to this, except that I switched to the system Ruby and still got the error.

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  • Dell R910 with Integrated PERC H700 Adapter

    - by Alex
    I am in the process of designing an architecture based around a single Dell R910 server running Windows Server 2008 Enterprise. I would like the server to have 8 RAID1 pairs of spinning disks, so I intend to implement: Dell R910 Server Integrated PERC H700 Adapter with 1 SAS expander on each SAS connector (so 8 expanders in total) 7 RAID1 pairs of 143Gb 15K HDD, each paired on one connector using an expander 1 RAID1 pair of 600Gb 10K HDD, paired on the remaining connector using an expander My main concern is not to introduce bottlenecks in this architecture, and I have the following questions. Will the PERC H700 Adapter act as a bottleneck for disk access? Will using SAS expanders for each RAID1 pair cause a bottleneck or would this be as fast as pairing disks directly attached to the SAS connectors? Can I mix the disks, as long as the disks in each RAID1 pair are the same? I assume so. Can anyone recommend any single-to-double SAS Expanders that are known to function well with the H700? Cheers Alex

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  • GoogleTest C++ Framework Incompatible With XCode 4.5.2 and OSX 10.8.2

    - by eb80
    I am trying to follow the instructions mentioned here for setting up Google's C++ framework in XCode Version 4.5.2 (4G2008a). First, I got "The run destination My Mac 64-bit is not valid for Running the scheme 'gtest-framework'". The answers here Xcode 4 - The selected run destination is not valid for this action are not working for me. I was able to change the build SDK following the instructions here Unable to build using Xcode 4 - The selected run destination is not valid for this action, except this resulted in many build failures such as "Unsupported compiler '4.0' selected for architecture 'x86_64'" and "Unsupported compiler '4.0' selected for architecture 'i386'" I've changed nothing out of the box, so this is very frustrating that I cannot seem to get this to build. Details of Machine: 64bit Mac OSX 10.8.2 Build 12C3006 Details of XCode: Version 4.5.2 (4G2008a)

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  • Is an Intel Atom D525 suitable to run MythTV

    - by Martin Thompson
    I have an oldish netbook with an Atom N450 (1.6GHz, 512KB cache) - I've been using it to experiment with MythTV, but it seems really slow, even just to work through the menus! Seconds, sometimes 10 or 20s, to load a new menu. Admittedly from a remote backend, but my older Core1 based laptop seems to be fine with the same setup. I was hoping to use one of the so-called "nettop" devices which currently seem to be D525-based (1.8GHz, 1MB cache) - is double the cache really going to make that much difference? Or has the internal architecture of the Atom moved on leaps and bounds in between? Given that I design non-Intel embedded computers for a living I was hoping to get lots of hardcore architecture detail from the Intel website, so I could see for myself, but I can't find it! So: will a D525 be fast enough to run a MythTV backend/frontend combined box?

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  • Pong: How does the paddle know where the ball will hit?

    - by Roflcoptr
    After implementing Pacman and Snake I'm implementing the next very very classic game: Pong. The implementation is really simple, but I just have one little problem remaining. When one of the paddle (I'm not sure if it is called paddle) is controlled by the computer, I have trouble to position it at the correct position. The ball has a current position, a speed (which for now is constant) and a direction angle. So I could calculate the position where it will hit the side of the computer controlled paddle. And so Icould position the paddle right there. But however in the real game, there is a probability that the computer's paddle will miss the ball. How can I implement this probability? If I only use a probability of lets say 0.5 that the computer's paddle will hit the ball, the problem is solved, but I think it isn't that simple. From the original game I think the probability depends on the distance between the current paddle position and the position the ball will hit the border. Does anybody have any hints how exactly this is calculated?

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  • Can I set up a 2nd home wireless router, with router2 connecting to the internet through a desktop which is wirelessly connected to router1?

    - by gil b.
    Hi, I apologize for the crudeness of my MSPaint drawing, but please view my diagram of what I'd like to accomplish: Proposed home network architecture Currently, all devices are connected to 1 wireless router. I would like to make my own subnet, with a box in-between my subnet and the shared wireless router, so that I can learn about IDS, traffic analysis, etc. I was also given a cisco PIX firewall to play around with, and it'd be an added bonus if I could incorporate that into my network. The reason for this proposed architecture is so that I can monitor all MY traffic, without seeing anything going on with my roommates' traffic. my MAIN Question is, is it possible to have my desktop connect to the wireless router with internet via wireless card AND share that connection via the ethernet card, hooked to wireless router 2? cable modem - wireless router - desktop pc connected wirelessly - wireless router 2 getting internet from wired connection to desktop pc - laptops connected wirelessly The PIX can be left out for now, but I'm wondering if it could eventually be incorporated? THANKS!

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  • What is the correct term for the number of bits used by an operating system

    - by benc
    Recently, some discussions came up about 32 bit vs. 64 bit implementations of operating systems. While I was composing a message about this topic, I realized that I did not know if there was a correct term for the number of bits supported by an operating system. For example, various versions of Solaris and Linux have 32bit and 64bit releases. Is the distinction "architecture"? In my experience, that has referred to chip types (Intel vs. PPC). Is it a "release"? Typically, I think of a release as a version number a consistent feature set, that might run on different architectures. Maybe it is just "architecture", after all, even though a chip family might have used several different bit sizes over time, the chips themselves are different when you jump from 32bit to 64bit.

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  • Can I set up a 2nd home wireless router, with router2 connecting to the internet through a desktop which is wirelessly connected to router1?

    - by gil b.
    Hi, I apologize for the crudeness of my MSPaint drawing, but please view my diagram of what I'd like to accomplish: Proposed home network architecture Currently, all devices are connected to 1 wireless router. I would like to make my own subnet, with a box in-between my subnet and the shared wireless router, so that I can learn about IDS, traffic analysis, etc. I was also given a cisco PIX firewall to play around with, and it'd be an added bonus if I could incorporate that into my network. The reason for this proposed architecture is so that I can monitor all MY traffic, without seeing anything going on with my roommates' traffic. my MAIN Question is, is it possible to have my desktop connect to the wireless router with internet via wireless card AND share that connection via the ethernet card, hooked to wireless router 2? cable modem - wireless router - desktop pc connected wirelessly - wireless router 2 getting internet from wired connection to desktop pc - laptops connected wirelessly The PIX can be left out for now, but I'm wondering if it could eventually be incorporated? THANKS!

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  • ASP.NET MVC multi-instance session management on amazon ec2

    - by gandil
    I have a web application written in asp.net mvc2. Currently hosted on amazon cloud ec2. Because of growing traffic we want move multi instance enviorenment. I have a custom session class which currently initiate at session start (global asax) and i am using via getter or setter class in application. Because of multi instance chore i have to handle hole security architecture. I am looking a better way to handle this problem. I am looking for good implementation of session and how to apply on amazon ec2 multi instance environment. What is road blocks for system architecture?

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  • Differences between Assembly Code output of the same program

    - by ultrajohn
    I have been trying to replicate the buffer overflow example3 from this article aleph one I'm doing this as a practice for a project in a computer security course i'm taking so please, I badly need your help. I've been the following the example, performing the tasks as I go along. My problem is the assembly code dumped by gdb in my computer (i'm doing this on a debian linux image running on VM Ware) is different from that of the example in the article. There are some constructs which I find confusing. Here is the one from my computer: here is the one from the article... Dump of assembler code for function main: 0x8000490 <main>: pushl %ebp 0x8000491 <main+1>: movl %esp,%ebp 0x8000493 <main+3>: subl $0x4,%esp 0x8000496 <main+6>: movl $0x0,0xfffffffc(%ebp) 0x800049d <main+13>: pushl $0x3 0x800049f <main+15>: pushl $0x2 0x80004a1 <main+17>: pushl $0x1 0x80004a3 <main+19>: call 0x8000470 <function> 0x80004a8 <main+24>: addl $0xc,%esp 0x80004ab <main+27>: movl $0x1,0xfffffffc(%ebp) 0x80004b2 <main+34>: movl 0xfffffffc(%ebp),%eax 0x80004b5 <main+37>: pushl %eax 0x80004b6 <main+38>: pushl $0x80004f8 0x80004bb <main+43>: call 0x8000378 <printf> 0x80004c0 <main+48>: addl $0x8,%esp 0x80004c3 <main+51>: movl %ebp,%esp 0x80004c5 <main+53>: popl %ebp 0x80004c6 <main+54>: ret 0x80004c7 <main+55>: nop As you can see, there are differences between the two. I'm confuse and I can't understand totally the assembly code from my computer. I would like to know the differences between the two. How is pushl different from push, mov vs movl , and so on... what does the expression 0xhexavalue(%register) means? I am sorry If I'm asking a lot, But I badly need your help. Thanks for the help really...

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  • SharePoint 2010 and Excel Calculation Services

    - by Cj Anderson
    I'm curious what the requirements are for Excel Calculation Services in Sharepoint 2010. I found an architecture document but it doesn't list out the specific requirements. (architecture I understand that you can install all the services on one server but it isn't recommended. It then talks about how you can scale up the application servers, and web front ends. What should the hardware look like for both the application server and web front ends? Do I need to setup a standalone box for each application server?

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  • why Apache with ssl but back end weblogic without ssl works?

    - by huangli
        Hello everyone. my question is very simple . The link below is a picture about my architecture. https://docs.google.com/open?id=0BxSXbpgYIZVOR212RVk4ZDN1Sm8.      The pic above shows the architecture right now and it works correctly ! which means I could visit apache with url https//apchehost:8080, could not visit the web app with https served by weblogic but I could visit these app with https served by Apache(Apache is proxy server).      My question is why the Apache is configured with ssl but weblogic without ssl works ? I think weblogic should also configured with ssl . If this works , what about security level ? Is the ssl really works if only Apache configured with ssl but Weblogic without it ? Thanks . condition: Apache 2.2.17 with weblogic module mod_wl_22.so Weblogic: 10.3 OS: Windows server 2003

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  • How to compile gcc-4.0 on Mountain Lion

    - by Frizlab
    So far I've successfully launched the configure, but when I type make, I get the following error, after some time (there's a lot which compile successfully): ld: unknown/unsupported architecture name for: -arch i686 /usr/bin/libtool: internal link edit command failed make[2]: *** [libgcc_s.dylib] Error 1 make[1]: *** [libgcc.a] Error 2 make: *** [all-gcc] Error 2 Is there a way to tell gcc not to compile itself for the i686 architecture? Here's my uname -a if it can help: Darwin Frizlabs-Computer.local 12.2.0 Darwin Kernel Version 12.2.0: Sat Aug 25 00:48:52 PDT 2012; root:xnu-2050.18.24~1/RELEASE_X86_64 x86_64 PS: I know gcc-4.0 is ancient, but I do need it.

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