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  • Easy Install Resets Hardware Settings

    - by bob5972
    I think there's a problem with the Easy Install setup. I selected "Installer disc image," and it came up and said that it would use "Easy Install," I think I hit next, and then I went back changed my mind, and selected "I will install the operating system later." After finishing the wizard, I think it still went and ran Easy Install, because it auto-installed VMware tools and I never got to select anything for my windows setup. Then, when it was finished, all the hardware changes I had made were lost. The RAM was changed from 2 GB back to the default of 1 GB, my CD ROM drive was set back to "Use a Physical Drive" and "Connect at Power On", and the Floppy Drive was also set to "Connect at Power On", after I disabled them. I was trying to install Windows 7, and I wasn't sure if I could change the RAM settings after installation without needing to reactivate it, so I deleted the VM and tried to start over. This time, the "Installer disc image" had my Win7 image pre-selected, so I clicked "I will install it myself later," set my hardware again, and tried to boot off my CD. Again,it did an Easy Install, and reset my RAM and my drive settings. So I deleted it again and the third time it still had the Win7 image pre-selected, but this time I unplugged all the drives and let it try to boot off the empty harddrive and fail, and made sure it kept all my hardware settings. Then, I powered it off, put my Win7 image in the guest CD ROM, and powered it on. This time it finally let me run the installer and pick my language, and type a user name. This time when I powered it off it kept my hardware settings. I can duplicate the error by doing exactly the steps above. Creating a new VM, selecting my "Installer Image," hitting next, going back, selecting "I will Install it myself," and then finish the wizard, and customizing my hardware right before the end, setting the CD Rom drive to the same installer media, and setting "Connect on Power On." (If I start it without the CD ROM in the first time, it doesn't do it). When I power on, I'm not prompted for any install information (like language and user name), and when it runs the first timemy hardware choices are reset (like the RAM back to 1 GB). If it helps, I'm running VMware Workstation 7.0.1 build-227600 on Gentoo Linux

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  • 12.04.1 Error After Upgrade

    - by rambo15
    Just update my dell Inspiron to 12.04.1. Upon reboot I get the following error: The disk drive for / is not ready yet or not present. I press "S" to skip mount and then I get the folllowing error: the disk drive for /tmp is not ready yet or not present. I have already tried the following from the maintanance shell prompt: dpkg --configure -a No luck same error. Any help would be greatly appreciated.

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  • HTG Explains: Why Does Rebooting a Computer Fix So Many Problems?

    - by Chris Hoffman
    Ask a geek how to fix a problem you’ve having with your Windows computer and they’ll likely ask “Have you tried rebooting it?” This seems like a flippant response, but rebooting a computer can actually solve many problems. So what’s going on here? Why does resetting a device or restarting a program fix so many problems? And why don’t geeks try to identify and fix problems rather than use the blunt hammer of “reset it”? This Isn’t Just About Windows Bear in mind that this soltion isn’t just limited to Windows computers, but applies to all types of computing devices. You’ll find the advice “try resetting it” applied to wireless routers, iPads, Android phones, and more. This same advice even applies to software — is Firefox acting slow and consuming a lot of memory? Try closing it and reopening it! Some Problems Require a Restart To illustrate why rebooting can fix so many problems, let’s take a look at the ultimate software problem a Windows computer can face: Windows halts, showing a blue screen of death. The blue screen was caused by a low-level error, likely a problem with a hardware driver or a hardware malfunction. Windows reaches a state where it doesn’t know how to recover, so it halts, shows a blue-screen of death, gathers information about the problem, and automatically restarts the computer for you . This restart fixes the blue screen of death. Windows has gotten better at dealing with errors — for example, if your graphics driver crashes, Windows XP would have frozen. In Windows Vista and newer versions of Windows, the Windows desktop will lose its fancy graphical effects for a few moments before regaining them. Behind the scenes, Windows is restarting the malfunctioning graphics driver. But why doesn’t Windows simply fix the problem rather than restarting the driver or the computer itself?  Well, because it can’t — the code has encountered a problem and stopped working completely, so there’s no way for it to continue. By restarting, the code can start from square one and hopefully it won’t encounter the same problem again. Examples of Restarting Fixing Problems While certain problems require a complete restart because the operating system or a hardware driver has stopped working, not every problem does. Some problems may be fixable without a restart, though a restart may be the easiest option. Windows is Slow: Let’s say Windows is running very slowly. It’s possible that a misbehaving program is using 99% CPU and draining the computer’s resources. A geek could head to the task manager and look around, hoping to locate the misbehaving process an end it. If an average user encountered this same problem, they could simply reboot their computer to fix it rather than dig through their running processes. Firefox or Another Program is Using Too Much Memory: In the past, Firefox has been the poster child for memory leaks on average PCs. Over time, Firefox would often consume more and more memory, getting larger and larger and slowing down. Closing Firefox will cause it to relinquish all of its memory. When it starts again, it will start from a clean state without any leaked memory. This doesn’t just apply to Firefox, but applies to any software with memory leaks. Internet or Wi-Fi Network Problems: If you have a problem with your Wi-Fi or Internet connection, the software on your router or modem may have encountered a problem. Resetting the router — just by unplugging it from its power socket and then plugging it back in — is a common solution for connection problems. In all cases, a restart wipes away the current state of the software . Any code that’s stuck in a misbehaving state will be swept away, too. When you restart, the computer or device will bring the system up from scratch, restarting all the software from square one so it will work just as well as it was working before. “Soft Resets” vs. “Hard Resets” In the mobile device world, there are two types of “resets” you can perform. A “soft reset” is simply restarting a device normally — turning it off and then on again. A “hard reset” is resetting its software state back to its factory default state. When you think about it, both types of resets fix problems for a similar reason. For example, let’s say your Windows computer refuses to boot or becomes completely infected with malware. Simply restarting the computer won’t fix the problem, as the problem is with the files on the computer’s hard drive — it has corrupted files or malware that loads at startup on its hard drive. However, reinstalling Windows (performing a “Refresh or Reset your PC” operation in Windows 8 terms) will wipe away everything on the computer’s hard drive, restoring it to its formerly clean state. This is simpler than looking through the computer’s hard drive, trying to identify the exact reason for the problems or trying to ensure you’ve obliterated every last trace of malware. It’s much faster to simply start over from a known-good, clean state instead of trying to locate every possible problem and fix it. Ultimately, the answer is that “resetting a computer wipes away the current state of the software, including any problems that have developed, and allows it to start over from square one.” It’s easier and faster to start from a clean state than identify and fix any problems that may be occurring — in fact, in some cases, it may be impossible to fix problems without beginning from that clean state. Image Credit: Arria Belli on Flickr, DeclanTM on Flickr     

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  • disk space error, cant use internet

    - by James
    after trying to install drivers using sudo apt-get update && sudo apt-get upgrade, im faced with a message saying no space left on device, i ran disk usage analyzer as root and there was three folders namely, main volume, home folder, and my 116gb hard drive (which is practically empty) yet both other folders are full, which is stopping me installing drivers because of space, how do i get ubuntu to use this space on my hard drive? its causing problems because i cant gain access to the internet as i cant download drivers when i havnt got enough space, this happens every time i try it

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  • How do I determine problems with bootup based on this bootchart?

    - by Tchalvak
    So I've been having issues with lots of hard-drive usage during bootup and long bootup lately, and I installed bootchart to get these two bootcharts, but damn are there a lot of unfamiliar system stuff on there, it's hard to tell what is a warning sign, and what is simply normal during boot. Here is a bootchart with the advantage of a previously packed/?cached? boot: http://imgur.com/ScTAU Here is the same bootchart without the advantage of a packed boot: http://imgur.com/9jocF Can anyone make suggestions on what this is telling me needs fixing?

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  • The Best How-To Geek Articles for October 2012

    - by Asian Angel
    This past month we covered topics such as how to troubleshoot internet connection problems, whether or not dust can actually damage your computer, 7 ways to free up hard disk space on Windows, and more. Join us as we look back at the best articles for October. 6 Start Menu Replacements for Windows 8 What Is the Purpose of the “Do Not Cover This Hole” Hole on Hard Drives? How To Log Into The Desktop, Add a Start Menu, and Disable Hot Corners in Windows 8

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  • How to setup stunnel so that gmail can use my own smtp server to send messages.

    - by igorhvr
    I am trying to setup gmail to send messages using my own smtp server. I am doing this by using stunnel over a non-ssl enabled server. I am able to use my own smtp client with ssl enabled just fine to my server. Unfortunately, however, gmail seems to be unable to connect to my stunnel port. Gmail seems to be simply closing the connection right after it is established - I get a "SSL socket closed on SSL_read" on my server logs. On gmail, I get a "We are having trouble authenticating with your other mail service. Please try changing your SSL settings. If you continue to experience difficulties, please contact your other email provider for further instructions." message. Any help / tips on figuring this out will be appreciated. My certificate is self-signed - could this perhaps be related to the problem I am experiencing? I pasted the entire SSL session (logs from my server) below. 2011.01.02 16:56:20 LOG7[20897:3082491584]: Service ssmtp accepted FD=0 from 209.85.210.171:46858 2011.01.02 16:56:20 LOG7[20897:3082267504]: Service ssmtp started 2011.01.02 16:56:20 LOG7[20897:3082267504]: FD=0 in non-blocking mode 2011.01.02 16:56:20 LOG7[20897:3082267504]: Option TCP_NODELAY set on local socket 2011.01.02 16:56:20 LOG7[20897:3082267504]: Waiting for a libwrap process 2011.01.02 16:56:20 LOG7[20897:3082267504]: Acquired libwrap process #0 2011.01.02 16:56:20 LOG7[20897:3082267504]: Releasing libwrap process #0 2011.01.02 16:56:20 LOG7[20897:3082267504]: Released libwrap process #0 2011.01.02 16:56:20 LOG7[20897:3082267504]: Service ssmtp permitted by libwrap from 209.85.210.171:46858 2011.01.02 16:56:20 LOG5[20897:3082267504]: Service ssmtp accepted connection from 209.85.210.171:46858 2011.01.02 16:56:20 LOG7[20897:3082267504]: FD=1 in non-blocking mode 2011.01.02 16:56:20 LOG6[20897:3082267504]: connect_blocking: connecting 127.0.0.1:25 2011.01.02 16:56:20 LOG7[20897:3082267504]: connect_blocking: s_poll_wait 127.0.0.1:25: waiting 10 seconds 2011.01.02 16:56:20 LOG5[20897:3082267504]: connect_blocking: connected 127.0.0.1:25 2011.01.02 16:56:20 LOG5[20897:3082267504]: Service ssmtp connected remote server from 127.0.0.1:3701 2011.01.02 16:56:20 LOG7[20897:3082267504]: Remote FD=1 initialized 2011.01.02 16:56:20 LOG7[20897:3082267504]: Option TCP_NODELAY set on remote socket 2011.01.02 16:56:20 LOG5[20897:3082267504]: Negotiations for smtp (server side) started 2011.01.02 16:56:20 LOG7[20897:3082267504]: RFC 2487 not detected 2011.01.02 16:56:20 LOG5[20897:3082267504]: Protocol negotiations succeeded 2011.01.02 16:56:20 LOG7[20897:3082267504]: SSL state (accept): before/accept initialization 2011.01.02 16:56:20 LOG7[20897:3082267504]: SSL state (accept): SSLv3 read client hello A 2011.01.02 16:56:20 LOG7[20897:3082267504]: SSL state (accept): SSLv3 write server hello A 2011.01.02 16:56:20 LOG7[20897:3082267504]: SSL state (accept): SSLv3 write certificate A 2011.01.02 16:56:20 LOG7[20897:3082267504]: SSL state (accept): SSLv3 write certificate request A 2011.01.02 16:56:20 LOG7[20897:3082267504]: SSL state (accept): SSLv3 flush data 2011.01.02 16:56:20 LOG5[20897:3082267504]: CRL: verification passed 2011.01.02 16:56:20 LOG5[20897:3082267504]: VERIFY OK: depth=2, /C=US/O=Equifax/OU=Equifax Secure Certificate Authority 2011.01.02 16:56:20 LOG5[20897:3082267504]: CRL: verification passed 2011.01.02 16:56:20 LOG5[20897:3082267504]: VERIFY OK: depth=1, /C=US/O=Google Inc/CN=Google Internet Authority 2011.01.02 16:56:20 LOG5[20897:3082267504]: CRL: verification passed 2011.01.02 16:56:20 LOG5[20897:3082267504]: VERIFY OK: depth=0, /C=US/ST=California/L=Mountain View/O=Google Inc/CN=smtp.gmail.com 2011.01.02 16:56:20 LOG7[20897:3082267504]: SSL state (accept): SSLv3 read client certificate A 2011.01.02 16:56:20 LOG7[20897:3082267504]: SSL state (accept): SSLv3 read client key exchange A 2011.01.02 16:56:20 LOG7[20897:3082267504]: SSL state (accept): SSLv3 read certificate verify A 2011.01.02 16:56:20 LOG7[20897:3082267504]: SSL state (accept): SSLv3 read finished A 2011.01.02 16:56:20 LOG7[20897:3082267504]: SSL state (accept): SSLv3 write change cipher spec A 2011.01.02 16:56:20 LOG7[20897:3082267504]: SSL state (accept): SSLv3 write finished A 2011.01.02 16:56:20 LOG7[20897:3082267504]: SSL state (accept): SSLv3 flush data 2011.01.02 16:56:20 LOG7[20897:3082267504]: 1 items in the session cache 2011.01.02 16:56:20 LOG7[20897:3082267504]: 0 client connects (SSL_connect()) 2011.01.02 16:56:20 LOG7[20897:3082267504]: 0 client connects that finished 2011.01.02 16:56:20 LOG7[20897:3082267504]: 0 client renegotiations requested 2011.01.02 16:56:20 LOG7[20897:3082267504]: 1 server connects (SSL_accept()) 2011.01.02 16:56:20 LOG7[20897:3082267504]: 1 server connects that finished 2011.01.02 16:56:20 LOG7[20897:3082267504]: 0 server renegotiations requested 2011.01.02 16:56:20 LOG7[20897:3082267504]: 0 session cache hits 2011.01.02 16:56:20 LOG7[20897:3082267504]: 0 external session cache hits 2011.01.02 16:56:20 LOG7[20897:3082267504]: 0 session cache misses 2011.01.02 16:56:20 LOG7[20897:3082267504]: 0 session cache timeouts 2011.01.02 16:56:20 LOG6[20897:3082267504]: SSL accepted: new session negotiated 2011.01.02 16:56:20 LOG6[20897:3082267504]: Negotiated ciphers: RC4-MD5 SSLv3 Kx=RSA Au=RSA Enc=RC4(128) Mac=MD5 2011.01.02 16:56:20 LOG7[20897:3082267504]: SSL socket closed on SSL_read 2011.01.02 16:56:20 LOG7[20897:3082267504]: Socket write shutdown 2011.01.02 16:56:20 LOG5[20897:3082267504]: Connection closed: 167 bytes sent to SSL, 37 bytes sent to socket 2011.01.02 16:56:20 LOG7[20897:3082267504]: Service ssmtp finished (0 left)

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  • Order of partitions for root, home and swap with respect to Windows partitions

    - by Tim
    I am installing Ubuntu on the same hard drive as Windows 7. The partitions of Windows 7 have already occupied the left part of the hard drive. I was wondering how to arrange the order of partitions of root, home and swap, i.e. which is on the left just besides one Windows partition, which is in the middle and which is on the far right? Is there some consideration regarding about this arrangement? Thanks and regards!

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  • Wireless is disabled by hardware switch on Dell Inspiron 1750

    - by lowerkey
    I have a problem where Ubuntu (12.04) says there is a wireless network card, but it is disabled by a hardware switch. How do I turn it on? I checked the BIOS, and the wireless card is enabled there. Fn + F2 was also no success. The results of rfkill list: 0: brcmwl-0: Wireless LAN Soft blocked: no Hard blocked: yes 1: dell-wifi: Wireless LAN Soft blocked: yes Hard blocked: yes sudo rfkill unblock wifi did nothing to the Wireless Status.

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  • How can Nautilus autodiscover a NAS?

    - by Private
    I have two machines: a 12.10 which autodiscovers my NAS fine and a 13.04 which does not autodiscover the NAS in Nautilus. The latter does not display the drive in Nautilus. I did install samba on the 13.04, I think a while ago, but I cannot remember what I did. Before I connected to the drive using afp, now I notice the 12.10 uses smb. How can I make my 13.04 autodiscover the NAS and how should I configure it?

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  • Are there "portable" versions of Opera for Linux/Ubuntu?

    - by cipricus
    I want to use the latest Opera browser, but v12 does not have opera-unite anymore. So, I would like to use a "portable" v11 Opera (v11 has unite). (By portable I mean a program with all files within a certain directory that can be put in any place on the hard drive or on an external drive, a program that can be started by running an executable file from the same directory, and which can be run separately of other installed versions of the same program.)

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  • Graphical disk surface check tool?

    - by sbergeron
    I need a program that can scan my hard drive for read and write errors so I can partition around them. I REALLY don't do well with numbers but if I can have something that shows an output like the graphical display on gparted that would be perfect. I know a lot of people would recommend replacing the disk but right now I can't as I NEED this laptop for school and can't wait for a hard drive to arrive (I have ordered one, yes, but I don't expect it to arrive for another couple weeks as I only figured out afterwards they still have to manufacture it)

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  • Suggestions for splitting server roles amongst Hyper-V virtual servers / RAID6 or RAID10? / AppAssure

    - by Anon
    We have 2 Hyper-V hosts at present running 1 virtual server that was converted from a physical box running all roles. My plan is to split the roles over various virtual machines, upgrading to the latest software versions as I go, and use the backup server as a standby in case the main server fails. AppAssure backup software has a feature called Virtual Standby, so the VHD's can be ready to be fired up on the backup server if necessary. Off-site backups will be done via external USB drive for now. I'm just seeking some input/suggestions into how I'm planning to split the roles out amongst various virtual servers. Also, I'm curious how to setup the storage on the servers. We do not have any NAS's, SAN'S or any budget for this. What would the best RAID level be to use? I'm thinking either RAID6 (which is currently used) however I'm concerned about the write speeds, or RAID10 but again I'm worried that I can only lose 1 drive (from the same mirror) as opposed to any 2 with RAID6. I realise I have a hot swap for this, but what if a further drive fails during a rebuild? Is the write penalty of RAID6 worth the extra reliability over RAID10? Or will it be too slow with all the roles I am planning, therefore RAID10 is my only real option? The reason for the needed redundancy is I am the only technician and I'm not always on-site. Options I've considered: 1) 5 drives in RAID6 set, 200gb for host OS, rest for VM storage. 1 drive for hot swap - this is how it is currently setup 2) 4 drives in RAID10 set, 200gb for host OS, rest for VM storage. 2 drives for hot swap 3) 4 drives in RAID10 set for VM storage, 2 drives in RAID1 set for host OS. No drives for hot swap - While this is probably the best option with the amount of drives I have, I don't like the idea of having no hot swap 4) 3 drives in RAID6 set for VM storage, 2 drives in RAID1 set for host OS. 1 drive for hot swap All options give us enough storage capacity for our files, etc. We don't have any budget for extra drives or extra hot swap HD chassis for the servers. We have about 70 clients and about 150 users. MAIN SERVER Intel Xeon 5520 @ 2.27 GHz (2 processors) 16GB RAM 6 x 1TB Seagate Barracuda ES.2 Enterprise SATA drives Intel SRCSATAWB RAID controller Virtual machine workload using Hyper-V on Windows Server 2008 R2: DC01 - Active Directory Domain Controller / DNS server / Global catalog - 1GB RAM DC02 - Active Directory Domain Controller / DNS server / Global catalog - 1GB RAM Member Server - DHCP server, File server, Print server - 1GB RAM SCCM Member Server - 4GB RAM Third Party Software Member Server - A/V server, Ticketing software, etc - 4GB RAM Exchange 2007 - 4GB RAM - however we are probably migrating to a hosted solution, therefore freeing up resources BACKUP SERVER Intel Xeon E5410 @ 2.33GHz (2 processors) 16GB RAM 6 x 2TB WD RE4 SATA drives Intel SRCSASRB RAID controller Virtual machine workload using Hyper-V on Windows Server 2008 R2: AppAssure backup software - 8GB RAM

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  • GRUB problem after uninstalling mint

    - by Yehonatan Tsirolnik
    I've uninstalled Linux Mint 13 today from my netbook. The netbook was running Windows XP and Linux Mint on dual boot. I've deleted the Linux's partition and now whenever I turn on the computer I get "Partitation not found" grub error... I have no CD drive so I can't insert any repair CDs or XP CD. I'm currently hopeless. And now I can't even load Linux Mint from my USB drive... Can someone help me?

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  • Would this be a good web application architecture?

    - by Gustav Bertram
    My problem Our MVC based framework does not allow us to cache only part of our output. Ideally we want to cahce static and semi-static bits, and run dynamic bits. In addition, we need to consider data caching that reacts to database changes. My idea The concept I came up with was to represent a page as a tree of XML fragment objects. (I say XML, but I mean XHTML). Some of the fragments are dynamic, and can pull their data directly from models or other sources, but most of the fragments are static scaffolding. If a subtree of fragments is completely static, then I imagine that they could unfold into pure XML that would then be cached as the text representation of their parent element. This process would ideally continue until we are left with a root element that contains all of the static XML, and has a couple of dynamic XML fragments that are resolved and attached to the relevant nodes of the XML tree just before the page is displayed. In addition to separating content into dynamic and static fragments, some fragments could be dynamic and cached. A simple expiry time which propagates up through the XML fragment tree would indicate that a specific fragment should periodically be refreshed. A newspaper section or front page does not need to be updated each second. Minutes or sometimes even longer is sufficient. Other fragments would be dynamic and uncached. Typically too many articles are viewed for them to be cached - the cache would overflow. Some individual articles may be cached if they are extremely popular. Functional notes The folding mechanism could be to be smart enough to judge when it would be more profitable to fold a dynamic cached fragment and propagate the expiry date to the parent fragment, or to keep it separate and simple attach to the XML tree when resolving the page. If some dynamic cached fragments are associated to database objects through mechanisms like a globally unique content id, then changes to the database could trigger changes to the output cache. If fragments store the identifiers of parent fragments, then they could trigger a refolding process that would then include the updated data. A set of pure XML with an ordered array of fragment objects (that each store the identifying information of the node to which they should be attached), can be resolved in a fairly simple way by walking the XML tree, and merging the data from the fragments. Because it is not necessary to parse and construct the entire tree in memory before attaching nodes, processing should be fairly fast. The identifiers of each fragment would be a combination of relevant identity data and the type of fragment object. Cached parent fragments would contain references to these identifiers, in order to then either pull them from the fragment cache, or to run their code. The controller's responsibility is reduced to making changes to the database, and telling the root XML fragment object to render itself. The Question My question has two parts: Is this a good design? Are there any obvious flaws I'm missing? Has somebody else thought of this before? References? Is there an existing alternative that I should consider? A cool templating engine maybe?

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  • Tips For Finding a Professional SEO Consultant

    There are some basic tips to finding a professional SEO consultant to drive traffic to your website, and implementing those tips means you're less likely to suffer financially. Whether you have an established online business, blog, or website you need to make sure you consider search engine optimization to drive a continual stream of new, targeted traffic to your site while getting the best possible results in the search engine results pages.

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  • Can't Boot Into Windows After Ubuntu Install

    - by user203808
    I recently installed ubuntu and I have two hard drives installed on my computer I have ubuntu on one and windows on the other after I finished installing ubuntu I go to boot into windows and I get an error no such partition. So I thought that I had erased windows but I didn't as the hard drive with Windows still shows up under ubuntu. Then I tried to fix the MBR but it shows up as windows not being installed but I can access all the files in ubuntu what the heck is going on?

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  • Using WKA in Large Coherence Clusters (Disabling Multicast)

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

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  • Windows Media Player Vulnerability, PCAnywhere Warning

    Windows Media Player Vulnerability Targeted by Drive-by-download Attack Security firm Trend Micro recently released details on malware that has been targeting the MIDI Remote Code Execution Vulnerability found in Microsoft's Windows Media Player. A post on Trend Micro's Malware Blog offered further insight into the malware that has been exploiting the CVE-2012-0003 vulnerability. The malware's authors have been successful in exploiting the vulnerability by tricking unsuspecting victims into opening a specially engineered MIDI file in Windows Media Player. This Web-based drive-by-download ...

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