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• 8 Backup Tools Explained for Windows 7 and 8

  - by Chris Hoffman

  Backups on Windows can be confusing. Whether you’re using Windows 7 or 8, you have quite a few integrated backup tools to think about. Windows 8 made quite a few changes, too. You can also use third-party backup software, whether you want to back up to an external drive or back up your files to online storage. We won’t cover third-party tools here — just the ones built into Windows. Backup and Restore on Windows 7 Windows 7 has its own Backup and Restore feature that lets you create backups manually or on a schedule. You’ll find it under Backup and Restore in the Control Panel. The original version of Windows 8 still contained this tool, and named it Windows 7 File Recovery. This allowed former Windows 7 users to restore files from those old Windows 7 backups or keep using the familiar backup tool for a little while. Windows 7 File Recovery was removed in Windows 8.1. System Restore System Restore on both Windows 7 and 8 functions as a sort of automatic system backup feature. It creates backup copies of important system and program files on a schedule or when you perform certain tasks, such as installing a hardware driver. If system files become corrupted or your computer’s software becomes unstable, you can use System Restore to restore your system and program files from a System Restore point. This isn’t a way to back up your personal files. It’s more of a troubleshooting feature that uses backups to restore your system to its previous working state. Previous Versions on Windows 7 Windows 7′s Previous Versions feature allows you to restore older versions of files — or deleted files. These files can come from backups created with Windows 7′s Backup and Restore feature, but they can also come from System Restore points. When Windows 7 creates a System Restore point, it will sometimes contain your personal files. Previous Versions allows you to extract these personal files from restore points. This only applies to Windows 7. On Windows 8, System Restore won’t create backup copies of your personal files. The Previous Versions feature was removed on Windows 8. File History Windows 8 replaced Windows 7′s backup tools with File History, although this feature isn’t enabled by default. File History is designed to be a simple, easy way to create backups of your data files on an external drive or network location. File History replaces both Windows 7′s Backup and Previous Versions features. Windows System Restore won’t create copies of personal files on Windows 8. This means you can’t actually recover older versions of files until you enable File History yourself — it isn’t enabled by default. System Image Backups Windows also allows you to create system image backups. These are backup images of your entire operating system, including your system files, installed programs, and personal files. This feature was included in both Windows 7 and Windows 8, but it was hidden in the preview versions of Windows 8.1. After many user complaints, it was restored and is still available in the final version of Windows 8.1 — click System Image Backup on the File History Control Panel. Storage Space Mirroring Windows 8′s Storage Spaces feature allows you to set up RAID-like features in software. For example, you can use Storage Space to set up two hard disks of the same size in a mirroring configuration. They’ll appear as a single drive in Windows. When you write to this virtual drive, the files will be saved to both physical drives. If one drive fails, your files will still be available on the other drive. This isn’t a good long-term backup solution, but it is a way of ensuring you won’t lose important files if a single drive fails. Microsoft Account Settings Backup Windows 8 and 8.1 allow you to back up a variety of system settings — including personalization, desktop, and input settings. If you’re signing in with a Microsoft account, OneDrive settings backup is enabled automatically. This feature can be controlled under OneDrive > Sync settings in the PC settings app. This feature only backs up a few settings. It’s really more of a way to sync settings between devices. OneDrive Cloud Storage Microsoft hasn’t been talking much about File History since Windows 8 was released. That’s because they want people to use OneDrive instead. OneDrive — formerly known as SkyDrive — was added to the Windows desktop in Windows 8.1. Save your files here and they’ll be stored online tied to your Microsoft account. You can then sign in on any other computer, smartphone, tablet, or even via the web and access your files. Microsoft wants typical PC users “backing up” their files with OneDrive so they’ll be available on any device. You don’t have to worry about all these features. Just choose a backup strategy to ensure your files are safe if your computer’s hard disk fails you. Whether it’s an integrated backup tool or a third-party backup application, be sure to back up your files.

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• ODI 12c's Mapping Designer - Combining Flow Based and Expression Based Mapping

  - by Madhu Nair

  post by David Allan ODI is renowned for its declarative designer and minimal expression based paradigm. The new ODI 12c release has extended this even further to provide an extended declarative mapping designer. The ODI 12c mapper is a fusion of ODI's new declarative designer with the familiar flow based designer while retaining ODI’s key differentiators of: Minimal expression based definition, The ability to incrementally design an interface and to extract/load data from any combination of sources, and most importantly Backed by ODI’s extensible knowledge module framework. The declarative nature of the product has been extended to include an extensible library of common components that can be used to easily build simple to complex data integration solutions. Big usability improvements through consistent interactions of components and concepts all constructed around the familiar knowledge module framework provide the utmost flexibility. Here is a little taster: So what is a mapping? A mapping comprises of a logical design and at least one physical design, it may have many. A mapping can have many targets, of any technology and can be arbitrarily complex. You can build reusable mappings and use them in other mappings or other reusable mappings. In the example below all of the information from an Oracle bonus table and a bonus file are joined with an Oracle employees table before being written to a target. Some things that are cool include the one-click expression cross referencing so you can easily see what's used where within the design. The logical design in a mapping describes what you want to accomplish  (see the animated GIF here illustrating how the above mapping was designed) . The physical design lets you configure how it is to be accomplished. So you could have one logical design that is realized as an initial load in one physical design and as an incremental load in another. In the physical design below we can customize how the mapping is accomplished by picking Knowledge Modules, in ODI 12c you can pick multiple nodes (on logical or physical) and see common properties. This is useful as we can quickly compare property values across objects - below we can see knowledge modules settings on the access points between execution units side by side, in the example one table is retrieved via database links and the other is an external table. In the logical design I had selected an append mode for the integration type, so by default the IKM on the target will choose the most suitable/default IKM - which in this case is an in-built Oracle Insert IKM (see image below). This supports insert and select hints for the Oracle database (the ANSI SQL Insert IKM does not support these), so by default you will get direct path inserts with Oracle on this statement. In ODI 12c, the mapper is just that, a mapper. Design your mapping, write to multiple targets, the targets can be in the same data server, in different data servers or in totally different technologies - it does not matter. ODI 12c will derive and generate a plan that you can use or customize with knowledge modules. Some of the use cases which are greatly simplified include multiple heterogeneous targets, multi target inserts for Oracle and writing of XML. Let's switch it up now and look at a slightly different example to illustrate expression reuse. In ODI you can define reusable expressions using user functions. These can be reused across mappings and the implementations specialized per technology. So you can have common expressions across Oracle, SQL Server, Hive etc. shielding the design from the physical aspects of the generated language. Another way to reuse is within a mapping itself. In ODI 12c expressions can be defined and reused within a mapping. Rather than replicating the expression text in larger expressions you can decompose into smaller snippets, below you can see UNIT_TAX AMOUNT has been defined and is used in two downstream target columns - its used in the TOTAL_TAX_AMOUNT plus its used in the UNIT_TAX_AMOUNT (a recording of the calculation).  You can see the columns that the expressions depend on (upstream) and the columns the expression is used in (downstream) highlighted within the mapper. Also multi selecting attributes is a convenient way to see what's being used where, below I have selected the TOTAL_TAX_AMOUNT in the target datastore and the UNIT_TAX_AMOUNT in UNIT_CALC. You can now see many expressions at once now and understand much more at the once time without needlessly clicking around and memorizing information. Our mantra during development was to keep it simple and make the tool more powerful and do even more for the user. The development team was a fusion of many teams from Oracle Warehouse Builder, Sunopsis and BEA Aqualogic, debating and perfecting the mapper in ODI 12c. This was quite a project from supporting the capabilities of ODI in 11g to building the flow based mapping tool to support the future. I hope this was a useful insight, there is so much more to come on this topic, this is just a preview of much more that you will see of the mapper in ODI 12c.

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• Caspol, VMs, Mapped Drives, VS2010

  - by Simon Woods

  Hi I have a VM (Win7 32 bit) with VS2010 installed. I have a drive mapped into it from the host machine (VM 64 bit), when I have some of my VS2010 projects and to where I am building them. One of my projects is looking to load an assembly. If I copy that assembly to a local drive, the program ruins fine. If I leave it on the mapped drive, then I get an error Exception is: FileLoadException - Could not load file or assembly 'file:///Z:\BusinessTier\bin\Debug\BusinessTier.dll I am unsure whether or not I need to run Caspol. There is another post on SO which pointed me to a post which indicated that VS2008 SP1+ removed the need for caspol wrt network drives, but I wondered if I still needed to because I am in a VM. I have tried running the following on the host machine in an attempt to give permissions to VS inside the VM, but to no avail C:\Windows\Microsoft.NET\Framework\v4.0.30128>caspol -m -ag 1.2 -url file://g:\* FullTrust where g:* is the drive being mapped into the VM (as drive z:) What am I missing (apart from understanding!) Thx Simon

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• Bacula & Multiple Tape Devices, and so on

  - by Tom O'Connor

  Bacula won't make use of 2 tape devices simultaneously. (Search for #-#-# for the TL;DR) A little background, perhaps. In the process of trying to get a decent working backup solution (backing up 20TB ain't cheap, or easy) at $dayjob, we bought a bunch of things to make it work. Firstly, there's a Spectra Logic T50e autochanger, 40 slots of LTO5 goodness, and that robot's got a pair of IBM HH5 Ultrium LTO5 drives, connected via FibreChannel Arbitrated Loop to our backup server. There's the backup server.. A Dell R715 with 2x 16 core AMD 62xx CPUs, and 32GB of RAM. Yummy. That server's got 2 Emulex FCe-12000E cards, and an Intel X520-SR dual port 10GE NIC. We were also sold Commvault Backup (non-NDMP). Here's where it gets really complicated. Spectra Logic and Commvault both sent respective engineers, who set up the library and the software. Commvault was running fine, in so far as the controller was working fine. The Dell server has Ubuntu 12.04 server, and runs the MediaAgent for CommVault, and mounts our BlueArc NAS as NFS to a few mountpoints, like /home, and some stuff in /mnt. When backing up from the NFS mountpoints, we were seeing ~= 290GB/hr throughput. That's CRAP, considering we've got 20-odd TB to get through, in a <48 hour backup window. The rated maximum on the BlueArc is 700MB/s (2460GB/hr), the rated maximum write speed on the tape devices is 140MB/s, per drive, so that's 492GB/hr (or double it, for the total throughput). So, the next step was to benchmark NFS performance with IOzone, and it turns out that we get epic write performance (across 20 threads), and it's like 1.5-2.5TB/hr write, but read performance is fecking hopeless. I couldn't ever get higher than 343GB/hr maximum. So let's assume that the 343GB/hr is a theoretical maximum for read performance on the NAS, then we should in theory be able to get that performance out of a) CommVault, and b) any other backup agent. Not the case. Commvault seems to only ever give me 200-250GB/hr throughput, and out of experimentation, I installed Bacula to see what the state of play there is. If, for example, Bacula gave consistently better performance and speeds than Commvault, then we'd be able to say "**$.$ Refunds Plz $.$**" #-#-# Alas, I found a different problem with Bacula. Commvault seems pretty happy to read from one part of the mountpoint with one thread, and stream that to a Tape device, whilst reading from some other directory with the other thread, and writing to the 2nd drive in the autochanger. I can't for the life of me get Bacula to mount and write to two tape drives simultaneously. Things I've tried: Setting Maximum Concurrent Jobs = 20 in the Director, File and Storage Daemons Setting Prefer Mounted Volumes = no in the Job Definition Setting multiple devices in the Autochanger resource. Documentation seems to be very single-drive centric, and we feel a little like we've strapped a rocket to a hamster, with this one. The majority of example Bacula configurations are for DDS4 drives, manual tape swapping, and FreeBSD or IRIX systems. I should probably add that I'm not too bothered if this isn't possible, but I'd be surprised. I basically want to use Bacula as proof to stick it to the software vendors that they're overpriced ;) I read somewhere that @KyleBrandt has done something similar with a modern Tape solution.. Configuration Files: *bacula-dir.conf* # # Default Bacula Director Configuration file Director { # define myself Name = backuphost-1-dir DIRport = 9101 # where we listen for UA connections QueryFile = "/etc/bacula/scripts/query.sql" WorkingDirectory = "/var/lib/bacula" PidDirectory = "/var/run/bacula" Maximum Concurrent Jobs = 20 Password = "yourekiddingright" # Console password Messages = Daemon DirAddress = 0.0.0.0 #DirAddress = 127.0.0.1 } JobDefs { Name = "DefaultFileJob" Type = Backup Level = Incremental Client = backuphost-1-fd FileSet = "Full Set" Schedule = "WeeklyCycle" Storage = File Messages = Standard Pool = File Priority = 10 Write Bootstrap = "/var/lib/bacula/%c.bsr" } JobDefs { Name = "DefaultTapeJob" Type = Backup Level = Incremental Client = backuphost-1-fd FileSet = "Full Set" Schedule = "WeeklyCycle" Storage = "SpectraLogic" Messages = Standard Pool = AllTapes Priority = 10 Write Bootstrap = "/var/lib/bacula/%c.bsr" Prefer Mounted Volumes = no } # # Define the main nightly save backup job # By default, this job will back up to disk in /nonexistant/path/to/file/archive/dir Job { Name = "BackupClient1" JobDefs = "DefaultFileJob" } Job { Name = "BackupThisVolume" JobDefs = "DefaultTapeJob" FileSet = "SpecialVolume" } #Job { # Name = "BackupClient2" # Client = backuphost-12-fd # JobDefs = "DefaultJob" #} # Backup the catalog database (after the nightly save) Job { Name = "BackupCatalog" JobDefs = "DefaultFileJob" Level = Full FileSet="Catalog" Schedule = "WeeklyCycleAfterBackup" # This creates an ASCII copy of the catalog # Arguments to make_catalog_backup.pl are: # make_catalog_backup.pl <catalog-name> RunBeforeJob = "/etc/bacula/scripts/make_catalog_backup.pl MyCatalog" # This deletes the copy of the catalog RunAfterJob = "/etc/bacula/scripts/delete_catalog_backup" Write Bootstrap = "/var/lib/bacula/%n.bsr" Priority = 11 # run after main backup } # # Standard Restore template, to be changed by Console program # Only one such job is needed for all Jobs/Clients/Storage ... # Job { Name = "RestoreFiles" Type = Restore Client=backuphost-1-fd FileSet="Full Set" Storage = File Pool = Default Messages = Standard Where = /srv/bacula/restore } FileSet { Name = "SpecialVolume" Include { Options { signature = MD5 } File = /mnt/SpecialVolume } Exclude { File = /var/lib/bacula File = /nonexistant/path/to/file/archive/dir File = /proc File = /tmp File = /.journal File = /.fsck } } # List of files to be backed up FileSet { Name = "Full Set" Include { Options { signature = MD5 } File = /usr/sbin } Exclude { File = /var/lib/bacula File = /nonexistant/path/to/file/archive/dir File = /proc File = /tmp File = /.journal File = /.fsck } } Schedule { Name = "WeeklyCycle" Run = Full 1st sun at 23:05 Run = Differential 2nd-5th sun at 23:05 Run = Incremental mon-sat at 23:05 } # This schedule does the catalog. It starts after the WeeklyCycle Schedule { Name = "WeeklyCycleAfterBackup" Run = Full sun-sat at 23:10 } # This is the backup of the catalog FileSet { Name = "Catalog" Include { Options { signature = MD5 } File = "/var/lib/bacula/bacula.sql" } } # Client (File Services) to backup Client { Name = backuphost-1-fd Address = localhost FDPort = 9102 Catalog = MyCatalog Password = "surelyyourejoking" # password for FileDaemon File Retention = 30 days # 30 days Job Retention = 6 months # six months AutoPrune = yes # Prune expired Jobs/Files } # # Second Client (File Services) to backup # You should change Name, Address, and Password before using # #Client { # Name = backuphost-12-fd # Address = localhost2 # FDPort = 9102 # Catalog = MyCatalog # Password = "i'mnotjokinganddontcallmeshirley" # password for FileDaemon 2 # File Retention = 30 days # 30 days # Job Retention = 6 months # six months # AutoPrune = yes # Prune expired Jobs/Files #} # Definition of file storage device Storage { Name = File # Do not use "localhost" here Address = localhost # N.B. Use a fully qualified name here SDPort = 9103 Password = "lalalalala" Device = FileStorage Media Type = File } Storage { Name = "SpectraLogic" Address = localhost SDPort = 9103 Password = "linkedinmakethebestpasswords" Device = Drive-1 Device = Drive-2 Media Type = LTO5 Autochanger = yes } # Generic catalog service Catalog { Name = MyCatalog # Uncomment the following line if you want the dbi driver # dbdriver = "dbi:sqlite3"; dbaddress = 127.0.0.1; dbport = dbname = "bacula"; DB Address = ""; dbuser = "bacula"; dbpassword = "bbmaster63" } # Reasonable message delivery -- send most everything to email address # and to the console Messages { Name = Standard mailcommand = "/usr/lib/bacula/bsmtp -h localhost -f \"\(Bacula\) \<%r\>\" -s \"Bacula: %t %e of %c %l\" %r" operatorcommand = "/usr/lib/bacula/bsmtp -h localhost -f \"\(Bacula\) \<%r\>\" -s \"Bacula: Intervention needed for %j\" %r" mail = root@localhost = all, !skipped operator = root@localhost = mount console = all, !skipped, !saved # # WARNING! the following will create a file that you must cycle from # time to time as it will grow indefinitely. However, it will # also keep all your messages if they scroll off the console. # append = "/var/lib/bacula/log" = all, !skipped catalog = all } # # Message delivery for daemon messages (no job). Messages { Name = Daemon mailcommand = "/usr/lib/bacula/bsmtp -h localhost -f \"\(Bacula\) \<%r\>\" -s \"Bacula daemon message\" %r" mail = root@localhost = all, !skipped console = all, !skipped, !saved append = "/var/lib/bacula/log" = all, !skipped } # Default pool definition Pool { Name = Default Pool Type = Backup Recycle = yes # Bacula can automatically recycle Volumes AutoPrune = yes # Prune expired volumes Volume Retention = 365 days # one year } # File Pool definition Pool { Name = File Pool Type = Backup Recycle = yes # Bacula can automatically recycle Volumes AutoPrune = yes # Prune expired volumes Volume Retention = 365 days # one year Maximum Volume Bytes = 50G # Limit Volume size to something reasonable Maximum Volumes = 100 # Limit number of Volumes in Pool } Pool { Name = AllTapes Pool Type = Backup Recycle = yes AutoPrune = yes # Prune expired volumes Volume Retention = 31 days # one Moth } # Scratch pool definition Pool { Name = Scratch Pool Type = Backup } # # Restricted console used by tray-monitor to get the status of the director # Console { Name = backuphost-1-mon Password = "LastFMalsostorePasswordsLikeThis" CommandACL = status, .status } bacula-sd.conf # # Default Bacula Storage Daemon Configuration file # Storage { # definition of myself Name = backuphost-1-sd SDPort = 9103 # Director's port WorkingDirectory = "/var/lib/bacula" Pid Directory = "/var/run/bacula" Maximum Concurrent Jobs = 20 SDAddress = 0.0.0.0 # SDAddress = 127.0.0.1 } # # List Directors who are permitted to contact Storage daemon # Director { Name = backuphost-1-dir Password = "passwordslinplaintext" } # # Restricted Director, used by tray-monitor to get the # status of the storage daemon # Director { Name = backuphost-1-mon Password = "totalinsecurityabound" Monitor = yes } Device { Name = FileStorage Media Type = File Archive Device = /srv/bacula/archive LabelMedia = yes; # lets Bacula label unlabeled media Random Access = Yes; AutomaticMount = yes; # when device opened, read it RemovableMedia = no; AlwaysOpen = no; } Autochanger { Name = SpectraLogic Device = Drive-1 Device = Drive-2 Changer Command = "/etc/bacula/scripts/mtx-changer %c %o %S %a %d" Changer Device = /dev/sg4 } Device { Name = Drive-1 Drive Index = 0 Archive Device = /dev/nst0 Changer Device = /dev/sg4 Media Type = LTO5 AutoChanger = yes RemovableMedia = yes; AutomaticMount = yes; AlwaysOpen = yes; RandomAccess = no; LabelMedia = yes } Device { Name = Drive-2 Drive Index = 1 Archive Device = /dev/nst1 Changer Device = /dev/sg4 Media Type = LTO5 AutoChanger = yes RemovableMedia = yes; AutomaticMount = yes; AlwaysOpen = yes; RandomAccess = no; LabelMedia = yes } # # Send all messages to the Director, # mount messages also are sent to the email address # Messages { Name = Standard director = backuphost-1-dir = all } bacula-fd.conf # # Default Bacula File Daemon Configuration file # # # List Directors who are permitted to contact this File daemon # Director { Name = backuphost-1-dir Password = "hahahahahaha" } # # Restricted Director, used by tray-monitor to get the # status of the file daemon # Director { Name = backuphost-1-mon Password = "hohohohohho" Monitor = yes } # # "Global" File daemon configuration specifications # FileDaemon { # this is me Name = backuphost-1-fd FDport = 9102 # where we listen for the director WorkingDirectory = /var/lib/bacula Pid Directory = /var/run/bacula Maximum Concurrent Jobs = 20 #FDAddress = 127.0.0.1 FDAddress = 0.0.0.0 } # Send all messages except skipped files back to Director Messages { Name = Standard director = backuphost-1-dir = all, !skipped, !restored }

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• 3 Ways to Make Steam Even Faster

  - by Chris Hoffman

  Have you ever noticed how slow Steam’s built-in web browser can be? Do you struggle with slow download speeds? Or is Steam just slow in general? These tips will help you speed it up. Steam isn’t a game itself, so there are no 3D settings to change to achieve maximum performance. But there are some things you can do to speed it up dramatically. Speed Up the Steam Web Browser Steam’s built-in web browser — used in both the Steam store and in Steam’s in-game overlay to provide a web browser you can quickly use within games – can be frustratingly slow on many systems. Rather than the typical speed we’ve come to expect from Chrome, Firefox, or even Internet Explorer, Steam seems to struggle. When you click a link or go to a new page, there’s a noticeable delay before the new page appears — something that doesn’t happen in desktop browsers. Many people seem to have made peace with this slowness, accepting that Steam’s built-in browser is just bad. However, there’s a trick that will eliminate this delay on many systems and make the Steam web browser fast. This problem seems to arise from an incompatibility with the Automatically Detect Proxy Settings option, which is enabled by default on Windows. This is a compatibility option that very few people should actually need, so it’s safe to disable it. To disable this option, open the Internet Options dialog — press the Windows key to access the Start menu or Start screen, type Internet Options, and click the Internet Options shortcut. Select the Connections tab in the Internet Options window and click the LAN settings button. Uncheck the Automatically detect settings option here, then click OK to save your settings. If you experienced a significant delay every time a web page loaded in Steam’s web browser, it should now be gone. In the unlikely event that you encounter some sort of problem with your network connection, you could always re-enable this option. Increase Steam’s Game Download Speed Steam attempts to automatically select the nearest download server to your location. However, it may not always select the ideal download server. Or, in the case of high-traffic events like big seasonal sales and huge game launches, you may benefit from selecting a less-congested server. To do this, open Steam’s settings by clicking the Steam menu in Steam and selecting Settings. Click over to the Downloads tab and select the closest download server from the Download Region box. You should also ensure that Steam’s download bandwidth isn’t limited from here. You may want to restart Steam and see if your download speeds improve after changing this setting. In some cases, the closest server might not be the fastest. One a bit farther away could be faster if your local server is more congested, for example. Steam once provided information about content server load, which allowed you to select a regional server that wasn’t under high-load, but this information no longer seems to be available. Steam still provides a page that shows you the amount of download activity happening in different regions, including statistics about the difference in download speeds in different US states, but this information isn’t as useful. Accelerate Steam and Your Games One way to speed up all your games — and Steam itself —  is by getting a solid-state drive and installing Steam to it. Steam allows you to easily move your Steam folder — at C:\Program Files (x86)\Steam by default — to another hard drive. Just move it like you would any other folder. You can then launch the Steam.exe program as if you had never moved Steam’s files. Steam also allows you to configure multiple game library folders. This means that you can set up a Steam library folder on a solid-state drive and one on your larger magnetic hard drive. Install your most frequently played games to the solid-state drive for maximum speed and your less frequently played ones to the slower magnetic hard drive to save SSD space. To set up additional library folders, open Steam’s Settings window and click the Downloads tab. You’ll find the Steam Library Folders option here. Click the Add Library Folder button and create a new game library on another hard drive. When you install a game in Steam, you’ll be asked which library folder you want to install it to. With the proxy compatibility option disabled, the correct download server chosen, and Steam installed to a fast SSD, it should be a speed demon. There’s not much more you can do to speed up Steam, short of upgrading other hardware like your computer’s CPU. Image Credit: Andrew Nash on Flickr     

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• How to Use Windows 8's Storage Spaces to Mirror & Combine Drives

  - by Chris Hoffman

  “Storage Spaces” is a new feature in Windows 8 that can combine multiple hard drives into a single virtual drive. It can mirror data across multiple drives for redundancy or combine multiple physical drives into a single pool of storage. You can even create pools of storage larger than the amount of physical storage space you have available. When the physical storage fills up, you can plug in another drive and take advantage of it with no additional configuration required. Storage Spaces is similar to RAID or LVM on Linux. The HTG Guide to Hiding Your Data in a TrueCrypt Hidden Volume Make Your Own Windows 8 Start Button with Zero Memory Usage Reader Request: How To Repair Blurry Photos

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• GetDiskFreeSpaceEx reports wrong number of free bytes

  - by rboorgapally

  __int64 i64FreeBytes unsigned __int64 lpFreeBytesAvailableToCaller, lpTotalNumberOfBytes, lpTotalNumberOfFreeBytes; // variables used to obtain // the free space on the drive GetDiskFreeSpaceEx (Manager.capDir, (PULARGE_INTEGER)&lpFreeBytesAvailableToCaller, (PULARGE_INTEGER)&lpTotalNumberOfBytes, (PULARGE_INTEGER)&lpTotalNumberOfFreeBytes); i64FreeBytes = lpTotalNumberOfFreeBytes; _tprintf(_T ("Number of bytes free on the drive:%I64u \n"), lpTotalNumberOfFreeBytes); I am working on a data management routine which is a Windows CE command line application. The above code shows how I get the number of free bytes on a particular drive which contains the folder Manager.capdir (it is the variable containing the full path name of the directory). My question is, the number of free bytes reported by the above code (the _tprintf statement) doesn't match with the number of free bytes of the drive (which i check by doing a right click on the drive). I wish to know if the reason for this difference?

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• 64 bit Ubuntu sees half my RAM

  - by koehn

  This is on my AMD FX(tm)-4100 Quad-Core Processor (according to /proc/cpuinfo) on a machine with two 4GB RAM DIMMs. BIOS shows 8GB RAM installed. Any help would be appreciated. RAM: Extreme Performance Sector 5 G Series 8GB DDR3-1333 (PC3-1066) Enhanced Latency Dual Channel Desktop Memory Kit (Two 4GB Memory Modules) MB: GA-78LMT-S2P Socket AM3+ 760G mATX AMD Motherboard CPU: FX 4100 Black Edition 3.6GHz Quad-Core Socket AM3+ Boxed Processor Here's what the software says: $ free total used free shared buffers cached Mem: 3515100 3293656 221444 0 19260 2670352 -/+ buffers/cache: 604044 2911056 Swap: 3650556 90916 3559640 $ uname -a Linux mythbuntu 3.2.0-30-generic #48-Ubuntu SMP Fri Aug 24 16:52:48 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux From lshw: *-memory description: System Memory physical id: 20 slot: System board or motherboard size: 4GiB *-bank:0 description: DIMM 1066 MHz (0.9 ns) product: None vendor: None physical id: 0 serial: None slot: A0 size: 2GiB width: 64 bits clock: 1066MHz (0.9ns) *-bank:1 description: DIMM 1066 MHz (0.9 ns) product: None vendor: None physical id: 1 serial: None slot: A1 size: 2GiB width: 64 bits clock: 1066MHz (0.9ns)

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• Atheros 922 PCI WIFI is disabled in Unity but enabled in terminal - How to get it to work?

  - by zewone

  I am trying to get my PCI Wireless Atheros 922 card to work. It is disabled in Unity: both the network utility and the desktop (see screenshot http://www.amisdurailhalanzy.be/Screenshot%20from%202012-10-25%2013:19:54.png) I tried many different advises on many different forums. Installed 12.10 instead of 12.04, enabled all interfaces... etc. I have read about the aht9 driver... The terminal shows no hw or sw lock for the Atheros card, nevertheless, it is still disabled. Nothing worked so far, the card is still disabled. Any help is much appreciated. Here are more tech details: myuser@adri1:~$ sudo lshw -C network *-network:0 DISABLED description: Wireless interface product: AR922X Wireless Network Adapter vendor: Atheros Communications Inc. physical id: 2 bus info: pci@0000:03:02.0 logical name: wlan1 version: 01 serial: 00:18:e7:cd:68:b1 width: 32 bits clock: 66MHz capabilities: pm bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=ath9k driverversion=3.5.0-17-generic firmware=N/A latency=168 link=no multicast=yes wireless=IEEE 802.11bgn resources: irq:18 memory:d8000000-d800ffff *-network:1 description: Ethernet interface product: VT6105/VT6106S [Rhine-III] vendor: VIA Technologies, Inc. physical id: 6 bus info: pci@0000:03:06.0 logical name: eth0 version: 8b serial: 00:11:09:a3:76:4a size: 10Mbit/s capacity: 100Mbit/s width: 32 bits clock: 33MHz capabilities: pm bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=via-rhine driverversion=1.5.0 duplex=half latency=32 link=no maxlatency=8 mingnt=3 multicast=yes port=MII speed=10Mbit/s resources: irq:18 ioport:d300(size=256) memory:d8013000-d80130ff *-network DISABLED description: Wireless interface physical id: 1 bus info: usb@1:8.1 logical name: wlan0 serial: 00:11:09:51:75:36 capabilities: ethernet physical wireless configuration: broadcast=yes driver=rt2500usb driverversion=3.5.0-17-generic firmware=N/A link=no multicast=yes wireless=IEEE 802.11bg myuser@adri1:~$ sudo rfkill list all 0: hci0: Bluetooth Soft blocked: no Hard blocked: no 1: phy1: Wireless LAN Soft blocked: no Hard blocked: yes 2: phy0: Wireless LAN Soft blocked: no Hard blocked: no myuser@adri1:~$ dmesg | grep wlan0 [ 15.114235] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready myuser@adri1:~$ dmesg | egrep 'ath|firm' [ 14.617562] ath: EEPROM regdomain: 0x30 [ 14.617568] ath: EEPROM indicates we should expect a direct regpair map [ 14.617572] ath: Country alpha2 being used: AM [ 14.617575] ath: Regpair used: 0x30 [ 14.637778] ieee80211 phy0: >Selected rate control algorithm 'ath9k_rate_control' [ 14.639410] Registered led device: ath9k-phy0 myuser@adri1:~$ dmesg | grep wlan1 [ 15.119922] IPv6: ADDRCONF(NETDEV_UP): wlan1: link is not ready myuser@adri1:~$ lspci -nn | grep 'Atheros' 03:02.0 Network controller [0280]: Atheros Communications Inc. AR922X Wireless Network Adapter [168c:0029] (rev 01) myuser@adri1:~$ sudo ifconfig eth0 Link encap:Ethernet HWaddr 00:11:09:a3:76:4a inet addr:192.168.2.2 Bcast:192.168.2.255 Mask:255.255.255.0 inet6 addr: fe80::211:9ff:fea3:764a/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:5457 errors:0 dropped:0 overruns:0 frame:0 TX packets:2548 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:3425684 (3.4 MB) TX bytes:282192 (282.1 KB) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:590 errors:0 dropped:0 overruns:0 frame:0 TX packets:590 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:53729 (53.7 KB) TX bytes:53729 (53.7 KB) myuser@adri1:~$ sudo iwconfig wlan0 IEEE 802.11bg ESSID:off/any Mode:Managed Access Point: Not-Associated Tx-Power=off Retry long limit:7 RTS thr:off Fragment thr:off Encryption key:off Power Management:on lo no wireless extensions. eth0 no wireless extensions. wlan1 IEEE 802.11bgn ESSID:off/any Mode:Managed Access Point: Not-Associated Tx-Power=0 dBm Retry long limit:7 RTS thr:off Fragment thr:off Encryption key:off Power Management:off myuser@adri1:~$ lsmod | grep "ath9k" ath9k 116549 0 mac80211 461161 3 rt2x00usb,rt2x00lib,ath9k ath9k_common 13783 1 ath9k ath9k_hw 376155 2 ath9k,ath9k_common ath 19187 3 ath9k,ath9k_common,ath9k_hw cfg80211 175375 4 rt2x00lib,ath9k,mac80211,ath myuser@adri1:~$ iwlist scan wlan0 Failed to read scan data : Network is down lo Interface doesn't support scanning. eth0 Interface doesn't support scanning. wlan1 Failed to read scan data : Network is down myuser@adri1:~$ lsb_release -d Description: Ubuntu 12.10 myuser@adri1:~$ uname -mr 3.5.0-17-generic i686  Any help much appreciated... Thanks, Philippe 31-10-2012 ... I have some more updates. When I do the following command it does see my Wifi router... So even if it is still disabled... the card seems to work and see the router (ESSID:"5791BC26-CE9C-11D1-97BF-0000F81E") See below: sudo iwlist wlan1 scanning wlan1 Scan completed : Cell 01 - Address: 00:19:70:8F:B0:EA Channel:10 Frequency:2.457 GHz (Channel 10) Quality=51/70 Signal level=-59 dBm Encryption key:on ESSID:"5791BC26-CE9C-11D1-97BF-0000F81E" Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s 9 Mb/s; 12 Mb/s; 18 Mb/s Bit Rates:24 Mb/s; 36 Mb/s; 48 Mb/s; 54 Mb/s Mode:Master Extra:tsf=000000025dbf2188 Extra: Last beacon: 108ms ago IE: Unknown: 002035373931424332362D434539432D313144312D393742462D3030303046383145 IE: Unknown: 010882848B960C121824 IE: Unknown: 03010A IE: Unknown: 0706424520010D14 IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (2) : CCMP TKIP Authentication Suites (1) : PSK IE: Unknown: 2A0100 IE: Unknown: 32043048606C IE: Unknown: DD180050F2020101030003A4000027A4000042435E0062322F00 IE: Unknown: DD0900037F01010000FF7F IE: Unknown: DD0A00037F04010000000000

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• MAAS/Juju architecture and issues

  - by Massimo

  I recently deployed a MAAS/Juju environment based on a six nodes cluster, using Ubuntu 12.04 LTS, to run a "proof of concept". I could appreciate how interesting the architecture is, and I'd like to understand if I can really base my future business on this technology. Therefore I'd like to understand more about any involved limitations, constraints and necessities. In particular I'd like to understand: 1) how can MAAS be made reliable, i.e. deployed over two or more physical nodes able to fail-over ? 2) can the same physical cluster host multiple juju environments, under the assumption openstack/virtualization is not used ? 3) can the same physical node host different charms of the same juju environment, deployed in a standard, reliable way by juju ?

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• Intel Centrino Wireless-N 1000 Again ! Ubuntu 13.04 x64

  - by vafa

  First I have to say that I tried everything written about this concept. The problem is that it stops working randomly in 3 main forms : 1 - sometimes it disconnect from wireless network and reconnect automatically 2 - sometimes it disconnect and wont connect no matter what (needs reboot) 3 - some times it's still connected but cannot ping or surf or whatever. I already tried disabling N mod using these commands : sudo modprobe -r iwlwifi modprobe iwlwifi 11n_disable=1 (or 0, whatever) it didn't help . these are the results of lspci, sudo lshw -C network, ifconfig, iwconfig, rfkill list when it disconnected and didn't connect till reboot : ifconfig : eth0 Link encap:Ethernet HWaddr c8:0a:a9:34:65:77 UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:1563213476557380 errors:9379306629148050 dropped:3126435543049350 overruns:1563217771524675 frame:7816088857623375 TX packets:1563217771524675 errors:6252871086098700 dropped:0 overruns:1563217771524675 carrier:3126435543049350 collisions:7816088857623375 txqueuelen:1000 RX bytes:1563217771524675 (1.5 PB) TX bytes:1563217771524675 (1.5 PB) ham0 Link encap:Ethernet HWaddr 7a:79:19:a5:e4:93 inet addr:25.165.228.147 Bcast:25.255.255.255 Mask:255.0.0.0 inet6 addr: fe80::7879:19ff:fea5:e493/64 Scope:Link inet6 addr: 2620:9b::19a5:e493/96 Scope:Global UP BROADCAST RUNNING MULTICAST MTU:1404 Metric:1 RX packets:7743 errors:0 dropped:0 overruns:0 frame:0 TX packets:1250 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:500 RX bytes:665642 (665.6 KB) TX bytes:204056 (204.0 KB) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:41138 errors:0 dropped:0 overruns:0 frame:0 TX packets:41138 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:6420962 (6.4 MB) TX bytes:6420962 (6.4 MB) wlan0 Link encap:Ethernet HWaddr 00:1e:64:45:fb:70 inet6 addr: fe80::21e:64ff:fe45:fb70/64 Scope:Link UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:286999 errors:0 dropped:0 overruns:0 frame:0 TX packets:226966 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:324386887 (324.3 MB) TX bytes:30674804 (30.6 MB) iwconfig : ham0 no wireless extensions. eth0 no wireless extensions. lo no wireless extensions. wlan0 IEEE 802.11bg ESSID:off/any Mode:Managed Access Point: Not-Associated Tx-Power=14 dBm Retry long limit:7 RTS thr:off Fragment thr:off Power Management:off sudo lshw -C network: *-network description: Wireless interface product: Centrino Wireless-N 1000 [Condor Peak] vendor: Intel Corporation physical id: 0 bus info: pci@0000:07:00.0 logical name: wlan0 version: 00 serial: 00:1e:64:45:fb:70 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=iwlwifi driverversion=3.8.0-30-generic firmware=39.31.5.1 build 35138 latency=0 link=no multicast=yes wireless=IEEE 802.11bg resources: irq:46 memory:c0400000-c0401fff *-network description: Ethernet interface product: AR8131 Gigabit Ethernet vendor: Qualcomm Atheros physical id: 0 bus info: pci@0000:09:00.0 logical name: eth0 version: c0 serial: c8:0a:a9:34:65:77 capacity: 1Gbit/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress vpd cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=atl1c driverversion=1.0.1.1-NAPI latency=0 link=no multicast=yes port=twisted pair resources: irq:47 memory:c0900000-c093ffff ioport:5000(size=128) *-network description: Ethernet interface physical id: 2 logical name: ham0 serial: 7a:79:19:a5:e4:93 size: 10Mbit/s capabilities: ethernet physical configuration: autonegotiation=off broadcast=yes driver=tun driverversion=1.6 duplex=full ip=25.165.228.147 link=yes multicast=yes port=twisted pair speed=10Mbit/s lspci: 00:00.0 Host bridge: Intel Corporation Mobile 4 Series Chipset Memory Controller Hub (rev 07) 00:01.0 PCI bridge: Intel Corporation Mobile 4 Series Chipset PCI Express Graphics Port (rev 07) 00:1a.0 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #4 (rev 03) 00:1a.1 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #5 (rev 03) 00:1a.7 USB controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #2 (rev 03) 00:1b.0 Audio device: Intel Corporation 82801I (ICH9 Family) HD Audio Controller (rev 03) 00:1c.0 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 1 (rev 03) 00:1c.3 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 4 (rev 03) 00:1c.5 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 6 (rev 03) 00:1d.0 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #1 (rev 03) 00:1d.1 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #2 (rev 03) 00:1d.2 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #3 (rev 03) 00:1d.3 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #6 (rev 03) 00:1d.7 USB controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #1 (rev 03) 00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev 93) 00:1f.0 ISA bridge: Intel Corporation ICH9M LPC Interface Controller (rev 03) 00:1f.2 SATA controller: Intel Corporation 82801IBM/IEM (ICH9M/ICH9M-E) 4 port SATA Controller [AHCI mode] (rev 03) 00:1f.3 SMBus: Intel Corporation 82801I (ICH9 Family) SMBus Controller (rev 03) 01:00.0 VGA compatible controller: NVIDIA Corporation G98M [GeForce G 105M] (rev a1) 07:00.0 Network controller: Intel Corporation Centrino Wireless-N 1000 [Condor Peak] 09:00.0 Ethernet controller: Qualcomm Atheros AR8131 Gigabit Ethernet (rev c0) rfkill list : 1: acer-wireless: Wireless LAN Soft blocked: no Hard blocked: no 2: acer-bluetooth: Bluetooth Soft blocked: yes Hard blocked: no 9: phy0: Wireless LAN Soft blocked: no Hard blocked: no any help will be REALLLYYYY appreciated

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• Wireless not working with an Atheros AR9285

  - by Neeraj

  I recently installed Ubuntu 12.04 and found my wireless card is not detected by OS. I tired to detect it by network manager but still it is not get output of the required command: toor@Linux:~$ sudo lshw -class network *-network description: Ethernet interface product: AR8131 Gigabit Ethernet vendor: Atheros Communications Inc. physical id: 0 bus info: pci@0000:03:00.0 logical name: eth0 version: c0 serial: f0:de:f1:9e:22:4d size: 100Mbit/s capacity: 1Gbit/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress vpd bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=atl1c driverversion=1.0.1.0-NAPI duplex=full firmware=N/A ip=124.123.227.84 latency=0 link=yes multicast=yes port=twisted pair speed=100Mbit/s resources: irq:44 memory:f2400000-f243ffff ioport:2000(size=128) *-network UNCLAIMED description: Network controller product: AR9285 Wireless Network Adapter (PCI-Express) vendor: Atheros Communications Inc. physical id: 0 bus info: pci@0000:04:00.0 version: 01 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: latency=0 resources: memory:f2500000-f250ffff and toor@Linux:~$ rfkill list all 0: ideapad_wlan: Wireless LAN Soft blocked: yes Hard blocked: no 1: ideapad_bluetooth: Bluetooth Soft blocked: yes Hard blocked: no Please let me know what more info is required to resolve it.

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• Algorithm to classify a list of products?

  - by Martin

  I have a list representing products which are more or less the same. For instance, in the list below, they are all Seagate hard drives. Seagate Hard Drive 500Go Seagate Hard Drive 120Go for laptop Seagate Barracuda 7200.12 ST3500418AS 500GB 7200 RPM SATA 3.0Gb/s Hard Drive New and shinny 500Go hard drive from Seagate Seagate Barracuda 7200.12 Seagate FreeAgent Desk 500GB External Hard Drive Silver 7200RPM USB2.0 Retail For a human being, the hard drives 3 and 5 are the same. We could go a little bit further and suppose that the products 1, 3, 4 and 5 are the same and put in other categories the product 2 and 6. We have a huge list of products that I would like to classify. Does anybody have an idea of what would be the best algorithm to do such thing. Any suggestions? I though of a Bayesian classifier but I am not sure if it is the best choice. Any help would be appreciated! Thanks.

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• How to prevent UI from freezing during lengthy process?

  - by OverTheRainbow

  Hello, I need to write a VB.Net 2008 applet to go through all the fixed-drives looking for some files. If I put the code in ButtonClick(), the UI freezes until the code is done: Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click 'TODO Find way to avoid freezing UI while scanning fixed drives Dim drive As DriveInfo Dim filelist As Collections.ObjectModel.ReadOnlyCollection(Of String) Dim filepath As String For Each drive In DriveInfo.GetDrives() If drive.DriveType = DriveType.Fixed Then filelist = My.Computer.FileSystem.GetFiles(drive.ToString, FileIO.SearchOption.SearchAllSubDirectories, "MyFiles.*") For Each filepath In filelist 'Do stuff Next filepath End If Next drive End Sub Google returned information on a BackGroundWorker control: Is this the right/way to solve this issue? If not, what solution would you recommend, possibly with a really simple example? FWIW, I read that Application.DoEvents() is a left-over from VBClassic and should be avoided. Thank you.

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• Where are Wireless Profiles stored in Ubuntu [closed]

  - by LonnieBest

  Where does Ubuntu store profiles that allow it to remember the credentials to private wireless networks that it has previously authenticate to and used? I just replaced my Uncle's hard drive with a new one and installed Ubuntu 10.04 on it (he had Ubuntu 9.10 on his old hard drive. He is at my house right now, and I want him to be able to access his private wireless network when he gets home. Usually, when I upgrade Ubuntu, I have his /home directory on another partition, so his wireless profile to his own network persists. However, right now, I'm trying to figure out which .folder I need to copy from his /home/user folder on the old hard drive, to the new hard drive, so that he will be able to have wireless Internet when he gets home. Does anyone know with certainty, exactly which folder I need to copy to the new hard drive to achieve this?

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• GIT Clones on Multiple Machines

  - by Adam

  Here's my setup... Laptop (Mac) - git clone of svn repository Thumb drive - git clone of laptop git repository Server (Win Server 08) - git clone of thumb drive repository I'm having trouble keeping them in sync for some reason... If I make a change on the server, I'll do a "git pull " on the thumb drive to get the changes. Take the thumb drive to the laptop and do "git pull " on the laptop. From there, I can do "git svn dcommit" and everything goes up to the SVN repo with no problem. If I pull changes from SVN with "git svn rebase" and then do a pull onto the thumb drive and do a "git status" it says that I'm ## revisions ahead of the master/origin and I can't figure out why.

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• Validating Petabytes of Data with Regularity and Thoroughness

  - by rickramsey

  by Brian Zents When former Intel CEO Andy Grove said “only the paranoid survive,” he wasn’t necessarily talking about tape storage administrators, but it’s a lesson they’ve learned well. After all, tape storage is the last line of defense to prevent data loss, so tape administrators are extra cautious in making sure their data is secure. Not surprisingly, we are often asked for ways to validate tape media and the files on them. In the past, an administrator could validate the media, but doing so was often tedious or disruptive or both. The debut of the Data Integrity Validation (DIV) and Library Media Validation (LMV) features in the Oracle T10000C drive helped eliminate many of these pains. Also available with the Oracle T10000D drive, these features use hardware-assisted CRC checks that not only ensure the data is written correctly the first time, but also do so much more efficiently. Traditionally, a CRC check takes at least 25 seconds per 4GB file with a 2:1 compression ratio, but the T10000C/D drives can reduce the check to a maximum of nine seconds because the entire check is contained within the drive. No data needs to be sent to a host application. A time savings of at least 64 percent is extremely beneficial over the course of checking an entire 8.5TB T10000D tape. While the DIV and LMV features are better than anything else out there, what storage administrators really need is a way to check petabytes of data with regularity and thoroughness. With the launch of Oracle StorageTek Tape Analytics (STA) 2.0 in April, there is finally a solution that addresses this longstanding need. STA bundles these features into one interface to automate all media validation activities across all Oracle SL3000 and SL8500 tape libraries in an environment. And best of all, the validation process can be associated with the health checks an administrator would be doing already through STA. In fact, STA validates the media based on any of the following policies: Random Selection – Randomly selects media for validation whenever a validation drive in the standalone library or library complex is available. Media Health = Action – Selects media that have had a specified number of successive exchanges resulting in an Exchange Media Health of “Action.” You can specify from one to five exchanges. Media Health = Evaluate – Selects media that have had a specified number of successive exchanges resulting in an Exchange Media Health of “Evaluate.” You can specify from one to five exchanges. Media Health = Monitor – Selects media that have had a specified number of successive exchanges resulting in an Exchange Media Health of “Monitor.” You can specify from one to five exchanges. Extended Period of Non-Use – Selects media that have not had an exchange for a specified number of days. You can specify from 365 to 1,095 days (one to three years). Newly Entered – Selects media that have recently been entered into the library. Bad MIR Detected – Selects media with an exchange resulting in a “Bad MIR Detected” error. A bad media information record (MIR) indicates degraded high-speed access on the media. To avoid disrupting host operations, an administrator designates certain drives for media validation operations. If a host requests a file from media currently being validated, the host’s request takes priority. To ensure that the administrator really knows it is the media that is bad, as opposed to the drive, STA includes drive calibration and qualification features. In addition, validation requests can be re-prioritized or cancelled as needed. To ensure that a specific tape isn’t validated too often, STA prevents a tape from being validated twice within 24 hours via one of the policies described above. A tape can be validated more often if the administrator manually initiates the validation. When the validations are complete, STA reports the results. STA does not report simply a “good” or “bad” status. It also reports if media is even degraded so the administrator can migrate the data before there is a true failure. From that point, the administrators’ paranoia is relieved, as they have the necessary information to make a sound decision about the health of the tapes in their environment. About the Photograph Photograph taken by Rick Ramsey in Death Valley, California, May 2014 - Brian Follow OTN Garage on: Web | Facebook | Twitter | YouTube

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• Can't boot 12.04 installed alongside Windows 7

  - by PalaceChan

  I realize there are other questions like this one here, but I have visited them and tried several things and nothing is helping. One of them had a suggestion to boot the liveCD, and sudo mount /dev/sda* /mnt and to then chroot and reinstall grub. I did this and it did not help. Then on the Windows side, I downloaded a free version of easyBCD and chose to add a Grub2 Ubuntu 12.04 entry. On restart I saw this entry, but when I click on it it takes me to a Windows failed to boot error, as if it wasn't even trying to boot Ubuntu. I have booted from Ubuntu liveCD once again and have a snapshot of my GParted I ran this bootinfoscript thing from the liveCD, here are my results: It seems grub is on sda. I just want to be able to boot into my Ubuntu on startup. Boot Info Script 0.61 [1 April 2012] ============================= Boot Info Summary: =============================== = Grub2 (v1.99) is installed in the MBR of /dev/sda and looks at sector 1041658947 of the same hard drive for core.img. core.img is at this location and looks for (,gpt7)/boot/grub on this drive. sda1: __________________________________________ File system: vfat Boot sector type: Windows 7: FAT32 Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: /efi/Boot/bootx64.efi sda2: __________________________________________ File system: Boot sector type: - Boot sector info: Mounting failed: mount: unknown filesystem type '' sda3: __________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Windows 7 Boot files: /bootmgr /Boot/BCD /Windows/System32/winload.exe sda4: __________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: sda5: __________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: /bootmgr /boot/bcd sda6: __________________________________________ File system: BIOS Boot partition Boot sector type: Grub2's core.img Boot sector info: sda7: __________________________________________ File system: ext4 Boot sector type: Grub2 (v1.99) Boot sector info: Grub2 (v1.99) is installed in the boot sector of sda7 and looks at sector 1046637581 of the same hard drive for core.img. core.img is at this location and looks for (,gpt7)/boot/grub on this drive. Operating System: Ubuntu 12.04 LTS Boot files: /boot/grub/grub.cfg /etc/fstab /boot/grub/core.img sda8: __________________________________________ File system: swap Boot sector type: - Boot sector info: ============================ Drive/Partition Info: ============================= Drive: sda _______________________________________ Disk /dev/sda: 750.2 GB, 750156374016 bytes 255 heads, 63 sectors/track, 91201 cylinders, total 1465149168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes Partition Boot Start Sector End Sector # of Sectors Id System /dev/sda1 1 1,465,149,167 1,465,149,167 ee GPT GUID Partition Table detected. Partition Start Sector End Sector # of Sectors System /dev/sda1 2,048 411,647 409,600 EFI System partition /dev/sda2 411,648 673,791 262,144 Microsoft Reserved Partition (Windows) /dev/sda3 673,792 533,630,975 532,957,184 Data partition (Windows/Linux) /dev/sda4 533,630,976 1,041,658,946 508,027,971 Data partition (Windows/Linux) /dev/sda5 1,412,718,592 1,465,147,391 52,428,800 Windows Recovery Environment (Windows) /dev/sda6 1,041,658,947 1,041,660,900 1,954 BIOS Boot partition /dev/sda7 1,041,660,901 1,396,174,572 354,513,672 Data partition (Windows/Linux) /dev/sda8 1,396,174,573 1,412,718,591 16,544,019 Swap partition (Linux) blkid output: ____________________________________ Device UUID TYPE LABEL /dev/loop0 squashfs /dev/sda1 B498-319E vfat SYSTEM /dev/sda3 820C0DA30C0D92F9 ntfs OS /dev/sda4 168410AB84108EFD ntfs DATA /dev/sda5 AC7A43BA7A438056 ntfs Recovery /dev/sda7 42a5b598-4d8b-471b-987c-5ce8a0ce89a1 ext4 /dev/sda8 5732f1c7-fa51-45c3-96a4-7af3bff13278 swap /dev/sr0 iso9660 Ubuntu 12.04 LTS i386 ================================ Mount points: ================================= Device Mount_Point Type Options /dev/loop0 /rofs squashfs (ro,noatime) /dev/sr0 /cdrom iso9660 (ro,noatime) =========================== sda7/boot/grub/grub.cfg: =========================== How can I get this option? When I was using easyBCD, it kept saying I had no entries at all, so I did the add entry thing for Ubuntu many times and I see several of those on boot screen now. I'd love to get rid of all those unusable options.

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• Brainless Backups

  - by Jesse

  I’m a software developer by trade which means to my friends and family I’m just a “computer guy”. It’s assumed that I know everything about every facet of computing from removing spyware to replacing hardware. I also can do all of this blindly over the phone or after hearing a five to ten word description of the problem over dinner ;-) In my position as CIO of my friends and families I’ve been in the unfortunate position of trying to recover music, pictures, or documents off of failed hard drives on more than one occasion. It’s not a great situation for anyone, and it’s always at these times that the importance of backups becomes so clear. Several months back a friend of mine found himself in this situation. The hard drive on his 8 year old laptop failed and took a good number of his digital photos with it. I think most folks can deal with losing some of their music and even some of their documents, but it really stings to lose pictures of past events and loved ones. After ordering a new laptop, my friend went out and bought an external hard drive so that he could start keeping a backup of his data. As fate would have it, several months later the drive in his new laptop failed and he learned the hard way that simply buying the external hard drive isn’t enough… you actually have to copy your stuff over every once in awhile! The importance of backup and recovery plans is (hopefully) well known in IT organizations. Well executed backup plans are in place, and hopefully the backup and recovery process is tested regularly. When you’re talking about users at home, however, the need for these backups is often understood far too late. Most typical users can’t be expected to remember to backup their data regularly and also don’t always have the know-how to setup automated backups. For my friends and family members in this situation I recommend tools like Dropbox, Carbonite, and Mozy. Here’s why I like them: They’re affordable: Dropbox and Mozy both have free offerings, though most people with lots of music and/or photos to backup will probably exceed the storage limitations of those free plans pretty quickly. Still, all three offer pretty affordable monthly or yearly plans. In my opinion, Carbonite’s unlimited storage plan for $50-$60 per year is the best value around. They’re easy to setup: Both Dropbox and Carbonite are very easy to get setup and start using. I’ve never used Mozy, but I imagine it’s similarly painless to get up and running. Backups are automatically “off-site”: A backup that is sitting on an external hard drive right next to your computer is great, but might not protect against flood damage, a power surge, or other disasters in that single location. These services exist “in the cloud” so to speak, helping mitigate those concerns. Granted, this kind of backup scheme requires some trust in the 3rd party to protect your data from both malicious people and disastrous events. This truly is a bit of a double edged sword, but I sleep well at night knowing that my data is being backed up and secured by a company made up of engineers that focus on the business of doing backups right. Backups are “brainless”: What I like most about services like these is that they work “automagically” in the background, watching for files to be updated and automatically backing up those changes. There’s no need to remember to plug in that external drive and copy your data over. Since starting to recommend these services to my friends and family I find myself wearing my “data recovery” hat far less often. The only way backups are effective for your standard computer user is if they’re completely automatic. Backups need to be brainless, or they just won’t work.

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• The enterprise vendor con - connecting SSD's using SATA 2 (3Gbits) thus limiting there performance

  - by tonyrogerson

  When comparing SSD against Hard drive performance it really makes me cross when folk think comparing an array of SSD running on 3GBits/sec to hard drives running on 6GBits/second is somehow valid. In a paper from DELL (http://www.dell.com/downloads/global/products/pvaul/en/PowerEdge-PowerVaultH800-CacheCade-final.pdf) on increasing database performance using the DELL PERC H800 with Solid State Drives they compare four SSD drives connected at 3Gbits/sec against ten 10Krpm drives connected at 6Gbits [Tony slaps forehead while shouting DOH!]. It is true in the case of hard drives it probably doesn’t make much difference 3Gbit or 6Gbit because SAS and SATA are both end to end protocols rather than shared bus architecture like SCSI, so the hard drive doesn’t share bandwidth and probably can’t get near the 600MiBytes/second throughput that 6Gbit gives unless you are doing contiguous reads, in my own tests on a single 15Krpm SAS disk using IOMeter (8 worker threads, queue depth of 16 with a stripe size of 64KiB, an 8KiB transfer size on a drive formatted with an allocation size of 8KiB for a 100% sequential read test) I only get 347MiBytes per second sustained throughput at an average latency of 2.87ms per IO equating to 44.5K IOps, ok, if that was 3GBits it would be less – around 280MiBytes per second, oh, but wait a minute [...fingers tap desk] You’ll struggle to find in the commodity space an SSD that doesn’t have the SATA 3 (6GBits) interface, SSD’s are fast not only low latency and high IOps but they also offer a very large sustained transfer rate, consider the OCZ Agility 3 it so happens that in my masters dissertation I did the same test but on a difference box, I got 374MiBytes per second at an average latency of 2.67ms per IO equating to 47.9K IOps – cost of an 240GB Agility 3 is £174.24 (http://www.scan.co.uk/products/240gb-ocz-agility-3-ssd-25-sata-6gb-s-sandforce-2281-read-525mb-s-write-500mb-s-85k-iops), but that same drive set in a box connected with SATA 2 (3Gbits) would only yield around 280MiBytes per second thus losing almost 100MiBytes per second throughput and a ton of IOps too. So why the hell are “enterprise” vendors still only connecting SSD’s at 3GBits? Well, my conspiracy states that they have no interest in you moving to SSD because they’ll lose so much money, the argument that they use SATA 2 doesn’t wash, SATA 3 has been out for some time now and all the commodity stuff you buy uses it now. Consider the cost, not in terms of price per GB but price per IOps, SSD absolutely thrash Hard Drives on that, it was true that the opposite was also true that Hard Drives thrashed SSD’s on price per GB, but is that true now, I’m not so sure – a 300GByte 2.5” 15Krpm SAS drive costs £329.76 ex VAT (http://www.scan.co.uk/products/300gb-seagate-st9300653ss-savvio-15k3-25-hdd-sas-6gb-s-15000rpm-64mb-cache-27ms) which equates to £1.09 per GB compared to a 480GB OCZ Agility 3 costing £422.10 ex VAT (http://www.scan.co.uk/products/480gb-ocz-agility-3-ssd-25-sata-6gb-s-sandforce-2281-read-525mb-s-write-410mb-s-30k-iops) which equates to £0.88 per GB. Ok, I compared an “enterprise” hard drive with a “commodity” SSD, ok, so things get a little more complicated here, most “enterprise” SSD’s are SLC and most commodity are MLC, SLC gives more performance and wear, I’ll talk about that another day. For now though, don’t get sucked in by vendor marketing, SATA 2 (3Gbit) just doesn’t cut it, SSD need 6Gbit to breath and even that SSD’s are pushing. Alas, SSD’s are connected using SATA so all the controllers I’ve seen thus far from HP and DELL only do SATA 2 – deliberate? Well, I’ll let you decide on that one.

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• Fresh Ubuntu Install - Grub not loading

  - by Ryan Sharp

  System Ubuntu 12.04 64-bit Windows 7 SP1 Samsung 64GB SSD - OS' Samsung 1TB HDD - Games, /Home, Swap WD 300'ishGB HDD - Backup Okay, so I'm very frustrated, so please excuse me if I miss anything out as my head is clouded by anger and impatience, etc. I'll try me best, though. First of all, I'll explain how I got to my predicament. I finally got my new SSD. I firstly installed Windows, which completed without a hitch. Afterwards, I tried to install Ubuntu, which failed several times due to problems irrelevant to this question, but I mention this to explain my frustrations, sorry. Anyway, I finally installed Ubuntu. However, I chose the 'bootloader' to be installed on the same partition as where I was installing the Ubuntu Root partition, as that was what I believed to be the best choice. It was of my thinking that it was supposed to go on the same partition and on the SSD, which is my OS drive, though with my problem, it apparently was wrong. So I tried to fix it by checking guides and following their directions, but seemed to have messed it up even more. Here is what I receive after I use the fdisk -l command: (I also added explanations for which I used each partition for) Disk /dev/sda: 64.0 GB, 64023257088 bytes 255 heads, 63 sectors/track, 7783 cylinders, total 125045424 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x324971d1 Device Boot Start End Blocks Id System /dev/sda1 * 2048 206847 102400 7 HPFS/NTFS/exFAT /dev/sda2 208896 48957439 24374272 7 HPFS/NTFS/exFAT /dev/sda3 48959486 125044735 38042625 5 Extended /dev/sda5 48959488 125044735 38042624 83 Linux sda1 --/ Windows Recovery sda2 --/ Windows 7 sda3/5 --/ Ubuntu root [ / ] Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xc0ee6a69 Device Boot Start End Blocks Id System /dev/sdb1 1024208894 1953523711 464657409 5 Extended /dev/sdb3 * 2048 1024206847 512102400 7 HPFS/NTFS/exFAT /dev/sdb5 1024208896 1939851263 457821184 83 Linux /dev/sdb6 1939853312 1953523711 6835200 82 Linux swap / Solaris sdb3 --/ Partition for Steam games, etc. sdb5 --/ Ubuntu Home [ /home ] sdb6 --/ Ubuntu Swap Partition table entries are not in disk order Disk /dev/sdc: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x292eee23 Device Boot Start End Blocks Id System /dev/sdc1 2048 625141759 312569856 7 HPFS/NTFS/exFAT sdc1 --/ Generic backup I also used a Boot Script that other users suggested, so that I can give more details on my partitions and also where Grub is located... ============================= Boot Info Summary: =============================== => Grub2 (v1.99) is installed in the MBR of /dev/sda and looks at sector 1 of the same hard drive for core.img. core.img is at this location and looks for (,msdos5)/boot/grub on this drive. => Grub2 (v1.99) is installed in the MBR of /dev/sdb and looks at sector 1 of the same hard drive for core.img. core.img is at this location and looks for (,msdos5)/boot/grub on this drive. => Windows is installed in the MBR of /dev/sdc. Now that is weird... Why would Grub2 be installed on both my SSD and HDD? Even weirder is why is Windows on the MBR of my backup hard drive? Nothing I did should have done that... Anyway, here is the entire Output from that script... PASTEBIN So, to summarize what I need: How can I fix my setup so grub loads on startup? How can I clean my partitions to remove unnecessary grubs? What did I do wrong so that I don't do something so daft again? Thank you so much for reading, and I hope you can help me. I've been trying to have a successful setup since Friday, and I'm almost at the point that I'm really tempted to throw my computer out the window due to my frustration.

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• FileSystem.GetFiles() + UnauthorizedAccessException error?

  - by OverTheRainbow

  Hello, It seems like FileSystem.GetFiles() is unable to recover from the UnauthorizedAccessException exception that .Net triggers when trying to access an off-limit directory. In this case, does it mean this class/method isn't useful when scanning a whole drive and I should use some other solution (in which case: Which one?)? Here's some code to show the issue: Private Sub bgrLongProcess_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles bgrLongProcess.DoWork Dim drive As DriveInfo Dim filelist As Collections.ObjectModel.ReadOnlyCollection(Of String) Dim filepath As String 'Scan all fixed-drives for MyFiles.* For Each drive In DriveInfo.GetDrives() If drive.DriveType = DriveType.Fixed Then Try 'How to handle "Access to the path 'C:\System Volume Information' is denied." error? filelist = My.Computer.FileSystem.GetFiles(drive.ToString, FileIO.SearchOption.SearchAllSubDirectories, "MyFiles.*") For Each filepath In filelist DataGridView1.Rows.Add(filepath.ToString, "temp") 'Trigger ProgressChanged() event bgrLongProcess.ReportProgress(0, filepath) Next filepath Catch Ex As UnauthorizedAccessException 'How to ignore this directory and move on? End Try End If Next drive End Sub Thank you. Edit: What about using a Try/Catch just to have GetFiles() fill the array, ignore the exception and just resume? Private Sub bgrLongProcess_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles bgrLongProcess.DoWork 'Do lengthy stuff here Dim filelist As Collections.ObjectModel.ReadOnlyCollection(Of String) Dim filepath As String filelist = Nothing Try filelist = My.Computer.FileSystem.GetFiles("C:\", FileIO.SearchOption.SearchAllSubDirectories, "MyFiles.*") Catch ex As UnauthorizedAccessException 'How to just ignore this off-limit directory and resume searching? End Try 'Object reference not set to an instance of an object For Each filepath In filelist bgrLongProcess.ReportProgress(0, filepath) Next filepath End Sub

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• MySQL – How to Find mysqld.exe with Command Prompt – Fix: ‘mysql’ is not recognized as an internal or external command, operable program or batch file

  - by Pinal Dave

  One of the most popular question I get after watching my MySQL courses on Pluralsight is that beginning users are not able to find where they have installed MySQL Server. The error they receive is as follows when they type mysqld command on their default command line. ‘mysql‘ is not recognized as an internal or external command, operable program or batch file. This error comes up if user try to execute mysqld command on default command prompt. The user should execute this command where mysql.exe file exists.  If you are using Windows Explorer you can easily search on your drive mysqld.exe and find the location of the file and execute the above command there. However, if you want to find out with command prompt the location of mysqld.exe file you can follow the direction here. Step 1: Open a command prompt Open command prompt from Start >> Run >> cmd >> enter Step 2: Change directory You need to change the default directory to root directory, hence type cd\ command on the prompt to change the default directory to c:\ . Here we are assuming that you have installed MySQL on your c: drive. If you have installed it on any other drive change the drive to that letter. Step 3: Search Drive Type the command dir mysqld.exe /s /p on the command prompt. It will search your directories and will list the directory where mysqld.exe is located. Step 4: Change Directory Now once again change your command prompt file location to the folder where your mysqld.exe is located. In my case it is located here in folder C:\Program Files\MySQL\MySQL Server 5.6\bin hence I will run following command: cd C:\Program Files\MySQL\MySQL Server 5.6\bin . Step 5: Execute mysqld.exe Now you can once again mysqld.exe on your command prompt. You can use this method to search pretty much any file with the help of command prompt. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: MySQL, PostADay, SQL, SQL Authority, SQL Query, SQL Tips and Tricks, T SQL

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• How To Disconnect Non-Mapped UNC Path “Drives” in Windows

  - by The Geek

  Have you ever browsed over to another PC on your network using “network neighborhood”, and then connected to one of the file shares? Without a drive letter, how do you disconnect yourself once you’ve done so? Really confused as to what I’m talking about? Let’s walk through the process. First, imagine that you browse through and connect to a share, entering your username and password to gain access. The problem is that you stay connected, and there’s no visible way to disconnect yourself. If you try and shut down the other PC, you’ll receive a message that users are still connected. So let’s disconnect! Open up a command prompt, and then type in the following: net use This will give you a list of the connected drives, including the ones that aren’t actually mapped to a drive letter. To disconnect one of the connections, you can use the following command: net use /delete \\server\sharename For example, in this instance we’d disconnect like so: net use /delete \\192.168.1.205\root$ Now when you run the “net use” command again, you’ll see that you’ve been properly disconnected. If you wanted to actually connect to a share without mapping a drive letter, you can do the following: net use /user:Username \\server\sharename Password You could then just pop \\server\sharename into a Windows Explorer window and browse the files that way. Note that this technique should work exactly the same in any version of windows. Similar Articles Productive Geek Tips Remove "Map Network Drive" Menu Item from Windows Vista or XPDisable the Annoying "This page has an unspecified potential security risk" When Using Files on a Network ShareCopy Path of a File to the Clipboard in Windows 7 or VistaMap a Network Drive from XP to Windows 7Defrag Multiple Hard Drives At Once In Windows TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Enable DreamScene in Windows 7 Microsoft’s “How Do I ?” Videos Home Networks – How do they look like & the problems they cause Check Your IMAP Mail Offline In Thunderbird Follow Finder Finds You Twitter Users To Follow Combine MP3 Files Easily

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• OSI Model

  - by kaleidoscope

  The Open System Interconnection Reference Model (OSI Reference Model or OSI Model) is an abstract description for layered communications and computer network protocol design. In its most basic form, it divides network architecture into seven layers which, from top to bottom, are the Application, Presentation, Session, Transport, Network, Data Link, and Physical Layers. It is therefore often referred to as the OSI Seven Layer Model. A layer is a collection of conceptually similar functions that provide services to the layer above it and receives service from the layer below it. Description of OSI layers: Layer 1: Physical Layer ·         Defines the electrical and physical specifications for devices. In particular, it defines the relationship between a device and a physical medium. ·         Establishment and termination of a connection to a communications medium. ·         Participation in the process whereby the communication resources are effectively shared among multiple users. ·         Modulation or conversion between the representation of digital data in user equipment and the corresponding signals transmitted over a communications channel. Layer 2: Data Link Layer ·         Provides the functional and procedural means to transfer data between network entities. ·         Detect and possibly correct errors that may occur in the Physical Layer. The error check is performed using Frame Check Sequence (FCS). ·         Addresses is then sought to see if it needs to process the rest of the frame itself or whether to pass it on to another host. ·         The Layer is divided into two sub layers: The Media Access Control (MAC) layer and the Logical Link Control (LLC) layer. ·         MAC sub layer controls how a computer on the network gains access to the data and permission to transmit it. ·         LLC layer controls frame synchronization, flow control and error checking.   Layer 3: Network Layer ·         Provides the functional and procedural means of transferring variable length data sequences from a source to a destination via one or more networks. ·         Performs network routing functions, and might also perform fragmentation and reassembly, and report delivery errors. ·         Network Layer Routers operate at this layer—sending data throughout the extended network and making the Internet possible.   Layer 4: Transport Layer ·         Provides transparent transfer of data between end users, providing reliable data transfer services to the upper layers. ·         Controls the reliability of a given link through flow control, segmentation/de-segmentation, and error control. ·         Transport Layer can keep track of the segments and retransmit those that fail. Layer 5: Session Layer ·         Controls the dialogues (connections) between computers. ·         Establishes, manages and terminates the connections between the local and remote application. ·         Provides for full-duplex, half-duplex, or simplex operation, and establishes checkpointing, adjournment, termination, and restart procedures. ·         Implemented explicitly in application environments that use remote procedure calls. Layer 6: Presentation Layer ·         Establishes a context between Application Layer entities, in which the higher-layer entities can use different syntax and semantics, as long as the presentation service understands both and the mapping between them. The presentation service data units are then encapsulated into Session Protocol data units, and moved down the stack. ·         Provides independence from differences in data representation (e.g., encryption) by translating from application to network format, and vice versa. The presentation layer works to transform data into the form that the application layer can accept. This layer formats and encrypts data to be sent across a network, providing freedom from compatibility problems. It is sometimes called the syntax layer. Layer 7: Application Layer ·         This layer interacts with software applications that implement a communicating component. ·         Identifies communication partners, determines resource availability, and synchronizes communication. o       When identifying communication partners, the application layer determines the identity and availability of communication partners for an application with data to transmit. o       When determining resource availability, the application layer must decide whether sufficient network or the requested communication exists. o       In synchronizing communication, all communication between applications requires cooperation that is managed by the application layer. Technorati Tags: Kunal,OSI,Networking

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