How To Recover lost data…….
When you delete files, they’re never permanently deleted.Even if you mistakenly delete a file, it still exists on thehard disk. This is termed as data remanence. The file namesare usually only removed from the system directory orshifted to a holding area for safe keeping (even if said areahasn’t been specified in advance by the user). One biggestcauses of data loss is logical damage. It is primarily causedby power outages that prevent files from being completelywritten to the storage medium. Problems with hardwarelike RAID controllers and system crashes usually cause thesame but the result is the same. The file system is left inan inconsistent state. This can lead to more problems suchas drives reporting negative amounts of free space, systemcrashes and actual lost data.Logical damage can be prevented through the use ofjournaling file systems like NTFS 5.0. It decreases theincidence of logical damage by rolling back to a consistentstate. Only the data present in the drive’s cache at the timeof system failure will be lost. That being said, two commontechniques for recovering data from logical damage include:1. Consistency checking – Scans the logical structure of thedisk and makes sure it is consistent with its specifications.A file repair system repair program reads each directoryand makes sure these entries exist and point to the correctdirectories.2. Data carving – Allows for data with no file systemallocation to be extracted by identifying sectors and clustersbelonging to the file. Usually searches through raw sectorslooking for specific file signatures.It should be mentioned that data recovery cannot be doneon a running system. A boot disk, Live USB, etc. containing aminimal operating system and a set of repair tools is usuallyrequired. One of these is Nero BackItUp Image Tool whichrestores the image created by the application to roll back thesystem to a consistent state. A good consistency checker isCheckdisk (CHKDSK, for short). It runs on DOS, OS/2 and Windows OS systems, displaying file system integrity statusof disk drives. It can fix logical file system errors and canalso check the disk surface for physical errors or bad sectors.CHKDSK can be run from the Windows Shell, the WindowsCommand Prompt or the Windows Recovery Console.Some general tips for recovering data: Don’t delete filesinstantly. Move them to a temporary location such as therecycle bin before deciding whether you need them or not.Mark important files as read-only. The OS will then warnyou if you try to delete the file. Under systems that allowfile system permissions, users can often only delete theirown files. This prevents the erasure of critical system files orother’s work.