| recover | |
|---|---|
| Original author | Chris Peters |
| Developers | Microsoft,IBM,Digital Research,Novell, Imre Leber |
| Initial release | 1983, 42–43 years ago |
| Written in | MS-DOS:x86 assembly language |
| Operating system | MS-DOS,PC DOS,SISNE plus,OS/2,eComStation,ArcaOS,Windows,DR DOS,FreeDOS |
| Platform | Cross-platform |
| Type | Command |
| License | MS-DOS:MIT FreeDOS:GPL |
| Website | docs |
Incomputing,recover is a primitivefile system error recovery utility[1] included inMS-DOS /IBM PC DOS versions prior to DOS 6.0[2] and a number of otheroperating systems.
Typingrecover at the DOScommand-line invoked the program fileRECOVER.COM orRECOVER.EXE (depending on the DOS version).recover proceeded under the assumption that alldirectory information included on a disk ordisk partition was hopelessly corrupted, but that theFAT and non-directory areas might still contain useful information (though there might be additional baddisk sectors not recorded in the FAT).
The program removed all subdirectories and all entries in theroot directory, and then created new files with names such as "FILE0001.REC" in the root directory, corresponding to the valid allocation chains that were found in the FAT area (excludingdisk clusters that were tested and found to have hardware errors). A formerlybootable disk would no longer be bootable afterrecover had executed. The range of circumstances in whichrecover was genuinely useful was quite limited, and well-meaning DOS users sometimes created havoc by runningrecover under the misconception that it was a fileundelete utility.[3]
In DOS version 5, another mode of operation was added: specifying a singlefilename on the command line would cause the program to test all the disk sectors used to store the file, and shorten the file by omitting sectors which tested bad.[4]
DR DOS 6.0 includes an implementation of therecover command.[5] The command is also available onSISNE plus[6] andIBMOS/2.[7] TheFreeDOS version was developed by Imre Leber and is licensed under theGPL.[8]
