Original author(s) | Chris Peters |
---|---|
Developer(s) | Microsoft, IBM, Digital Research, Novell, Imre Leber |
Initial release | 1983, 38–39 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 |
In computing, recover
is a primitive file system error recovery utility [1] included in MS-DOS / IBM PC DOS versions prior to DOS 6.0 [2] and a number of other operating systems.
Typing recover
at the DOS command-line invoked the program file RECOVER.COM or RECOVER.EXE (depending on the DOS version). recover
proceeded under the assumption that all directory information included on a disk or disk partition was hopelessly corrupted, but that the FAT and non-directory areas might still contain useful information (though there might be additional bad disk sectors not recorded in the FAT).
The program removed all subdirectories and all entries in the root 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 (excluding disk clusters that were tested and found to have hardware errors). A formerly bootable disk would no longer be bootable after recover
had executed. The range of circumstances in which recover
was genuinely useful was quite limited, and well-meaning DOS users sometimes created havoc by running recover
under the misconception that it was a file undelete utility. [3]
In DOS version 5, another mode of operation was added: specifying a single filename 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 the recover
command. [5] The command is also available on SISNE plus [6] and IBM OS/2. [7] The FreeDOS version was developed by Imre Leber and is licensed under the GPL. [8]
File Allocation Table (FAT) is a file system developed for personal computers. Originally developed in 1977 for use on floppy disks, it was adapted for use on hard disks and other devices. It is often supported for compatibility reasons by current operating systems for personal computers and many mobile devices and embedded systems, allowing interchange of data between disparate systems. The increase in disk drives capacity required three major variants: FAT12, FAT16 and FAT32. The FAT standard has also been expanded in other ways while generally preserving backward compatibility with existing software.
Disk partitioning or disk slicing is the creation of one or more regions on secondary storage, so that each region can be managed separately. These regions are called partitions. It is typically the first step of preparing a newly installed disk, before any file system is created. The disk stores the information about the partitions' locations and sizes in an area known as the partition table that the operating system reads before any other part of the disk. Each partition then appears to the operating system as a distinct "logical" disk that uses part of the actual disk. System administrators use a program called a partition editor to create, resize, delete, and manipulate the partitions. Partitioning allows the use of different filesystems to be installed for different kinds of files. Separating user data from system data can prevent the system partition from becoming full and rendering the system unusable. Partitioning can also make backing up easier. A disadvantage is that it can be difficult to properly size partitions, resulting in having one partition with too much free space and another nearly totally allocated.
IBM PC DOS, an acronym for IBM Personal Computer Disk Operating System, is a discontinued disk operating system for IBM PC compatibles. It was manufactured and sold by IBM from the early 1980s into the 2000s. Developed by Microsoft, it was also sold by that company as MS-DOS. Both operating systems were identical or almost identical until 1993, when IBM began selling PC DOS 6.1 with new features. The collective shorthand for PC DOS and MS-DOS was DOS, which is also the generic term for disk operating system, and is shared with dozens of disk operating systems called DOS.
NTLDR is the boot loader for all releases of Windows NT operating system from 1993 with the release of Windows NT 3.1 up until Windows XP and Windows Server 2003. From Windows Vista onwards it was replaced by the BOOTMGR bootloader. NTLDR is typically run from the primary storage device, but it can also run from portable storage devices such as a CD-ROM, USB flash drive, or floppy disk. NTLDR can also load a non NT-based operating system given the appropriate boot sector in a file.
Disk formatting is the process of preparing a data storage device such as a hard disk drive, solid-state drive, floppy disk, memory card or USB flash drive for initial use. In some cases, the formatting operation may also create one or more new file systems. The first part of the formatting process that performs basic medium preparation is often referred to as "low-level formatting". Partitioning is the common term for the second part of the process, dividing the device into several sub-devices and, in some cases, writing information to the device allowing an operating system to be booted from it. The third part of the process, usually termed "high-level formatting" most often refers to the process of generating a new file system. In some operating systems all or parts of these three processes can be combined or repeated at different levels and the term "format" is understood to mean an operation in which a new disk medium is fully prepared to store files. Some formatting utilities allow distinguishing between a quick format, which does not erase all existing data and a long option that does erase all existing data.
In computing, the fdisk command-line utility provides disk-partitioning functions, preparatory to defining file systems. fdisk
features in the DOS, DR FlexOS, IBM OS/2, and Microsoft Windows operating systems, and in certain ports of FreeBSD, NetBSD, OpenBSD, DragonFly BSD and macOS for compatibility reasons. In versions of the Windows NT operating-system line from Windows 2000 onwards, fdisk
is replaced by a more advanced tool called diskpart
. Similar utilities exist for Unix-like systems, for example, BSD disklabel.
A bootloader, also spelled as boot loader or called boot manager and bootstrap loader, is a computer program that is responsible for booting a computer.
AUTOEXEC.BAT
is a system file that was originally on DOS-type operating systems. It is a plain-text batch file in the root directory of the boot device. The name of the file is an abbreviation of "automatic execution", which describes its function in automatically executing commands on system startup; the filename was coined in response to the 8.3 filename limitations of the FAT file system family.
In computing, CHKDSK
is a system tool and command in DOS, Digital Research FlexOS, IBM/Toshiba 4690 OS, IBM OS/2, Microsoft Windows and related operating systems. It verifies the file system integrity of a volume and attempts to fix logical file system errors. It is similar to the fsck
command in Unix and similar to Microsoft ScanDisk which co-existed with CHKDSK
in Windows 9x and MS-DOS 6.x.
Long filename (LFN) support is Microsoft's backward-compatible extension of the 8.3 filename naming scheme used in DOS. Long filenames can be more descriptive, including longer filename extensions such as .jpeg
, .tiff
, .html
, and .xhtml
that are common on other operating systems, rather than specialized shortened names such as .jpg
, .tif
, .htm
, or .xht
. The standard has been common with File Allocation Table (FAT) filesystems since its first implementation in Windows NT 3.5 of 1994.
In computing, tree
is a recursive directory listing command or program that produces a depth-indented listing of files. Originating in PC- and MS-DOS, it is found in Digital Research FlexOS, IBM/Toshiba 4690 OS, PTS-DOS, FreeDOS, IBM OS/2, Microsoft Windows, and ReactOS. A version for Unix and Unix-like systems is also available.
In computing, sys
is a command used in many operating system command-line shells and also in Microsoft BASIC.
In computing, label
is a command included with some operating systems. It is used to create, change, or delete a volume label on a logical drive, such as a hard disk partition or a floppy disk. Used without parameters, label
changes the current volume label or deletes the existing label.
In computing, format
, a command-line utility that carries out disk formatting. It is a component of various operating systems, including 86-DOS, MS-DOS, IBM PC DOS and OS/2, Microsoft Windows and ReactOS.
MS-DOS is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few operating systems attempting to be compatible with MS-DOS, are sometimes referred to as "DOS". MS-DOS was the main operating system for IBM PC compatibles during the 1980s, from which point it was gradually superseded by operating systems offering a graphical user interface (GUI), in various generations of the graphical Microsoft Windows operating system.
DOS is a platform-independent acronym for "disk operating system" that later became a common shorthand for disk-based operating systems on IBM PC compatibles. DOS primarily consists of Microsoft's MS-DOS and a rebranded version under the name IBM PC DOS, both of which were introduced in 1981. Later compatible systems from other manufacturers include DR DOS (1988), ROM-DOS (1989), PTS-DOS (1993), and FreeDOS (1998). MS-DOS dominated the IBM PC compatible market between 1981 and 1995.
In computing, diskcomp
is a command used for comparing the complete contents of a floppy disk to another one.
A FAT file system is a specific type of computer file system architecture and a family of industry-standard file systems utilizing it.
MS-DOS 7 is a real mode operating system for IBM PC compatibles. Unlike earlier versions of MS-DOS it was not released separately by Microsoft, but included in the Windows 9x family of operating systems. Windows 95 RTM reports to be MS-DOS 7.0, while Windows 95 OSR 2.x and Windows 98 report as 7.1. Windows 9x runs under DOS similar to Windows 3.1x, and while according to Microsoft the role of MS-DOS was reduced to a boot loader and acted as the 16-bit legacy device driver layer, it has been stated that there is almost no difference in the relationship between Windows 9x and its included MS-DOS 7.x and Windows 3.x and MS-DOS 6.x.