FORMAT.COM
| Company type | Command-line utility |
|---|---|
| Industry | Computing / Software |
| Founded | 1981 |
| Products | Disk formatting tool |
In the realm of computing, the format utility is a command-line tool designed for disk formatting operations. It is incorporated within numerous operating systems such as 86-DOS, MS-DOS, IBM's PC DOS, OS/2, Microsoft Windows, and ReactOS.
Overview
The format utility configures storage devices—including floppy disks, hard drives, solid-state drives (like USB drives), and other magnetic media—by executing the following steps:
- Resetting the entries in the File Allocation Table (FAT) to
- Clearing the root directory in the FAT by initializing its entries to
- Examining each cluster to detect and flag usable or defective sectors within the FAT
This formatting procedure organizes the storage device to facilitate file system creation, a fundamental requirement for making the device operational. Although Unix-like systems utilize distinct commands to establish various file systems compatible with DOS, Windows, and OS/2, format remains indispensable for disk initialization in DOS-centric platforms.
Implementations
This command is also present in a wide range of other operating systems such as Intel ISIS-II, iRMX 86, MetaComCo TRIPOS, AmigaDOS, Zilog Z80-RIO, Microware OS-9, DR FlexOS, TSL PC-MOS, SpartaDOS X, Datalight ROM-DOS, IBM/Toshiba’s 4690 OS, PTS-DOS, SISNE plus, and the DEC RT-11 OS.
Microsoft DOS and Windows
The format command has been included in MS-DOS since its initial release. The optional /S parameter installs a Volume Boot Record by writing bootstrap code into the first sector, along with a mandatory BIOS Parameter Block. Using /Q triggers a "Quick Format," which bypasses some formatting stages without erasing existing data.
In MS-DOS versions 3.2 and earlier, executing "format" without arguments would immediately format the current drive without confirmation; starting from MS-DOS 3.3, this action results in an error due to missing parameters.
DR/Novell DOS
The format utility is also part of DR DOS 6.0, offering disk preparation and management capabilities specific to that environment.
FreeDOS
The version included with FreeDOS was created by Brian E. Reifsnyder and is distributed under the terms of the GPL, providing an open-source solution for disk formatting.
ReactOS
In ReactOS, the format utility originates from a free clone developed by Mark Russinovich for Sysinternals in 1998 under GPL licensing. It was later adapted by Emanuele Aliberti in 1999. This implementation supports multiple file systems such as FAT, FAT32, FATX, EXT2, and BtrFS, broadening ReactOS’s compatibility across diverse storage formats.
See also
- Disk formatting
- Data recovery
- convert
- File Allocation Table
- Design of the FAT file system
- fdisk
- PC DOS 7.10 Format32
Notes
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Further reading
External links
- Official Microsoft Windows XP Professional Documentation: "format" command
- Source code for FORMAT from MS-DOS version 2.0
- Microsoft Knowledge Base Article 255867: Guidance on using Fdisk and Format utilities for disk partition management
- Overview of the Microsoft DOS format command
- Explanation of the Recovery Console format command