A disk operating system (DOS) is a computer operating system that resides on and can use a disk storage device, such as a floppy disk, hard disk drive, or optical disc. A disk operating system provides a file system for organizing, reading, and writing files on the storage disk, and a means for loading and running programs stored on that disk. Strictly speaking, this definition does not include any other functionality, so it does not apply to more complex OSes, such as Microsoft Windows, and is more appropriately used only for older generations of operating systems.
In computer data storage, drive letter assignment is the process of assigning alphabetical identifiers to volumes. Unlike the concept of UNIX mount points, where volumes are named and located arbitrarily in a single hierarchical namespace, drive letter assignment allows multiple highest-level namespaces. Drive letter assignment is thus a process of using letters to name the roots of the "forest" representing the file system; each volume holds an independent "tree".
COMMAND.COM is the default command-line interpreter for MS-DOS, Windows 95, Windows 98 and Windows Me. In the case of DOS, it is the default user interface as well. It has an additional role as the usual first program run after boot. As a shell, COMMAND.COM has two distinct modes of operation: interactive mode and batch mode. Internal commands are commands stored directly inside the COMMAND.COM binary; thus, they are always available, but can only be executed directly from the command interpreter.
AmigaDOS is the disk operating system of the AmigaOS, which includes file systems, file and directory manipulation, the command-line interface, and file redirection.
Atari BASIC is an interpreter for the BASIC programming language that shipped with Atari 8-bit computers. Unlike most American BASICs of the home computer era, Atari BASIC is not a derivative of Microsoft BASIC and differs in significant ways. It includes keywords for Atari-specific features and lacks support for string arrays.
Apple DOS is the family of disk operating systems for the Apple II series of microcomputers from late 1978 through early 1983. It was superseded by ProDOS in 1983. Apple DOS has three major releases: DOS 3.1, DOS 3.2, and DOS 3.3; each one of these three releases was followed by a second, minor "bug-fix" release, but only in the case of Apple DOS 3.2 did that minor release receive its own version number, Apple DOS 3.2.1. The best-known and most-used version is Apple DOS 3.3 in the 1980 and 1983 releases. Prior to the release of Apple DOS 3.1, Apple users had to rely on audio cassette tapes for data storage and retrieval.
An environment variable is a user-definable value that can affect the way running processes will behave on a computer. Environment variables are part of the environment in which a process runs. For example, a running process can query the value of the TEMP environment variable to discover a suitable location to store temporary files, or the HOME or USERPROFILE variable to find the directory structure owned by the user running the process.
CONFIG.SYS is the primary configuration file for the DOS and OS/2 operating systems. It is a special ASCII text file that contains user-accessible setup or configuration directives evaluated by the operating system's DOS BIOS during boot. CONFIG.SYS was introduced with DOS 2.0.
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.
Atari DOS is the disk operating system used with the Atari 8-bit computers. Operating system extensions loaded into memory were required in order for an Atari computer to manage files stored on a disk drive. These extensions to the operating system added the disk handler and other file management features.
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.
Optimized Systems Software (OSS) was a company that produced disk operating systems, programming languages with integrated development environments, and applications primarily for Atari 8-bit computers. The founders of OSS previously developed Atari DOS, Atari BASIC, and the Atari Assembler Editor for Atari, Inc., and many OSS products are substantially improved versions. OS A+ and DOS XL are based on Atari DOS. BASIC A+, BASIC XL, and BASIC XE are based on Atari BASIC. EASMD and MAC/65 are modeled on the Atari Assembler Editor. Action! is an ALGOL-inspired compiled programming language with an integrated full-screen editor. OSS also sold some software for the Apple II.
DOS Plus was the first operating system developed by Digital Research's OEM Support Group in Newbury, Berkshire, UK, first released in 1985. DOS Plus 1.0 was based on CP/M-86 Plus combined with the PCMODE emulator from Concurrent PC DOS 4.11. While CP/M-86 Plus and Concurrent DOS 4.1 still had been developed in the United States, Concurrent PC DOS 4.11 was an internationalized and bug-fixed version brought forward by Digital Research UK. Later DOS Plus 2.x issues were based on Concurrent PC DOS 5.0 instead. In the broader picture, DOS Plus can be seen as an intermediate step between Concurrent CP/M-86 and DR DOS.
Atari Assembler Editor is a ROM cartridge-based development system released by Atari, Inc. in 1981. It is used to edit, assemble, and debug 6502 programs for Atari 8-bit computers without the need for additional tools. It was programmed by Kathleen O'Brien of Shepardson Microsystems, the company which wrote Atari BASIC, and Assembler Editor shares many design concepts with that language implementation.
MSX-DOS is a discontinued disk operating system developed by Microsoft's Japan subsidiary for the 8-bit home computer standard MSX, and is a cross between MS-DOS v1.25 and CP/M-80 v2.2.
SpartaDOS X is a disk operating system for the Atari 8-bit family of computers that closely resembles MS-DOS. It was developed and sold by ICD, Inc. in 1987-1993, and many years later picked up by the third-party community SpartaDOS X Upgrade Project, which still maintains the software.
AmigaOS is a family of proprietary native operating systems of the Amiga and AmigaOne personal computers. It was developed first by Commodore International and introduced with the launch of the first Amiga, the Amiga 1000, in 1985. Early versions of AmigaOS required the Motorola 68000 series of 16-bit and 32-bit microprocessors. Later versions were developed by Haage & Partner and then Hyperion Entertainment. A PowerPC microprocessor is required for the most recent release, AmigaOS 4.
DOS is a family of disk-based operating systems for IBM PC compatible computers. The DOS family primarily consists of IBM PC DOS and a rebranded version, Microsoft's MS-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.
MAC/65 is a 6502 assembler written by Stephen D. Lawrow for the Atari 8-bit family of home computers. MAC/65 was first released on disk by Optimized Systems Software in 1982, with the program requiring 16 KB RAM. A bank switched "SuperCartridge" from OSS followed in January 1984 for US$99, occupying only 8 KB.
