Atari DOS

Last updated
Atari DOS
Ataridos-2.5.PNG
Atari DOS version 2.5, main menu
Developer Atari, Inc., Atari Corporation
Working stateDiscontinued
Source model Closed source
Initial release1979;45 years ago (1979)
Latest release XE 1.0 / 1987;37 years ago (1987)
Available in English
Platforms Atari 8-bit family
Default
user interface
Menu
License Proprietary EULA

Atari DOS is the disk operating system used with the Atari 8-bit family of 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.

Contents

The most important extension is the disk handler. In Atari DOS 2.0, this was the File Management System (FMS), an implementation of a file system loaded from a floppy disk. This meant at least an additional 32 KB RAM was needed to run with DOS loaded.

Versions

There were several versions of Atari DOS available, with the first version released in 1979. [1] Atari was using a cross assembler with Data General AOS.

DOS 1.0

In the first version of DOS from Atari all commands were only accessible from the menu. It was bundled with the 810 disk drives. This version was entirely memory resident, which made it fast but occupied memory space.

DOS 2.0

Also known as DISK OPERATING SYSTEM II VERSION 2.0S

The second, more popular version of DOS from Atari was bundled with the 810 disk drives and some early 1050 disk drives. It is considered to be the lowest common denominator for Atari DOSes, as any Atari-compatible disk drive can read a disk formatted with DOS 2.0S.

DOS 2.0S consisted of DOS.SYS and DUP.SYS. DOS.SYS was loaded into memory, while DUP.SYS contained the disk utilities and was loaded only when the user exited to DOS.

In addition to bug fixes, DOS 2.0S featured improved NOTE/POINT support and the ability to automatically run an Atari executable file named AUTORUN.SYS. Since user memory was erased when DUP.SYS was loaded, an option to create a MEM.SAV file was added. This stored user memory in a temporary file (MEM.SAV) and restored it after DUP.SYS was unloaded. The previous menu option from DOS 1.0, N. DEFINE DEVICE, was replaced with N. CREATE MEM.SAV in DOS 2.0S.

Version 2.0S was for single-density disks, 2.0D was for double-density disks. 2.0D shipped with the 815 Dual Disk Drive, which was both expensive and incompatible with the standard 810, and thus sold only a small number; making DOS version 2.0D rare and unusual.

DOS 3

DOS 3 diskette as supplied with a 1050 disk drive Atari Master Diskette 3 DOS 3 Floppy Disk in Sleeve.jpg
DOS 3 diskette as supplied with a 1050 disk drive

A new version of DOS that came originally bundled with the 5.25-inch Atari 1050 disk drive. This made use of the new Enhanced Density (ED) [lower-alpha 1] capability, also referred to by Atari as Dual Density. This increased storage from 88 KB to 130 KB per disk. There was a single density (88 KB) formatting option to maintain compatibility with older Atari 810 disk drives.

By organizing sectors into blocks, Atari was anticipating larger capacity floppy disks, but this resulted in incompatibility with DOS 2.0S. Files converted to DOS 3 could not be converted back to DOS 2.0. As a result, DOS 3 was extremely unpopular and did not gain widespread acceptance amongst the Atari user community.

DOS 3 provided built-in help via the Atari HELP key and/or the inverse key. Help files needed to be present on the system DOS disk to function properly. DOS 3 also used special XIO commands to control disc operations within BASIC programs.

DOS 2.5

Also known as DISK OPERATING SYSTEM II VERSION 2.5

Version 2.5 is an upgrade to 3.0. [2] After listening to complaints by their customers, Atari released an improved version of their previous DOS. This allowed the use of Enhanced Density disks, and there was a utility to read DOS 3 disks. An additional option was added to the menu (P. FORMAT SINGLE) to format single-density disks. DOS 2.5 was shipped with 1050 disk drives and some early XF551 disk-drives.

Included utilities were DISKFIX.COM, COPY32.COM, SETUP.COM and RAMDISK.COM.

DOS 4.0

Codename during production: QDOS

DOS 4.0 was designed for the never-released 1450XLD . The rights were returned to the author, Michael Barall, who placed it in the public domain. It was later published by Antic Software. DOS 4.0 used blocks instead of single sectors, and supported single, enhanced, and double density, as well as both single- and double-sided drives. DOS 4.0 was not compatible with DOS 2 or 3 disks but could read files from them. It also did not automatically switch densities, and it was necessary to go to the menu and manually select the correct density.

DOS XE

Codename during production: ADOS

DOS XE supported the double-density and double-sided capabilities of the Atari XF551 drive, as well as its burst I/O. DOS XE used a new disk format which was incompatible with DOS 2.0S and DOS 2.5, requiring a separate utility for reading older 2.0 files. It also required bank-switched RAM, so it did not run on the 400/800 machines. It supported date-stamping of files and sub-directories.

DOS XE was the last DOS made by Atari for the Atari 8-bit family.

Third-party DOS programs

Many of these DOSes were released by manufacturers of third-party drives, anyone who made drive modifications, or anyone who was dissatisfied with the available DOSes. Often, these DOSes could read disks in higher densities, and could set the drive to read disks faster (using Warp Speed or Ultra-Speed techniques). Most of these DOSes (except SpartaDOS) were DOS 2.0 compatible.

SmartDOS

Menu driven DOS that was compatible with DOS 2.0. Among the first third-party DOS programs to support double-density drives.

Many enhancements including sector copying and verifying, speed checking, turning on/off file verifying and drive reconfiguration.

Published by Rana Systems. Written by John Chenoweth and Ron Bieber, last version 8.2D.

OS/A+ and DOS XL

DOS produced by Optimized Systems Software. Compatible with DOS 2.0 - Allowed the use of Double Density floppies. Unlike most ATARI DOSses, this used a command line instead of a menu. DOS XL provided a menu program in addition to the command line.

SuperDOS

This DOS could read SS/SD, SS/ED, SS/DD and DS/DD disks, and made use of all known methods of speeding up disk-reads supported by the various third-party drive manufacturers.

Published by Technical Support[ clarification needed ]. Written by Paul Nicholls.

Top-DOS

Menu driven DOS with enhanced features. Sorts disk directory listings and can set display options. File directory can be compressed. Can display deleted files and undelete them. Some advanced features required a proprietary TOP-DOS format.

Published by Eclipse Software. Written by R. K. Bennett.

Turbo-DOS

This DOS supports Turbo 1050, Happy, Speedy, XF551 and US Doubler highspeed drives. XL/XE only.

Published by Martin Reitershan Computertechnik. Written by Herbert Barth and Frank Bruchhäuser.

MyDOS

This DOS adds the ability to use sub-directories, and supports hard-drives.

Published by Wordmark Systems, includes complete source code.

SpartaDOS

This DOS used a command-line interface. Was not compatible with DOS 2.0, but could read DOS 2.0 disks. Supports subdirectories and hard drives being capable of handling filesystems sized up to 16 MB. Included the capability to create primitive batch files.

SpartaDOS X

Screenshot of SpartaDOS X by FTE & DLT SpartaDOS X prompt.png
Screenshot of SpartaDOS X by FTE & DLT

A more sophisticated version of SpartaDOS, which strongly resembles MS-DOS in its look and feel. It was shipped on a 64 KB ROM cartridge.

RealDOS

A SpartaDOS compatible DOS (in fact, a renamed version of SpartaDOS 3.x, due to legal reasons).

RealDOS is shareware by Stephen J. Carden and Ken Ames.

BW-DOS

Screenshot of BW-DOS by Jiri Bernasek Bwdos.png
Screenshot of BW-DOS by Jiří Bernasek

A SpartaDOS compatible DOS, the last version 1.30 was released in December 1995. It has a much lower memory footprint compared to the original SpartaDOS and does not use the RAM under the ROM of XL/XE machines, allowing it to be used on the older Atari 400/800 models.

BW-DOS is freeware by Jiří Bernasek.

XDOS

XDOS is freeware by Stefan Dorndorf.

Disk formats

A number of different formats existed for Atari disks. Atari DOS 2.0S, single-sided, single-density disk had 720 sectors divided into 40 tracks. After formatting, 707 sectors were free. Each 128-byte sector used the last 3 bytes for housekeeping data (bytes used, file number, next sector), leaving 125 bytes for data. This meant each disk held 707 × 125 = 88,375 bytes of user data.

The single-density disk holding a mere 88 KB per side remained the most popular Atari 8-bit disk format throughout the series' lifetime, and almost all commercial software continued to be sold in that format (or variants of it modified for copy protection), since it was compatible with all Atari-made disk drives.

Percom standard

In 1978, Percom established a double-density layout standard which all other manufacturers of Atari-compatible disk drives such as Indus, Amdek, and Rana —except Atari itself— followed. A configuration block of 12 bytes defines the disk layout. [3]

Related Research Articles

<span class="mw-page-title-main">Apple ProDOS</span> Operating system on Apple II series computers

ProDOS is the name of two similar operating systems for the Apple II series of personal computers. The original ProDOS, renamed ProDOS 8 in version 1.2, is the last official operating system usable by all 8-bit Apple II series computers, and was distributed from 1983 to 1993. The other, ProDOS 16, was a stop-gap solution for the 16-bit Apple IIGS that was replaced by GS/OS within two years.

In computer science, group coded recording or group code recording (GCR) refers to several distinct but related encoding methods for representing data on magnetic media. The first, used in 6250 bpi magnetic tape since 1973, is an error-correcting code combined with a run-length limited (RLL) encoding scheme, belonging into the group of modulation codes. The others are different mainframe hard disk as well as floppy disk encoding methods used in some microcomputers until the late 1980s. GCR is a modified form of a NRZI code, but necessarily with a higher transition density.

<span class="mw-page-title-main">TRSDOS</span> Operating system for Tandy TRS-80 computers

TRSDOS is the operating system for the Tandy TRS-80 line of eight-bit Zilog Z80 microcomputers that were sold through Radio Shack from 1977 through 1991. Tandy's manuals recommended that it be pronounced triss-doss. TRSDOS should not be confused with Tandy DOS, a version of MS-DOS licensed from Microsoft for Tandy's x86 line of personal computers (PCs).

This article details versions of MS-DOS, IBM PC DOS, and at least partially compatible disk operating systems. It does not include the many other operating systems called "DOS" which are unrelated to IBM PC compatibles.

<span class="mw-page-title-main">Rainbow 100</span> DEC microcomputer

The Rainbow 100 is a microcomputer introduced by Digital Equipment Corporation (DEC) in 1982. This desktop unit had a monitor similar to the VT220 and a dual-CPU box with both 4 MHz Zilog Z80 and 4.81 MHz Intel 8088 CPUs. The Rainbow 100 was a triple-use machine: VT100 mode, 8-bit CP/M mode, and CP/M-86 or MS-DOS mode using the 8088. It ultimately failed to in the marketplace which became dominated by the simpler IBM PC and its clones which established the industry standard as compatibility with CP/M became less important than IBM PC compatibility. Writer David Ahl called it a disastrous foray into the personal computer market. The Rainbow was launched along with the similarly packaged DEC Professional and DECmate II which were also not successful. The failure of DEC to gain a significant foothold in the high-volume PC market would be the beginning of the end of the computer hardware industry in New England, as nearly all computer companies located there were focused on minicomputers for large organizations, from DEC to Data General, Wang, Prime, Computervision, Honeywell, and Symbolics Inc.

Optimized Systems Software (OSS) was a company that produced disk operating systems, programming languages with integrated development environments, and applications primarily for the Atari 8-bit family of home computers. OSS was best known for their enhanced versions of Atari DOS, Atari BASIC, and the Atari Assembler Editor, all of which were substantially improved over Atari's products, as well as the Action! programming language. OSS also sold some software for the Apple II.

Floppy disk format and density refer to the logical and physical layout of data stored on a floppy disk. Since their introduction, there have been many popular and rare floppy disk types, densities, and formats used in computing, leading to much confusion over their differences. In the early 2000s, most floppy disk types and formats became obsolete, leaving the 3+12-inch disk, using an IBM PC compatible format of 1440 KB, as the only remaining popular format.

<span class="mw-page-title-main">DOS XL</span>

DOS XL is a discontinued Disk Operating System (DOS) written by Paul Laughton, Mark Rose, Bill Wilkinson, and Mike Peters and published by Optimized Systems Software (OSS) for the Atari 8-bit family of home computers. It was designed to be compatible with Atari DOS which came shipped with Atari, Inc.'s disk drives, which had also been written by the same team.

CrossDOS is a file system handler for accessing FAT formatted media on Amiga computers. It was bundled with AmigaOS 2.1 and later. Its function was to allow working with disks formatted for PCs and Atari STs. In the 1990s it became a commonly used method of file exchange between Amiga systems and other platforms.

Atari 8-bit computer peripherals include floppy drives, printers, modems, and video game controllers for Atari's 8-bit computer family, which includes the 400/800, XL, XE, and XEGS.

<span class="mw-page-title-main">Atari TOS</span> Operating system of the Atari ST range of computers

TOS is the operating system of the Atari ST range of computers. This range includes the 520ST and 1040ST, their STF/M/FM and STE variants and the Mega ST/STE. Later, 32-bit machines were developed using a new version of TOS, called MultiTOS, which allowed multitasking. More recently, users have further developed TOS into FreeMiNT.

<span class="mw-page-title-main">History of the floppy disk</span>

A floppy disk is a disk storage medium composed of a disk of thin and flexible magnetic storage medium encased in a rectangular plastic carrier. It is read and written using a floppy disk drive (FDD). Floppy disks were an almost universal data format from the 1970s into the 1990s, used for primary data storage as well as for backup and data transfers between computers.

<span class="mw-page-title-main">SpartaDOS X</span> Disk operating system

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.

Happy drives are series of disk drive enhancements for the Atari 8-bit and Atari ST computer families produced by a small company Happy Computers. Happy Computers is most noted for the add-in boards for the Atari 810 and Atari 1050 disk drives, which achieved a tremendous speed improvement for reading and writing, and for the ability to "back up" floppies. Happy's products were among the most popular Atari computer add-ons. They were still in use and active in the aftermarket as of 2009.

<span class="mw-page-title-main">MAC/65</span> Atari 8-bit family 6502 assembler

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.

<span class="mw-page-title-main">Floppy disk variants</span> Types of floppy disk formats

The floppy disk is a data storage and transfer medium that was ubiquitous from the mid-1970s well into the 2000s. Besides the 3½-inch and 5¼-inch formats used in IBM PC compatible systems, or the 8-inch format that preceded them, many proprietary floppy disk formats were developed, either using a different disk design or special layout and encoding methods for the data held on the disk.

<span class="mw-page-title-main">Atari 810</span> Disk drive for the Atari 8-bit family

The Atari 810 is the official floppy disk drive for the Atari 400 and 800, the first two models in the Atari 8-bit family of home computers. It was released by Atari, Inc. in 1980.

<span class="mw-page-title-main">Atari 1050</span>

The Atari 1050 was a floppy disk drive for the Atari 8-bit family home computers, released in June 1983. It was compatible with the 90 kB single-density mode of the original Atari 810 it replaced, and added a new "enhanced" or "dual density" mode that provided 130 kB. Based on a half-height Tandon mechanism, it was smaller than the 810 and matched the styling of the new 600XL and 800XL machines.

The FAT file system is a file system used on MS-DOS and Windows 9x family of operating systems. It continues to be used on mobile devices and embedded systems, and thus is a well suited file system for data exchange between computers and devices of almost any type and age from 1981 through the present.

<span class="mw-page-title-main">Atari XF551</span> Floppy disk drive

The XF551 was the last floppy disk drive produced by Atari for the 8-bit series home computers. It was the first drive from the company that officially supported double-density, adding double-sided support, providing 360 kB of storage per disk. It also introduced a faster transfer speed when used in double-density mode, doubling performance. It was packaged in the new gray-colored design language of the XE series computers.

References

  1. Atari Archived February 21, 2009, at the Wayback Machine
  2. Chadwick, Ian (1985). "Appendix Seventeen: Dos 2.5 And The 1050 Drive". Mapping the Atari. Greensboro, North Carolina: Compute! Publications, Inc. ISBN   0-87455-004-1.
  3. Wilkinson, Bill (October 1985). "Atari Disk Drive Compatibility". Compute!. pp. 110–111. Retrieved 16 October 2013.
Notes
  1. Not to be confused with the much later extra-high density (ED) perpendicular recording floppy disks.