Atari DOS
Encyclopedia
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 access a disk drive
. These extensions to the operating system added the disk handler and other file management features.
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 Random access memory was needed to run with DOS loaded,.
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.
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
In addition to bug fixes, DOS 2.0S featured improved
Version 2.0S was for single-density disks, 2.0D was for double-density disks. 2.0D was for the 815 Dual Disk Drive.
By organizing sector
s 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 3.0 was extremely unpopular and did not gain widespread acceptance amongst the Atari user community. Due to complaints and bugs, Atari released DOS 2.5, which was actually released after DOS 3.0, in contravention of standard version naming practices.
DOS 3.0 provided built-in help via the Atari HELP key and/or the inverse key. Help files needed to be present on the dos disk to function properly.
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 (
Included utilities were
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.
When the Atari XF551 drive came out, not only was it Atari's first drive that could read double-density disks, it was also double-sided. So support was added in the DOS for double-density and double-sided disks.
A new proprietary disk format made DOS XE incompatible with DOS 2.0S or DOS 2.5. A separate utility was needed for reading older 2.0 files.
Only XL/XE computers were supported, DOS XE did not work with the older 400/800 computers.
DOS XE also supported date-stamping of files, sub-directories and burst I/O for the XF551 drive.
DOS XE was the last DOS made by Atari for the Atari 8-bit family.
Many enhancements including sector copying and verifying, speed checking, turning on/off file verifying and drive reconfiguration.
Written by John Chenoweth and Ron Beiber.
. 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.
Published by Technical Support. Written by Paul Nicholls.
Published by Eclipse Software.
Published by Wordmark Systems, includes complete source code.
.
RealDOS is Shareware by Stephen J. Carden and Ken Ames.
BW-DOS is Freeware by Jiří Bernasek.
with an Atari 2 compatible DOS, 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.
DOS
DOS, short for "Disk Operating System", is an acronym for several closely related operating systems that dominated the IBM PC compatible market between 1981 and 1995, or until about 2000 if one includes the partially DOS-based Microsoft Windows versions 95, 98, and Millennium Edition.Related...
used with the Atari 8-bit family
Atari 8-bit family
The Atari 8-bit family is a series of 8-bit home computers manufactured from 1979 to 1992. All are based on the MOS Technology 6502 CPU and were the first home computers designed with custom coprocessor chips...
of computers. Operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
extensions loaded into memory were required in order for an Atari computer to access a disk drive
Disk storage
Disk storage or disc storage is a general category of storage mechanisms, in which data are digitally recorded by various electronic, magnetic, optical, or mechanical methods on a surface layer deposited of one or more planar, round and rotating disks...
. These extensions to the operating system added the disk handler and other file management features.
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
File system
A file system is a means to organize data expected to be retained after a program terminates by providing procedures to store, retrieve and update data, as well as manage the available space on the device which contain it. A file system organizes data in an efficient manner and is tuned to the...
loaded from a floppy disk
Floppy disk
A floppy disk is a disk storage medium composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic carrier lined with fabric that removes dust particles...
. This meant at least an additional Random access memory was needed to run with DOS loaded,.
Versions
There were several versions of Atari DOS available, with the first version released in 1979.DOS 1.0
In the first version of DOS from AtariAtari
Atari is a corporate and brand name owned by several entities since its inception in 1972. It is currently owned by Atari Interactive, a wholly owned subsidiary of the French publisher Atari, SA . The original Atari, Inc. was founded in 1972 by Nolan Bushnell and Ted Dabney. It was a pioneer in...
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 was for the 815 Dual Disk Drive.
DOS 3.0
A new version of DOS that came bundled with the 1050 disk drives from Atari. This made use of the new Enhanced Density capability (referred to by Atari as Dual Density) offered by the 1050.By organizing sector
Disk sector
In computer disk storage, a sector is a subdivision of a track on a magnetic disk or optical disc. Each sector stores a fixed amount of user data. Traditional formatting of these storage media provides space for 512 bytes or 2048 bytes of user-accessible data per sector...
s 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 3.0 was extremely unpopular and did not gain widespread acceptance amongst the Atari user community. Due to complaints and bugs, Atari released DOS 2.5, which was actually released after DOS 3.0, in contravention of standard version naming practices.
DOS 3.0 provided built-in help via the Atari HELP key and/or the inverse key. Help files needed to be present on the dos disk to function properly.
DOS 2.5
- Also known as DISK OPERATING SYSTEM II VERSION 2.5
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
Public domain
Works are in the public domain if the intellectual property rights have expired, if the intellectual property rights are forfeited, or if they are not covered by intellectual property rights at all...
. It was later published by ANTIC Software
ANTIC Software
Antic Software was the name of the software company founded by Gary Yost of Antic, a magazine for the Atari 8-bit computers. The catalog of software was bound into issues of Antic, and products were sold via mail order....
. 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
When the Atari XF551 drive came out, not only was it Atari's first drive that could read double-density disks, it was also double-sided. So support was added in the DOS for double-density and double-sided disks.
A new proprietary disk format made DOS XE incompatible with DOS 2.0S or DOS 2.5. A separate utility was needed for reading older 2.0 files.
Only XL/XE computers were supported, DOS XE did not work with the older 400/800 computers.
DOS XE also supported date-stamping of files, sub-directories and burst I/O for the XF551 drive.
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 Sparta DOS) 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.
Written by John Chenoweth and Ron Beiber.
OS/A+ and DOS XL
DOS produced by Optimized Systems SoftwareOptimized Systems Software
Optimized Systems Software was a small company producing operating systems and programming languages for the Atari 8-bit and Apple II computer families...
. 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
DOS XL
DOS XL was a Disk Operating System written by Paul Laughton, Mark Rose, Bill Wilkinson and Mike Peters and produced by Optimized Systems Software for Atari 8-bit microcomputers...
provided a menu program in addition to the command line.
SuperDOS
This DOS could read SS/ED/DD/DS 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. Written by Paul Nicholls.
TopDOS
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 TOPDOS format.Published by Eclipse Software.
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
A more sophisticated version of SpartaDOS, which strongly resembles MS-DOS in its look and feel. It was shipped on a 64K ROM cartridgeROM cartridge
A ROM cartridge, sometimes referred to as a cart, is a removable enclosure containing read-only memory devices designed to be connected to a computer or games console....
.
Real.Dos
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
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 is not using the RAM under the ROM of XL/XE machines, so it can be used on the older Atari 400/800 models.BW-DOS is Freeware by Jiří Bernasek.
DOS 2.6
Someone in the Atari hacker community modified DOS 2.0 to add a few features and allow the use of dual density disk drives, with the "look and feel" of DOS 2.0. One new feature added was "RADIX", which one could use to translate hexadecimal numbers to base 10 or base 10 to hex.Disk formats
A number of different formats existed for Atari disks. The standard Atari single-sided, single-density disk had 720 sectors divided into 40 tracks. After formattingDisk formatting
Disk formatting is the process of preparing a hard disk drive or flexible disk medium for data storage. In some cases, the formatting operation may also create one or more new file systems...
with an Atari 2 compatible DOS, 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.
- Single-Sided, Single-Density: 40 tracks with 18 sectors per track, 128 bytes per sector. 90K capacity.
- Single-Sided, Double-Density: 40 tracks with 18 sectors per track, 256 bytes per sector. 180K capacity.
- Single-Sided, Enhanced-Density: 40 tracks with 26 sectors per track, 128 bytes per sector. 127K capacity.
- Double-Sided, Double-Density: 80 tracks (40 tracks per side) with 18 sectors per track, 256 bytes per sector. 360K capacity.
External links
- What are Atari DOS 1, DOS 2.0S, DOS 3, DOS 2.5, and DOS XE? — From the Atari 8-bit FAQ.
- Atari DOS Reference Manual — Reference manual for DOS 3.
- Antic Vol.4 No.3 Everything You Wanted To Know About Every DOS
- Atari Dos 4 Documentation on Atari DOS 4
- BEWE-DOS 1.30 BEWE-DOS Manual
- XFormer, a free Atari Emulator which needs no ROM's and other items