Supported DOS Versions
======================


DOS2 compatible DOS versions
============================

Most ATARI DOSes uses DOS2 compatible directory entries and VTOCs. However,
the VTOC may be placed on different sectors, so original DOS 2 might not be
able to read files on the disks and vice versa.

DOS2 is "optimized" for serial read/write access und space. It's structure
is very simple.


ATARI DOS 1
-----------

The first ATARI DOS, shipped with first ATARI 810 disk drives.
Supported just for completeness. I didn't found any documentation, but
it seems that is uses the same disk layout as DOS 2.0S except the
"version 2" flags.
This DOS supports only Single Density disks (40 tracks, 18 sectors per track,
128 bytes per sector, FM coding).

Supported Density: Single
Supported Functions: STATFS, READDIR, READ


ATARI DOS 2.0S
--------------

The DOS distributed with later ATARI 810 and early ATARI 1050 disk drives.
Single Density only. Although the structures are compatible with DOS 1,
two new flags are used to distinguish from this version.

Supported Density: Single
Supported Functions: STATFS, READDIR, READ


ATARI DOS 2.0D
--------------

A double density version of DOS 2.0S, shipped with the ATARI 815 dual
disk drive. Supports Double Density disks (40 tracks, 18 sectors per
track, 256 bytes per sector, MFM coding) only.

Supported Density: Double
Supported Functions: STATFS, READDIR, READ


ATARI DOS 2.5
-------------

The DOS distributed with later ATARI 1050 and earfy XF551 disk drives,
Single and Medium (Enhanced) density disks (40 tracks, 26 sectors per
track, 128 bytes per sector, FM coding).
Single density disks are fully compatible to DOS 2, Medium Disk can be read
by DOS 2.0.
The "standard" DOS for 8bit machines.

Supported Density: Single (== DOS 2.0S), Medium
Supported Functions: STATFS, READDIR, READ


BiboDOS 5, 6
------------

Produced by CompyShop this DOS offers 1050 Speedy/Happy/Turbo and
ATARI XF551 disk drive support.
Supports all standard densities. DOS 2 compatible directory and VTOC.
Single and Medium density disks are fully compatible with DOS 2.5.

Supported Density: Single (== DOS 2.0S), Medium (== DOS 2.5),
Double (== DOS 2.0D), Quad
Supported Functions: STATFS, READDIR, READ


MyDOS
-----

DOS with hard disk and subdirectory support. Extended DOS2 format that
supports disk images with up to 65535 sectors of 128 or 256 bytes per sector.
DOS 2 compatible directory and VTOC.
Source code available.
Single density disk without subdirectories are fully compatible with DOS 2.

Supported Density: Single (== DOS 2.0S +SubDirs), Medium, Double, Quad, HD
Supported Functions: STATFS, READDIR, READ


TopDos
------

DOS 2 compatible directory and VTOC, but version flag 3.

Supported Density: Single, Medium, Double, Quad
Supported Functions: STATFS, READDIR, READ


SmartDOS
--------

DOS 2 compatible directory and VTOC.
Single density disks are fully compatible to DOS 2.0S, Double density
disk to DOS 2.0D.

Supported Density: Single (== DOS 2.0S), Double (== DOS 2.0D)
Supported Functions: STATFS, READDIR, READ
Note: cannot be detected because identical formats


TurboDOS
--------

DOS 2 compatible directory and VTOC.
Single density disks are fully compatible to DOS 2.5, Medium density
disks to DOS 2.5.

Supported Density: Single (== DOS 2.0S), Medium (== DOS 2.5),
Double (== DOS 2.0D), Quad (== MyDOS w/o subdirs)
Supported Functions: STATFS, READDIR, READ


ATARI DOS 3
===========

A FAT based dos, distributed with some ATARI 1050 disk drives.
Supports Single and Medium density disks. Wastes a lot of disk space,
because the allocation unit is 1k, rarely used.

Supported Density: Single, Medium
Supported Functions: STATFS, READDIR, READ


ATARI DOS XE
============

The last ATARI DOS, shipped with late ATARI XF551 disk drives.
Supports all standard Densities on ATARI drives.
FAT based, 256byte allocated unit.
Sometimes called "ADOS".

Supported Density: Single, Medium, Double, Quad
Supported Functions: currently none


ATARI DOS 4 (Antic DOS)
=======================

This DOS was distributed by ANTIC. Supports the XF551 and non-ATARI diskdrives.
New densities Double (40 tracks, 26 sectors per track, 256 bytes
per sector, MFM coding) and Quad (40 tracks, 26 sectors per track, 256 bytes
per sector, MFM coding, 2 sides).
FAT based as DOS 3, but with a allocation unit of 768 bytes, rarely used.

Supported Density: Single, Medium, Double, Quad
Supported Functions: STATFS, READDIR, READ


SPARTADOS compatible DOSes
==========================

SPARTADOS
---------

Not compatible to any other ATARI DOSes this originally ICD produced DOS uses a
filesystem with sector maps. Supports all densities, hard disks up to
65525 sectors, 128/256 bytes per sector, subdirectories and creation times.
SpartaDOS files can be up to 2^24-1 bytes long.
Its boot mechanism allows to boot any file on the image (as long as this is a
bootable image).
Supports real random access.

Supported Density: Single, Medium, Double, Quad, HD
Supported Functions: STATFS, READDIR, READ


BWDos
-----

A fully compatible SpartaDOS clone. Sourcecode available. Cannot be detected
due to identical format (will be reported as SpartaDOS 2+)

Supported Density: Single, Medium, Double, Quad, HD
Supported Functions: STATFS, READDIR, READ


Special files
=============

ATR8FS supports several "virtual" files that can be shown in the root
directory of an Atari disk image:

.boot This file allows to access the boot sectors of a filesystem
(All DOSes)
.vtoc This file allows to access the DOS2 VTOC (DOS2 compatible
DOSes)
.sfat This file allows to access to DOS3 FAT (DOS3)
.s720 This file allows to access sector 720 on DOS2.0 disks (DOS2.0)
.s1025 This file allows to access sectors 1025 and above on DOS2.5
disks (DOS2.5)
.atrhead This file allows to access the ATR header (ATR images)
.bootfile This file is a hard-link to the SpartaDOS boot file
(SpartaDOS)

Note that these special files cannot be deleted or renamed, neither there length can be changed. The mount option "no_specials" will disable special file support.

Jurgi/Tristesse hat geschrieben:Haven't You really seen this stuff before? It's goddam old (the files in the archive are dated May 2003... almost 2 years old), so, probably the project is dead, I'm afraid...

But maybe someone would like to continue it?