The disc operating system VDOS was developped by the german company Vortex.
VDOS was supplied on an EPROM, and was released in 3 versions:
- VDOS 1.0
- VDOS 2.0
- VDOS 2.11
Further there were German and English versions of this ROMs.
The VDOS ROM also contained a machine language monitor.
VDOS supported as first DOS the Vortex format, which become a standard format later on.
Germanized-English RSX Commands and VDOS differences compared to AMSDOS
- Vortex apparently considered the normal AMSDOS RSX commands |TAPE.xx and |DRIVE/|USER too difficult for german users, and changed them to |CAS and |SELECT (which resemble equivalent german words Kassette and Selektieren). This is making VDOS slightly incompatible with AMSDOS and all other AMSDOS clones (except for Dobbertin's X-DDOS, which supports both the english and germanized dialects).
|SELECT is used to both select user and/or drive. e.g. |SELECT,"3" for user 3, |SELECT,"B" for drive B, |SELECT "4B" for user 4 on drive B. VDOS doesn't have USER or DRIVE commands.
- When using CAS CATALOG you give the address of a buffer to fill with the list of files in the current user and drive. The format of this data differs compared to AMSDOS.
<ff> <8 bytes filename> <3 bytes extension> <2 bytes size in K> with a byte of 00 to indicate the end of the list.
<user> <8 bytes filename> <3 bytes extension> <2 bytes size in K> with a byte of FF to indicate the end of the list.
This is important if you use CAS CATALOG and parse the data to fetch the list of files.
- AMSDOS allows you to specify both the user and drive in a filename.
e.g. "3B:TEST.BIN" is valid and will try to find TEST.BIN in user 3 of drive B.
VDOS doesn't allow this. VDOS only allows the drive to be specified.
Therefore it's recommended to use SELECT to specify the user.
- VDOS will autoboot a file called "HELLO" if it exists on the disc. AMSDOS doesn't have this.
- Vortex Vdos 2.0 Manual (pdf) (also describes how to upgrade from VDOS 1.0 to 2.0)