Many people have called me asking whether or not DOS 11 is available for sale
from Atari or its dealers. As far as I know DOS 11 is not included with the disk
drives as of this writing. However, I have seen DOS II being advertised by a few
companies. You can get a copy of DOS II free of charge from Atari providing you
have an 850 Interface, or if you purchase a disk program from the Atari Program
Exchange library (DOS 11 is included on most of the APEX disk programs). Here a
few interesting differences between the old DOS I and DOS II:
Occasional random errors in the duplication of the first eight sectors of
a diskette when using the Duplicate Disk command. If DOS was the first file on
a diskette this would cause DOS to sometimes be incorrectly duplicated and as
a result a newly duplicated diskette would sometimes not boot. Old FMS users
are well advised to check for the successful duplication of any file which is
located in the first eight sectors (fixed in DOS II).
Use of wildcards in Copy File and Duplicate File command was not
prohibited and can cause problems (fixed in DOS II).
Will not accept full length filenames in some instances; e.g.
D2:A2345678.ABC will fail to delete etc. (fixed in DOS II).
Duplicate disk does not copy sector 720. FMS does not use sector 720 so
most disks will have no problems because of this. Those programs which write
to this sector with the disk handler will lose track 720 when a DUPLICATE DISK
is performed.
Margins are not reset when entering DOS (fixed in DOS 11).
Have a long wait for unit to cycle through a long file if file is open to
append (fixed in DOS II).
User is not informed if Format Disk command finds any bad sectors (fixed
in DOS 11).
AUTO.SYS didn't work properly. It loads files but will not execute them
(fixed in DOS 11).
Append option in copy didn't work (fixed in DOS II).
Directory sector available data could be invalidated when a file which had
been opened and appended was not properly closed. This resulted in reduced
sectors available on the diskette as sectors were marked in use which were not
a part of a valid file.
Update mode will cause damage to a file if the user was writing to a
sector and that sector was not written before closing the file (the write
modify bit in the FCBFLG is set). When closing a file, the close routine
modifies the FCBFLG location to test if the mode is acquiring sectors (output
only) or update (not acquiring sectors) and does not resume the location. If
the file is in update mode then the write next sector routine is called (WRTNS).
This routine assumes that the FCBFLG location has not been modified. Therefore
when it tests to see if mode was output only or update it mode what it
actually is testing is the write modify stop. If the sector was modified when
the routine assumes it was acquiring sectors for this file and will allocate a
sector and like the write modified sector to this new sector. The sector just
allocated is not legally within the file, its control bytes are never set.
Because of the bad link in the file number mismatch error (164) will occur if
this file is read (open input). Also, the data after the sector with the bad
link will be lost. The error is in the close routine not the write sector,
POINT or NOTE routines. The error occurred because a ROL was used on FCBFLG
for testing the flag when a Bit Test instruction should have been used.
When the Run Cartridge Command is executed and no cartridge is present,
the test for no cartridge in the computer fails occasionally (fixed in DOS
II).
No more or less than three files can be open simultaneously and this is
supposed to be user adjustable by poking location 1801 (Dec) (fixed in DOS
II).