The following information is also based on my own basic knowledge of the Dragon disk drive systems. I have never owned a DeltaDOS or CumanaDOS disk drive system. Most of what I know about these systems came from reading articles in Dragon User (and other) magazines. It is possible that some of the information about the Delta and Cumana systems may not be 100% accurate.
The first ever disk drive system to become available for the Dragon 32 was the DeltaDOS system from Premier Microsystems. It was well built and came with a pretty good DOS (except for the SAVEM command which did not allow the third option of an EXEC address) and an excellent user guide.
The next disk drive system to become available was the official DragonDOS system from Dragon Data. This system was also well built and came with a pretty good (but
very buggy) DOS and a rather poor user guide. This system has much faster disk read/write times than the Delta system. Floppy disks from this system are NOT interchangable with the Delta system.
The third disk drive system to become available was the CumanaDOS system from Cumana Ltd. This system was also well built and came with a pretty good DOS and user guide. The controller of this system was so similar to the DragonDOS controller that you could fit a DragonDOS ROM and it would work exactly like the DragonDOS system. Floppy disks from this system were not 100% compatible with any of the other two systems unless you swapped the CumanaDOS ROM for a DragonDOS or compatible ROM such as SuperDOS or DOSPlus. Floppy disks could then be swapped between the Cumana and DragonDOS systems once the CumanaDOS ROM had been replaced with a DragonDOS or compatible ROM chip.
Copies of the user guides are all available here at the Dragon Archive.
DeltaDOS system user guide
DragonDOS system user guide
CumanaDOS system user guide
An article published in the May 1985 issue of Dragon User (
Correcting the faults and problems with Dragondos by Philip G Scott) describes in detail all of the known DragonDOS 1.0 bugs and how to fix them. I have attached copies of DragonDOS versions 1.2 and 1.2a which include all of the bug fixes and enhancements from that article. DragonDOS 1.2 is a copy of the original DragonDOS 1.0 which has been patched with all of the bug fixes and enhancements from Mr Scott's article. DragonDOS 1.2a is the same as DragonDOS 1.2 but with a bug fixed CHAIN command and an added routine which gives a superdos-like paged directory display.
Mr Scott also did a complete bug-free rewrite of DragonDOS with enhancements which he called DOSPlus. There is a very interesting review of what appears to be a very early version (2.3) of DOSPlus (BOSS DOS by R.E. Warwick) on pages 6 to 8 of the
February 1987 issue of Dragon User magazine. The last known official release version of DOSPlus was 4.9B.
The Spanish company Eurohard later released DragonDOS 4.0 which they also claimed was an enhanced bug-free version of the original DragonDOS. But, according to the following quote from the "BOSS DOS" article mentioned above, their claim of a bug-free DOS could be false.
R.E. Warwick wrote:
it also appears that all the DRAGON DOS version 1 errors have been corrected (including any still in version 4 from Eurohard)
After reading the above it would seem that the attached DragonDOS 1.2 is the only version of DragonDOS which has all of the bugs correctly fixed. Both SuperDOS and Eurohard's DragonDOS 4.0/4.1 still have bugs which have not been fixed.
There is a letter from Philip G Scott on page 2 (Letters) of the
August 1988 issue of Dragon User in which he states that "SuperDOS E6 appears to be DragonDOS with about half the faults corrected".
EDIT: Archive updated on the 29th of March, 2014.