Dragon DOS variants

A place to discuss everything Dragon related that doesn't fall into the other categories.
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unumlapis
Posts: 97
Joined: Sat May 04, 2019 11:29 pm
Location: Malmo, Sweden

Dragon DOS variants

Post by unumlapis » Sun Feb 16, 2020 4:17 pm

Based on that there are couple of different version available of the Dragon DOS, I curious to hear which version you're running and why. Obviously the SuperDos looks like the most interesting one while it have a few bugs and then there is Eurohard Dos 4.0 which seems to be the safe bet.

What's the take here and where would it be possible to source EPROMs with the upgraded version of the DOS?

Dragon DOS 1.0:
Original release by Dragon Data Ltd.
Patches for EPROM appeared in Dragon User
(with corrections in Dragon User )
Bugs: No more than 127 files can be accessed
80 Track DS disks wrongly written
Doesn't recognise disk changes
{7} adds the following:
Files on DS disks could be read incorrectly if immediately
following thefollowing first the disk access
First file control block was corrupted when sectors 19-36 of
Tr20 of a DS disk were written
First file control block corrupted when DIR was used
Files extensions could be appended to wrong file if >127 files
on the disk or the master directory entry and any extension
entry were separated by more than 3 sectors

Cumana Dos 1.2/2.0:
Shipped with Cumana Disk system
DragonDOS compatible at disk level and command level but with
enhanced commands (SCOPY and Tape/disk oriented copying)
Used 8K rather than 4K eprom for OS
Supposedly a large number of Bugs

Eurohard Dos 4.0:
Improved Dragon Dos 1.0
Features:
Scrolling directory, autoboot at power up
Bugs:
(Unknown)

SuperDos E4/5/6:
Much improved Dragon Dos 1.0 by Mike Kerry of Grosvenor Software
Features:
Paged directory, fixes all known 1.0 bugs
Bugs:
Corrupts mem/files/hangs on FWRITE time out on open files
RENAME allows creation of zero length filenames when used to
copy across disks
WP error can occur 3 or 4 times in succession.
ERROR GOTO not always cancelled on return to BASIC
LOAD'd files remain open
EOF errors occurs whilst FLREADing from large fragmented files

DosPlus x.x:
Complete rewrite by Phil Scott
Features:
Disk labels, close individ files
Bugs:
(Unknown)

sixxie
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Joined: Fri Jul 18, 2008 8:36 am
Location: Hertfordshire
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Re: Dragon DOS variants

Post by sixxie » Sun Feb 16, 2020 5:04 pm

Can definitely add for SuperDOS E6 that it’s easy to get ?NE ERROR trying to access a file while motor still running (eg DIR then quickly RUN a program).

Meant I used to fill programs that CHAINed each other with calls to CLOSE (IIRC). Out of preference I usually go for DOSplus tho.

Alastair
Posts: 619
Joined: Fri Jul 18, 2008 11:33 pm

Re: Dragon DOS variants

Post by Alastair » Sun Feb 16, 2020 11:09 pm

I've been using Pere's DragonDOS 1.3a (see viewtopic.php?f=8&t=5289#p13272) with XRoar for some years now. Obviously for testing purposes this is not comparable with using real hardware, no motor still running issues for starters, but from my limited tests it does seem pretty compatible with the original DragonDOS. The posts in the above linked thread state the changes and bug fixes Pere has applied to DragonDOS.

Another thread you may wish to check out is about Steve Woolham's DragonDOS 5.0 project (work stopped in 2010) - see viewtopic.php?f=7&t=5415

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