I have just ported the Infocom adventure series for the CoCo to the Dragon64 (25 games)
They will not work on machines with only 32K because the games switch to MAP1 (all RAM)
Basically these adventures are started with the DOS command (our BOOT equivalent)
CoCo DOS loads track 34 to RAM $2600 and executes it.
The loaded part consists of a relocator that moves 800 bytes of code to $5000 and then executes it
This relocated code is a loader that reads from Track 00 Sector 01 untill Track 06 Sector 13 decimal and puts it from $1100 till $3000
This part is the engine that is able to work with all the disks of that collection
After unassembling it, I found two parts that needed changes to work properly on the Dragons:
- disc read and write need rewritting from scratch due to hardware differences
- keyboard scan routines need patching for the different wiring of the keyboards
The disk part was 'relatively' easy because I could re-use the mini-DOS that I had programmed for the conversion of the Orchestra90 for the Dragon.
The keyboard part was even simpler, I have converted some CoCo ROMs to Dragon and have done this many times before.
I decided to have a disc that will contain *only* the engine to be loaded and executed for all of the games. The name of the disk is: ENGINE.VDK
If you are a Dragon user that loves adventures, then be ready to play with this 25 titles:
Code: Select all
DISK-NAME - Game Name, Year
-----------------------------------------------------
BALLYHOO.VDK - Ballyhoo, 1985
CUTHROTS.VDK - Cutthroats, 1984
DEADLINE.VDK - Deadline, 1982
ENCHANTR.VDK - Enchanter, 1983
HEARTS.VDK - Plundered Hearts, 1987
HOLLYWD.VDK - Hollywood Hijinx, 1986
HTCHHKER.VDK - Hitchhikers Guide to the Galaxy, 1984
INFIDEL.VDK - Infidel, 1983
LEATHER.VDK - Leather Goddesses of Phobos, 1986
LURKINGH.VDK - The Lurking Horror, 1987
MINIZORK.VDK - Mini-ZORK, 1988
MOONMIST.VDK - Moonmist, 1986
PLANETF.VDK - Planetfall, 1983
SEASTALK.VDK - Seastalker, 1984
SORCERER.VDK - Sorcerer, 1984
SPELLBRK.VDK - Spellbreaker, 1985
STARCRSS.VDK - Starcross, 1982
STATIONF.VDK - Stationfall, 1987
SUSPECT.VDK - Suspect, 1984
SUSPEND.VDK - Suspended, 1983
WISHBRNG.VDK - Wishbringer, 1985
WITNESS.VDK - Witness, 1983
ZORK_I.VDK - Zork I, 1980
ZORK_II.VDK - Zork II, 1981
ZORK_III.VDK - Zork III, 1982
These discs have NO data visible in the directory (they are CoCo disks) so if you attempt to do a DIR you will get an ?IV ERROR message
The recommended procedure will be:
- For just one drive:
1) Insert ENGINE.VDK and issue LOAD"ENG04V32.BIN"
2) then insert the disc that contains the adventure you want to play with
3) EXEC&H1100
4) in case you want to savegame, then have a clean disk ready for that. The engine asks for disk change as requied
- For twin drives
1) Insert ENGINE.VDK on drive 2 and issue LOAD"2:ENG04V32.BIN"
2) then insert on drive 1 the disc that contains the adventure you want to play with
3) you may insert a clean disc on drive 2 for savegames
4) EXEC&H1100
cheers
pere