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
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