HDD install patch for Illusion City, PC98 version

[sangfroid]

These set of patches change some executables of Illusion City, version PC98, to run directly from a Hard Drive.

• It runs directly from the HD, no ERCVFD, no HSB, nothing needed. It also saves and restores directly to HD, no extra steps needed.
• Removed the subroutine that requested a new floppy disk and waited for a keypress, now it will totally skip that part.
• The filenames were encoded in the ICITY98.EXE, MENU98.EXE and MTABLE.COM (this last one a very small binary), as templates of the form X:<filename>, the executable replaced that X by a A or B drive depending on in which drive it expected the file. This was replaced by .\filename, so it should work on any drive and directory supported by MS-DOS.
• No executable compression, but the disk is the 5.25" version that also supports PC88VA (which has a CPU more or less x86 compatible) and uses a minimal MS-DOS compatible DOS called MEGDOS. This is not a problem, as it works fine with MS-DOS.
• Some drivers are loaded in CONFIG.SYS, so I provide a AUTOEXEC.bat that uses adddrv.exe (from MSDOS) and a file config.dev to load them after system boot. This means you can execute it normally from command line without changing your master CONFIG.SYS.
• The patches are meant for these versions of the files:
• Illusion City (Disk 1).hdm MD5 sum BBE086812C3DD96DAD8B50D444A1EA72
•   The changes can surely be adapted easily to other versions, but these are the ones I worked with.
• This was tested on original hardware, a PC9821-Ap3, I played until the point you get a robot companion after the cutscenes showing the SIVA council. If you can, please test it more to check everything works as it should.
• I also did a X68000 version HDD patch if you prefer that version.

Installation:

• Patch Disk 1 image with one of the above patches, I made .IPS and .BPS, there are many utilities supporting those.
• Copy all the files from Disk 1 to Disk 7 (and also User Disk if you like) to a directory in a HD drive
• Optionally remove COMMAND.COM. CONFIG.SYS, CONFIG.98, and ICITY_0 to ICITY_6 (these were used to detect disk number)
• There are many other files for the PC88VA, including the OS (confusingly named PC-engine). I did not try to remove them, but it should be possible.
• Rename AUTOEXEC.BAT to !Start.bat or whatever you like

Illusion City PC98 HDD.zip