rgt@LANL.GOV (Richard Thomsen) (12/09/87)
This is in response to the following message: From @po2.andrew.cmu.edu:rl1b+infodec.errors.arpa@andrew.cmu.edu Mon Dec 7 02:57:51 1987 > I am quite interested in the changes Richard Thomsen has made >to his system permitting him to use TEAC drives in place of his >RX50's. I've read his last message, and it sounds like he will be >able to distribute his DIFFERENCE files. Forgive my ignorance, >but what are DIFFERENCE files? How would they be of use to >someone else? If I wanted to make these changes on my machine, would >I have to type in the Rainbow's BIOS code and recompile it? Would >I need an E-PROM to change the Z80 bootstrap loader code? Difference files are the result of taking my changes and using the FC (file compare) program to list out the differences between them and the standard files that came from DEC. Thus, if you have the source code, you could modify your souces to add these differences to get my system. There are some other utilities (such as PATCH on other systems) that would automatically put in the changes, but I do not know if it exists for the Rainbow. Given that DEC does not release the source code, I am not convinced that difference files would make any sense to anyone. Apparently Jim Wolfe has offered to change my sources into a form acceptable by DEC for difference files, but again I am not sure what use it would be since the sources are not available. As far as I can see, you would have to do the following things (which is the same things that I did): 1) Type in the Rainbow BIOS from the manuals. 2) Figure out the missing files from the manuals and enter them. 3) Assemble the whole thing, and use FC to insure that they are identical (within reason) to the DEC BIOS. 4) Add my changes to the BIOS. 5) Disassemble the MS-DOS bootstrap program. 6) Add my changes to the MS-DOS bootstrap program. 7) Disassemble the floppy disk primary bootstrap. 8) Add my changes to the floppy disk primary bootstrap. 9) Disassemble the FORMAT program. 10) Add my changes to the FORMAT program. 11) Disassemble the Z-80 program. 12) Add my changes to the Z-80 program. 13) Assemble everything and put it into the correct files. 14) Boot the system. To assemble the Z-80 programs, including the floppy primary bootstrap, you need a Z-80 assembler. I used a public domain one called Z80MR, along with its linker. It does not do macros, however, which the DEC code uses, so I had to do without them. No changes are needed to the EPROMS, although that would be nice. Since I did not have an EPROM programmer, and no source code for the EPROMS, I did not attempt this feat. I started it, but disassembling 32K bytes of EPROM is not an easy task, especially when much of it is apparently tables. Also, it is very complex code, with multiple jump tables. I tried to follow parts of it, and it is not at all easy. Note: DEC and Rainbow are trademarks of Digital Equipment Corporation. MS-DOS is a trademark of Microsoft, Inc. Z-80 is a trademark of Zilog, Inc. Richard Thomsen Mountain Route Box 234 Jemez Springs, NM 87025 (Sorry, but the ZIP code was wrong last time)