Date   : Mon, 20 Jul 1992 10:42:24 -0400
From   : Jay Sage <sage@ll.mit.edu>
Subject: Miscellaneous Replies

   To "williams9027@iscsvax.uni.edu" about "converting files":  There are
very nice programs that run on a PC that will read hundreds of CP/M disk
formats.  One of the nicest ones is 22DISK, shareware from Sydex in Oregon
and available on just about all MS-DOS BBS systems.  Whether it will do the
trick depends on what CP/M disk format you are dealing with.

   This technique will copy the data in the files over to the DOS machine as
binary data, i.e., completely unchanged.  What you do with the data then is
a separate problem.  ASCII text is never a problem.  If they are WordStar
files, for example, they can be used with DOS versions of WordStar.  The
same goes for dBaseII files.  Lots of other programs have the ability to
convert data that is in those popular formats.  If the data is for some
strange program, then you will have more trouble and might have to write
your own conversion software.

   If you want to move to a Mac, I'd suggest converting to DOS first.  There
are programs available for the Mac that allow it to read DOS diskettes.

   Matthew Kasdorf was looking for a boot disk for the iBEX 7102.  Don
Maslin of the Dino(saur)SIG in San Diego probably has this boot disk in his
collection.  If not, I have a friend who HAD an iBEX.  It may have been the
7102, and he may still have it.  If Don does not have the disk, let me know
and I will try to track it down.

   On the subject of undocumented Z80 opcodes, Dag Erik Lindberg recently
wrote, "Zilog recognized that some useful things could be done with those
op-codes, but flat stated that if their manufacturing process changed, or
micro-code was modified, those op-codes may not work any more.  As it turned
out, the Z80 sort of dead-ended development wise, and that never happened."

   Not at all!  The Z80 was far from dead-ended.  The Z180 and Z280 chips
have followed it.  Both are Z80-code-compatible.  They are supposed to run
everything written properly for the Z80.  Thus, they are not guaranteed to
run programs that used the undocumented codes (and I don't know if the Z180
or Z280 run those codes or not).

   I once built a computer (actually, it is still running my home electrical
and heating systems) using an Intel 8085, and I made use of its undocumented
opcodes.  Later I had to replace the chip with one from Toshiba, and I had a
sudden sinking feeling that the software would no longer run because I had
used those opcodes.  But it ran fine.  Either Toshiba had licensed the mask
designs or the operation of those codes followed automatically from the
obvious implemention of the documented codes.

-- Jay Sage