[sebhc] design parameters for H8 emulation

Jack Rubin jack.rubin at ameritech.net
Tue May 11 07:49:53 CDT 2004

You might find it worth while to take a look at Mike Evenson's FLEX
emulator for the Motorola 680x family (
http://www.evenson-consulting.com/swtpc/ ) for some helpful ideas about
emulator design - 

- the design is modular in a way that follows the architecture of the
original systems. You can change monitor ROMs and bus cards at will, so
that you can upgrade from a 6800 to a 6809 processor and boot various
operating systems. Mike has also provided a stub template so that other
cards can be emulated or even prototyped. 

Given our ROM library (I just got a copy of PAM8/GO to complete the
collection) and the real-world incompatibility of some
CPU/ROM/controller/OS combinations, this is a valuable feature.

- there is a full virtual disk system which allows reading/writing disks
at the file level and transparently moving from real to virtual disks

- the virtual disk system is enhanced by NetPC (Scott talked about this
last week) which allows a PC to act as a large disk on either a real or
virtual system. As with the SVD, you can mix real and virtual disks in
real time.

Wouldn't it make sense to spend time now on developing some overall
system design parameters before getting too deep into issues like disk
formats? It sounds like there is a lot of overlap in the several
projects currently underway; it would be a shame to lose the synergy
further down the road because of unexamined assumptions at the beginning
of the process. It will also allow people to work independently on
various aspects of the system (e.g. terminal emulation, storage
subsystems, etc.) simultaneously.


Delivered by the SEBHC Mailing List

More information about the Sebhc mailing list