<All my 'bows have 2 processors. An 8088 and a Z80. The Z80 runs the VT100
<emulation from ROM, etc, _but_ it's also possible to run user programs on
<it (CP/M on a rainbow will run CP/M80 or CP/M86 programs).
All rainbows had both that was the base configuration. The later B and B+
versions were allabout adding hard disk and hard disk booting, IE firmware.
IT did run CPM80/86, that was the base OS and the system was set uyp so that
you could run z80 or 8088 code. in z80 mode the 8088 was idle. In the 8088
mode the z80 was doing IO processing. Obviously the 8088 mode hard far more
performnce than many turbo PCs as the z80 is a pretty good io processor.
<I don't recall there being any processors on the disk daughterboard (and
<I think I'd remember that), unlike, say, the Pro where there's a
<microcontroller between the system bus and the FDC chip.
The HD controller was 8x300, teh floppy was on the main board and relied
on the z80. Formatting was possible on all models. Only that the early
OS packages didn't include the formatter(Pournelle got a first off the
line). For a long while Rainbows were popular for formatting rx50s.
That and people that had them really liked them.
Allison
Received on Tue May 25 1999 - 21:55:52 BST