This was my first "real" computer. (My first computer was a
Sinclair ZX80, which by the time I got this computer was not
recognizable as a ZX80.) When I bought this computer, it was just
a circuit board and power supply sitting on the table. It had a
"Jaws" memory card with 16k of ram, used a cassette recorder to save
and load programs, and was connected to a Hazeltine 1000
terminal. It had Microsoft basic in ROM. I purchesed the
enclosure and 6 slot S100 buss extender kit from Netronics. I
filled out the memory card to 64k. Eventualy, with a few small
modifications I expaned the memory card to 256k! That was unheard
of on a CP/M computer. I used 192k as a RAM disk. Other
additions were a SD sales versafloppy disk controller, a 8 inch floppy
drive (241k per disk), and a Solid State Music IO card. There was
nothing musical about the Solid State Music card, it had 2 serial, and
3 parallel ports. I dont know how they came up with that company
name. Eventually I added a Morrow Disk Jockey double density
floppy controller, and double sided 8 inch floppy drives, for a
whopping 2.4 mega bytes of disk storage (1.2 mb each). I used
this computer from about 1982 until 1990.
You can see three controls on the front. A key was used to turn
the power on and off. The two buttons on the left were "Reset"
and "Interupt". The interupt button allowed the user to generate
a hardware interupt, and if there was software there to catch it, do
something. I used this with DDT, the CP/M equivilent of
debug. If a program I was debugging locked up, I could press the
I button and get back to DDT without rebooting.
In the last years we used it, it was very frustating for Cyndee (my
wife). Every so often (maybe everytime we used it) I would need
to pull out the circuit boards, and flex them, than put them back
in. The chips no longer made good contact with the sockets, and
flexing the boards would scrape off the tarnish and let it work again
for a while.
Stats: 3.072 mhz 8085 processer (6.144 mhz crystal), later updated to a
5 mhz 8085, then overclocked to 6 mhz, 16k RAM, later updated to 256k.
I have written a wikipedia article about the Explorer 85
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