<My earliest Intel SBC's have room for 4 24-pin EPROMs, each of which can
<hold 4K, and, if you use a jumpering arrangement derived from the schemati
<rather than from the manual, you can use the 8K parts from MOT. That give
<you 32KB. Isn't that enough to support a customized version of the BASIC
I have 8k rom Basic (actually about 7.25k in size) from Netronics for the
8085 SBC. That was very complete Microsoft Basic-80 cassette basic.
It reqired 1k of ram for the most minimal of programs. IO was vis the SBCs
2k monitor rom.
Another good basic with FP is LLL basic, about 5k (of 8080 code) with
floats.
32k would be Ms disk basic + most of CPM! So size is not an issue.
Often most SBC users only need integer math plus control strutures so they
can run things.
<wouldn't you? There are some public-domain CP/M-compatible I/O handlers
<which use some of the CP/M i/o calls. Naturally, it's a lot of work, but
<you can do it, given you have the source code.
You can fit CPM with BIOS in 8k easily (CCP-2k, BDOS-3.5k, Bios 2.5k)!
If your really lazy yu only need ram to copy it to from a rom so a boot
device is not required.
I have a little SBC I did that has two 32k ram (000-F7FFh), 2k Eprom at
F800 and several IO ports that runs SPM via romdisk (27010 x2 on a 8255
parallel port device). Everything runs from ram. If storage is needed
I have a bit of bios code that routes drive B: to the serial port and a
host system fakes a disk. It's on a 6x4" card no SMT and common stuff
using 8085 running at 5mhz. Everything but the bios is stock code and
the bios is nothing fancy (nearly textbook actually).
Allison