During the Christmas break I built the CPUville Z80 single board, plus the ‘slow board’ which is really a really nice ‘blinkenlights’ display board for the Z80 single board. That was a fun build.

I also built the CPUville 8-bit computer (3 boards) plus register display board and added that to a separately built Z80 single board (with Z80 replaced by the 8-bit boards). That was also a fun build.

But the real fun began with the Z80 single board once I added an IDE 40-pin to CF (compact flash) controller board with a 4+ GB CF card. Following the CPUville instructions, I was able to modify/compile/install CPM 2.2 on the CF card giving me 4 large “hard disk” CP/M partitions.

THEN… I started playing. After reading a few CP/M manuals, I began to learn my way around the system. ED was perhaps the hardest to learn, only because the first manual neglected to mention that the display buffer was NOT filled ‘on entry’. One has to type ‘#A’ to load it with the file contents before you can see/edit anything.

I started with a few Z80 (or 8080) assembler programs, then found and loaded FORTRAN (F80). I then spent days playing with my FORTRAN programs that I wrote in the 1980’s during my Engineering degree and post-grad courses. Interestingly, they compiled and linked easier than when I tried them on the PiDP8 replica I built several years ago. The version of FORTRAN in F80 was just a bit more modern than the FORTRAN IV on the PiDP8, making things much easier and more fun.

Last week I found an loaded High Tech C compiler on the Z80. I compiled a few C programs from my earlier C programming days, as well as a few versions of the “calculate PI to N digits” programs. Again, tons of fun.

The interesting bits came trying to install the C compiler. It’s a lot of files, and when I tried loading them individually via “PCGET”, they crashed the terminal program. Seeking a better solution, I tried LZH unpack programs (didn’t work on modern LZH files), and eventually found that using modern WINZIP and an old CP/M UNZIP18.COM program, I was able to load whole groups of files to the Z80 and then unzip them in place. The only condition is that the CP/M unzip does not understand ‘modern’ zip methods, so you must zip them on the PC (Windows 7 in my case) with NO COMPRESSION.

The other ‘gotcha’ I discovered tonight is that you must be sure the ZIP files are named in CAPITAL letters. If you unzip lowercase named files on the Z80, they remain lowercase and kind of ‘disappear’ to CP/M. I could not even delete them until I asked on the ‘comp.os.cpm’ google group and was told about NSWEEP (or NSWP.COM). That program was able to delete them easily. I then rebuilt the zip with uppercase file names and it was fine.

So onward and upward with this wonderful true Z80 computer running CP/M 2.2, with FORTRAN, C and 8080/Z80 assembler.