Still in love with CP/M and the Z80 architecture, I bought the SB-180 single board system from Micromint. It had advanced features like 256kB of SRAM, partially configured as a RAM disk. It was capable of driving 3 1/2" floppies (single density) and came with ZCPR3 and lots of useful software. The 9 MHz HD64180 CPU and the 3 1/2" floppies were a BIG performance boost over the "Bigboard".
So I bought a "single density" 3 1/2" floppy disk drive and single density (720 kB) floppy disks, but the software was delivered on a set of 5 1/4" floppies. The "old" MPI floppy drives which I had used on the "Bigboard" came in handy here: I connected one 3 1/2" and one 5 1/4" drive and copied the software and the operating system files. The console was a serial connection to a PC running Hyperterm.
Some time ago, I ran across the "NoICE" debugging software http://www.noicedebugger.com/ and added the NoICE monitor SW to the SB-180 ROM monitor. It was quite ineresting to see how advanced debugging of low-level software on an "old" CPU like the HD64180 had become.
more Info: Circuit Cellar Books Volume 6 page 119
SB-180 web pages by Dave Dunfield
SB-180 web pages by William f. Sotomayor
SB-180 disk 1 SB-180 disk 2 SB-180 disk 3 SB-180 disk 4 SB-180 Boot disk
CP/M Cobol Compiler CP/M Utils