At 23:20 10/07/98 -0400, Allison wrote: Oh gosh, it's been a long time but the software was (for the most part!) compatible. I'm going back 9 or 10 years now since I last really hit the keyboards of my H8/H19 and H/Z89 machines. Third-party s/w could have had Z80-specific code written-in at the expense of some of the older 8080-based H8 machines of the time which were not yet upgraded to Z80. Usually, it seems though, everybody wrote assembler code so that either the s/w checked to see which processor was used or wrote straight 8080 asm code to just cover everybody without having the extra CPU checking code taking up space. Most commercial language interpreters and compilers, especially from Heath, handled 8080-based machines for sure. Allison, for the H8 there were at least two third-party Z80 CPU boards made (I can look up the mfgrs if anybody wants) and a Heath-made Z80 board. Early on when the Z80 became rather popular, the original 8080 CPU board was of course found to be lacking in performance compared to the TRS-80's, N*, Kaypros, various S100's and other contemporary CP/M Z80 machines. Hence, the little cottage industry, so to speak, which sprang up to deal with making Z80 boards. A 4 MHz CPU by DG Micro (I think that's the name) really was a performer up against many other machines. The H-89 was a Z80 machine when it first was introduced around 1980 or thereabouts. Anybody recall Trionyx Electronics who were in Southern California? The fellow who ran it was an ambitious sort when it came to making H8 accessory boards and a Z80 CPU board. I've got a significant stash of H8, H/Z-89/90 and H/Z-100 paper stored away in boxes plus the hardware to go with it. I've got a bunch of H-11 stuff too although I just got the equipment and paper in the past year and don't know much about it yet. I can look up H8/H89/H100/H11 info if anybody needs it and if they can wait 'till I can dig through a mountain of boxes and equipment (I just moved much of the collection from the old house. It's a mess! Just ask Hans and his wife who were visiting us several weeks ago. Even more was stuffed into this house since they were here.) Regards, Chris -- -- Christian Fandt, Electronic/Electrical Historian Jamestown, NY USA Member of Antique Wireless Association URL: http://www.ggw.org/freenet/a/awa/