While I was at Weirdstuff Warehouse in Sunnyvale, CA, this afternoon, I noticed that they had two boxes full of these docs: "Introduction to The Instructor 50 (tm) Desktop Computer" and "The Instructor 50 (tm) Desktop Computer Users' Guide" both are copyright 1978. The first is, oh, about 100 pages long, and the second is 200 pages. They were intended to be sold with the Signetics Instructor 50 computer, which uses a 2650 processor. Weirdstuff wants $1 apiece. Here is a link to a picture of one: http://www.zianet.com/kromeke/pastcomp/misc/signetic.htm They go through some rudiments of computers, some particulars of the 2650, some example programs, and then the usual description of all the opcodes. Hey, it even has an S-100 expansion capability. Schematics included. Anyway, if you are in the area and are interested, check it out. There are at least 20 of each, all completely unused (although a bit yellowed). I'll try to describe where -- it is in the back section, pretty much as far away from the entrance to the rear section as you can get. It is on a bottom shelf along the rear aisle. If you don't live in the area but are really interested, I'll consider filling a limited number of requests. (eg, you have an instructor 50, or you have a 2650-based computer but don't have any idea about its instruction set). I'd rather not find, address, stuff, and mail 20 packages for a bunch of tire kickers. ;-) ----- Jim Battle == frustum(a)pacbell.net