Hello: Let me chime in on the number of Mark-8 computers, etc. Several years ago I went through some old records that showed the royalties paid to me by both Radio-Electronics magazine and Techniques. R-E paid a small royalty for each of the instruction booklets they sold. You may recall the original magazine article could not hold all the information and construction details. Techniques paid a royalty on the sets of printed-circuit boards (PCBs) they sold. Based on the information I still have, I figure R-E sold about 7500 copies of the booklet, and Techniques sold about 400 sets of PCBs. Unfortunately, the original R-E article and the booklet failed to publish a key piece of information: the wiring diagram for the board-to-board connections. So, I heard from many people who needed this information, but these communications took place before email and low-cost fax, so I have no record nor recollection of how many people I spoke with. As you can probably guess, I also have no idea how many people actually built a Mark-8, nor do I know how many of those built systems still exist. My original Mark-8 is in the Smithsonian, and it was in working condition when it left here, so that counts as one system. The prototype memory board for the original point-to-point wired Mark-8 prototype went to the American Computer Museum in Bozeman, MT in October. The ACM also got mimeographed copies of the original "Mark-8 Newsletter" and its successor, the "Micro-8 Newsletter." If anyone has questions about the Mark-8, refer to the Web site: http://www.his.com/~jlewczyk/adavie/mark8b.html which contains information I wrote back in 1999. (I need to go back and clean it up a bit.) Please note, the email addresses in that posting are incorrect. People can reach me at the permanent email addresses: KZ1G(a)ARRL.NET or jontitus(a)hendrielane.com For a while longer, the jontitus(a)attbi.com email still works. We expect a shift to comcast.net sometime soon, though. Cheers, Jon Jon Titus 36 Sunset Drive Milford, MA 01757-1362 USA Phone: +1-508-478-8040 E-mail: jontitus(a)attbi.com Member, National Association of Science Writers