It sounds like the system you have acquired is a Cromemco System 3. This (if I'm right) was the high-end model of Cromemco's original S-100 systems. It can run either the CP/M or C-DOS OS.This machine, as you've already found out, is quite heavy because the outer casing is 1/8" (!) thick! This thing could withstand a nuclear blast. ____________________________________________________________ David Vohs, Digital Archaeologist & Computer Historian. Computer Collection: "Triumph": Commodore 64C, 1802, 1541, FSD-1, GeoRAM 512, Okimate 20. "Leela": Macintosh 128 (Plus upgrade), Nova SCSI HDD, Imagewriter II. "Delorean": TI-99/4A. "Monolith": Apple Macintosh Portable. "Spectrum": Tandy Color Computer 3. ____________________________________________________________ ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com