Due to massive amounts of caffeine & sleep deprivation, Kai Kaltenbach said: FYI: Mine was built in September, 1985, so I would imagine they would need some time to ramp up production for the introduction. Not bootable, 'cause it boots from ROM. BTW, SSDD 80 Track, 9SPT. I'm at work, 600 at home (awaiting new internal nicads...) but unless Tandy or Zenith (OEM) designed a floppy-port-based whatever, the external floppy port is a 1-for-1 pinout of a standard floppy interface... so you can hook up either a 3.5" or 5.25" floppy, provided it's 80 tracks or more. (That means I could hook up my 2" floppy, if I designed an interface cable, as it only has a 22-pin cable (all standard signals, plus power... just need to align the signals.) AC adapter is 8V DC, 1.5A, IIRC. (hafta look when I get home...) It's called HH/OS, (Hand-Held Operating System... tho I doubt you'd call the 600 a hand-held!) and it was produced by MicroSoft. Didn't the Basic ROM originally cost $139.95, or did it go up from original? (I'll have to look that one up in my '89 catalog...) Tandy still sells the ROM, and they still want $120 for it!!!!! :-( HTH, "Merch" -- Roger Merchberger | If at first you don't succeed, Programmer, NorthernWay | nuclear warhead disarmament should zmerch(a)northernway.net | *not* be your first career choice.