TRS-80 Model 12 versus 16B

SPC spedraja at
Wed Apr 26 07:30:14 CDT 2017

I can only say that I'm always looking for Unix-like systems. I've been
trying to get a Tandy 6000 or TRS-16 for years. Maybe someday...


2017-04-26 13:51 GMT+02:00 Bill Gunshannon via cctalk <cctalk at

> ________________________________________
> From: cctalk [cctalk-bounces at] on behalf of Peter Cetinski
> via cctalk [cctalk at]
> Sent: Tuesday, April 25, 2017 10:47 PM
> To: Jim Brain
> Cc: General Discussion: On-Topic and Off-Topic Posts
> Subject: Re: TRS-80 Model 12 versus 16B
> The Model 16 was introduced in 1982 and was an upgraded Model II with the
> addition of an MC68000 subsystem that allowed you to run 16bit OSes, like
> TRSDOS-16, CPM-68K and TRSXENIX 1.x.  On all Tandy 68K machines and
> operating systems the z80 ran in concert with the 68k.  The z80 handled all
> I/O as the 68k subsystem did not have direct access to any I/O ports.  The
> 2 CPUs would talk through shared memory and interrupts. The Model 16 also
> had the first appearance of the TM-848 thin line drives, white case and
> superior green screen CRT.
> The Model 12 was introduced in 1983 as the next version of the Model II.
> It was considered the base Tandy business system.  The case dimensions were
> somewhat larger than the previous II/16. It had a simplified architecture
> in that the entire Z80 system was now on a single main board instead of the
> 4 separate cards of the Model II.  A base Model 12 has a lot of empty space
> inside as it was meant to be optionally upgraded with the card cage if you
> needed a hard drive or 68K functionality.  It also had the new lower
> profile keyboard with reverse gender connector compared to the II/16.
> The 16B released around 1984 is essentially a factory upgraded Model 12
> with the card cage and the 6Mhz MC68000 subsystem consisting of a CPU card
> and 1 or more 16 bit memory cards.  The 16B for a time was the best selling
> Unix workstation in the world.
> The 6000 released in 1985 was a slightly enhanced 16B with the biggest
> difference being the upgrade to an 8Mhz MC68000.  This system allowed you
> to run XENIX 3.x and address up to 1MB of RAM.
> _____________________________________
> You missed the addition of cards with three serial ports each and multiple
> ones
> could be installed limited only by the space in the card cage.  I ran a
> BBS connected
> to the Sytek Serial Network boxes at USMA for a while as a user interface
> to local
> and USENET groups.  It was fun.  Oh yeah, My later employer got their
> first Model 16
> in 1981.  Documentatioin was all xeroxes and the Xenix documentation
> refered heavily
> to the Intel architecture.  :-)  It went home with me when they stopped
> pushing them
> to the government as it went on the GSA List and they no longer nbeeded a
> contractor
> to sell them one.  Don't remember who got it, but it might be in
> Pittsburgh now.
> bill

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