Recently came into possession of a SriTek Microcard PC card with a 68000 Motorola CPU and 512k memory. The problem is that the software needed to activate and run the card no longer appears available anywhere online.
The card shown below features a stacked setup with the backplane (Versacard) holding 256K DRAM and support circuitry, and both the 68000 Microcard and and an addtional 256K memory card mounted via interconnects. This particular card was meant for the XT or PC class IBM machine and features an ISA BUS connection, partially hidden in the photo.
“What is so important about the stupid software? Can’t you just plug-n-play?”
No—without getting too technical, I learned while setting up Xenix on the Tandy TRS-80 Model 12, 16, and 6000 that it was designed as an asymmetric-multiprocessing system. The 68k acts as the primary CPU, while the Z80 manages I/O. Similarly, this card uses a software driver between itself and the 8088, disk, LPT, and serial interfaces. On Tandy 68k systems, this is called z80ctl; on the Microcard, it’s the software needed to bring the card online.
Here’s a closer shot of the CPU, the Motorola MC68000ZB8. The Motorola 68000 is an OEM/tray microprocessor, 8-12 MHz in this package specifically, which is a 68-lead ceramic LCC. The processor has a 32-bit data width using a 16-bit bus. The cpu supported a max memory size of 16 MB and memory-mapped I/O.
The memory stacked together on the board is composed of NEC D4164C-2, a 65,536 words (64k) by 1 bit Dynamic N-Channel MOS RAM designed to operate at 200ns with a 335ns W/R Cycle. The card contains the Versacard, with the first 36 DRAM chips, the additonally mounted card contains the other 36 DRAM packages totalling 512k DRAM.
Where have I looked?
Starting with the VCF Forums post- https://forum.vcfed.org/index.php?threads/looking-for-documentation-for-sritek-68000-microcard.64705/ Yep, that is my comment last but still no reply, as expected this post was over 5 years ago. Still, I posted and tagged them both, so fingers crossed!
Next is the Worthpoint link to a previous sale that looks like part of the 16-bit version card posted on the VCF Forum, https://www.worthpoint.com/worthopedia/sritek-inc-68000-microcard-1823599010. This tells me that there are different-sized versions of the 68000 setup, this one being 10MHz and 2MB, while mine is only 8MHz and 512k. Still, for Xenix (UNIX), there is still plenty to do.
The USENET Archived post written by David Bryant of Bell Labs at the time – https://www.megalextoria.com/usenet-archive/news004f1/b10/net.micro.pc/00000068.html – gives a good example of the card structure and tons of details. From the site:
The building blocks for the SriTek products consist of the PC VersaCard and the processor MicroCards with various operating systems, programming languages, and commercial applications. The VersaCard is a single-slot expansion memory for the IBM PC. In a stand-alone mode, it is a 256 K-byte memory expansion. The memory can be easily expanded from 256K to 512K bytes by mounting a RAM Module.
A processor MicroCard can also be mounted on the VersaCard, which effectively changes the “personality” of the IBM PC. The VersaCard is dual-ported memory; to the MicroCard, it appears as 16-bit memory, and to the 8088, it appears as an 8-bit memory. When a processor MicroCard is mounted on the VersaCard, and the standard SriTek software is used, all application programs are automatically redirected to the MicroCard, which acts as the Main Processing Unit (MPU).
All input and output chores, such as communication with the CRT terminals, the disk drives, and the printer, are handled by the PC; the 8088 processor functions as the Input/Output Processor (IOP) and operates in parallel with the MPU. This type of task-partitioning provides additional performance for I/O-demanding applications such as multi-user and multi-tasking systems or systems with a local area network facility.
A visual representation done by David Bryant of Bell Labs showing the different CPU cards and how they mounted, via text diagram.
Still, no software links… : (
The next link is the SAMS 68000, 68010, 68020 Primer, which contains resources for different contacts a user could use to purchase this and other hardware options back in the day. Looks like this card was pretty pricy- https://vintageapple.org/macprogramming/pdf/SAMS_68000_68010_68020_Primer_1987.pdf.
SRITEK, Inc.
10230 Brecksville Road
Cleveland, OH 44141
(216) 526-9433
K/SBC/S/U
MC68000 Versabus/microcard to run XENIX on IBM XT @ $1995-$2995
including software
Still, no software links… or contact email. : (
World Radio History hosts an archive of BYTE magazine, where users were writing in about the new card and its not being included in other reviews. https://www.worldradiohistory.com/Archive-Byte/80s/Byte-1984-04.pdf
Next was a duplicate link to the full text of the SAMS primer previously mentioned.
Next link found is an interesting timeline “Micro implementations of Unix” which lists the Microcard along with a few others: https://www.landley.net/history/mirror/robotwisdom/nonnix.html.
‘uNETix’ from Lantech ($298)
‘Venix’ from VenturCom ($400) [crit]
‘Coherent’ from Mark Williams ($500) [crit]
‘QNX’ from Quantum Software ($650)
‘Idris’ from Whitesmith’s ($1100)
‘Microcard 68k’ from Sritek ($2695)
Again, it appears to be a top-of-the-line card! NEAT!
On to the next link, a PC World ad and an article titled “Ma Bell’s Favorite DOS” where the Microcard again gets mentioned. The color photo indeed shows several software titles for the various card CPU add-ons.
So this is where my journey currently sits: I am looking for the necessary software to run and set up Xenix, which requires a similar I/O manager to those found in larger Tandy systems. I am reaching out to my contacts to open communication and am specifically seeking anyone who may have worked with this card and still has the required software.