There actually two aspects of the Dimension 6800 operation that were interesting. I got paid for programming in 68000 code in CPM68 to do some aspect of the Apple emulation; I ended up with a Dimension as part of my pay.
I’m not sure how the Apple card for the PC worked, but in the Dimension memory had 17 bits and the 17th was used to trip an interrupt to go to a routine that handled the task the 6502 or Z80 processor wanted to do, like display or keyboard input, so almost nothing was frozen in the accessory board hardware.
The other “interesting” – as in fatal – aspect was the introduction of the Dimension in Byte magazine set a record for responses on those cards, has the company went down the tubes being uncertain as to exactly who they were targeting to sell a machine to, all of the thousands of customer information cards were found in a closet never having been used to get buyers.
That must have been challenging. I did something similar at Xerox. We were selling the 820-II Z-80 CP/M computer at the time. As the IBM PC was taking off, we added an 8086 coprocessor card to allow running MS-DOS programs. The Z-80 did all of the I/O since the coprocessor did not have access to very much of the hardware. At that time, we did not realize just how important compatibility to the lowest level of the hardware was going to be. Well, Multiplan worked. Lotus 1,2,3? No way.
The QuadLink card had to be installed between the PC’s floppy controller card and the drives and there was a funky patch cable to route the output from the PC’s display adapter through the QuadLink then to the monitor. When running in Apple mode, it (essentially an Apple II Plus on a card) took over the peripherals.
So that is why I never got a response, not that I could have afforded one and still get the IBM that I felt I needed to have.
If my memory serves me correctly, I actually used the Dimension for my PC programming for at least a couple of years probably until Windows hit the scene. I was programming mostly in basic and 6502 code but I had an odd sequence where a program I had written an Applesoft BASIC needed to run in MS BASIC, so I wrote a converter to do most of the work. Somewhere in there I wrote a 6502 and then a 68000 emulator both in BASIC to teach classes in machine code up at Brookhaven. Basically they each just displayed the registers and showed how a small portion of memory and branching worked.
My experience with Xerox had to do with the brief mania for introducing new machines and stores to sell them, like when Sears had a computer and office equipment store*. I was hired to do a presentation on VisiCalc and Multiplan (as I recall) and was given some data to make it more realistic for the executives who were seeing the presentation to see what was so wonderful about VisiCalc. So I set up the data so it looked like their report and was going to emphasize the flexibility and immediate response of VisiCalc over the more mainframe operation of the other program. I got about half a sentence into my presentation with the data showing on monitors, when a voice from down the other end of the long table said something on the order of, “Who let this data out of the office?” Which killed the presentation. It seems that they had given me an actual sheet of data that showed what Xerox thought was going to happen in the next couple of months! Of course I got nothing from the numbers, and assured them of non-disclosure, but that ended the presentation and I got paid for my time.
- there were something like a dozen computer stores at one point and close to two dozen computer user groups, so I made up padded cards listing all the user groups and gave them to the stores to give cards to customers needing help with their computers. Of course there was an ad for my programming services at the end of it.