Yet Another Piece of Computer History! When I picked up this morning this – very heavy – FutureData AMDS FD Z80 64k and its AMDS MD/3 dual floppy unit, I was not suspecting that I was carrying home a part of the local history, originated back in 1978. But before getting into this story itself, let’s have a look at this so-called universal microprocessor development system. It is 1978 and microprocessor-based applications are getting increasing momentum in the industry.
To develop such novelties of that time, one needed to design the hardware as well as the software from the ground up. In the late ’70s this meant that you had to develop your hardware – essentially pick a CPU – and tediously write and debug the software to make it somehow useful. I always recall the NASA report published in 1968 on Flight Software Complexity, stating in the short that “HW is easy, SW is *&#@% hard”. This is where FutureData gets into the picture. The Californian company – founded in 1975 and purchased in February 1979 by GenRad for ~$5 million – was promising a universal, versatile and modular microprocessor development system. Indeed, the same system could be used to target a wide variety of CPUs. You just had to buy and install the right CPU board (8080, 8085, 6800, 6802, Z80, 6502 and later 68000+) as well as its specific boards. One interesting and original feature of the AMDS was the in-circuit simulator. Using this in-circuit emulator/logic analyzer, it was possible to plug it into the CPU socket of your target hardware.
The fake CPU was driven by the computer, where your hardware under debug had no idea of the substitution. Although it was a tremendous help – simply imagine how cool it is to have an integral view of the processor running in the real board –, it also introduced some issues. For example, NMIs were trapped and logically decided if it was issued by the microsystem or the target hardware, which makes it hard to debug timing-related issues. My new toy has two – massive – components: the microsystem and the microdisk. The microsystem is, in fact, a terminal and a chassis. The chassis has a motherboard equipped with 14 expansion slots. Although they have the same physical edge connectors as the S-100 bus, the signals and power lines are different (although equivalent). The microdisk has two floppy drives (8-inch) and is booting the OS and serves as mass storage for programs (26 sectors of 128 bytes). The system boots into a monitor (BOOT80D V02) and gives access from the floppy drives to an editor, an assembler, a linker, a debugger, a BASIC interpreter and few additional systems tools. Very classic! Unfortunately, my Z80 AMDS didn’t come with the RDOS disk (well, it makes our hobby even more interesting).
It worth signaling at this stage that this solution was acquired for $19.725 in 1978! And this was an economic pick, compared to what Tektronix or HP wax selling at the time. I will keep you posted as I progress reviving this beast. And now la pièce de résistance: the piece of history announced in the intro. It turns out that this very system was purchased by Rodgers Instruments, a local – but known worldwide – organ manufacturer (Hillsboro Oregon). As a side story, Rodgers Instruments was founded in 1958 and was successively acquired by CBS (the system still has the CBS tags attached), Roland and in 2016 by the Vandeweerd family. In June 1978. Rogers Organ (CMD) decided to acquire this system to develop software for high-quality cost-effective organs they would eventually manufacture instead of the analog models. The project’s initiators rightfully believed that all future organs will be microprocessor-based, and therefore they would need a solid software development system. Indeed, Rogers purchased a license from the National Research & Development Corporation of Great Britain for manufacturing rights to a microprocessor-controlled digital organ. The company had the choice between investing in this system and controlling their destiny, or to have all their software developed in the U.K. at Bradford University. As we know today, they went for the local choice! Enjoy the pics…