Does anyone know what the purpose of this is?

[ohiomil]

Is this considered a mini-computer? Or just the front panel of a piece of equipment? I can't read the panel; too blurry.

 

[commodorejohn]

A search for "Multidata Model A" brings up this PDF, which refers to it as a minicomputer. I'm going to guess that's not the whole system there, but with that many boards I'd think it's likely not just the front panel - perhaps the front panel plus the CPU?

The Multidata minicomputer was first delivered to customers this year (1970). The Model A basic configuration includes 4,096 16-bit words of core memory in tandem with 32,768 words of disk memory, a memory-access controller, a central processor, an input/output bus, and a teletypewriter (ASR-33). The memory-access controller enables the central processor to execute programs approaching 32,768 words in length from a 4,096-word core. A larger core is necessary only if the time-critical portion of a program, which must be resident, will not fit into the basic module. The controller divides core memory into 256-word pages and transfers program segments a page at a time from disk into core. Any program segment may go into any page, which means that continuous program segments may be scattered in core. A memory map (a complement of 20-nsec registers in the controller) keeps track of the page assigned to each program segment.

The core memory of 4,096 words is expandable to 65,536 words. Disk memory of 32,768 words is expandable to 131,072. The system has eight programmable registers, up to 256 nested interrupts, and a basic complement of 125 instructions. Model A software is based on a 32,768-word memory rather than 4,096 words. Software includes a monitor which maintains system programs in core only while they are active, the FORTRAN IV compiler, a two-pass macroassembler, and utility programs. Price of the basic 4k system with Teletype and disk is $14,995.

Looks like it had virtual memory? Interesting...

 

[Chuck(G)]

CHM has a number of documents on this system, mostly software (OS, FORTRAN, Assembler, BASIC), all dated about 1970, so the company perhaps didn't exist for too long.

@CJ, not exactly what I would call "virtual memory", but a segmented system where memory not physically present produces an interrupt. When I think of "virtual memory", I tend to associate a mapping mechanism of some sort with it. (This has been the subject of bitter debate over at classiccmp).

All in all, it sounds as if it uses some of the same approaches as a number of minis of the time, such as the DG Nova.

The system looks at first blush to be fairly complete; only the peripherals are missing.

 

[commodorejohn]

@CJ, not exactly what I would call "virtual memory", but a segmented system where memory not physically present produces an interrupt. When I think of "virtual memory", I tend to associate a mapping mechanism of some sort with it. (This has been the subject of bitter debate over at classiccmp).

And thusly was much blood spilt and many tears shed over the True Meaning of "virtual memory." For lo, it was Serious Business. ;D

The system looks at first blush to be fairly complete; only the peripherals are missing.

Hmm, interesting. I'd assume it's fairly simple to make a modern terminal sub for a teletype, but I wonder what kind of disk it uses, and how well the virtual mem-uh, disk-swapping controller works without it? ohiomil, is this something you have, or something you're looking at getting?

 

[ohiomil]

ohiomil, is this something you have, or something you're looking at getting?

Looking to get! I really want to look at the boards. I know where it is and it was offered "$" to me once. I'll see if it is still available. If I do acquire it, I'll post pictures.