29 votes

Denys Fisher, of Spirograph fame, using a computer late 1976, early 1977

My name is Duncan Fisher and I'm the youngest son of Denys Fisher. I remember dad's HP programmable calculator and plotter set up very well - can't shed any light on the specific model though. What I ...
Duncan's user avatar
  • 291
24 votes
Accepted

Denys Fisher, of Spirograph fame, using a computer late 1976, early 1977

TL;DR: It's a HP 9825B desktop calculator and a HP 9872 flatbed plotter. By the looks it can be either a HP 9825 desktop calculator (*1) introduced in 1976, or a 1978 HP9831 computer (*2). (HP 9825A ...
Raffzahn's user avatar
  • 223k
21 votes

Did any CPUs have a special instruction for multiplying or dividing by ten?

Yes. But not as you think. The Z80 has the RLD and RRD instructions which rotate a packed BCD in memory by 4 bits left or right, that effectively results in a multiplication or division by ten of that ...
tofro's user avatar
  • 35k
11 votes

Denys Fisher, of Spirograph fame, using a computer late 1976, early 1977

The pen plotter appears to be an HP 7221 or 9872. They look identical but differ in their interfacing: the 7221 is the RS-232 version and does not speak HP-GL; the 9872 uses HP-IB and HP-GL. If the ...
John Dallman's user avatar
  • 13.2k
11 votes

Did any CPUs have a special instruction for multiplying or dividing by ten?

As mentioned by others BCD operation require multiplication and division by 10 (and multiples there of) implemented as shift by 4. It is necessary when floating point numbers are represented with BCD ...
Patrick Schlüter's user avatar
10 votes

What computer is this, a clone of a ZX Spectrum?

Judging from the block graphics on the number keys, this computer is a ZX Spectrum clone. On the 8 key, it's a solid graphic, and on the 7 key it's filled in in the lower left corner. This is ...
Omar and Lorraine's user avatar
8 votes

Xerox 3700 Documentation?

I was the Principal Technical Consultant on the Xerox 2700/3700 and 4235 (follow on product). It is the ESS (Electronic Sub System) of a Xerox 3700 LPS (Laser Printing System) printing at 24 ppm. The ...
Ole Sandner's user avatar
4 votes

Is the Coleco computer from The Simpsons based on a real computer?

Yeah, looks nothing like an Adam, but Coleco did make a computer called the Adam. Honestly, as somebody above mentioned, it looks closer to a Commodore PET. But it also looks very similar to the TRS-...
Greg's user avatar
  • 41
4 votes

Did any CPUs have a special instruction for multiplying or dividing by ten?

TL;DR: No, There is No Such CPU - But Compilers (may) Use Approximation I can't come up with any CPU with an instruction fitting that description. But replacement of certain values by shift and add ...
Raffzahn's user avatar
  • 223k
3 votes

What was this Desktop Programmable Calculator circa 1975

Hard to say (*1) as the early 1970s were the era of such devices - from calculators with multiple terminals like Wang offered, over machines like Olivetti's P101/P102 (and follow up 602/603/652/...), ...
Raffzahn's user avatar
  • 223k
3 votes

Does the video game Control (2019) depict a real computer system? What is it?

The question has already been answered, but as the color scheme topic came up in the contents, I'd like to add some pictures from the technikum29 museum, with all three color schemes (orange, green, ...
dirkt's user avatar
  • 27.3k
2 votes
Accepted

What is the likely function of these circuit boards?

Looking at the Russian Wikipedia for the EVM S5-21, the specs are quite good: Microcomputer based on a single-chip 16-bit N-MOP microprocessor K586VM1 (old name K586IK1). The developer of the ...
dirkt's user avatar
  • 27.3k
2 votes

What 1970's terminal was black on white and had an orange keyboard?

In the 1970s I worked for TDS (Terminal Display Systems) the UK importers Of ADDS (Applied Digital Data Systems). I tested and repaired these consoles (520 and 980) to component level. There was also ...
brent dobson's user avatar
1 vote

Did any CPUs have a special instruction for multiplying or dividing by ten?

UCSD p-System Not really a CPU per se, but some UCSD p-System reserved some space in zero page for "power of 10" constants, and compilers would generate special instructions for common cases ...
André LFS Bacci's user avatar

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