Questions tagged [minicomputers]

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12 votes
4 answers
2k views

History of High Availability in the mainframe and minicomputer eras?

When tracing the source of High Availability, I found to my surprise it led to a company named Tandem Computers which since 1974 made a series of minicomputers called NonStop system, to my surprise ...
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2 votes
2 answers
230 views

How the I/O performance of legacy mainframes/minicomputers in different architectures is measured and benchmarked comparatively?

Powerful in computing power, mainframes were irreplaceable thanks to the capability of processing numerous transactions rather than doing the math. While computing power is measured in FLOPS and MIPS, ...
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5 votes
2 answers
167 views

Data on the BBN C/70?

I am trying to find info on the BBN C/70, a 1970s minicomputer (roughly equivalent to a high-end PDP-11) which played a role in the early days of the ARPANET (predecessor or Internet) The thing that ...
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21 votes
2 answers
2k views

What was this mini-computer tape troubleshooting process

Back in the early 1980s I worked at a bank. My department input data into a mini-computer which was then to a mainframe system each day. I'm pretty sure it was a DEC mini, if only because the ...
9 votes
0 answers
205 views

Plessey computer at Stanford?

While updating the wiki article on the 4004, I came across an interesting claim by Ted Hoff, who stated the idea of using a general-purpose CPU in a calculator came to him due to a minicomputer that ...
0 votes
1 answer
166 views

How the technology keeps improving [closed]

How does the technology keep improving despite having everything discovered already? I mean the same sized chips and electronics are used from year to year but with every new version of the main board ...
14 votes
2 answers
502 views

Raytheon 704 mini uses?

I came across this little machine in a roundabout fashion - 4kW of RAM and 1usec cycle for "under $10,000"! (not including ASR33) It seems this is largely lost to history. Does anyone know ...
13 votes
2 answers
2k views

Did the PDP-8 designers consider a stack?

The PDP-8 was a remarkable exercise in minimalist computer design; some of the aspects of its design are discussed in detail at PDP-8 transistor count One feature it did not have was a stack. Instead, ...
  • 55k
11 votes
2 answers
435 views

Did any core-memory computers have a read-and-erase instruction?

Magnetic core, the primary form of computer memory from the mid-fifties to the early seventies or thereabouts, had the slightly awkward property that reading it erased it, so every time the CPU ...
  • 55k
8 votes
3 answers
627 views

Uh, oh, I've woken up in 1973. Can I get a job in computing? [closed]

I've woken up in 1973. Until I can figure out how to monetize my knowledge of coming political, economic, and social trends, I need to support myself somehow. So... I walk into one of the major ...
  • 205
6 votes
1 answer
2k views

What programming languages were most commonly used on the AS/400 in the 90s?

The IBM AS/400, formerly known as System/38, subsequently known as i (sic), is remarkable in being essentially the most future-proof of all the minicomputers, thanks among other things to the use of ...
  • 55k
9 votes
6 answers
1k views

What did order processing on a teletype look like?

The earliest business data processing systems were based on batch processing of punchcards. Prepare cards off-line, feed a batch of them through the computer. (Why does one so often hear of payroll, ...
  • 55k
18 votes
1 answer
1k views

How did the Nova 1200 divide so quickly?

According to https://en.wikipedia.org/wiki/Data_General_Nova The Nova 1200 executed core memory access instructions (LDA and STA) in 2.55 microseconds (μs). Use of read-only memory saved 0.4 μs. ...
  • 55k
3 votes
1 answer
282 views

Can I restore an S/38 program to a current IBM i?

The IBM System/38 or just S/38 was an IBM mini-computer launched in 1978. I don't know when IBM stopped marketing it but their AS/400 was released in 1988 and it was very easy to switch from the S/38 ...
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3 votes
2 answers
469 views

Trying to recall an OS I worked on that was called CPM but was not DR's CP/M

I'm trying to trace a type of system I did a little work on in my first job, which was for a company which no longer exists and I am not in regular touch with most of my former colleagues. It was a ...
  • 1,135
12 votes
1 answer
706 views

Why did IBM develop 5250 block mode terminals when 3270 already existed?

IBM introduced the 3270 family of block mode terminals in 1971, for use with IBM mainframes (System/370 and successors). Then, in 1977, IBM introduced the 5250 family of block mode terminals for use ...
6 votes
1 answer
467 views

How many hours of labor did it take to assemble a minicomputer?

A minicomputer like the PDP-8 contained several thousand discrete transistors and other components, all of which had to be soldered by hand, and that was among the simplest computers on the market; ...
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5 votes
3 answers
999 views

Indirect addressing using address bits as marker (tagged address)

After reading about the Signetics 2650, and being a bit familiar with the HP2100's, I'm curious how common the style of "indirect addressing via the address value" instruction was at the time? CPUs ...
24 votes
1 answer
848 views

Reconstruct the loop from "The Story of Mel"

From Ed Nather's hacker-epic "The Story of Mel" (using the original paragraph-formatting to save space in this question): The firm manufactured the LGP-30, a small, cheap (by the standards ...
16 votes
5 answers
2k views

Has there ever been a instruction set architecture that did not require instruction decoding at all?

I am studying basic principles of instruction set architectures and am considering what it would take to not have any instruction decoding at all. I.e., all the control lines of the computer would be ...
16 votes
4 answers
5k views

Why are old computers so vulnerable to temperature changes and moisture?

Interesting discussion by someone thinking of procuring a PDP-11/34, though having difficulty finding suitable space for it: https://www.reddit.com/r/retrobattlestations/comments/dztvci/...
  • 55k
27 votes
1 answer
7k views

What was the first operating system called DOS?

MS-DOS a.k.a. PC-DOS nee QDOS, was commonly just referred to as DOS. But 'disk operating system' is a very obvious acronym; there must have been previous operating systems so called. What was the ...
  • 55k
4 votes
1 answer
174 views

What was the first company to sell an IBM compatible punchcard reader?

Punchcards were the primary way to get information into computers up through the sixties. The familiar eighty column format was designed by IBM, and was a factor in the later de facto standard eighty ...
  • 55k
7 votes
5 answers
844 views

When did smart terminals arrive?

In the days of mainframes and minicomputers, a common user interface was a serial terminal where each keystroke was sent to the computer, which could respond with an update to the contents of the ...
  • 55k
8 votes
3 answers
3k views

Floating point performance of classic minicomputers

Are there any numbers available for the floating point performance of classic minicomputers of the seventies and eighties? For example, the VAX 11/780 for integer calculations was generally rated in ...
  • 55k
8 votes
1 answer
574 views

Typical mid-scale business computer system of the late 70s

What was the most common business computer system of the late 70s, just before the Apple II and CP/M really started proliferating? For concreteness, let's say we are talking about a U.S. company on ...
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