Questions tagged [minicomputers]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
11 votes
1 answer
544 views

Origin of what seems to be a Front-Panel

Reorganizing my desk - more exact the piles below - I once again came across this mystery front-panel. I can't remember what it was from nor who owns the ||/ logo present on chips and board(*1). ...
Raffzahn's user avatar
  • 223k
20 votes
2 answers
3k views

Did the IBM ServiceFree really reach 80 MIPS in 1975?

According to Computer Wars by Charles H Ferguson and Charles R Morris, page 40-41, an IBM researcher named Cocke in the early 70s built a RISC minicomputer called the ServiceFree (because it was meant ...
rwallace's user avatar
  • 61k
2 votes
0 answers
132 views

Micropolis 1325 ST506 MFM drive giving "Address mismatch"

I am trying to recover an old mini-machine that is using a Micropolis 1325 drive, and I am successfully reading parts of the drive. I am trying to recover as much as data from the drive, and ...
Ronny's user avatar
  • 121
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 ...
Schezuk's user avatar
  • 3,752
2 votes
2 answers
268 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, ...
Schezuk's user avatar
  • 3,752
5 votes
2 answers
197 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 ...
fi11222's user avatar
  • 153
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 ...
TheMadturk's user avatar
9 votes
0 answers
217 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 ...
Maury Markowitz's user avatar
0 votes
1 answer
173 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 ...
Borislav Stefanov's user avatar
18 votes
4 answers
865 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 ...
Maury Markowitz's user avatar
14 votes
2 answers
3k 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, ...
rwallace's user avatar
  • 61k
10 votes
2 answers
539 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 ...
rwallace's user avatar
  • 61k
8 votes
3 answers
653 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 ...
SlowMagic's user avatar
  • 205
12 votes
1 answer
3k 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 ...
rwallace's user avatar
  • 61k
11 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, ...
rwallace's user avatar
  • 61k
17 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. ...
rwallace's user avatar
  • 61k
3 votes
1 answer
315 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 ...
badjohn's user avatar
  • 2,024
3 votes
2 answers
505 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 ...
Liam Proven's user avatar
  • 1,175
12 votes
1 answer
1k 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 ...
Simon Kissane's user avatar
6 votes
1 answer
481 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; ...
rwallace's user avatar
  • 61k
5 votes
3 answers
1k 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 ...
Maury Markowitz's user avatar
25 votes
1 answer
954 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 ...
Quuxplusone's user avatar
17 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 ...
Gunther Schadow's user avatar
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/...
rwallace's user avatar
  • 61k
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 ...
rwallace's user avatar
  • 61k
4 votes
1 answer
187 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 ...
rwallace's user avatar
  • 61k
7 votes
5 answers
968 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 ...
rwallace's user avatar
  • 61k
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 ...
rwallace's user avatar
  • 61k
8 votes
1 answer
595 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 ...
rwallace's user avatar
  • 61k