102
votes
Accepted
Why were programs entered on punch cards instead of paper tapes?
The basic issue that paper tape is hard to edit. In theory you can cut the existing tape and splice in a new section, but in practice there is no easy way to find the correct location except by ...
- 6,646
79
votes
Accepted
Why did 1950s-60s computers have such wide words?
And if you go back further, e.g. to the ENIAC, you'll see a word size of 40 bits.
And if you go back even further, to mechanical calculators, you'll see word sizes determined by the number of decimal ...
- 26k
75
votes
Accepted
How big is a mainframe?
In the 1980's a certain bank with its headquarters in Edinburgh has a problem with (IBM) disc storage that had to be kept online for live customer account information for branch and ATM machine ...
- 5,597
57
votes
Accepted
What was the first operating system called DOS?
DOS/360
(As distinct from TOS/360, the tape OS)
Announced at the end of 1964 per Wikipedia.
- 33.5k
55
votes
What accounted for the cost of ENIAC?
R&D stuff isn't manufactured (at first).
It's usually partially constructed, ripped up, and redone, multiple times, with long testing and debug cycles in between, all the while with payroll ...
- 8,125
53
votes
Accepted
History behind the text column restriction
Old COBOL standards were based around 80-column punched cards, and columns beyond 71 (or 72) were reserved for line numbers. They were little used, but a numbered deck, if dropped, could be sorted by ...
- 2,829
53
votes
Accepted
What did code on punch cards do with the other six bits per column?
TL;DR;
Punch card code is not binary but a collection of n out of m encodings.
Long Story
Yes, really a long story, so I'll only cover the main line from Hollerith to EBCDIC. There are many sidelines ...
- 213k
45
votes
Accepted
Why was IBM's Scientific Subroutine Package superseded?
Specifically concerning EISPACK. what happened was that James Hardy "Jim" Wilkinson in the UK (whose career as an applied mathematician started with practical ballistic modelling in WWII, ...
- 6,646
42
votes
Why were programs entered on punch cards instead of paper tapes?
Punch cards long long long predated paper tape.
But there's a practical consideration you're not thinking of. If you had ever used punch cards and paper tape, you'd know:
Punch cards can be dropped, ...
- 6,119
41
votes
Can anyone help me identify this old computer part?
According to this page it's a wire punch tool for a 1940 IBM 402 computer programming board.
From that page (screenshot of the page is below):
1940 IBM 402 Computer Programming Board A tidbit fact: ...
- 501
40
votes
Accepted
Why did mainframes have big conspicuous power-off buttons?
Yes, huge safety concerns as I remember engineers sitting inside the cabinets of large mainframes while it was running, fully powered, large currents in each cabinet powering fans. Cooling water being ...
- 5,597
37
votes
Accepted
Were any IBM mainframes ever run multiuser?
Yes. There were CP/CMS and VM/370 - true multiuser operating systems running on the mainframe with individual users logged in. AFAIK it was mainly used for software developers (to develop IBM ...
- 6,119
33
votes
How big is a mainframe?
But I can't seem to find any pictures of a computer filling an entire room, much less a whole multi-story building.
(Image taken form Centre for Computing History)
Well, for example look at this ...
- 213k
32
votes
What did code on punch cards do with the other six bits per column?
Uppercase text only needs six bits per character.
The fundamental mistake that you are making is assuming that punch codes were binary numbers.
They were not.
The encodings were patterns, ...
- 2,278
32
votes
Why did the VT100 terminal have to be connected to a host computer if it already had a processor?
"Having a processor" is not sufficient for something to be a general purpose computing device. The VT100 was designed for a specific purpose, and adding more features like storage and I/O ...
- 6,849
31
votes
What did code on punch cards do with the other six bits per column?
Although you have many correct answers describing the nature of the coding used in punched cards, no one has touched on the mechanical properties of the cards. Regular users of punched cards in the ...
- 5,597
30
votes
Accepted
What date is 74029 on an IBM Mainframe?
TL;DR: DATE=74029 reads as: Year (19)74, Day 029 (Jan 29th),
It's an Ordinal Date in truncated form, expressed in terms of 2 digit year and 3 digit day of the year.
Does anyone know when was it ...
- 213k
29
votes
Accepted
What is a good COBOL specification to target when aiming to support ~75% or more of mainframe and minicomputer software bases?
[Preface: While the basic question may seem to be off-topic, as it's about today's use of COBOL, I like to see it as asking in help to educate about COBOL. The noble effort to keep the language alive ...
- 213k
28
votes
What accounted for the cost of ENIAC?
So what was the other $478,000 spent on?
Paying people to design and build it would have been a fairly big component. People often underestimate the cost of labour, particularly if it is their own ...
- 11.4k
27
votes
Accepted
References for the complexity of the COBOL language
No, COBOL is not complex and didn't require complex compilers.
At least not for COBOL up to 74 (*1) which was the standard at the time of introduction of micros (mid 70s to late 80s). From the ...
- 213k
26
votes
How big is a mainframe?
Here's a picture of the "Strela" (arrow) computer (1954)
Vacuum tubes, 2000 op/sec (on 43-bit fixed point), 150kWt, 300 m³
- 2,131
26
votes
Accepted
Was any indentation-sensitive language ever used with a teletype or punch cards?
I agree to an extent that COBOL was "indentation-sensitive", but it really wasn't "indentation-sensitive" but rather "column-sensitive". The original COBOL coding format ...
- 3,264
25
votes
How big is a mainframe?
The excellent history book "AN/FSQ-7: the computer that shaped the Cold War" describes the size of a 1950's era radar monitoring air defence computer.
A single installation (a single computer) was ...
- 351
25
votes
Accepted
What was the most critical supporting software for COBOL on IBM mainframes?
TL;DR:
Which components or facilities were the biggest obstacle to porting typical COBOL applications?
Simply that there were not many applications that made sense to be ported to (desktop) micros. ...
- 213k
25
votes
Accepted
What accounted for the cost of ENIAC?
One of the biggest factors is that when you have a machine that requires 5,000,000 successful solder joints to function properly, you need to make sure that all of your solder joints are really really ...
- 366
24
votes
How big is a mainframe?
Here's the computer room of the Shuttle Mission Simulator (SMS), building 5 of NASA's Johnson Space Center, in the early 1980s. Most of the boxes are parts of a Sperry-Univac 1100 mainframe, but some ...
- 571
23
votes
Accepted
What was the last non-monolithic CPU to come to market?
The world of large computers is amazing. MCM systems of monstrous in the eyes of a PC user parameters were widely popular right up to the cloud revolution, and even now, taking into account legal ...
- 2,131
21
votes
Why did 1950s-60s computers have such wide words?
Longer words mean more bits can be processed at once. An 8 bit processor can perform a 32 bit calculation, but it has to do it in 4 stages of 8 bits each. A 32 bit processor can do it in one stage.
...
- 15.1k
Only top scored, non community-wiki answers of a minimum length are eligible