All Questions

Filter by
Sorted by
Tagged with
48
votes
4answers
6k views

Why did the IBM 650 use bi-quinary?

The IBM 650, announced in 1953, was the world's first mass-produced computer. It represented numbers in decimal, which is understandable, both because it needed to work with exact money amounts, and ...
48
votes
3answers
8k views

Why did line printers have 132 columns?

From what I read, most line printers have 132 columns. Also, the VT-220 and presumably other terminals may be switched between 80 columns (that's a usual width) and 132 columns. As I recall, 80 ...
48
votes
1answer
5k views

Why do we use caret (^) as the symbol for ctrl/control?

From my understanding, the caret character (^) has been used to indicate Ctrl-key combinations since the early UNIX days, if not earlier. Why was this character used to indicate this? Was it simply ...
47
votes
11answers
20k views

Why not use fractions instead of floating point?

Considering all those early home computers, the ZX Spectrum, the Galaksija, the VIC-20, the Apple I/II/III, and all of those, they all have some 8-bit CPU which does integer arithmetic and no floating ...
47
votes
9answers
11k views

Why weren't bootable game disks ever common on the IBM PC?

While for other platforms of that era (primarily, Amiga), putting a game on a bootable disk was quite a normal practice, this approach never taken off on IBM PC. Why not? I do remember people having ...
47
votes
7answers
10k views

Did any compiler fully use Intel x87 80-bit floating point?

There is a paradox about floating point that I'm trying to understand. Floating point is an eternal struggle with the problem that real numbers are both essential and incomputable. It's the best ...
47
votes
1answer
10k views

What is the context of the button “Is MS DOS a feminist?”

I just saw this button in the Computer History Museum, and I'm wondering what is the context? Context removed, "Is MS DOS a feminist?" is about the most non-sequitur thing I've seen.
47
votes
2answers
9k views

What is the origin of this bizarre advert of people wearing swimsuits in a room with computer hardware?

This image of people wearing swimsuits in a room with computer hardware popped up on Twitter recently. Where was this advertisement published, and what computing product or service is it offering?
47
votes
4answers
4k views

Why do older computer cases turn yellow?

Why do plastic cases of old computers turn yellow? Is this yellowing a problem that has been solved in modern plastics?
46
votes
13answers
17k views

How was it back then in 1984, when the Apple II had color, and the new Macintosh didn't?

I imagine it being a huge downgrade for some, not to have color on the Macintosh. Macintosh games were black and white in the beginning, while Apple II had color. I'm especially interested in ...
46
votes
13answers
7k views

What languages are better fit for generating efficient code for 8-bit CPU's than C?

I found Why do C to Z80 compilers produce poor code? very interesting as it pointed out that C (which was designed to be an abstraction of a CPU for porting Unix) was not a very easy language to ...
46
votes
8answers
12k views

Why were chips socketed in early computers?

In many early computers, many of the chips were in sockets rather than soldered directly to boards, e.g. this series of pictures of the Tandy CoCo 1 has a note to the effect that all the chips are ...
46
votes
5answers
15k views

Why did C have the return type before functions?

In general, there are two types of syntax of defining functions - Something like C, C++, C#, or Java (int functionName(char arg)) vs the ML (and others) tradition of defining the return type after the ...
46
votes
3answers
8k views

What's the relationship between early 90s Pentium microprocessor and today's Intel designs?

My simplified understanding of the evolution of the Intel processors over the last 20 years is that the Pentium II and Pentium III architectures were sort of "dead-ends", and today's Intel processors ...
46
votes
2answers
7k views

Why did the PDP-11 include a JMP instruction?

The PDP-11's program counter was addressable in two ways: as a general purpose register or as a memory location. Still, the PDP-11's instruction set included separate instructions for moving a new ...
46
votes
2answers
6k views

What did the DoD think Fortran lacked?

According to https://en.wikipedia.org/wiki/COBOL the project to design COBOL began when On 28 and 29 May 1959 (exactly one year after the Zürich ALGOL 58 meeting), a meeting was held at the Pentagon ...
46
votes
4answers
7k views

Why would older video games include fragments of source code?

One thing that was surprisingly common in older video games (around the same era assembly language was king) was the inclusion of uncompiled, plaintext source code in the ROM. You can see many ...
45
votes
26answers
15k views

How were files transferred between different systems in the late 1980s?

Today there are adapters available allowing you to connect historic floppy drives to a modern PC. This allows you to copy data from historic floppy disks to the PC. In the late 1980s and the early ...
45
votes
10answers
10k views

Why did 1950s-60s computers have such wide words?

Modern general-purpose computers typically have a 64-bit word size, but looking back in time, we see narrower CPUs. In the early 80s, the 68000 dealt with 32-bit addresses but the ALU was only 16 bits ...
45
votes
5answers
6k views

What protocol do Teletypes use?

(By "Teletype" I mean all teletypewriters compatible with the protocol used by the Teletype.) The Teletype was the dumbest of all dumb terminals, which meant that it was cheap. This means that it was ...
45
votes
5answers
4k views

Filesystems with versioning

I've been reading through The Unix Hater's Handbook. It has many, many very valid criticisms. (I'm still raging that terminal escape codes aren't in the terminal driver...) There is one anomaly though:...
45
votes
2answers
11k views

Why does the 80486 take longer to execute simple instructions than complex ones?

The 80486 processor can execute many instructions in a single cycle, such as a register-to-register add instruction (ADD EAX, EBX, for example), which one would generally assume is fairly complex, ...
45
votes
5answers
16k views

Why did CPU designers in the 70s prioritize reducing pin count?

A lot of 70s era microprocessors were packaged in DIP packages with 40 pins. This was a reasonably good fit for 8-bit processors: 16 address lines, 8 data lines, 2 power and clock are all absolutely ...
45
votes
2answers
5k views

What computer system is this from 1984 Doctor Who?

In the 1980s, the popular BBC science fiction series Doctor Who used some real computer system(s) to display impressive (for the time, OK, maybe not!) graphics. They actually ran the software real-...
45
votes
4answers
35k views

Commodore 64 to modern TV

I've been thinking about getting a Commodore 64 machine. However, I realise there's obviously no video cables I have that will work. But when I looked online there are many people using S-Video to VGA ...
45
votes
1answer
5k views

Where and when did the `0x` convention for hexadecimal literals originate?

By the early 1980s, C was using 0x as a prefix to indicate integer literals expressed in hexadecimal, e.g., 0xCAFE. This did not exist in B as of 1972, though B did support octal integer literals via ...
44
votes
9answers
13k views

Why did the IBM PC need a sound card?

The original IBM PC and later variants used an Intel 8253 or 8254 as a sound chip. Why did users add sound cards such as the Adlib or Sound Blaster. I remember voice output with programs like ...
44
votes
11answers
9k views

What is the oldest computer capable of running a modern version of GNU/Linux?

A bit of a trivia question: What is the oldest hardware capable of running a modern Linux-based operating system, including user-space? (Not necessarily GNU userspace, but running a standard GNU/Linux ...
44
votes
2answers
5k views

Why are paddles called paddles?

A paddle is a sort of input device, common on early video game consoles and home computers, consisting of a handheld wheel with one or more fire buttons. Unlike dial boxes, which spin freely, paddles ...
44
votes
4answers
5k views

Why are C64 games inconsistent with which joystick port they use?

The Commodore 64 has two DE-9 joystick ports. If I'm the only person that ever plays games on it, you would assume that you could just leave a joystick plugged into Port 1 and be done with it. However,...
44
votes
2answers
7k views

Did IBM encourage Bill Gates to retain the rights over PC-DOS?

As is well-known, Microsoft's negotiations with IBM to deliver PC-DOS 1.0 with the original IBM PC resulted in: IBM licensing the OS from Microsoft, as opposed to purchasing it outright. Microsoft ...
44
votes
2answers
11k views

How did the Z80 instruction set differ from the 8080?

The Zilog Z80 microprocessor, known for its use in the ZX Spectrum, was designed to be a backwards-compatible extension to the Intel 8080 processor. It introduced several new instructions to the 8080'...
44
votes
3answers
6k views

How did C64 games handle music during gameplay?

On the C64 there was no threading, so how did games handle treating at the same time music and game code? Music requires exact timings, and the SID had to be instructed to change the note at the right ...
43
votes
8answers
7k views

What was the first programming book

I'm curious, what was the first book, about programming for digital computers. I tried to google it, but it led me to multiple results. I'm mostly interested in the language it was about and the ...
43
votes
12answers
8k views

Was it actually possible to do the cartoon “coin on a string trick” for old arcade and slot machines?

In cartoons, you often see characters like Scrooge McDuck with a coin where they have drilled a hole in the middle and attached a string, enabling them to insert the coin multiple times and keep ...
43
votes
7answers
5k views

Why does the Commodore C128 perform poorly when running CP/M?

I have seen several claims of poor performance of the C128 when running CP/M, and would like to better understand these claims, especially in comparison to other CP/M machines of the early to mid-...
43
votes
3answers
4k views

Why are the symbols on the number keys of PC & Mac keyboards different to ASCII keyboards?

On a US-layout PC keyboard, the symbols above the number keys are as follows: Whereas the keyboard on an Apple II is different: Note, for example, the '(' and ')' symbols are now above 8 and 9, and '...
43
votes
2answers
5k views

Locked-up DOS computer beeped on keypress. What mechanism caused that?

Long time ago I had an old IBM PS/2 that I had fished out of a dumpster. It ran IBM DOS 5.0 and was a solid little machine. Occasionally I would encounter the following scenario, and I recently ...
43
votes
8answers
5k views

Executable ASCII files before x86?

I've known about a technique allowing to bootstrap arbitrary 16-bit x86 code from a subset of instructions representable as printable ASCII bytes since the early 1990s. The first example of an ASCII ...
43
votes
2answers
9k views

Why were some early PC 3D cards unsuitable for 2D graphics?

Some of the early PC 3D graphics cards such as the 3dfx Voodoo Graphics cards had a passthrough port to enable them to switch to a secondary card to display 2D graphics. I am curious to know why these ...
43
votes
1answer
6k views

Can anyone identify this unknown 1988 PC card from The Palantir Corporation?

I'm trying to restore order to my junk pile office, and I ran across this card. I am usually pretty good at generally identifying old (PC?) stuff, but this one is outside my experience. I think it ...
43
votes
2answers
23k views

Why were the /\ (min) and the \/ (max) operators abandoned in the C language?

In the UNIX V7 version of the C language (but not yet in the V6 version), there were the /\ (min) and the \/ (max) operators. In the source of the scanner part of the compiler, case BSLASH: if (...
42
votes
9answers
7k views

What was the point of separating stdout and stderr?

I occasionally need to work with console commands and 100% of the time I want to redirect my output to a file I fail to redirect stderr as well as stdout the first time. I can't think of a single ...
42
votes
6answers
7k views

How did old games from 8-bit era game consoles store music?

Some time ago I found that the audio of a game called Ninja Gaiden 1 (NES) is around 1 hour. This is excluding the sound effects like jump and hit e.t.c. Then I found that the entire game size is ...
41
votes
3answers
7k views

What is between the sectors of floppy disks?

I've found this page which has an informative description of how sectors were encoded on floppy disks: http://nerdlypleasures.blogspot.com.au/2015/11/ibm-pc-floppy-disks-deeper-look-at-disk.html Do ...
41
votes
6answers
9k views

How did the SysRq key get onto modern keyboards if it's rarely used?

Was the SysRq key ever used on any common operating system? Google tells me it wasn't. But then how did it end up on so many keyboards?
41
votes
6answers
12k views

What limited the use of the 6809 CPU in personal computers?

Why did manufacturers of home computers avoid using the 6809 CPU? I realize that the Z80 and 6502 had a 3- or 4-year head start in availability. But once it did become available in 1978, I don't ...
41
votes
3answers
5k views

What happened to the SEV instruction on the 6502?

The 6502 has a group of opcodes which copy bit 5 from the opcode into one of the status flags. (I know it's not implemented this way, but it looks as though the bit fields are: 2 bits to select the ...
41
votes
7answers
9k views

The history of the NULL pointer

As we know, in C to dereference a null pointer is undefined behaviour. From what I understand, the PDP-7 and the PDP-11 both have ordinary memory that can be written to and read from at address 0. On ...
41
votes
3answers
6k views

How can I visit HTTPS websites in old web browsers?

I'm having trouble accessing HTTPS websites using Netscape Communicator 4.8. This is the error message I get: Is there a way I can configure some sort of proxy that will allow me to access HTTPS ...

15 30 50 per page
1 2
3
4 5
84