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48 votes
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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 ...
Brian H's user avatar
  • 60.8k
48 votes
4 answers
8k views

Why are first four x86 General Purpose Registers named in such unintuitive order?

On x86 the first four general-purpose registers are named AX, CX, DX, BX. It would be quite intuitive if their indices (those used in instruction encoding) were in alphabetical order, but instead of ...
Ruslan's user avatar
  • 1,444
48 votes
1 answer
6k 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 ...
cjs's user avatar
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47 votes
6 answers
12k views

Why does the 6502 have the BIT instruction?

The 6502 has a bit instruction which copies two of the bits into the N and V flags, pretends to and the byte with the accumulator, but discards the result and only affects Z. I'm having a hard time ...
Omar and Lorraine's user avatar
47 votes
8 answers
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 ...
rwallace's user avatar
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47 votes
3 answers
23k views

Were any of the books mentioned in this scene from the movie Hackers real?

In this scene from the 1995 movie Hackers, Cereal pulls out several books referred to by different colors of the "technicolor rainbow", including a "green one", "luscious ...
Neil Meyer's user avatar
  • 6,869
47 votes
8 answers
54k views

Latest web browser compatible with Windows 95 / 98

Do you know which is the latest web browser compatible with Windows 95 / 98? At the moment I have an Opera 10 working fine; it is very lightweight but very outdated. I assume that software that works ...
Daniel Perez's user avatar
47 votes
3 answers
6k 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 ...
Omar and Lorraine's user avatar
47 votes
6 answers
8k views

What is a Dumb Terminal?

There seems to be some confusion what a 'Dumb' terminal is as visible in answers and comments to this question about portable dumb terminals. So: What is a Dumb Terminal? Points that would help to ...
Raffzahn's user avatar
  • 225k
47 votes
2 answers
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 ...
rwallace's user avatar
  • 62.4k
47 votes
3 answers
7k 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 ...
Stefano Borini's user avatar
46 votes
6 answers
15k views

How should we interpret Dave Cutler's criticism of Unix?

Dave Cutler is well known for his contributions to operating systems, having led the effort on VAX VMS at DEC and Windows NT at Microsoft. According to his Wikipedia page, he is also known for ...
Brian H's user avatar
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46 votes
5 answers
7k 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,...
bjb's user avatar
  • 16.4k
46 votes
2 answers
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 ...
Psychonaut's user avatar
  • 7,661
46 votes
2 answers
6k 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-...
CJ Dennis's user avatar
  • 2,517
46 votes
2 answers
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 ...
smitelli's user avatar
  • 1,769
46 votes
1 answer
7k views

Which "very esoteric processor instructions" are used by OS/2?

According to the Oracle VirtualBox 6.0 manual, "Certain rare guest operating systems like OS/2 make use of very esoteric processor instructions that are not supported with our software ...
TeaRex's user avatar
  • 676
46 votes
4 answers
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 ...
Mike Nielsen's user avatar
  • 2,897
45 votes
9 answers
9k 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 ...
Sidney's user avatar
  • 587
45 votes
10 answers
16k views

Fastest non-emulated CP/M Z80-based computer ever built?

What were the fastest CP/M computers ever built? I'll restrict this to the Z80 variant of CP/M, no CP/M-86, CP/M-68k etc. Z80 compatibles with higher clock frequencies or more instructions/clock or ...
dirkt's user avatar
  • 28.1k
45 votes
4 answers
8k views

How did Woz write the Apple 1 BASIC before building the computer?

According to his 1984 interview with Byte magazine, Steve Wozniak created the BASIC for the Apple 1 computer before he actually built the computer: I sat down and wrote the BASIC first, and that took ...
DrSheldon's user avatar
  • 16.3k
45 votes
3 answers
4k views

Origin of the 8.3 file names scheme

On microcomputers, the famously laughed 8.3 file names (by Amiga and Mac users!) were used by PC/MS-DOS, which in turn inherited this limit from CP/M. But why did Gary Kildall use this scheme of eight ...
Krackout's user avatar
  • 1,528
45 votes
3 answers
9k views

Where did the free parameters of IEEE 754 come from?

It's clear where many of the design decisions of IEEE 754 floating point come from. For example, the binary format maximizes efficiency on binary hardware. And 32 and 64 bits for single and double ...
rwallace's user avatar
  • 62.4k
45 votes
3 answers
9k views

Why does nobody attempt to build Charles Babbage's Analytical Engine?

The Difference Engine was built in the 90s. Why has nobody succeeded in building the Analytical Engine? Charles Babbage designed the Analytical Engine as a general-purpose computer to succeed his ...
Peter Parker's user avatar
  • 1,025
45 votes
3 answers
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 '...
Kaz's user avatar
  • 8,166
45 votes
2 answers
8k 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 ...
Brian H's user avatar
  • 60.8k
45 votes
2 answers
10k 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 ...
user3570736's user avatar
  • 1,802
45 votes
3 answers
6k views

How was a demo mode implemented in arcade machines

On many arcade machines when running in attract mode, they often show a demo gameplay. I wondered how they did this?I guess those are not pre-recorded movies, so I think that they probably ran the ...
Devolus's user avatar
  • 553
45 votes
8 answers
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 ...
Leo B.'s user avatar
  • 19.4k
45 votes
1 answer
8k views

What warning was given on attempting to post to USENET, circa 1990?

I recall a confirmation/warning message that read something like "this will post to thousands of sites... are you sure?" What was a typical such message in the days of pay-per-minute dialup access?
Whit3rd's user avatar
  • 2,170
45 votes
4 answers
42k 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 ...
crabcrabcam's user avatar
44 votes
26 answers
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 ...
Martin Rosenau's user avatar
44 votes
6 answers
10k views

Why didn't C++ specify filename extensions?

Apparently even today there is no single "official" standard for C++ file extensions. There are just common conventions. To me this stands out as an anomaly... file extensions are heavily ...
StayOnTarget's user avatar
  • 3,856
44 votes
7 answers
8k views

Who invented the clipboard?

Just as the wheel, the clipboard on a computer is indeed a very useful invention! Who came up with such bright idea? Additionally, did it exist on non-graphical environments as well ?
aybe's user avatar
  • 7,102
44 votes
9 answers
12k views

Is DOS being shipped with or as an installed OS?

Given the very small size of DOS, it would seem it might still be ideal for some applications such as handheld games. Is any system manufacturer still shipping DOS with their machine? If no one is ...
Barnstormer's user avatar
  • 1,359
44 votes
11 answers
10k views

Was it actually possible to do the cartoon "coin on a string trick" for old arcade and slot machines? [closed]

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 ...
Dailey's user avatar
  • 407
44 votes
4 answers
15k views

Why did 80x25 become the text monitor standard?

Prior to the 1981 release of the IBM PC, the VT05 (72x20 1970), VT50 (80x12 1974), VT52 (80x24 1975), and VT100 (80x24 1978) text terminals were used on many Unix machines and the PDP-11 (probably the ...
Barnstormer's user avatar
  • 1,359
44 votes
4 answers
6k views

Was the term "master" in source code management systems first used with the sense of master/replica or master/slave?

In recent years there has been a push by some to move away from using the term "master" in source code management systems, often by renaming the "master" branch to a "main&...
curiousdannii's user avatar
44 votes
7 answers
10k 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 ...
Omar and Lorraine's user avatar
44 votes
2 answers
11k views

Why does the original Donkey Kong update the screen in a curtain closing pattern?

For those of you who don't know, Billy Mitchell, the former Donkey Kong world record champion was caught cheating due to differences between the original Donkey Kong format, and MAME. In other words, ...
Badasahog's user avatar
  • 4,041
44 votes
3 answers
10k 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 ...
Jaap Joris Vens's user avatar
44 votes
2 answers
7k views

How did Windows ME "cripple" DOS?

Windows ME includes the ability to create a bootable DOS floppy. This floppy contains versions of COMMAND.COM and IO.SYS that are "crippled" to remove real mode. This is done with only one changed ...
wizzwizz4's user avatar
  • 18.7k
43 votes
5 answers
10k views

Why do keyboards have an asterisk key?

While we're all accustomed to using * as the multiplication symbol (not to mention other esoteric meanings in programming, command-lines, etc.) it is of course not actually the everyday standard ...
StayOnTarget's user avatar
  • 3,856
43 votes
7 answers
8k views

Did any computers use the Z80B?

The Z80 was one of the most popular CPUs of the seventies and eighties. In almost all cases that I know of, the version used was the Z80A, rated for 4 MHz, sometimes clocked a little slower in order ...
rwallace's user avatar
  • 62.4k
43 votes
11 answers
9k views

How did early laser printers get by with so little memory?

The first HP Laserjet only had 128K of memory. To print an area of 7.5 by 10 inches at 300 DPI requires 844K if it's kept as a single bitmapped image. Obviously they were doing something clever to ...
Mark Ransom's user avatar
43 votes
3 answers
5k views

How did Apple II BASIC programs protect against listing?

I seem to recall from my high-school days that certain Apple II programs protected themselves from being listed and therefore modified. If you tried to do it, the machine would simply reboot. How did ...
user avatar
43 votes
1 answer
7k views

What's this computer in the 1988 movie "Vampire's Kiss"?

This is a grab from a 1988 movie called Vampire's Kiss. It has twin disk drives (5.25" from the looks) and what looks like a built-in printer?
Jonathan Potter's user avatar
43 votes
1 answer
6k views

How did Super Mario Bros. 3 create this tunnel vision effect?

In a certain section of World 8's map, the screen is black except for a small circle surrounding Mario (as seen below during this speedrun). After doing a little research, I discovered that the game'...
user avatar
43 votes
1 answer
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 ...
Geo...'s user avatar
  • 10.2k
43 votes
1 answer
8k views

Why does the kill-screen glitch occur in Pac-man?

Pac-man is a game where you navigate a small yellow circle around a maze, collecting dots and fruit whilst avoiding brightly-coloured monsters, or ghosts. As long as there was at least one 'man left, ...
wizzwizz4's user avatar
  • 18.7k

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