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14
votes
2answers
2k views

Did Xerox really develop the first LAN?

Did the computer scientist at Xerox really develop the first LAN, but had no backing from the company to further develop these technologies, later showing this to both Steve Jobs and Bill Gates? Just ...
3
votes
1answer
335 views

Did Xerox engineers really develop the first graphical user interface? [closed]

Did the computer scientist at Xerox really develop the first graphical user interface, later showing this to both Steve Jobs and Bill Gates? Just for reference, it is in reference to this story.
14
votes
1answer
583 views

How does a biquinary adder work?

I whipped together a quick answer to this question and then realised, that I have no idea how these tubes manipulate the numbers. A binary adder is easy to understand to the modern mind; for each bit ...
44
votes
2answers
5k 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 ...
11
votes
1answer
317 views

How were Zuse Z22 Instructions Encoded?

The title says it all: How to En-/Decode Z22/Z23 Instructions? (History and Linkage: The question was raised by Wilson in a comment on my answer to his question "Why are PDP-7-style microprogrammed ...
12
votes
2answers
2k views

Why are PDP-7-style microprogrammed instructions out of vogue?

DEC, and at least some of their computers, especially those in the 18-bit family and 12-bit family, had these opr instructions, which contained many bitfields which encoded something like "...
12
votes
2answers
331 views

Protected/virtual memory support in classic AmigaOS

It is a well-known fact that AmigaOS is a single address space, totally unprotected memory operating system. The original implementation ran on a Motorola 68000, that did not support virtual memory if ...
22
votes
2answers
5k views

What was the last x86 CPU that did not have the x87 floating-point unit built in?

This Wikipedia page says the following: Most x86 processors since the Intel 80486 have had these x87 instructions implemented in the main CPU So the above quote implies that some CPUs that were ...
5
votes
1answer
290 views

What can an 8086 CPU do if an x87 floating-point coprocessor is attached to it? [duplicate]

As far as I know, old x86 CPUs (for example: the 8086 CPU) couldn't do floating point arithmetic, and in order to be able to do floating-point arithmetic, an x87 floating-point coprocessor should be ...
14
votes
4answers
5k views

Did any laptop computers have a built-in 5 1/4 inch floppy drive?

In the early era of "portable" or luggable computers, such as the mains powered Osborne 1 and the Compaq Portable, 5 1/4 inch floppy drives were the standard storage medium. When battery-powered ...
2
votes
2answers
436 views

What is a .95END file?

While cleaning out some old computers owned by my grandfather I came across some files marked with the file format .95END that had creation dates in early 1995 (though they could be from much earlier, ...
10
votes
2answers
373 views

What role did the BBC have in the development and marketing of Acorn Archimedes computers?

The BBC's Computer Literacy Project was launched in 1982, and saw the public service broadcaster seek to raise awareness and educate the general public about the growing field of computing. They ...
12
votes
1answer
2k views

Why did Acorn's A3000 have red function keys?

Acorn's line of ARM-based Archimedes computers was common in UK schools in the 1990s, and many classrooms had an A3000, A4000, or A5000 computer. The function keys of the A3000 were a distinctive red ...
9
votes
2answers
759 views

Why could you hear an Amstrad CPC working?

I had my first programming experience in the late 80s / early 90s on a Schneider (Amstrad) CPC 464 in Basic. I remember that when a program was running, depending on the current workload of the ...
5
votes
2answers
324 views

Was Apple's Developer Release DR1 of Copland ever distributed?

From 1994 to 1996 Apple developed a complete new Mac OS, codenamed Copland, intended to be published as System 8. A first public demo was made at the May 1996 WWDC. Shortly before it was canceled, a ...
7
votes
1answer
252 views

How were arcade games developed?

For some systems, such as the Super NES (SNES), there existed a development kit, which consisted of specialized hardware. I believe this kit allowed the developer to present recently assembled machine ...
2
votes
2answers
180 views

Sinclair ZX Spectrum with DivMMC load issue

I use a Sinclair ZX Spectrum Issue 2 with a DivMMC EnJOY! Pro One and the boot process shows no error and I'm even able to enter the file browser but if I choose any game/demo/program I get always ...
4
votes
2answers
217 views

DOS/4DOS Prompt with animated characters?

I have a vivid memory of a guy I knew back in the day who had a custom prompt with a small character animation. The way I remember it there was a sequence like |,/,--,\,| in the prompt. This wasn't ...
10
votes
3answers
1k views

DOS, create pipe for stdin/stdout of command.com(or 4dos.com) in C or Batch?

I'm working on a retro project and was trying to create a pipe of stdin/out/err in DOS, but I can't find any functions to to this? For instance the pipe() command from unistd.h isn't present in ...
1
vote
2answers
61 views

DOS, create pipe for stdin/stdout of command.com(or 4dos.com) in C or Batch? [duplicate]

I'm working on a retro project and was trying to create a pipe of stdin/out/err in DOS, but I can't find any functions to to this? For instance the pipe() command from unistd.h isn't present in ...
2
votes
1answer
133 views

Why was the DEC Q-Bus called the Q-bus?

The bus used for DEC's LSI-11 microcomputer implementation of the PDP-11 was originally and prosaically referred to as the LSI-11 bus, but thereafter it was universally referred to as the Q-bus. Does ...
1
vote
2answers
268 views

IBM PC memory map - why RAM at the bottom?

The 8088 provided an address space of one megabyte. The IBM PC allocated that address space as 640K RAM (not that the 5150 could physically take that much, but the address space was allocated) ...
2
votes
1answer
124 views

Windows 98 hangs after entering password on fresh install

I am doing a fresh reinstall of Windows 98 SE on a Dell Optiplex GX1 550Mbr+. I previously had this very same version of Windows on this machine. The install works perfectly, but when I get to the ...
9
votes
5answers
280 views

Alternatives for TurboVision on DOS

TurboVision was a library by Borland for developing TUI's (Text User Interfaces). It was included with their C++ and Pascal compilers. Were there any other TUI libraries that supported multiple ...
2
votes
2answers
107 views

What are the HSync and VSync frequencies of these common VGA tweak modes?

Most VGA cards and monitors support additional undocumented resolutions, accessed by changing the VGA registers. Most are just variations on the regular modes (320x100 is the same as 320x200, but with ...
3
votes
2answers
345 views

How did 2-chip CPUs work?

The 1970s saw a big transition from CPUs built from thousands of discrete components, to CPUs implemented on a single chip, with the occasional use of bit-slice components along the way. There were, ...
1
vote
1answer
118 views

Why did CGA RGBI output leave DAC to the monitor?

CGA on the original IBM PC produced sixteen colors, one bit each for red, green, blue and overall intensity modifier. The preferred output device was the later-arriving 5153 color monitor, which ...
33
votes
2answers
4k views

Can an x86 CPU running in real mode be considered to be basically an 8086 CPU?

When an x86 CPU is running in real mode, can it be considered to be basically an 8086 CPU (or maybe 8088)? Or are there differences between the two?
2
votes
1answer
132 views

IBM 5153 vs color TV in actual picture tube

The IBM 5153 Personal Computer Color Display was a monitor designed to accompany the original IBM PC (albeit released a couple of years later) and provide a color display at sharp enough resolution ...
20
votes
3answers
4k views

How much RAM could one put in a typical 80386 setup?

I read on Wikipedia that 80386 could theoretically handle 4GiB of RAM. Knowing how long ago that was, I find it impossible to believe that anyone could actually connect as much to the CPU. So, given ...
4
votes
6answers
3k views

Were any external disk drives stacked vertically?

There was a time when floppy disk drives were big, expensive devices that in many cases, instead of being components of a computer, would be separate machines connected by a cable, in some cases with ...
9
votes
1answer
172 views

Mac Plus flyback transformer replacements

The short: How can I tell which flyback transformers would work for a 9" Macintosh? The long: I've soldered on flyback transformers on old Macs that have gone bad in the past, but when my Mac Plus ...
4
votes
1answer
141 views

How was the 8 to 16 bit transition of data lines managed for S-100

The S-100 bus had 8 data lines, logically enough since it was originally used with the 8080 and then Z80 CPUs. However, it actually had two sets of 8 data lines. The reason why is discussed in Why ...
5
votes
1answer
341 views

What was Burst Mode on the 68030 and why didn't the A2630 support it?

Inspired by this question, I'm curious what burst mode was on the 68030 and why wasn't it supported on the A2630 accelerator card commonly found in the Amiga 2500/30? I had one of these machines and ...
9
votes
5answers
575 views

Drilling 720Kb floppies to 'upgrade' them to 1440Kb?

I remember back then, there were few people that used to drill an extra hole on them to double their capacity. Surprisingly, it worked! While the other way around is plausible I am quite unsure of ...
6
votes
2answers
301 views

How advanced was the Amiga Walker prototype?

The Amiga Walker was a prototype Amiga computer that never made it to market. Wikipedia has some info including a photo of a motherboard. How advanced was the prototype? Could it boot and run Amiga ...
5
votes
2answers
217 views

Why don't manufacturers make handheld computers like the Jornada 720 any more? [closed]

One of my favorite PCs in old times were HP Jornada handheld pcs (680, 720) - perfect match of usable hardware keyboard, large-enough screen, protected by keyboard when closed, and usable OS designed ...
2
votes
0answers
90 views

How many units did TI Invaders sell?

I'm trying to get a feel for the scale and dynamics of the early home computer game industry. Statistics for arcade games and console cartridges are relatively easy to come by, e.g. that Pac-Man on ...
1
vote
2answers
100 views

How to use the MOD operator in TRS-80 model 100 BASIC?

I'm finding the MOD operand is not working when I enter it in the BASIC prompt. This is how I write it out. PRINT 1 * MOD(23) ?SN Error I have looked into a reference guide and it is too broad on ...
1
vote
1answer
124 views

Decoding the Workings of the TRS-80 BASIC Game “Escape!”

I've decided to port Chase! to Swift, apparently because I am insane. In any event, I'm trying to collect the various switches in versions from the era. One of these is unique, found here under the ...
3
votes
1answer
149 views

How much RAM did the first version of Oregon Trail on the Apple II require?

The later iterations of the series could have hundreds of kilobytes of RAM, but the original Apple II had 4K in the minimum configuration and 48K maximum (the latter using 16kbit chips which were ...
22
votes
6answers
6k views

Why was the shrinking from 8″ made only to 5.25″ and not smaller (4″ or less)?

Answers and comments to Why were 5.25" floppy drives cheaper than 8"? suggest some reasons why floppy disks moved from 8" to 5.25"; basically it seems the smaller size reduced engineering ...
24
votes
2answers
4k views

Why were 5.25“ floppy drives cheaper than 8”?

The first floppy disks were eight inches. This size was set by IBM; I haven't been able to find any indication of why they chose it, but maybe it was just because it seemed quite small to them ...
2
votes
2answers
178 views

How can I use the Commodore KERNAL to print a character to the screen?

The routine at 0xffd2 which is called chrout will print a character to some output stream. I would like to use this call to print a message to the screen, but I have a file open for output on a disk. ...
26
votes
4answers
3k views

Was the Stack Exchange “Happy April Fools” page fitting with the '90's code?

We nostalgia fans were all treated to a nineties-esque page on the various Stack Exchange sites, complete with guest books, obnoxious tiled backgrounds, Comic Sans, etc. However, when I went to view ...
1
vote
1answer
89 views

Data retrieval from 5.25 floppy disks [closed]

Can anyone direct one toward a service which can retrieve data stored on 5.25 single-sided dual-density floppy disks (MS-DOS 1.25, written using EasyWriter, on a Sanyo MBC-550)?
9
votes
4answers
1k views

Early programmable calculators with RS-232

In the early seventies, companies like HP and Wang sold 'programmable desktop calculators' that were really personal computers in the time before what is usually thought of as the dawn of personal ...
31
votes
7answers
10k views

Why did some early computer designers eschew integers?

Several early computer designs regarded a 'word' as representing not an integer, with the bits having values 2^0, 2^1, 2^2, ..., but as representing a fixed-point fraction 2^-1, 2^-2, 2^-3, ... (For ...
4
votes
2answers
478 views

When did computers stop needing to be marketed as calculators?

According to https://en.wikipedia.org/wiki/Hewlett-Packard_9100A The Hewlett-Packard 9100A (hp 9100A) is an early programmable calculator[3] (or computer), first appearing in 1968. HP called it a ...
3
votes
1answer
287 views

Graph of the history of databases

There are several nice graphs (in the computer science sense: nodes and arcs) of the history of programming languages, such as http://rigaux.org/language-study/diagram.html I haven't found one of ...

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