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2answers
73 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
141 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
363 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
127 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
299 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
110 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
363 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
130 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
135 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
177 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
142 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
384 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
598 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
314 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
231 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
98 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
102 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 ...
2
votes
1answer
130 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
185 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
185 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
90 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
558 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
290 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 ...
8
votes
2answers
320 views

How did the Amiga uses compare to uses for other personal computers in 1985? [closed]

The Amiga 1000 came out in July 1985. This was an era in which personal computers were designed by their manufacturers to meet a unique set of bespoke requirements. For example, some computers came ...
2
votes
0answers
233 views

How was the prototype-robot for the Atari 2600 kept in the same position as the robot on screen?

QUESTION How was the prototype-robot for the Atari 2600 kept in the same position as the robot on screen? A photo and some details here : https://www.retrothing.com/2008/12/atari-2600-cont.html ...
6
votes
1answer
321 views

What's the fastest way to ignore keypresses?

I'm writing a game for the IBM PC (running MS-DOS), complete with fancy cutscenes. Unfortunately, though, the keys pressed during those fancy cutscenes are carried out once the fancy cutscene has ...
4
votes
4answers
277 views

Did the PC/AT-bus use its expanded address space?

The system bus of the IBM PC had 8 data lines and 20 address lines, in a logical correspondence to the 8088 CPU. The AT added a second inline edge connector to expand this to 16 data lines and 24 ...
6
votes
1answer
142 views

Which Amiga systems did access RAM with fast page access?

I'm pretty sure Chip and Fast RAM access on an Amiga 1000 does not support FPM access. Which Amiga system, chipset or motherboard "glue logic" first introduced FPM access to Fast RAM? Which one to ...
5
votes
4answers
596 views

How does the Z80 determine which peripheral sent an interrupt?

My understanding of how interrupts (and more specifically, interrupt daisy-chaining) works in the Z80 is limited, to say the least, so if I get anything wrong please correct me. Anyway, let's say I ...
5
votes
3answers
302 views

Were there computers whose text touched( or came close to ) the overscan border? [closed]

QUESTION - . Were there computers whose text in text-mode, touched( or came close to ) the overscan border, and could this sometimes result in some of the computer-generated-display not being ...
12
votes
5answers
3k views

What was the first Unix version to run on a microcomputer?

I have read that the first version of Unix was created for the PDP-7, and later versions were created for the PDP-11. But I am wondering, what was the first Unix version to run on a microcomputer?
5
votes
5answers
491 views

Did any assemblers work like this?

Once you get past the stage of manually entering numeric machine code, the most primitive programming tool is a machine code monitor. Intended primarily as a debugging tool, this works with a target ...
31
votes
2answers
5k views

How did people program for Consoles with multiple CPUs?

I'm specifically interested in the Sega Mega Drive/Genesis, which used a 68000 CPU, but also a Z80, mainly used to control the sound hardware and provide backward compatibility with the Master System. ...
2
votes
0answers
133 views

Looking for Complex Algorithms to Demonstrate Ascota 170 Capabilities

I am restoring the Ascota 170 antique mechanical programmable computer. It is already working. Now I’m looking for an algorithm to demonstrate its capabilities — like calculating trigonometric or ...
4
votes
1answer
961 views

When did Lisp start using symbols for arithmetic?

Looking through the August 1979 issue of Byte magazine, it discusses a dialect of Lisp in which arithmetic operations are denoted by words like PLUS and TIMES. Later dialects like Common Lisp and ...
4
votes
2answers
180 views

Macintosh SE/30 cover screw size

I lost the 4 Torq (T15) screws that hold together the case for a Mac SE/30. Does anyone know the size and the groove spacing to order a compatible one? I found these on eBay, but I'm not sure about ...
23
votes
1answer
2k views

Where does the Z80 processor start executing from?

Strangely I can't find this information anywhere online -- I've thoroughly looked at the datasheet, and I've searched things like "Z80 program counter initial value" -- but I can't find anything! My ...
5
votes
1answer
237 views

Does “Unix” and “UNIX” represent the same thing?

In some articles I see the word Unix written as "Unix", while in other articles I see the word Unix written as "UNIX". Does "Unix" and "UNIX" represent the same thing?
-4
votes
1answer
214 views

What does ld a,(hl) do in this piece of Z80 ASM code, and why is HL incremented?

ThinkPositive equ 1 PrintChar equ &BB5A org &8100 ld hl,Introduction call PrintString call NewLine ld hl,Message call PrintString ret PrintString: ld a,(hl) cp ...
4
votes
4answers
423 views

How can I implement the modulus operator in Commodore 64 Basic?

How can I implement the modulus operator in Commodore 64 Basic? There are not a lot of math functions to work with, and modulus would be very handy.
4
votes
1answer
271 views

Did the 286 go out of its way to follow the 8088 bus protocol?

In general, different CPUs don't use the same bus protocol. A 16-bit CPU would not in general be expected to use the same protocol as an 8-bit CPU. For example, the 68000 would not be expected to use ...
3
votes
0answers
113 views

Vic-20 total game cartridge sales

The Vic-20, like many home computers of its time, had a cartridge slot that could be used both as a general expansion slot, and for game cartridges like a console. Game cartridges on the Commodore ...

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