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7
votes
6answers
2k views

Connecting a Vintage Monochrome Monitor to a Modern PC

I am considering taking my nostalgia for the eighties to the next level and getting hold of a green monochrome monitor. In particular, the nine inch monitor of the Apple IIc, but maybe something else ...
15
votes
7answers
3k views

Could a Z80 address a total of 128 KB of ROM and RAM?

In a nutshell, could the Z80 address 64 KB of ROM and 64 KB of RAM, or just 64 KB for both RAM and ROM? Unfortunately, I couldn't find an exact and a direct answer to my question while searching. ...
18
votes
1answer
3k views

What is the function of this strange IBM apparatus?

Does anyone know what kind of device this is? I found it in my late dad's stuff, probably from the 1970s. It has no number, type, model, serial number or anything else on it that could be used for ...
4
votes
1answer
183 views

Reviving a Powerbook 145B, but it still struggles to power up correctly

Some weeks ago I got a non-working Powerbook 145b for 20€ (~23USD). The first thing I did was to test the power supply, which was giving a good 7.8V. I saw that the battery was still in place and I ...
5
votes
1answer
133 views

Did any S-100 cards have multi-byte peripheral registers?

This question asks about endian issues of the S-100 bus. A peripheral card that has a register larger than one byte (e.g. a 16-bit or larger word) would need to be read/written by more than one ...
8
votes
1answer
867 views

Is there a seamless, Wine-like AmigaOS emulator for Linux, specifically for text-based programs?

After trying out FS-UAE on my Fedora Linux system, which worked quite nicely, I got to thinking. Even though when the Amiga was originally released in the middle 1980s, it was revolutionary in its ...
11
votes
3answers
681 views

How was the main mechanic of the game Qix implemented?

Qix was a quite unique Taito arcade video game that saw ports to nearly any home computing platform of its time. At first glance, the game mechanics seem to be targeted at low-performance hardware - ...
31
votes
5answers
3k views

Did IBM originally plan to use the 68000 in the PC?

One of the big turning points in the history of the industry was IBM choosing the Intel 8088 over the Motorola 68000. Given that most people outside IBM considered the 68000 preferable, there has been ...
2
votes
1answer
110 views

Intel vs Motorola device communication protocols

On this page about "An S-100 68000 CPU Board" it is said: From a hardware perspective there are some very significant differences how Intel and Motorola CPU's talk to the world. Somewhat ...
5
votes
3answers
150 views

Did 68000 on S-100 have any problem with being big endian?

The S-100 bus was extremely versatile; originally designed for the 8080, computers using it had no trouble with the Z80 as a drop-in upgrade, and it even went to 16-bit with the 8086. To my surprise, ...
11
votes
1answer
298 views

Ratio of code density between 8080 and Z80

The Z80 was (except for a handful of tiny incompatibilities) a superset of the 8080, adding a number of new instructions as well as the alternate register set. It seems therefore that it must have at ...
2
votes
3answers
203 views

Are the control characters any useful nowadays? [closed]

I asked this question on Super User, but the community at the site told me to redirect to this site. If this is again an off-topic question, do not blame me please! I am sorry if the control ...
5
votes
3answers
314 views

MS-DOS adventure game heavily based on Blade Runner, circa 1991

I'd like to identify a game I played on my first PC (x386, 2MB RAM) which I built in 1991. It was also one of the first, if not the first game I ever played on a PC. The game was heavily, and I mean ...
23
votes
7answers
4k views

Why did 8-bit Basic use 40-bit floating point?

Nowadays floating point is usually either 32 or 64 bits, sometimes 16, occasionally 128. But of course, the Basic interpreters on the 8-bit machines, having to implement floating point in software ...
10
votes
1answer
642 views

Difference between INT 0x20 and INT 0x21 (0x4C)?

Checking the MS-DOS interrupt list we see INT 0x20 "Terminate the program" (see https://en.wikipedia.org/wiki/DOS_API) but if we check the same page we see INT 0x21 with function 0x4C will &...
4
votes
3answers
337 views

What is this Intel Hexadecimal-like file format in this Tiny BASIC dump?

I am looking at this Tiny BASIC dump which seems to consist of two sections, the first being a list of symbol addresses, and the second one containing Intel Hexadecimal records with a leading space: ...
7
votes
1answer
373 views

How did old car games, using “sprite illusions”, function on a technical level?

Example: https://youtu.be/E9QJZSBpvg0?t=80 The road turns not only left and right, like in the classic Pole Position, but also goes up and down. Other than the cars and the road, there are numerous ...
1
vote
2answers
144 views

Commodore C386SX-LT, what is causing this hissing sound

I'm trying to work out what is wrong with this laptop. There is a hissing sound coming from the power board mid left. The laptop screen remains off and there is no output to external VGA unless it ...
12
votes
1answer
1k views

When did the Altair move ROM to the top of memory?

The 8080 starts running code at location 0 on reset. The natural layout of memory on a computer using that CPU is therefore ROM at the bottom of the memory map and RAM at the top. CP/M demands the ...
32
votes
2answers
3k views

What did Pete Stewart think he knew about efficient implementation of floating point denormals?

The most controversial part of the IEEE 754 floating-point standard is gradual denormals. Typically they trap to software rather than being implemented in hardware. In the common case where a workload ...
2
votes
2answers
168 views

Why did the SWTPC 6800 Computer System not take off? [closed]

In 1974, a major semiconductor company released its first 8-bit CPU that was good enough to build a serious computer around. In 1975, a smaller company built a computer around it, a horizontal box ...
1
vote
1answer
113 views

Why was the SWTPC 6800 Computer System cheaper than the Altair?

In 1974, Intel released the 8080, which basically was the first microprocessor good enough to build a serious computer around. That led to the Altair 8800 the following year, which was the beginning ...
36
votes
2answers
3k views

Was AGP only ever used for graphics cards?

Reading on the AGP spec, the little bits I've found on sites like https://old.pinouts.ru/Slots/agp_pinout.shtml, say: The Accelerated Graphics Port (also called Advanced Graphics Port) is a high-...
9
votes
3answers
711 views

ZX Spectrum 48k Power Supply outputting 15V

I got a working ZX Spectrum 48k (issue 6a) with the original power supply. Before hooking up the power supply I tested with my multimeter to see if it was good. The power supply specifies it outputs ...
0
votes
1answer
102 views

VICE loads files slowly on Fedora 32 Linux [closed]

I lately wanted to try some of the Commodore 64 games I have kept as D64 files on my Fedora Linux system using VICE. I have lately upgraded the system from Fedora 26 to Fedora 32. After I started up ...
8
votes
1answer
516 views

Why did the Altair use 100-pin edge connectors?

The Altair 8800 was based on what came in later years (much to the displeasure of MITS) to be known as the S-100 bus, because it had 100 lines, because MITS found 100-pin edge connectors were ...
5
votes
4answers
333 views

Better way to do Z80 “bank switch & call”?

I have a memory setup where the whole address space can be exchanged (default 2 slots with 2 banks each, but may change depending on "expansion cards" plugged in). Banks are switched by ...
5
votes
2answers
228 views

What were the alternative graphic cards for the Apple II?

In this question, it's mentioned the Apple II's slot 7 was used by third party graphics cards. Is there any documentation on those? What were those cards and what were their capabilities?
8
votes
2answers
2k views

Was there a way to directly print out a deck of punch cards without involving a computer?

Was there any equipment which could directly print out the program or data on a stack of punchcards, without first loading the deck into a general-purpose computer? In other words, a transfer from the ...
2
votes
1answer
150 views

How did VisiCalc decide how many decimal places to display?

VisiCalc represented numbers in BCD to be able to handle decimals precisely. But how did it decide how many decimal places to display? In some screenshots like https://www.researchgate.net/figure/A-...
3
votes
2answers
294 views

How did databases use the 8087?

A discussion on programs that used the 8087 mentions several categories I expected, and one I did not: Database programs (dBase IV, FoxBase, Paradox, Revelation) The more I think about it, the more ...
17
votes
1answer
1k views

Why did the 6502 handle BCD with a special mode?

The 6502 had special support for BCD arithmetic, because it was widely used in those days; this much, it had in common with other CPUs. But the 8080 and 6800 implemented this in the form of a 'decimal ...
8
votes
3answers
530 views

What performance increase did an Amiga typically get with an FPU?

After seeing this question, I reminisced about how my old Amiga 2500/030 had a 68882 FPU unit. I recall that the Amiga's floating point routine library was smart enough to detect if you had an FPU or ...
3
votes
1answer
343 views

What were the most common applications of the 8087?

The original IBM PC had a slot for the 8087 floating-point coprocessor. This was a somewhat esoteric feature at the time – previous microcomputers had done all their floating-point in software – but ...
6
votes
2answers
833 views

Does the 6800 always handle unaligned access correctly?

I asked a similar question about the Intel 8080 to which I guessed the answer would probably be yes, because later Intel CPUs did fully handle unaligned access. I am less sure about the Motorola 6800, ...
25
votes
12answers
6k views

Did computers come with circuit diagrams?

If you purchased a computer, back when they were actually made from discrete components, would you expect to get a circuit diagram as part of the documentation? Was that something you could purchase ...
3
votes
2answers
839 views

Does the 8080 always handle unaligned access correctly?

The 8080 is referred to as an 8-bit CPU because it has an 8-bit data bus, but there are a number of cases where it must perform 16-bit memory access, for example when reading or writing a 16-bit ...
8
votes
2answers
318 views

Did Econet have security?

Econet was used in a classroom setting to connect a room full of BBC Micros to a single floppy disk drive. This was an important capability because in those days, a floppy disk drive cost in the ...
11
votes
2answers
1k views

Was natural convection ever a consideration in orienting expansion cards?

Many computers have followed the design pattern of a backplane with expansion cards, including arguably the three most influential microcomputers ever built: the Altair 8800, the Apple II and the IBM ...
2
votes
1answer
134 views

Does there exist a MPU-401 to OPL3 TSR for MS-DOS?

There are a few games for MS-DOS with music only through MPU-401, like the platformer Abuse and the RPG Avalon. Is there a TSR available that intercepts MPU-401 port accesses and transforms them into ...
10
votes
1answer
253 views

Did the Harris 80C286 differ from Intel's 80286 in its behaviour?

The Harris company, well known for being an early second source making x86 chips under license, eventually produced a fully static CMOS 80C286 of their own design (later known as the Intersil 80C286 ...
5
votes
1answer
406 views

Was Steve Jobs really Atari employee number 40?

To be clear, I am not questioning that Steve Jobs spent a while working for Atari; that much is indubitably historical fact. Apparently he joined the company in 1974. Atari was founded in the summer ...
15
votes
2answers
2k views

Who owned the rights to the TIA chip?

The two most important chips in a game console are the CPU and GPU. In the Atari 2600, the CPU was a cut down version of the 6502, a very common low-cost microprocessor. The GPU was the TIA, which was ...
-1
votes
1answer
111 views

Windows 95 early build's “Windows protection error” on the post-installation boot up [closed]

On the first boot up, the early builds of Windows 95 (pre-OSR2) would commonly show the following error screen during the post-installation boot-up, Restarting the computer doesn't fix the issue. How ...
5
votes
1answer
354 views

SSH for DOS / Win 3.1

Is there an SSH client for DOS 6.22 or Windows 3.1 that supports certificates and could be used to connect to AWS or Azure instances, or any other server for that matter? I have another laptop ...
-6
votes
1answer
157 views

Why do alleged cheat codes for classic games frequently not work? [closed]

Example: https://gamefaqs.gamespot.com/nes/563470-tetris/cheats Warp 10 levels ahead[:] Select the level you want to go to and hold A, then press START If I select the level and hold/press A, the ...
2
votes
1answer
205 views

Where can I donate Old Mags and Media in bulk in UK?

I am taking advantage of lockdown(s) and scanning/imaging all old media to archive.org, but would like to donate the boxes when finished. A bit like Donating old Computer Shopper Magazines The Centre ...
16
votes
1answer
2k views

Processor and operating systems for automatic lifts/elevators

Most automatic elevators have an algorithm that optimises travel between floors and users. Presumably this can be tailored to a particular building. The first elevators were hand-operated purely by ...
2
votes
2answers
227 views

Modern HDD replacement for an old laptop

What is the modern solution I could use in Commodore C386SX-LT? It requires selection of disk type in bios, otherwise it won't work. Max setting allows up to 63MB, so would a 64MB CF with IDE adapter ...
5
votes
1answer
184 views

A demoscene production from mid-2000s featuring four seasons animation

I recall seeing a PC demo - meaning an executable program demonstrating various graphics and sound effects - in mid-2000s (does this count as sufficiently retro?) that featured animations of the four ...

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