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63
votes
5answers
9k views

Back in 1984 I wrote some games for Spectrum - Will they still be playable?

Back in 1984, I was commissioned to write some games for ZX-Spectrum. They were sold together. To my amazement I found that someone is selling a copy online. I thought of buying it but it is in the ...
26
votes
1answer
2k views

When and where did the $ convention for hexadecimal literals originate?

I found this question asking about the origin of 0x to denote hexadecimal to be interesting. However, when I cut my teeth programming on 8-bit 65xx systems in the early 80's everything I saw used a $ ...
43
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 ...
5
votes
1answer
288 views

Sega Genesis and Sega CD interaction

Sega must have thought about upgradability prior to the Genesis’s release, as there is a expansion slot to the right of the unit when looked at from the front. Is this the only expansion slot? Is it ...
3
votes
1answer
173 views

Does anyone have information about the nj32disk.sys driver?

I'm currently trying to use the nj32disk.sys driver to use my USB stick as a virtual hard drive. The problem is that the driver acts like a floppy disk. My question is: Is there a documentation about ...
6
votes
2answers
760 views

What was the first microcomputer capable of working with Japanese kanji?

Apparently the first microcomputer capable of working with the Chinese language in Chinese characters was the Microprofessor II (or MPF-II-C), a Taiwanese Apple II clone from 1982. Now I'm 99% sure ...
7
votes
1answer
1k views

Which was this game with collectibles, that came with a washing machine detergent?

Availability I most likely played it in the late 90s (1997+). It might have been the early 2000s as well, but it's less likely. My computer at the time was running Windows 95 or 98. The game came on a ...
15
votes
2answers
2k views

Looking for information on a programming language called WhatDoesItDo

I am looking for information on a training language called "WhatDoesItDo". It was used in 1978 at Austin Community College on a Motorola 6800 CPU. If anyone has any information, I would ...
15
votes
2answers
2k views

What is the oldest reference to PEEK, POKE, and USR?

I've been reading manuals for BASIC implementations and the earliest reference I can find to PEEK, POKE, and USR is in the Altair BASIC 3.2 manual, published in 1975. This morning I came across this ...
20
votes
1answer
2k views

Who ended up owning Commodore's semiconductor IP?

The question of ownership of Amiga-related intellectual property post-Commodore is famously difficult to answer. My question is: does anyone "own" Commodore's semiconductor IP now, and if so,...
10
votes
3answers
990 views

How can I understand numerical precision of values in Microsoft BASIC (on the Dragon 32)?

I implemented a differential equation solver on my Dragon 32 (which uses Microsoft Extended Color BASIC) but the results I get quickly diverge from those I expect, which are the same as those I get ...
12
votes
1answer
4k views

Is this an Amiga? If so, which model?

In the 1998 Swedish comedy musical "Åke från Åstol", there's a moment toward the end when a man is pushing around some sort of Amiga-looking computer with a monitor and mouse on a ...
12
votes
1answer
524 views

How did Sony, Panasonic and Mitsumi CD-ROM drives differ from the later ATAPI standard?

In the early days of computer CD-ROM drives, aside from SCSI interfaces, there were a number of proprietary interfaces developed by individual manufacturers. This was exemplified by PC sound cards ...
8
votes
6answers
7k views

Why do keyboards with a NumPad repeat the numbers?

This question is related to this one. I realise not all keyboards have the NumPad, but why do those who do have a NumPad have two sets of keys for numbers ( the numbers above the letters and below the ...
3
votes
3answers
2k views

Connecting old Floppy Drive to modern computer

I need a way to write on floppy disks from my modern PC (motherboard GIGABYTE z730p). I own a Panasonic JU-257A606P I took from an old machine of mine, and before buying a USB floppy drive I wanted to ...
6
votes
1answer
147 views

What floppy disk format and layout and what disk image format are used for the Coleco Adam?

I just found out that emulators for the Coleco Adam use a disk image file format with the DSK file extension. This is a very very overused extension on many different disk formats. Though a few DSK ...
18
votes
3answers
4k views

Is the Coleco computer from The Simpsons based on a real computer?

In the episode Lisa Gets an "A" of The Simpsons, there is a fictional computer called Coleco: Is that computer based on a real one or are there any records of computers resembling that?
1
vote
1answer
287 views

N64 displays dark picture with barely recognisable contours

I'm trying to hook up my EUR N64 to a TV that handles both Composite and RGB SCART alright (A1200, CDTV, Megadrive). The picture is very dark and I can only make out the shapes and contours. There is ...
5
votes
1answer
219 views

Why are the CBM control codes for color setting so spread out?

The control codes (my C64 handbook actually calls them ASCII codes) for color changing on the Commodore 64 are as follows: Color Control Code Color number BLACK $90 0 ...
3
votes
2answers
431 views

Was it possible to win the “Lunar Lander” game with less fuel than the default?

A while ago I asked about the possible origin of a Russian version of the "Lunar Lander" game. No definitive answers were given. Meanwhile, I was able to decompile the binary into a semi-...
34
votes
4answers
3k views

How did musicians acquire samples for tracker music (MOD, S3M, XM and the like)?

Many songs in the so called "tracker" format quite popular in the early 90s (think .MOD, .S3M, .XM, .IT and the like) seemingly used sound samples from real synthesizers. This sometimes ...
0
votes
2answers
249 views

ZX Spectrum red stripes during loading

When we load any game on ZX Spectrum from cassette player... Should red stripes move smoothly for better result or they should be static for perfect result? What is the theory?
2
votes
3answers
196 views

Where to find a Toshiba T1900, T1910,T1950,T1960 laptop fdd drive cable, non standard 26 pin flex flat cable (ffc)?

I was trying to take apart a Toshiba T1950ct laptop to replace slim floppy drive:s belt. Unfortunately, I broke the delicate flat flex cable (ffc) which is non standard 26 pin floppy cable. ...
3
votes
1answer
257 views

When did the faster versions of the NMOS 6502 become commercially available?

The 6502 was released in 1975 with an advertised speed of about 1mhz but I can't find reliable information on what year faster versions became available (was 2mhz possible at launch?) or what the true ...
4
votes
4answers
472 views

Would some BASIC interpreters for microcomputers be considered operating systems?

As software for micros developed, you could use the BASIC interpreter just to CLOAD and RUN assembly language programs. Those might call BASIC ROM routines (say, for converting ASCII input to binary ...
7
votes
1answer
1k views

What is the point in interpreting an integer literal differently depending on the machine?

I was reading the user manual for an old program "UNRAVEL": http://www.ml1.org.uk/pdf/Unravel_User_Manual_1971.pdf. On page 9, it describes the syntax for integer constants: Unsigned ...
2
votes
2answers
250 views

What is a 4002's “RAM Status Character”?

I was looking at this emulator of a Intel 4004, and I noticed something with the RAM. It had something called "Status Chars". There were 4 of them per memory line and all were 4-bit numbers ...
0
votes
1answer
116 views

Carry flag in the Intel 8008

Datasheet for the Intel 8008 CPU mentions that the Carry (C) flag is affected with the logic operations (AND, OR, XOR), but it does not make any sense. I believe Carry will be zeroed, but I have no ...
3
votes
1answer
318 views

Intel 8008 stack behavior

Intel 8008 CPU has an internal stack, implemented as an 8 x 14-bit scratchpad. How does it work exactly? Is there any "invisible 3-bit stack pointer"? I want to know what happens when the ...
4
votes
0answers
169 views

Undefined opcodes for the Intel 8008 CPU

What happens when I8008 CPU reads the "undefined" opcode (22h, 2Ah, 32h, 38h, 39h, 3Ah)? Are these opcodes evaluated as a NOP instruction, or lead to some side effects (RESET, etc). How many ...
1
vote
1answer
102 views

Help in finding signals on schematics

Where are the missing signals that I can't pair between amiga external drive connector and gotek drive? I'd like to connect GOTEK to CDTV, there is a way to do it directly (caddy died), but I can't ...
5
votes
2answers
265 views

Commodore Plus/4 jiffy clock tied to screen refresh frequency? (warning: flashing images)

Warning: There are flashing images below, do not scroll down if you are sensitive to them! According to various sources (for example this for the Plus/4), both the C64 and Plus/4 have a "jiffy&...
3
votes
2answers
230 views

Is there a way to blank out a portion of a screen on Commdore C64?

I would like to blank out a couple of lines between two given rasterlines. Above that I'm planning to have a scrolling background and sprites, below that is a textual info area. I'm thinking of a ...
2
votes
2answers
594 views

Were the 80s more educational on IT? [closed]

I keep telling to everyone who wants to hear it (or not) that my personal IT education as a kid in the 80s was superior to what kids are exposed to today (to the degree that I can observe that as a ...
5
votes
2answers
286 views

Were the VAX eXtended Function Control (XFC) instructions ever used commercially?

The DEC VAX has a set of 256 instructions set aside for user addition via microcode edits. Were extension sets ever commercially produced and sold, or was this functionality mostly used in-house? ...
2
votes
0answers
162 views

Hitting the CMS Limits of Portable Code

I wrote this arbitrary precision arithmetic utility on BSD in my postgraduate days, then after graduating ported it to DOS using TurboC. Was proud that it would do the same thing with 16bit word ...
1
vote
1answer
173 views

Working on programming a retro z80 computer (SDCC error)

I am working on coding a driver of sorts for a Z80 based computer I am making. I am compiling with SDCC and I have been getting the following? ASlink-Warning-Undefined Global 'data' referenced by ...
2
votes
0answers
116 views

Is there any statistical data about the modern vintage games marketshare by system?

I know that every year there are still at least a couple of new games for old systems like VIC-20, C64, Amiga, different ZX Spectrum and Amstrad variants, DOS, different games consoles, and so on, ...
1
vote
0answers
221 views

How does the Hard Drivin' game engine work?

Hard Drivin' is a classic Atari video game released in the arcades and then ported to many home systems. How does the game engine work? How is the world data handled, how is collision detection done ...
4
votes
0answers
289 views

What is it with DS emulation being so slow?

I have a fairly decent computer, and I have been messing around with DS Emulation recently. I have found that if a game is running on the emulator, and if I have anything else running, the performance ...
2
votes
1answer
230 views

Dosbox with C-compiler and gui [closed]

I have Ubuntu 20.04 and Dosbox 0.74-3. Is is possible to install GUI for this dosbox? Can one install C compiler for this box?
4
votes
1answer
153 views

What is the interface of the proprietary memory card connector in CDTV

Is this an IDE or something completely different. Could it be used to connect gotek?
6
votes
2answers
237 views

How can the number of cylinders be different from the number of tracks?

In the IBM PC 5150 documentation, it is stated that the floppy drive has 40 tracks, 8 sectors/track and 512 bytes/sectors, for a total of 163 840 bytes of data. It makes sense, 40x8x512 = 163 840 ...
3
votes
1answer
395 views

How can I get MAME to run modified ROMs whose checksums don't match the originals?

In the aftermath of the question about running the arcade Pac-Man ROM on a Sinclair ZX Spectrum I discovered that about the same time that was done, somebody else did the reverse, porting a classic ...
1
vote
0answers
199 views

What is the best way to run Red Hat Linux 5.1 (the original version) with more than 640x480 with with 16 colors resolution? [closed]

So appearently there's a Red Hat Linux Enterprise 5.1 and I'd just like to make it clear that I'm not trying to install that. I'm trying to install the original Red Hat Linux 5.1 from 1998 in a ...
18
votes
1answer
5k views

Could Pac-Man be replicated perfectly on the ZX Spectrum?

We all know that various ports of Pac-Man exist but my question is just for one specific computer. Could the Spectrum, with time and proper knowledge, run the Arcade version of Pac-Man despite it's ...
2
votes
1answer
202 views

Could the STC Executel possibly have had any games available?

Could the STC Executel possibly have had any games available ? It had a very small inbuilt CRT screen on the right side. It looked somehow impressive with how it displayed things on the screen, a very ...
27
votes
6answers
8k views

What did the “programs” that “human computers” executed look like?

The Wikipedia article Computer (job description) says that before the invention of electronic computers, the term "computer" used to refer to people who worked as "computers". My ...
2
votes
1answer
157 views

Execution time for conditional jumps on the Intel 8080

On the Intel 8080, all conditional instructions have varying execution time depending on whether the condition is true or not, except conditional jumps. Why is this? The Intel 8085 changes this; there,...
5
votes
1answer
391 views

Who are we quoting when we note that “Code is written once but read many times”? [closed]

I have often heard or read the expression, "code is written once but read many times". I think this is a fairly well-known principle of software development. But I have no idea with whom to ...

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