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17 votes
2 answers
3k views

In 16-bit MS-DOS, how do I get a file handle to the currently running .exe?

The context is that I have additional data in the .exe file and wish to access it. I know this is possible, as plenty of programs would store extra data after the loadable part of an MZ .exe — most 32-...
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19 votes
3 answers
5k views

Windows 98 setup preparation hangs at 100%

I am trying to install Windows 98 on a pretty modern computer, from 2010. Why? Because I want to see if I can. Anyway, I am booting off a USB flash drive with FreeDOS on it. I formatted the USB flash ...
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6 votes
5 answers
389 views

Is there a CPU ISA preferring a test for the value of one over testing for zero?

While discussing a question about the origin of Zero as value for the default exit code for success, I reflected if there is any Instruction Set Architecture or implementation thereof where testing a ...
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  • 173k
39 votes
4 answers
5k views

What's the origin of process return status 0 meaning success?

Why, usually, does 0 mean success in process return status codes? When I worked at TANO Corp in New Orleans in the late 70s and early 80s, the convention there was the opposite: 1, true, was the "...
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  • 817
2 votes
0 answers
113 views

Using the (An)+ to Memory addressing mode when address register is pointed to ROM causes Sega Genesis DMA to fail

This is a weird one, and I haven't found it documented anywhere. I was testing Sega Genesis DMA during scanline interrupts and found something very odd. When writing to VDP_CTRL to initiate DMA, if ...
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  • 1,538
4 votes
1 answer
245 views

70s/80s combined horizontal and vertical scrolling coin-op shooter game

I would love to know the name of a coin-operated game I played in late 70s/early 80s. It was a small space ship game and initially you flew over buildings horizontally firing forwards and dropping ...
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  • 41
10 votes
1 answer
401 views

Could the N64 have supported more than 8MB of RAM

The N64 came with 4MB of RAM soldered on the board. With the Expansion Pak, you could add an additional 4MB of RAM to bring it to a total of 8MB. Was 8MB the maximum amount of RAM that the N64 could ...
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  • 963
4 votes
1 answer
205 views

Is sound generation on the Nintendo DS always clipped to 10 bits?

The Nintendo DS hardware has 16 audio channels that support 16-bit audio (PCM16) at a sample rate of 32,768 Hz. However, the mixer limits the output to 10 bits (-200h to 1FFh). From GBATEK: When ...
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  • 1,830
1 vote
0 answers
156 views

Wizard combat game on early online service

Trying to remember the name of a game I played a couple of times, probably in the 1984-1990 timeframe. It would have been on either CompuServe or GEnie - I don't think it was on a BBS, as I rarely ...
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  • 245
23 votes
2 answers
4k views

How did Joysticks with more than 4 buttons and all those extra features work on a Game Port?

The question is pretty straight forward. How did they do so much more than the simple, unidirectional 4 axis of analog control, plus 4 on/off buttons? There was surprisingly precise force feedback ...
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  • 331
2 votes
0 answers
175 views

What's this game: "You broke my robomatic machine!"

I'm trying to identify a game from somewhere around ~1996-2001. Played it on a mac This was a breakout-style game (I think) and the story was you were fighting some mad scientist who was making lots ...
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11 votes
1 answer
3k views

What is this early 3D platformer?

Video: https://www.youtube.com/watch?v=8_-fcFivTS8&t=599s Image: I'm having a hard time tracking down a game I played when I was a kid. It was on DOS in the early 90s. It had flat-shaded polygon ...
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  • 213
0 votes
0 answers
106 views

TI-99/4a RF modulator, fuzzy video

I recently purchased a TI-99/4a. Well, 2 actually. Both work, but I only have one RF modulator. I ordered a composite adapter, but that hasnt arrived yet. Both work on the RF modulator, but the ...
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  • 225
5 votes
1 answer
391 views

Oldest UNIX I can run on my modern system?

What is the oldest UNIX(-like) system that can be legally downloaded and run (in a VM or emulator) on a modern PC (running Linux)?
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  • 153
12 votes
0 answers
221 views

Was there a hard disk type that had a SMART overflow crash/bug?

A data center employee told me a story about 25 years ago, explaining why that data center took some time to assemble a RAID array. Recently, I wasn't able to verify the facts by googling, and I may ...
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3 votes
1 answer
757 views

Commodore SX-64 White screen

I recently acquired a Commodore SX-64. It powers on, but the CRT just displays a white screen. I dont have a test cartridge yet, not that it would help as thereis no display. I havent tried an ...
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  • 225
1 vote
0 answers
174 views

How can I connect the Psion 5mx email client to a secure email provider?

My Psion 5mx is connected to the Internet via the built in TCP stack, and serial cable to a raspberry pi running a PPP server. The Psion message suite has an email client which will connect via POP3 ...
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9 votes
4 answers
1k views

Did the Algol 68 standard allow a procedure to be called before its declaration?

In Algol 68, is it legal to say this? proc even = (int x) bool: (x = 0 | true | odd(x – 1)); proc odd = (int x) bool: (x = 0 | false | even(x – 1)); Forward references in structures are used in the ...
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  • 3,357
18 votes
4 answers
3k views

What was the purpose of those special user accounts in Unix?

In a modern Linux system – modern enough to have upgraded useradd to a version from no earlier than February 2008 – it is usually the case that user accounts with UIDs no less than 1000 (other than ...
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  • 17.2k
4 votes
1 answer
158 views

What systems had digital RGBI output at frequencies other than ~15.7 kHz?

Plenty of early '80s microcomputer systems with 16-colour graphics offered digital RGBI output: four TTL (or at least digital on/off) signals for red, green, blue and intensity. These included many ...
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  • 21.9k
13 votes
2 answers
2k views

Why does OpenGL use counterclockwise order to determine a triangle's front face by default?

OpenGL by default determines a triangle to be facing towards the camera if the triangle's vertexes are ordered in a counterclockwise order from the perspective of the camera. This seems to have been ...
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  • 233
30 votes
3 answers
3k views

How did the IBM 5153 color display detect and modify the signal to make low-intensity yellow into "brown"?

The IBM CGA video card generated 16 colours indicated via four binary TTL signals: R, G, B and I (red, green, blue and intensity). This was not an entirely linear transformation: in particular, RGBI=...
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  • 21.9k
2 votes
1 answer
264 views

How to wrap 32 bits drivers on 64 bits based Windows or even vxd?

Current state : There are more and more computers like mine which are 64 bits uefi only and thus unable to boot 32 bits based Windows. And as Windows 11 is 64 bits only this means in a few years (ens ...
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13 votes
2 answers
1k views

Resources about 1980s GPCPU video controller designs

Reading about the Fujitsu Micro 7, I found out that it used a pair of 6809 microprocessors: one as main CPU and one as graphics processor. That made me remember that when running old arcade games with ...
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  • 947
17 votes
3 answers
2k views

Why does CP/M use CALL 0005h for its syscalls?

CP/M, the operating system for Intel 8080 and Z80 (and others as well, but later) used to call 0005h for syscalls. The application would load the syscall number into a specific register (I think it ...
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  • 34.8k
3 votes
1 answer
200 views

Is there a way to boot CP/M automatically on a RC2014? [closed]

I'm using the RC2014 (Z80), running CP/M. The "24886009" ROM chip (photo below) comes with 32k BASIC, 56k BASIC, SCM and CP/M for SIO/2 serial. When you run CP/M from the RC2014 ROM, you're ...
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5 votes
2 answers
1k views

How do I best simulate a 80386? [closed]

I have used emu8086 to simulate the Intel 8086 before. I like that it allows me to view the opcodes, the data in the registers in a very user friendly way. What simulators are available for the 80386?...
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5 votes
0 answers
133 views

Looking for documentation or source for CERN Fortran programming aids

In the 1970s, the CERN Program Library for IBM/CDC included a few FORTRAN source analysis tools. As mentioned in CERN Computer Newsletter 141, Q. SERVICE OR HOUSEKEEPING-PROGRAMMING AIDS ... *X ...
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  • 16.4k
3 votes
0 answers
226 views

What does this image in Space Travel represent?

I was touching up the Space Travel article on the Wiki and realized no one had answered a question I posted some time ago. I suspect someone here knows the answer. This image is used in the infobox to ...
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20 votes
1 answer
3k views

What date is 74029 on an IBM Mainframe?

I have an old printout of a Fortran code. It's a simple code intended for educational purposes. The header is: FORTRAN IV G LEVEL 21, MAIN, DATE=74029, 15/28/03, PAGE 001 I assume it's from an IBM ...
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2 votes
1 answer
141 views

Need help finding an old 90s edutainment game with "Number Line" Train

This is an old edutainment game that I used to play at school. We used Mac OS 9 there. This game taught you all about various subjects (possibly focusing on math?), all taking place in a zoo or ...
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5 votes
3 answers
844 views

Does Intel Inboard 386/PC work on XT clone systems?

I don't have an Intel Inboard 386/PC, but I have a plan to buy it in the future. When I read its manual, there was no support for XT clones. It says: Install the Inboard 386/PC only in the computers ...
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  • 151
5 votes
5 answers
330 views

Chaining IRQs in x86 ROM code

Objective Summary: I need to write a sleep() function to be used in 8088 (PC/XT ISA) ROM code with 1 ms resolution. Though the question can be more generalized to chaining INTs with data in different ...
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  • 923
12 votes
2 answers
4k views

Was 36-bits needed for LISP?

Came across a curious claim today about the PDP-6: First, 36 bits was the standard for scientific computing. This extended word length also accommodated LISP, a new language developed for work in ...
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21 votes
2 answers
2k views

What was this mini-computer tape troubleshooting process

Back in the early 1980s I worked at a bank. My department input data into a mini-computer which was then to a mainframe system each day. I'm pretty sure it was a DEC mini, if only because the ...
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15 votes
3 answers
2k views

Running CP/M on my own Intel 8080 emulator

I recently finished writing an emulator for the Intel 8080, having passed all of the usual test suites, and wanted to try running an actual OS on it (such as CP/M). I'm aware that I would have to ...
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12 votes
1 answer
828 views

Carry handling during address generation on a 6502

I'm trying to learn a bit more about the internal workings of the 6502. The manual says that the branch instructions do not affect the carry flag. However, my understanding is that some carry handling ...
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12 votes
2 answers
994 views

Null-terminated strings on the PDP-7?

I came across a post that states that Unix uses null-terminated strings, ASCIZ, because it was a feature of the PDP-7. This triggered my reading on the CIS instructions in the PDP-11, but these were ...
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11 votes
2 answers
419 views

When 8086 and 8088 actually sample READY to determine if wait states need to be inserted?

Just for hobby and research purposes I design an XT compatible machine based on 8086, and now I have to come up with a wait state generator for IO devices that are slow and require additional time to ...
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  • 113
16 votes
1 answer
416 views

How is FSTSW AX implemented on the 80286/80287?

The x87 instruction set does not support direct transfers between general purpose registers and floating point registers. This is mainly a consequence of the 8087/80287/80387 being a separate chip ...
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  • 1,492
9 votes
1 answer
395 views

How robust was floating point format output in pre-IEEE systems?

Most pre-IEEE floating point formats that used biased exponent and a 2's-complement mantissa without a hidden bit, were asymmetric. That is, there was a representable negative value which had no ...
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  • 16.4k
27 votes
4 answers
2k views

Amiga multitasking - different resolution for each program on screen dragging

I'm wondering about screen resolution while having two or more multitasking programs - concurrently on screen using dragging such as: Dpaint is on a 320x256 screen, 32 colours Workbench is on a ...
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  • 1,375
0 votes
1 answer
551 views

Why did my CRT TV back in the day have such noisy RF picture on the NES when a same-age one does not today? [closed]

Back when the NES was current, I got one for my birthday. I connected it using the RF thingie to my cheap noname 14" CRT TV bought a couple of years earlier, in the late 1980s or 1990 or so. The ...
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10 votes
1 answer
1k views

What are the “building bricks” of ARM’s design that this magazine article is referring to?

I came across an early mention of the ARM in New Scientist of June 18, 1987: https://books.google.ca/books?id=LvhAoKR-ixwC&pg=PA41 It has this statement: They realised that many of the ...
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4 votes
2 answers
855 views

How can SPI be used with a Z80 CPU to control an RFM95 LoRa module?

I’m trying to communicate with my Z80 computer (RC2014) using a wireless radio. The easy way to do this is to use something like an ESP8266 (and there’s even an RC2014 module for this), but where’s ...
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2 votes
1 answer
95 views

Floating point for HP 2000F TSB port to MSP430FR5994

The HP 2000F TSB system doesn't (could not, as it didn't yet exist) support IEEE 754 formats. HP's early design extends from the range of 2−(255−127)−1 to 2+(255−127)−1. The (−1) shown there is ...
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  • 170
3 votes
2 answers
536 views

PDP-11 CIS MOVTC instruction... does what?

I'm looking over the PDP-11 CIS instruction set. Here is the listed description of the MOVTC (and MOVTCI) instruction: MOVTC(I): Move translated character A longer description can be found in the ...
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1 vote
0 answers
83 views

Can a floppy disk be formatted in another size for (read-only) backwards compatibility? [duplicate]

Is it possible to format a 3.5″ floppy disk in another size? For example an original 1440 KiB floppy as a 720 KiB or 360 KiB disk thats (at least read-only) compatible with 720 KiB or 360 KiB drives? ...
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  • 1,321
8 votes
3 answers
504 views

Did the ARM-1 really outperform the 387?

According to a comment on https://news.ycombinator.com/item?id=31985142 The first benchmarks indicated the plain Archimedes had higher FP throughput than a 16MHz 386 with a 387. The original ...
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  • 49.6k
2 votes
1 answer
124 views

DEC RLV12 Disk Controller Register Access

The RLV12 Technical Description (EK-RLV12-TD-001) describes the RLV12 registers as "word-addressable". I presume that means these registers can only be accessed as words and byte access ...
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  • 21

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