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votes
1answer
23 views

How do I examine and use the SWTBUG monitor ROM in the SIMH SWTP6800 simulator?

I'd like to examine (disassemble and memory dump) and run the SWTBUG monitor ROM in the SIMH SWTP6800 emulator. I've got copies of the swt6800mp-a and swtp6800mp-a2 binaries, which seem to start ok: $...
2
votes
1answer
60 views

Could somebody remind me how to access the WAP browser on the Nokia N73?

From memory, the Nokia N73 had two web browsers; one WAP browser, and another, fully-functional HTML application. Would somebody be able to remind me what both of these options are labeled as when ...
3
votes
1answer
92 views

Sharp Super Scientific EL-9000 English Manual

I have a Sharp Super Scientific EL-9000 calculator (that used to be my mom's back in the day) which came with a Korean manual. I am a Korean American, and I can't understand the manual well. Does ...
8
votes
1answer
125 views

Why were TECO variables called Q-registers?

The TECO editor, (originally Tape Editor and COrrector, later Text Editor...) found in some form on just about every computer and operating system DEC ever made, provides variables in which you can ...
0
votes
1answer
164 views

What programming languages appeared in 1961?

I'm trying to get Programming Languages Through The Years over on the Code Golf site going again. The Wikipedia article that the challenge has been working from only lists COMIT for 1961, and calling ...
5
votes
4answers
385 views

6502: is BCD *fundamentally* the same performance as non-BCD?

Furthering my reading of MS BASIC and Woz's FP code and comparing the two leads to another question specific to the 6502... From what I can see looking over the 6502 instruction guides, it appears ...
18
votes
4answers
3k views

What was the intention with the Commodore 128?

The Commodore 128 had 2 CPUs, 2 video graphic chips, and 2 I/O systems/chips. It had 3 modi: Commodore 64 mode, Commodore 128 mode and CP/M. The first shared one of each CPU/chip, the CP/M mode the ...
7
votes
1answer
203 views

Commercial C64 software implemented in Forth?

There has been several implementations of Forth that were running on, and targeting, the C64. Were there any commercial software releases (not throw-away hobby projects or in-house utilities) that ...
25
votes
4answers
3k views

What's the relationship betweeen MS-DOS and XENIX?

Browsing MS-DOS sources on GitHub, I often see mentions of XENIX: DOSSYM.ASM: ; XENIX calls all return error codes through AX. If an error occurred then the ; carry bit will be set and the ...
49
votes
4answers
6k views

What should we do with manuals from the 80s?

I have access to several meters of manuals of various sorts around CP/M on PCs and various bits on mainframes. These are earmarked to go after decades of "cannot dump that" heartbleed. Most are ...
8
votes
3answers
286 views

What are the Ultra-Highres registers in ECS and AGA for?

The Amiga custom chip set, in its ECS and AGA versions, seems to contain some registers for what is called an "Ultra-HighRes/DUAL" mode: DFF078 SPRHDAT W Ext. logic UHRES sprite pointer and ...
24
votes
1answer
2k views

Did DOS zero out the BSS area when it loaded a program?

As an example, say we have a DOS MZ EXE file that's around 20 KiB in size. The EXE header contains the value 0x1400 at offset 0x0A indicating that the program is requesting 5,120 paragraphs (or 80 KiB)...
6
votes
2answers
241 views

Where can I find the Applesoft line-drawing algorithm?

I’m trying to make some graphics in Processing that look just like what I’d get on an Apple //e. I think this info is in rom disassembly but I can’t find anything by googling. Im also interested in ...
3
votes
1answer
105 views

How to write directly to the Commodore 64 (or similar) DAC [duplicate]

I read some related information in a SAM question but I want to know exactly how to write amplitudes directly to the DAC, sample by sample, like in a bytebeat formula. I understand it is possible on ...
62
votes
8answers
15k views

Why did IBM make the PC BIOS source code public?

IBM released the IBM 5150 Technical Reference manual in August, 1981, and included in it the fully commented source code listing for the BIOS. I find this odd for two reasons: IBM must have realized ...
3
votes
1answer
225 views

Did any devices use the Commodore 64 joystick ports as outputs or two-way communications ports?

Looking at the schematic and explanation of how the C64 joystick ports work, it seems clear that the stick direction and button lines (JOYA0, through JOYA3 for port 1 and JOYB0, through JOYB3 for port ...
2
votes
1answer
142 views

Xerox 3700 Documentation?

Cannot find any documentation on this computer, need some help identifying it. I am pretty sure this is some kind of print server and the date on the parts is 1989.
1
vote
3answers
227 views

When was Tantalum first used in computing?

I know that nowadays Tantalum is very common in computer components, specifically capacitors, due to its desirable electrical properties. I'm curious when it was first used specifically in the ...
10
votes
3answers
566 views

0xF1 opcode-prefix on i80286

On intel IAPX 80286, as I recall from experience, the undocumented - officially unassigned - "opcode" position 0xF1 was actually decoded as an instruction-prefix, thus counting for maximum allowed ...
4
votes
0answers
205 views

First use of “destructuring” in computing?

Which programming system first introduced "destructuring" denoting accessing various parts of an object using some sort of pattern, and binding those parts to variables, like Common Lisp's ...
2
votes
2answers
228 views

How can I extract game data from Nitemare 3D files?

I am trying to reverse engineer an old Wolf3D style Dos game named "Nitemare 3D". I can get a raycasting engine with directional sprites running pretty easily using SDL2, but I have no experience with ...
10
votes
1answer
272 views

Unix utility “smiley” to decode emoticons: Where to get it?

I remember in the 90s, there existed a Unix command line utility named smiley that decoded emoticons. A sample use would be like this (the output is likely not the exact output the program gave): $ ...
4
votes
1answer
313 views

Why did MS BASIC use the line number for FOR loops?

I was always under the impression that MS BASIC implemented NEXT by pushing the address of the FOR on the stack. So convinced that when I read the source code I assumed CURLIN had to be referring to ...
13
votes
2answers
545 views

Atari ST DRAM timing puzzle

From the Atari SM124 Monochrome Monitor Service Manual, I get that the video signal timing for one line is 20µs. With the horizontal resolution of 640 pixels, this gives a 31.25ns pixel clock. Using ...
11
votes
1answer
973 views

Why was CPU32 core created, and how is it different from 680x0 CPU cores?

I am doing a design based on the Motorola 68332 MCU made for embedded applications, which is based on the CPU32 core. The CPU32 core is very similar to the 680x0 CPUs, but there are some subtle ...
1
vote
0answers
92 views

Identify Toshiba CRT

Didn't find anything with a search and need to replace the tube due to it being severely burnt in. [] []
13
votes
5answers
3k views

What was the first multiprocessor x86 motherboard?

I know dual socket motherboards were around in the 90's before Intel released the Core series. And SMP hardware and operating systems have been around earlier than the PC platform of course. ...
3
votes
3answers
214 views

Steps to recover data from Conner CP341

Trying to recover data from Conner CP341 HDD i took from an old Compaq Portable III. The data is important enough to go through the effort of recovering it, and i would like to do this myself (rather ...
0
votes
2answers
314 views

What 486 motherboard is this, with American Megatrends BIOS identifying is DPAQ-6156-043090-KF?

I've got an early 486 motherboard that doesn't seem to have a manufacturer name or FCC number on it and I'm having trouble identifying it. I've placed some photos of the motherboard in this Imgur ...
3
votes
2answers
203 views

Reference material for building a DIY Stack Computer from Logic Gates

I've been following Ben Eater's series of videos about designing a small computer from discrete logic gates, I'm curious if there is a similar tutorial/book/reference for building a stack computer. I ...
25
votes
6answers
14k views

Is it true that control+alt+delete only became a thing because IBM would not build Bill Gates a computer with a task manager button?

Is it true that ctrl+alt+del only became a thing because IBM would not build Bill Gates a computer with a button specifically for the task manager? Making it so that Microsoft had to develop a ...
16
votes
1answer
1k views

What was the role of Commodore-West Germany?

Most of the history of Commodore in personal computers took place while East and West Germany were divided, and Commodore maintained a significant corporate presence in West Germany. While I believe ...
2
votes
0answers
114 views

What was the influence of the 'Legion of Doom' and the e-zine Phrack on early computer culture? [closed]

I was reading a bit about the 'Hacker Manifesto' written by Loyd 'The Mentor' Blakenship and was also reading about the hacker group 'Legion of Doom' and was wondering what influence these groups / ...
15
votes
3answers
2k views

How to switch an 80286 from protected to real mode?

It's pretty well documented how to get the 286 from real mode to its 16-bit protected mode. It's also widely stated that the 286 had no officially supported way of going back from protected mode into ...
25
votes
1answer
390 views

Why were pipes removed from the Lisa?

I was recently looking at some documentation for programming the Apple Lisa: https://lisa.sunder.net/LOS_Reference.pdf and I was surprised how advanced it was for the time. It had a lot of features ...
11
votes
1answer
2k views

3 beeps on a 486 computer with an American Megatrends bios?

So far I've figured out that means something about the ram bit I haven't been able to figure out what the problem is Edit: video link
2
votes
2answers
316 views

Anyone heard of 'something like' EDITLN or EDITLINE or LINEDIT statement in BASIC?

Anyone heard of 'something like' EDITLN or EDITLINE or LINEDIT statement in BASIC for editing lines of a program's own code while executing ? I seem to remember a statement that was spelled '...
12
votes
2answers
767 views

IBM mainframe classic executable file formats

Most modern platforms have pretty well-defined file formats; e.g. Windows uses PE, Linux and BSD - ELF (previously a.out), macOS - Mach-O, AIX - XCOFF and so on. What were (are?) common executable ...
8
votes
3answers
385 views

How was concurrent programming achieved on the PDP-10?

A useful way to do concurrent programming is, say, a Compare-And-Swap instruction, which really is two operations, executed one after the other, atomically. This was available on the IBM 370 and on ...
3
votes
0answers
238 views

How do Apple II BASIC compilers compare? [closed]

Programs like The Beagle Compiler allow AppleSoft BASIC or other Apple II BASIC variants to be compiled. How do the compilers compare in terms of speed, compatibility, and features?
13
votes
3answers
410 views

Did any micros use the 6502 BCD mode in their OS?

I know the Atari's FP package used BCD for rather dubious reasons, but does anyone know of other examples of basic "operating system" level code on common platforms that used BCD? I suspect BCD was ...
10
votes
1answer
250 views

How did restarts resolve parity errors triggered by broken core-rope wires?

In his account of the history of the Apollo Guidance Computer, Don Eyles describes the role of a parity bit as follows (p. 80): ... if one of those hair thin wires in our woven core-rope memory ...
7
votes
3answers
594 views

What were the first chips with hardware support for SPI?

The SPI four-wire serial bus is a very common interface between chips and other small devices these days, but was originally developed by Motorola in the mid-1980s. What were the first Motorola and ...
7
votes
3answers
279 views

How is PETSCII used by assembly-language programs?

First, a bit of context. I wrote an interactive disassembler for 6502 code that, among other things, attempts to identify ASCII strings automatically. Appropriate source code for different assemblers ...
5
votes
1answer
328 views

How was text handled on the Amstrad CPC 464?

The three official video modes described on the CPC wiki are all bitmap modes, and this page mentions that the "screen is bitmapped. You must draw/erase your own sprites and text." So what was the ...
12
votes
1answer
576 views

What's the timeline of Motorola 6800-family CPUs from 1974 to 1979?

According to Wikipedia, The Motorola 6800 was released in 1974. Between that and the release of the 6809 in 1979 (or 1978?) there was at least one other 6800-series CPU released, the 6802 ...
1
vote
1answer
125 views

What is a more featureful and/or better coded 6800 disassembler for modern machines than f9dasm?

I'm currently using [this version of f9dasm] on Linux to disassemble a moderately large Motorola 6800 program (Altair 680 Basic, about 8 KB in size). f9dasm isn't too bad, but I'd prefer to use ...
1
vote
0answers
197 views

What technologies were used to harden Windows against Bluescreens [closed]

Quoting a comment from this question: Why did Windows 95 crash the whole system but newer Windows only crashed programs? "A lot of effort has gone into automatically enforcing that drivers are more ...
7
votes
1answer
269 views

How did the Sinclair compare on price with the C64 in the UK?

As far as I know, the popular low-end home computers in the UK around the mid-1980s were the Sinclair ZX-Spectrum ("Speccy") and the Commodore C64. I know the BBC micro also had a following, but my ...
5
votes
2answers
199 views

Are there any CPUs or MCUs object-compatible with the 6800 that have additional index registers or addressing modes?

Having only a single index register and no addressing mode indexing against 16-bit addresses in memory seems to have been widely considered a primary reason that the Motorola 6800 fared poorly in ...

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