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9
votes
3answers
209 views

Commodore 64 with partly working keyboard (part 2)

I have a C64 that has recently stopped responding to two 'columns' of keys, namely '9,0' 'i,o' 'j,k' and 'n,m' - I've swapped the CIA chips (U1 and U2) to no effect, so I pulled a keyboard from a ...
49
votes
4answers
11k views

Did the Apollo Guidance Computer really use 60% of the world's ICs in 1963?

This NASA webpage makes this claim about the Apollo Guidance Computer: By 1963, MIT - during the testing and development of the AGC Block I units - had ordered and consumed some 60% of the then ...
14
votes
2answers
985 views

What are the IPSE’s, the ASPE’s, the FRIPSE’s and the GRIPSE’s?

In one of Edsger Dijkstra's most famous essays "By way of introduction" there is this paragraph: As final example of skirting the programming issue I mention “software engineering”, the IPSE’s, the ...
7
votes
1answer
409 views

How to read Microware OS-9 RBF Filesystem under Windows / Linux?

I have a virtual disk image file os9000-xibase.img and Windows can't read it nor mount it. With ImDisk Virtual Disk, I'm able to mount it, but not read it, because it is a Random Block File System ...
5
votes
0answers
185 views

Origin of VIC-II (PAL) chip labelled 8656R2?

Wondering why a C64 VIC chip (fully functional) that I got off eBay had an 8565R2 label fitted on top of it: I peeled it off to find this: I haven't ever heard of a VIC-II (PAL) labelled MOS 8656R2. ...
8
votes
2answers
2k views

Are game port joystick button circuits more than plain switches? Is this one just faulty?

I'm building a custom interface unit for a game port joystick. To use/test it, I have a CH Products Mach III. (This is the IBM PC version, not the Apple version.) I purchased the joystick for this ...
0
votes
2answers
203 views

Arduino Uno (ATMega328) vs Motorola 68000/68010 [closed]

Since ATMega328 is a microcontroller, and Motorola 68000/68010 is a CPU, we consider only the processor core - command execution speed, memory access speed, arithmetic speed, registers in RAM or CPU, ...
5
votes
2answers
755 views

GPU chip implementation on CPU - will it be faster? [closed]

So, modern video cards include two devices - a video signal generator and a graphic accelerator. The first of them converts data from video memory into MDA / CGA / VGA / RCA / DVI / HDMI / etc format....
5
votes
1answer
137 views

What are examples of providing non-RST instructions for 8080 interrupts?

When a peripheral in an 8080 system generates an interrupt request and the 8080 acknowledges the interrupt, the peripheral is expected to put an instruction opcode on the data bus which the 8080 will ...
3
votes
2answers
310 views

Was the Music System for the Exidy Sorcerer as exceptional as I remember?

I am trying to remember about a bare-board sound card which plugged into the parallel port of an Exidy Sorcerer (circa 1980). The card and software ("Music System") was made by Arrington Software ...
6
votes
1answer
206 views

Digital PCB Plans for Retro Computers

I use software like Fritzing or Autodesk EAGLE to draw my Raspberry Pi or Arduino projects and was wondering if there is a source for PCB plans of for example an Amiga 500 in a format readable for ...
4
votes
0answers
147 views

Modern Alternative to Malvino's Digital Computer Electronics

For those who want to study retro computing in depth, starting by understanding 74xxx logic and CPU design is (IMHO), one of the best paths there is. Malvino's "Digital Computer Electronics" (DCE), ...
9
votes
6answers
3k views

Is there any music source code for sound chips? [closed]

I’ll clarify what I mean. The sound chip (c64's SID, spectrum's Yamaha, etc.) is connected either to the input / output port, which will be reserved for the sound chip, or directly to the CPU data bus....
13
votes
4answers
2k views

Do AT motherboards (286, 386, 486) really need -5V (besides redirecting it to ISA connectors)?

The power supply of my 386DX computer (an unknown brand M320 motherboard) is not trustworthy anymore, so I'm planning to use an ATX power supply, plus an ATX to AT adapter for P8-P9 connectors. The ...
88
votes
1answer
26k views

Why did MS-DOS applications built using Turbo Pascal fail to start with a division by zero error on faster systems?

On faster MS-DOS systems, it wasn't entirely uncommon for applications built using Borland's Turbo Pascal to fail to start, and (before exiting back to the command prompt) to report a division by zero ...
15
votes
1answer
805 views

Were there 486SX revisions without an FPU on the die?

I know that the 486SX had its FPU disabled, maybe by binning 486 CPUs into those with and without functioning FPUs. But did Intel eventually make a 486SX revision without an FPU on the die?
22
votes
5answers
3k views

What is the hex versus octal timeline?

When and why did hexadecimal representation become more common than octal for displaying and printing out multi-bit binary fields?
4
votes
2answers
174 views

Need circuit - manual step-by-step clock for 8086/8088

I finally bought a ceramic 8086-1 (from ebay, from China - I'm not sure that it is not fake chip) and 8284 (it make the necessary synchronization signal for the processor from the crystal). Now I ...
6
votes
2answers
460 views

How to setup a teletype to a unix shell

So, recently I've been researching old tech because I want to write some fiction about some typewriter that can access the command line(yep) that shows up in many youtube videos like This one. I want ...
0
votes
1answer
95 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, but I seem to be having difficulty getting the devices attached properly, or I'm lost in ...
3
votes
1answer
155 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
116 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 ...
13
votes
2answers
283 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
388 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
509 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 ...
19
votes
4answers
4k 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 ...
10
votes
1answer
274 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 ...
27
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
7k 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 ...
9
votes
3answers
413 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 ...
27
votes
1answer
3k 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
413 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 the info I seek is in the ROM disassembly but I can’t find anything by googling. I'm also ...
3
votes
1answer
124 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 ...
63
votes
8answers
16k 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
276 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
152 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
248 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 ...
11
votes
3answers
612 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
222 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
272 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 ...
11
votes
1answer
316 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
367 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
574 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
1k 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
110 views

Identify Toshiba CRT

Didn't find anything with a search and need to replace the tube due to it being severely burnt in. [] []
14
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
239 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
333 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 ...
4
votes
2answers
288 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 ...
26
votes
6answers
15k 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 ...

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