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19
votes
1answer
1k views

Why does PAUSE key have a long make code and no break code?

On IBM keyboards, scan code sets 1 and 2 have a long make code and lack a break code for the Pause/Break key. Moreover, when Ctrl is pressed, the make code is different, although break code still ...
3
votes
0answers
147 views

Can a bootable Win9x HDD be made interchangeable between PCs?

Normally, Windows 9x must be installed on each PC individually so that it can be loaded/configured with the appropriate set of drivers. I'm wondering if there is any way to make a boot HDD that can be ...
4
votes
4answers
263 views

Are there standard DIN pinouts for cassette and video ports on early Japanese 8-bit computers?

I have several different Japanese 8-bit computers, and they use similar DIN connectors for video and cassette I/O: Composite video: 180° 5-pin DIN: Fujitsu FM-7, NEC PC-8001mkII Color TTL (digital) ...
10
votes
3answers
328 views

Set keyboard layout in Amiga Workbench 3.1

I did a fresh install of the Cloanto amiga-os-310-install.adf disk to a hard drive, and then I wanted to change the keyboard layout to Swedish. I tried SYS:System/SetMap s but then I've learned that ...
6
votes
2answers
191 views

How do I use NEC PC-6001 .p6 or .cas files?

The Neo Kobe - NEC PC-6001 "software capsule" on Internet Archive includes a 126 MB ZIP file, Neo Kobe - NEC PC-6001 (2016-02-25).zip, containing a subdirectory 1-Screen Programs (Kaw)/. This contains ...
11
votes
1answer
706 views

Does the Commodore CDTV-CR contain a 65C02 for some reason?

Browsing around the FS-UAE source code I discovered a 65(S)C02 emulation core, which appears to not be referenced anywhere outside of some CDTV-CR related source file. Apparently, a CDTV is ...
30
votes
3answers
6k views

Why does 8 bit truecolor use only 2 bits for blue?

From Wikipedia: The other form is where the 8 bits directly describe red, green, and blue values, typically with three bits for red, three bits for green and two bits for blue. This second form is ...
0
votes
0answers
90 views

What cable do I need to connect my old commodore64 with a tv (as monitor) [duplicate]

I want to use an old commodore64. In the 80s we connected a small tv, as a monitor, but the cable for that connection is missing. What kind of cable connection do I need?
3
votes
1answer
250 views

TRS-80 Model 100 is frozen, even after multiple resets

I replaced all leaking capacitors about 4 months ago. I cleaned it out the board tediously. Every-time I switch on my old computer it is stuck on the menu screen. The machine does not respond to the ...
4
votes
4answers
662 views

How slow is Z80 compared to Arduino Uno?

How slow is z80 compared to Arduino Uno when they read an output pin if the Z80 is 2.5Mhz?? I/O cycle and cpu herz and is there anything else to consider?
16
votes
1answer
3k views

Do we know the problems the University of Manchester's Transistor Computer was intended to solve?

We can see that the University of Manchester built a transistor computer in 1952. This appears to have been the first transistor computer. We can see that the design was used in the Metrovick 950. ...
9
votes
3answers
492 views

Why did 1970s front panels prefer momentary toggle switches to push buttons?

This question is about computers with front panels that use only toggle switches for input of binary data (such as address and data values), as opposed to keypads for numerical input or other methods. ...
53
votes
6answers
15k views

Why do old games use flashing as means of showing damage?

When you play old games, especially platformers, a common "special effect" is rapid blinking of your character when they are hit. Also, enemies often blinked before dying. Not all games did this, but ...
33
votes
3answers
3k views

Why did the VIC-II and SID use 6 µm technology in the era of 3 µm and 1.5 µm?

In short, 3 µm looks like it was the "standard" process size at the time, and it was available to Commodore before the chips were designed. Therefore it looks like using the larger 5 to 7 µm process ...
13
votes
3answers
1k views

What are the electrical characteristics of a PC gameport?

I'm considering building some custom gizmos to connect to the gameport on my retro-hobby PC (SNES controller adapter, macro/turbo box, etc.) but I haven't been able to find much information on details ...
12
votes
3answers
856 views

How did the Altair 8800 front panel load the program counter?

My understanding is that when you toggle in an address on the Altair 8800 front panel switches and then press the EXAMINE switch, it loads the program counter with that address, or at any rate does ...
10
votes
2answers
1k views

Small RAM 4 KB on the early Apple II?

Most of the reference material for the Apple II that I have seen refers to the 4116 RAM chip which held 16x1 kbit. This provided 16, 32 or 48 KB in banks of 8 chips. The Apple II motherboard layout ...
5
votes
2answers
338 views

Build a hardware clone or emulator of Apple II?

These days we are constantly seeing low-cost boards that have huge power (raspberry pi, various arduino-like microcontrollers.) I am hoping I could make, or get, a clone or emulation of an Apple II ...
4
votes
1answer
256 views

Discharging an AT power supply for maintenance

The power supply for one of my computers needs a new fan. How do I discharge the power-supply capacitors to make it safe to open up? With an ATX power supply, it's just a matter of unplugging it, ...
2
votes
2answers
327 views

emulator library that allows to partially emulate old games [closed]

EDIT: previously I added a lot of examples to this questions. I removed the examples, because the question was voted to be "too broad", so I put more emphasis on the question again. Question: Is ...
6
votes
7answers
2k views

What ways are there to “PEEK” of memory sections in (different) BASIC(s)?

Question Was there any BASIC or extension or toolbox for BASIC allowing to PEEK multiple bytes from memory in one instruction - besides the often-used DPEEK (or alike) to read a word? I'm asking ...
7
votes
2answers
437 views

Saving screen pixels to string in ZX Basic

I remember programming a ZX spectrum in 128 basic (about 20 years ago). I remember I was able to save a third of the screen into a variable. Something like this: 10 LET A$ = [16384 BYTES starting at ...
10
votes
3answers
288 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
1k 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
465 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 ...
7
votes
1answer
250 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
260 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
767 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
151 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
319 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
221 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
150 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 ...
91
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
808 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
210 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 ...
7
votes
2answers
480 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
102 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
158 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
123 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
303 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 ...
2
votes
1answer
482 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
563 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 ...
23
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 modes: Commodore 64 mode, Commodore 128 mode and CP/M. The first shared one of each CPU/chip, the CP/M mode the ...
12
votes
3answers
548 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 ...
28
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 ...

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