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2
votes
2answers
77 views

What was the earliest microcomputer Logo language implementation?

Wikipedia has a long list of Logo implementations, but I'd like to know what the earliest implementation on a microcomputer is or, more likely, what the earliest ones are if there isn't one with clear ...
4
votes
3answers
340 views

Amiga 500 OCS/ECS vs Mega Drive VDP

Superficially the Amiga 500 and Mega Drive are similar. Both run a Motorola 68000 CPU at similar clocks and both have dedicated hardware for sprite and other graphics operations Comparing the arcade ...
7
votes
1answer
164 views

What was the purpose of the Apple /// interlace mode?

I know that a video interlace mode was available on the Apple /// prototype and eventually on the Apple ///+, but I haven't seen anything that says what it was for. Did it provide a higher resolution ...
4
votes
5answers
1k views

Real mode flat model

I am interested in old Intel processors. I'll try to be as concise as possible. I have been studying both Jeff Duntemann's Assembly Language Step-by-Step - Chapter 4 and Modes of Memory Addressing on ...
18
votes
3answers
2k views

Bit one of the Intel 8080's Flags register

Did bit one of the Intel 8080's Flags register, the bit between the carry and parity flags, get set to one on startup? If so what was the reason for this, and was this inherited from the 8008 Flags ...
1
vote
1answer
167 views

Can you help me identify this AMD 386-DX40 motherboard?

I'd like to find some documentation for this mainboard I just picked up for my very first retro computer, but I don't see any brand or model markings whatsoever. Does anyone have any tips? P. S. I ...
23
votes
3answers
2k views

What are uses of the byte after BRK instruction on 6502?

The BRK instruction on the MOS 6502 seems to be one of the more ill-documented features of the processor. The 1976 preliminary data sheet from MOS indicates that it's a 1-byte instruction using the "...
2
votes
2answers
210 views

How much PSU power do I need for an AMD 386DX-40 computer?

Just picked up my first retro PC the other day. Unfortunately, it's lacking a PSU so I need to find one. What kind of a PSU (in terms of wattage) do I need to comfortably run an AMD 386DX-40 system? ...
13
votes
3answers
499 views

Did Apple really advise customers to lift up and then drop their computers?

This led to the infamous technical note where Apple recommended users facing problems with the Apple III to lift the computer two inches and then drop it, as this would set the circuits back in place.[...
8
votes
1answer
2k views

What was the first LISP compiler?

LISP is generally considered an interpreted language, but compilers have been made for it. What was the first compiler? To be clear, this is about compilers that compile LISP code stored for ...
9
votes
2answers
335 views

How do you send code to a Commodore disk drive and run it?

Commodore disk drives such as the 1541 used with the Commodore 64 and similar computers, and the earlier 8050 used with the PET series, had their own 6502 CPU and 2 kB or so of RAM used to run the ...
5
votes
1answer
70 views

What is the floppy disk port pinout for the NEC PC-8001mkII?

I have a NEC PC-8001mkII computer (sometimes incorrectly called a "PC-8001mk2") which has a built-in disk controller for PC-8000-series double-density 5.25" drives. (The English and Japanese Wikipedia ...
2
votes
2answers
213 views

ZX Spectrum +2 not saving

I have a ZX Spectrum+2 with the built in tape deck. I can load tapes no problem, when I try to save, I get the border lines. When I try to reload the program I get nothing Any help would be greatly ...
10
votes
1answer
317 views

When was “Cable Select” introduced for IDE devices?

Conventional IDE (or parallel ATA) controllers support two devices per controller; these are designated Master and Slave, and need to be configured as such with jumpers on the devices. In later years,...
38
votes
4answers
7k views

When did computers stop checking memory on boot?

I remember my old 8088 used to do this (640K OK) but can't remember seeing anything like this since. Does this still happen and it's just not visible? If not, when did it stop, and why? (Imagining ...
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 ...
2
votes
0answers
113 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
3answers
171 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) ...
8
votes
3answers
180 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 ...
5
votes
2answers
164 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 ...
10
votes
1answer
650 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
84 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
232 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 ...
3
votes
4answers
463 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
2k 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. ...
8
votes
3answers
435 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. ...
51
votes
5answers
14k 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 ...
32
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
774 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 ...
9
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
252 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
221 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
314 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
1k views

What ways are there to “PEEK” 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 - beside the often used DPEEK (or alike) to read a word. I'm asking ...
7
votes
2answers
389 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 ...
9
votes
3answers
203 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 ...
48
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
969 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
373 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
178 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
173 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
717 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
127 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
292 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
194 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
136 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....

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