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2
votes
2answers
322 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
776 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
389 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
242 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
415 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
253 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
600 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
287 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
334 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
696 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
128 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
201 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
277 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
201 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 ...
12
votes
7answers
2k views

8086 stack segment and avoiding overflow in interrupts

This is a followup to Could the Intel 8086 CPU have many segments in memory of the same type? In the event of a hardware interrupt or user interrupt through the INT instruction, was there a risk that ...
27
votes
5answers
14k views

Why did Windows 95 crash the whole system but newer Windows only crashed programs?

Example situation. You are using a program in Windows 95 and screen goes blue only for you to restart the whole computer You are using a program in Windows 7 and the program stops responding only to ...
38
votes
6answers
9k views

How did the SysRq key get onto modern keyboards if it's rarely used?

Was the SysRq key ever used on any common operating system? Google tells me it wasn't. But then how did it end up on so many keyboards?
3
votes
3answers
217 views

Interrupt pin type on the 6502

I have a really basic question. I have to design an 65C02-based personal computer for a school project. I have to draw my own footprint for the 65C02. My question is what type of pin is the IRQB (...
8
votes
6answers
733 views

Low-cost sound chip

I want to make a homebrew 8-bit computer and I want to include a sound chip in it. It needs to be as cheap as possible (under 5$) and I also want it to be possibly controlled by an Arduino or ATmega-...
4
votes
1answer
113 views

Was there any VIC-20 expansion to bring memory beyond the default maximum of 40 KiB?

The Commodore 64 was very flexible in terms of how RAM could be controlled. ROMs and I/O devices could easily be swapped out by setting bits in the first two addresses of memory. The VIC-20's ROMs and ...
8
votes
1answer
433 views

Will any serial mouse connect to Classic Macs?

The Macintosh 128k, 512k, and Plus use a DE-09 Serial port for the mouse. Is there some proprietary data-transfer method? Or is any DE-09 Serial mouse compatible? Furthermore: has anyone documented ...
5
votes
5answers
335 views

Could the Intel 8086 CPU have many segments in memory of the same type?

The Intel 8086 CPU could address up to 1 MB of memory using segmentation, and this CPU have 4 segment registers, which are CS and SS and DS and ES. Each segment in memory can have a maximum size of ...
16
votes
4answers
1k views

Did the IBM PC use the 8088's NMI line?

As I understand it, the Intel 8088 CPU used in the original IBM PC had two interrupt lines: INTR and NMI. INTR was fed from the Intel 8259 Programmable Interrupt Controller, which handled the IRQs ...
12
votes
5answers
2k views

Does the Intel 8086 CPU have user mode and kernel mode?

Does the Intel 8086 CPU have user mode and kernel mode as modern CPUs do? and if it doesn't have user mode and kernel mode, does that mean that any user program written for the Intel 8086 CPU could do ...
4
votes
0answers
224 views

Why is the original Altair BASIC (for the 8080 CPU) source code not available on-line?

As described by The Register in 2001, around 1987 journalists and others started asking Bill Gates for a copy of the source code for the original version of Altair (eventually Micro-Soft) BASIC, ...
4
votes
3answers
225 views

In what way does the Straight-8 expand on the PDP-5?

A quote from the Wikipedia: The PDP-5's instruction set was later expanded in its successor, the PDP-8, to handle more bit rotations and to increase the maximum memory size from 4K words to 32K ...
37
votes
3answers
5k views

How did C64 games handle music during gameplay?

On the C64 there was no threading, so how did games handle treating at the same time music and game code? Music requires exact timings, and the SID had to be instructed to change the note at the right ...
4
votes
3answers
218 views

How does states, bus cycles and clock cycles differ in the M68000?

I'm trying to understand the difference in bus cycles, clock cycles and states within a 68000 processor. According to the user manual, A bus cycle consists of eight states... Lets assume the 68K ...
4
votes
2answers
333 views

Is the Game Boy Sharp LR35902 object-compatible with the 8080/Z-80?

(Note: by "object-compatible" I mean that the opcodes and their following operands are the same—the assembler produces the same output for equivalant assembler mnemonics. This of course excludes ...
3
votes
2answers
225 views

How does Game Boy / Sharp LR35902 HRAM work?

The Nintendo Game Boy has RAM called "HRAM" (meaning "high ram") decoded at locations $ff80 through $fffe. (All other decoded locations in the $ffxx page appear to be I/O device and system control ...
2
votes
1answer
268 views

Long variable names in MS BASIC

From the Wiki: The final major release of BASIC-80 was version 5.x, which appeared in 1981 and added support for 40-character variable names, WHILE...WEND loops, dynamic string allocation, and ...
44
votes
7answers
9k views

What was the rationale behind 36 bit computer architectures?

Was there some particular design theory or constraint that made a 36 bit word size attractive for early computers? As opposed to the various power-of-2 word sizes which seem to have won out?
3
votes
4answers
301 views

What determined the type of error dialog being shown in Windows 3.1?

In Windows 3.X we had multiple type of error dialogs that could be displayed: Application crash: Application error that could be recovered: What did the Ignore button do in Windows 3.1 when an ...
2
votes
1answer
195 views

Connecting Computer to GameCube Controller Port

I want to have my computer listen to messages between my Nintendo GameCube and a controller. (This is just for fun, not for streaming or anything.) I've spliced into the cable as described here in ...
8
votes
1answer
195 views

String libraries for BASIC

Looking over old BASICs I find two general approaches to handling string variables. HP/Wang/Atari/et al used C-like array-of-char whose memory size is specified with a DIM statement, with the upside ...
2
votes
2answers
156 views

Non-obvious compatibility of M1297 monitor

I bought an Apple IIgs recently. I didn't do my research well enough and wound up with an M1297 monitor, which of course appears to only be compatible with Macintosh IIs and such, rather than the ...
35
votes
7answers
12k views

Why did computer video outputs go from digital to analog, then back to digital?

While early microcomputers used analog video outputs (often to use a television as a display), higher end machines such as the BBC Micro or Commodore 128 supported a digital RGB (or RGBI) video output....
75
votes
9answers
17k views

Why did modems have speakers?

Everyone who used early telecommunications services, not to mention the early dial-up Internet services, is familiar with the tones and hissing sounds of a modem establishing a connection. I recall ...
13
votes
5answers
5k views

Does switching on an old games console without a cartridge damage it?

This is inspired by the question "What does a Nintendo Game Boy do when turned on without a game cartridge inserted?": Growing up in the 80s and 90s in the UK, it was "common knowledge" amongst my ...
9
votes
2answers
2k views

On a Gameboy, what happens when attempting to read/write external RAM while RAM is disabled?

According to the GBdevwiki: 0000-1FFF - RAM Enable (Write Only) Before external RAM can be read or written, it must be enabled by writing to this address space. It is recommended to disable ...
1
vote
1answer
141 views

How does the Gameboy address external hardware?

Where in the memory map ($0000-$ffff) does the Gameboy address the memory of these accessories? (for example, the battery or the Gameboy Printer). Is this something I should implement in an emulator?
26
votes
3answers
9k views

What does a Nintendo Game Boy do when turned on without a game cartridge inserted?

When a Nintendo Game Boy is turned on, it displays a logo read from the cartridge (looking like this) before starting the game. What does it display if there's no cartridge inserted from which to read ...
14
votes
4answers
1k views

Why is the unchangable Nintendo Game Boy logo in the cartridge?

According to Gameboy [sic] Development Wiki page The Cartridge Header, locations 0x104 through 0x133 in the cartridge contain a bitmap of the Nintendo logo that's displayed when the Game Boy is turned ...
24
votes
2answers
2k views

What does Windows' “Tuning up Application Start” do?

When installing an old version of Windows, there is a step about application start tuning: This is not about the PREFETCH folder, since this feature appeared in Windows XP. Question: Does anyone ...
18
votes
3answers
3k views

How does the Gameboy's memory bank switching work?

I'm writing a Game Boy emulator, but I don't completely understand how its memory mapping works. Here is what I (think) I know (and don't know). The CPU can address up to 0x10000 memory locations ...
4
votes
1answer
127 views

ACA1221 cooling

I have an ACA1221 accelerator (not EC). The card is clocked at 28MHz and get's VERY hot. Even when running on default 17MHz the temperature can go as high as 65'C. Is there any way to use any of the ...
3
votes
1answer
247 views

Old SCSI controller won't boot on certain PC

I have an old Adaptec PCI SCSI controller from around 1995 (BIOS date, will get full model if needed). It's lived its life in an old 133 MHz Pentium from around 1995 as well. The controller is 50 ...
19
votes
3answers
3k views

What makes MOVEQ quicker than a normal MOVE in 68000 assembly?

I'm "re-learning" 68000 assembly language and came across the "MOVEQ" command that is labeled "MOVE QUICK". According to the NXP Programmers Reference Manual (reference below), the command MOVEQ (...
42
votes
2answers
4k views

Locked-up DOS computer beeped on keypress. What mechanism caused that?

Long time ago I had an old IBM PS/2 that I had fished out of a dumpster. It ran IBM DOS 5.0 and was a solid little machine. Occasionally I would encounter the following scenario, and I recently ...
10
votes
5answers
2k views

What was the difference between a Games Console and a Home Computer?

In the world of home entertainment and video games, two terms that were commonly used to describe machines from the 1970s onward are "games console" and "home computer". Some devices appear to ...

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