All Questions
5,789
questions
6
votes
6
answers
2k
views
When was the end of the floppy-only IBM PC clone?
Can we pinpoint in what year the number of IBM-compatible PCs (whether original IBM machines or clones) sold without a hard disk drive became so negligible that almost all new commercial software, ...
- 703
49
votes
7
answers
26k
views
Why did the Motorola 68000 processor family fall out of use in personal computers in the 21st century?
In the '80s and '90s the Intel x86 and Motorola 68000 families were the two leading microcomputer architectures in the 16-bit/32-bit personal computer scene. The 68000s were even preferred by the ...
- 2,159
25
votes
1
answer
3k
views
What's the most recent version of AmigaOS?
Simply as the heading states. What is the most recent version of AmigaOS?
- 5,271
4
votes
2
answers
2k
views
AmigaOS 3.9 - where can I buy it?
I've been looking all over for a source to buy AmigaOS 3.9.
My A1200 has Workbench 3.2.2 and it would be nice to get OS 3.9 since I'm also adding an 68060 card and lots of RAM.
Where might I find OS 3....
- 143
0
votes
1
answer
132
views
Monitor connector for C64 and ST the same?
I have a monitor (colour) that works on my Atari ST. The connector looks similar to that of my Commodore 64, but it doesn’t seem to fit. Now I don’t know if I just have to use a bit more force, or ...
- 366
11
votes
6
answers
3k
views
What made the ENIAC "programmable"?
The ENIAC was the first programmable, electronic, general-purpose digital computer. However, it was programmed by "rewiring", and this is what I do not understand.
When we say "...
- 691
0
votes
2
answers
244
views
An idea about memory management [closed]
The other day, I had an idea. This conclusively proves that people smarter than me already thought of this decades ago. What I'm wondering is... Is this a good idea? Was it ever implemented in ...
- 3,045
3
votes
2
answers
443
views
Apple IIc making grinding sounds when accessing disks beyond normal clicks
I'm looking for resources and/or advice.
What problems with a IIc could be causing either the internal or external drive to make this horrible grinding sound? It's different than the usual startup ...
- 180
4
votes
1
answer
484
views
How do you find the EBDA address?
Normally, the "Extended BIOS Data Area" (EBDA) is located at the segment stored at 0x0040:0x000E, but this is only true for EISA and MCA systems (at least that's what I found in various ...
- 2,277
-2
votes
1
answer
213
views
How did Jon von Neumann come up with the idea of the Von Neumann architecture? [duplicate]
The Von Neumann architecture has the following components:
A processing unit with both an arithmetic logic unit and processor registers
A control unit that includes an instruction register and ...
- 691
5
votes
2
answers
548
views
Apple ][ nibble disk format specification
Is there an official specification for .nib format disks for the Apple? I'm currently debugging through a CP/M boot disk for a Cirtech //e Z80 which works fine on real hardware but fails in an ...
- 5,277
2
votes
0
answers
70
views
What was the hardware-level data format on IBM 1316 or 2316 disk packs?
A description of the hardware-level track format of the IBM media used on the BESM-6 I've found is as follows (translated by Google with minimal corrections):
Track header structure:
...
- 18.3k
8
votes
0
answers
458
views
How was the Amiga console supposed to work with only 32KB of RAM?
During the development of the Amiga, one of the targets was a game console with 32KB of RAM. How was it supposed to work?
by blitting ahead of the beam with the Copper to avoid double buffering?
was ...
- 1,239
4
votes
1
answer
227
views
Documentation for the SALUT preprocessor of the IBM Macro Assembler 2.0
The IBM Macro Assembler 2.0 included the SALUT program, which was a preprocessor for assembly language for structured programming. It was also included in the IBM Macro Assembler/2.
I am looking for ...
2
votes
1
answer
546
views
Windows 95 Protection bootup error? [closed]
I'm installing Windows 95 (OSR2.5) on a semi-modern PC.
The PC has ran Windows 3.1 and even a version of 2, but I just can't seem to get 95 to work.
after installing it, then fixing a memory error, I ...
22
votes
2
answers
4k
views
Were there any PCs using the i376?
The Intel 80376 was an x86 CPU that didn't support Real Mode or paging. It was targeted for embedded applications and it wasn't very successful at that (the 80386EX overtook it).
Under these ...
- 2,277
8
votes
0
answers
394
views
Can you name this 386/486 era computer case?
Escort Computer is a Local PC brand in Turkey. They had popular Escort Multimedia series in late 90's. Prominent with distinctive case design. They were using off the shelf OEM hardware. I believe, ...
- 2,728
2
votes
0
answers
126
views
Compaq Contura 430C replacement hard drive
I have a working Compaq Contura 430C laptop, but its hard disk is really aging and making noises when under load. I don't want to stress it any further and thinking of replacement and preserve the ...
- 121
9
votes
4
answers
2k
views
Detecting if a video mode is supported by INT 0x10
The PC BIOS uses the INT 0x10, AH=0x00 function to change the video mode.
There's a big list of video modes available, but how can I be sure that the video mode I want to set is supported?
For example,...
- 2,277
3
votes
0
answers
202
views
How do you jump to an absolute address in a SNES ROM, in IDA Pro?
I used to know more about the SNES memory mapping than I do now, apparently.
I'm using a combination of bsnes-plus (a debug oriented fork of bsnes) and IDA pro in an attempt to figure out something ...
- 1,463
15
votes
4
answers
5k
views
How could early computers perform data operations before John von Neumann proposed the concept of ALU?
According to Wikipedia, John von Neumann proposed the Arithmetic and Logic Unit concept in 1945.
Mathematician John von Neumann proposed the ALU concept in 1945 in a report on the foundations for a ...
- 691
7
votes
1
answer
236
views
Does MSX support DMA from slots?
I was looking at the signals present on the slot connector of an MSX machine, but can't find any valid option to implement DMA.
So, no such an option on these systems?
- 429
4
votes
0
answers
77
views
Is there information available to diagnose DLT2000/4000 POST errors?
I'm trying to read some DLT CompactTape IIIXL tapes.
The Quantum TH3AA (DLT2000XT) drive I have was last working in 2018 but on powerup all the lights illuminate then the lights on the left go out but ...
- 621
4
votes
1
answer
116
views
What is the power adapter voltage and polarity for an Avatex 1200 modem?
My very first modem was an Avatex 1200 connected to my trusty C64. Unfortunately, the power adapter has long since been, let's say, disassociated from the hardware. I probably still have it, but the ...
- 9,795
1
vote
1
answer
207
views
ZX Spectrum Plus 2a not loading any games
I've just purchased another ZX Spectrum Plus 2a and this one has an issue loading games. At first I thought it was just the tape heads needing to be cleaned and the alignment being out. However, I ...
- 43
19
votes
1
answer
4k
views
What is the arcade game played in the "The Boys Next Door" movie?
This is from the movie The Boys Next Door (1985). The character is playing an arcade game.
There is the name, but is impossible to read. I read "mrrruders" but searching on the net nothing ...
- 1,697
14
votes
4
answers
3k
views
Why does Sinclair BASIC have all of the characters twice in the token table?
I'm looking over the table of tokens for Sinclair BASIC and I'm struck by two things. One is that it's not ASCII. Some parts are in the same order, but others are not, so it would seem conversion is ...
- 19.5k
1
vote
1
answer
480
views
Name of Commodore tape format?
How did Commodore call their tape format, if there ever was a specific name for it?
OK, let me clarify. I would be interested in the technical term of the encoding as well as any specific name, should ...
- 31
23
votes
1
answer
2k
views
Where can I find the code of the ancestors of the WebKit family of web browsers?
I want to trace the development of the web browser back to the earliest point.
The code that would become WebKit began in 1998 as the KDE HTML (KHTML) layout engine and KDE JavaScript (KJS) engine.
--...
- 333
6
votes
1
answer
616
views
AMD Interwave audio fx
I hope it's retro enough. Does anyone have any info on how AMD Interwave did sound effects?
I'm mostly interested in reverb, but others would be nice to know about as well. The question is ...
- 477
1
vote
0
answers
109
views
FBAS to RGB converter available? [closed]
I am looking for a FBAS to RGB converter, small size, low cost.
Background:
Back in the day and until 2008 BMW used to use RGB as the video standard in its cars.
Three separate wires, red green and ...
- 111
14
votes
1
answer
1k
views
PDP-11 Program to Execute Only in the Registers
The contents of processor registers of a PDP-11/05, etc were available at UNIBUS memory addresses and it was possible to execute a small test program just in the processor registers without accessing ...
- 581
6
votes
1
answer
137
views
How did MSX memory slot mapping differ between the Sharp Hotbit HB-8000 and the Gradiente Expert?
I posted an answer to the question MSX's primary and secondary slots but while researching some references in the msx.org wiki to ensure my answer was accurate, I found some discrepancies between ...
- 214
5
votes
2
answers
856
views
MSX's primary and secondary slots
Is it correct to say:
"MSX defines 4 primary slots, which can hold up to 64K each. Since the access window is 16K, every primary slot is split in 4 secondary slots."
In my understanding, the ...
- 429
10
votes
0
answers
250
views
How was BOS on the Apple III different from SOS?
The original operating system for the Apple III was SOS, a.k.a. "Sophisticated Operating System". Though the Apple III and SOS didn't last very long as the platform was considered a failure, ...
- 15.8k
14
votes
2
answers
4k
views
Why does the Manchester Baby have two jump instructions?
The Manchester Baby has 32 words of memory, 32 bits each. An instruction word occupies the full 32 bits, so that the maximum length of a program is 32 instructions.
Of course, like any other computer, ...
- 38.2k
2
votes
0
answers
324
views
Trying To Understand DOS Game Assembly Instructions [closed]
I am trying to understand assembly language instructions, for a DOS Game. I have looked at the following Link :- https://atrevida.comprenica.com/atrtut07.html
reading about how VGA Graphics work in ...
- 21
18
votes
2
answers
4k
views
Did the Z8000 ever hit the home computer market?
The Z80 had a massive presence in the 8-bit revolution, but I can’t remember any system with a Z8000. Did it ever hit this market?
- 366
3
votes
3
answers
423
views
How to run certain .COM files on Amstrad CPC6128?
I have obtained Amstrad CPC6128 with Locomotive BASIC 1.1. Everything works fine except one thing.
I don't know how to properly run certain .COM files. I have tried general commands such as RUN or ...
- 51
5
votes
0
answers
344
views
Did the Soviets need industrial espionage to get IBM software pre-1970?
Due to lack of the OS-level file system on the BESM-6, and to deficiencies of data visualization tools which could help people decide which blocks of a system disk could be reused (the line of ...
- 18.3k
7
votes
0
answers
288
views
Were there ever any commercial products produced for the BeBox GeekPort?
I know that the BeBox was a short lived product, but whenever someone mentions it they never fail to also point out the "GeekPort".
While the possibilities of the GeekPort were tremendous, I'...
- 15.8k
30
votes
3
answers
8k
views
Why did 1990s-2000s LCD all use 60 Hz refresh?
In the CRT era, refresh rates ranged from 50 to 160 Hz. Some displays could barely do 65, high-end Mitsubishi and Sony tubes could run 120+; most people used 70-100 Hz. GPU DACs and monitor circuits ...
8
votes
1
answer
858
views
What computer is this, a clone of a ZX Spectrum?
Recently I stumbled over this article with an interesting teaser image. It shows some home computer, presumably of the eighties. Unfortunately the image is too blurry to read the keywords on the keys:
...
- 1,054
5
votes
2
answers
594
views
ZX Spectrum+ 48K with faulty memory writing address
I have ZX Spectrum+ 48k (board issue 6a) with writing to memory issue.
When I try to write a value by POKE command to address 49152 (C000h) then it overwrites additionally value with address 16384 (...
- 51
5
votes
1
answer
190
views
Correct voltages and current draw for Commodore PC-1
I am fixing a Commodore PC-1 PSU for a friend and want to know if the PSU is behaving as expected. No modern PSU suggestions (e.g. Meanwell), if you don't mind! :)
Question: What are the voltage ...
- 819
15
votes
2
answers
892
views
Drawing Asteroids DVG vector objects
I'm trying to draw the vector objects from the original coordinates of the Asteroids arcade game, starting with the ship from here, but I'm having trouble figuring it out and getting weird results. E....
- 153
5
votes
0
answers
203
views
Harris 80C286 double fault does not push an error code
I'm using a Harris CS80C286-20 CPU.
If I set the access rights byte of the Divide Error Exception descriptor to 0x80 (which indicates a present system descriptor of an invalid type), and then execute ...
- 61
11
votes
3
answers
806
views
TMS9918 - why have separate data-in and data-out?
Usually 8bit video chips interface with DRAM using:
an address bus for rows and columns,
a bidirectional data bus
in the case of 1bit DRAM data-in and data-out pins are shorted on the same data line....
- 1,239
4
votes
0
answers
244
views
First machine with dedicated scatter/gather?
I know the Cray-1 had scatter/gather addressing, but I am curious if anyone knows what the first machine with this feature might be?
I suspect it is one of the vector machines from this era, perhaps ...
- 19.5k
4
votes
1
answer
556
views
How did John Carmack develop DOS games in Softdisk?
I recently listened to a podcast of Carmack and he said that in early DOS days he mostly uses assembly. The host asked him about Pascal and he said back then only Wizardry was written in Pascal.
I ...
