All Questions
5,788
questions
9
votes
2
answers
3k
views
Did a serial port card reader sink the prospects of consumer chip card readers?
According to https://groups.google.com/g/alt.folklore.computers/c/z4sm_W1MZXg
at the start of the century there were several efforts for secure
payments involving chip cards (and chip readers).
in ...
- 58.4k
8
votes
1
answer
594
views
Were punching tools for punch cards with rectangular holes easier to keep sharp than those for round holes?
There is a question here on retrocomputing if round punch card holes where mechanically stiffer:
Were round punchcard holes mechanically stiffer?
I wondered if the reason for the rectangular holes on ...
- 831
12
votes
2
answers
1k
views
Floppy drive detection on an IBM PC 5150 by PC/MS-DOS
The only functions of INT 13h available for pre-XT systems are the first six, from AH=00 to AH=05 (see here and here)
Since function AH=08 (Get current drive parameters) is unavailable, how does PC-...
- 445
6
votes
2
answers
368
views
Mixing small and big data models in 16-bit DOS & Watcom
I want to write an application for DOS using small code/data model, but I would like to use far pointers for some selected memory blocks. I would like to use the OpenWatcom C++/16 compiler.
So, for ...
- 237
13
votes
3
answers
2k
views
What's the convention for < > low/high-byte in 8-bit assembler?
It's a little hard to Google for greater-than and less-than symbols in assembler math...
If you saw, let's say, 6502 code like...
lda #>SOME_LABEL
or Z80 code like...
ld a,>SOME_LABEL
...would ...
- 331
12
votes
2
answers
1k
views
What are the electrical properties of the EAR and MIC sockets on a ZX Spectrum, and can they be connected between machines?
I'm interested in the possibility of connecting two ZX Spectrum computers together using as simple an interface as possible.
The ZX Spectrum has two mono audio sockets at the back labelled EAR and MIC....
- 11.8k
3
votes
4
answers
459
views
Couldn't people just buy mainframes from the same manufacturer and connect them before the arpanet?
I was reading the TCP/IP Protocol Suite by Forouzan and at one point it says:
In the mid-1960s, mainframe computers in research organizations were
stand-alone devices. Computers from different ...
ashi
13
votes
2
answers
917
views
Simple doubling of ZX80 RAM
Many moons ago when I owned a ZX80, I remember (or possibly mis-remember) seeing a simple way to double the RAM to 2K by simply piggy-backing two extra 1Kx4 chips on top of the existing two (with pin-...
- 4,594
2
votes
1
answer
367
views
Breakout style arcade game from 90s
I'm looking for a breakout style game where the paddle was holding by a Chinese character, with red clothes. The character was on the holding above his head the paddle and he was running to not allow ...
- 29
12
votes
1
answer
773
views
Were there 6502 revisions B and C, and what were they like?
The first 6502 was the 6502 revision A, which famously does not include the ROR instruction (this is sometimes described as a hardware bug, but that's apparently a myth).
Then, some time later, there'...
- 38.2k
4
votes
1
answer
484
views
Invoke BASIC 7.0 NEW command from C128 Assembly
I want to end a C128 lm program the same way as the BASIC NEW command was executed. I tried to call the known entry point at $51D6 via JSR but is seems to not perform.
- 41
4
votes
2
answers
599
views
Manual of Resident Evil 4 Greatest Hits version for PS2 is too large for the case [closed]
I just bought a used copy of RE4 for PS2 and saw that the Greatest Hits version of the manual was all wrinkled. I improved it by putting it under a pile of heavy books for a couple days just to ...
- 167
7
votes
0
answers
310
views
Origin of Cisco-like CLI?
Loads and wagons of networking devices all over the world use the same manner for commandline interface (CLI). First I met it in 1990s at Cisco devices (switches, routers...) which used Cisco IOS. It ...
- 520
16
votes
2
answers
475
views
Did the PC Engine/Turbografx Super CD-ROM have a standardized file system?
I have a few PC Engine Super CD-ROM games, and they have an unconventional mixed mode layout: Track 1 is an Audio track (a warning to not play this disc in a CD Player), Track 2 is a data track, then ...
- 1,670
7
votes
0
answers
257
views
Bloodsport: Which version of Karate Champ is it?
In the movie "Bloodsport", there's a sequence which is famous among video game players, where Frank Dux and Jackson "fight" through a Karate Champ arcade game machine.
Now I'm ...
- 10.7k
2
votes
3
answers
516
views
Z80 to 68000 translator for CP/M
CP/M was mostly portable across systems but most of them were z80 based. It was ported to 8086, 68000 and maybe more but without binary compatibility.
No z80 systems that wanted CP/M compatibility ...
- 1,239
8
votes
1
answer
420
views
Did the Vic-20 save money using static RAM?
The unexpanded Vic-20 had 5K of RAM. This was quite small even by 1981 standards, but it was trying to be cheap enough for consumers to buy, and it succeeded, selling over 2 million units.
One reason ...
- 58.4k
8
votes
1
answer
571
views
How did the Dragon modify 6847 video output timing for PAL?
The Motorola MC6847 Video Display Generator (VDG) generates video output with NTSC timings. (It does not do NTSC colour, however; it gives luma, R-Y and B-Y signals that need an external NTSC colour ...
- 24.6k
33
votes
1
answer
3k
views
"Quit all programs, and then restart your computer" in the Windows 95 "Illegal operation" dialog
Back in the Windows 95/98 days, the "illegal operation" dialog was (from here):
but sometimes, in that dialog, it would say "Quit all programs, and then restart your computer" (...
- 727
8
votes
2
answers
918
views
Documentation for an old computer: ICL 4120
This is a follow on to my first question in this site: Help identifying a very old computer: 1974, maybe an NCR This established that the first computer that I used was an ICL 4120. Now that I know ...
- 2,014
10
votes
1
answer
525
views
Relay computer performance
I'm looking for performance data on relay based computers, and even human based computers. Performance, as in, time to perform an addition, multiple, etc.
The Nordhaus data is all I have been able to ...
- 101
20
votes
2
answers
3k
views
Did the IBM ServiceFree really reach 80 MIPS in 1975?
According to Computer Wars by Charles H Ferguson and Charles R Morris, page 40-41, an IBM researcher named Cocke in the early 70s built a RISC minicomputer called the ServiceFree (because it was meant ...
- 58.4k
0
votes
2
answers
273
views
Using a Roland LAPC-I without a PC
This is inspired by the video Using an old 8 bit ISA sound card (Roland LAPC-I) without a PC.
I would like to find detailed instructions (for those unlearned in electronics), including a parts list, ...
- 19
5
votes
1
answer
252
views
How many units of the ZX81 RAM pack were sold?
The Sinclair ZX81 was an extremely popular low-cost home computer, on strength of price, being a computer for less than 100 pounds. It sold over 1.5 million units, according to https://web.archive.org/...
- 58.4k
11
votes
2
answers
2k
views
What could SID do that APU could not?
Two of the more famous and highly regarded sound chips in the 8-bit era were the Commodore 64's SID and the Nintendo APU. Which of the two was overall better, seems to be a matter on which there is a ...
- 58.4k
4
votes
1
answer
278
views
Can someone help me port the fat32 library used in the x16 to my homebrew 65c02? [closed]
A little background:
As a retired electronics technician, (not engineer), I decided to design and build a 65C02 based computer. Only after building it did I realize how important advanced or ...
- 101
13
votes
3
answers
2k
views
How did the Fairchild Channel F provide a 2K frame buffer?
The Fairchild Channel F, released in 1976, was the first modern game console, in the sense of being the first one to accept games as software, rather than just modular configuration switches.
Looking ...
- 58.4k
4
votes
1
answer
1k
views
How to use / start Windows 3.11 with FreeDOS
I can't start Windows 3.11 in FreeDOS due some protected mode issues:
win /s (standard mode) => Can't start Windows in Standard Mode. Try to use the extended mode win /3
win /3 (extended mode for ...
- 267
7
votes
2
answers
524
views
Bit names/indexing in the TMS99xx family
What was the reason Texas Instruments indexed bit names (of data bus, address bus, registers) in the TMS99xx family (e.g. TMS9900, TMS9995) from MSBit (=bit0) to LSBit (=bit15) instead of the other ...
- 243
6
votes
2
answers
786
views
Parallel port to IDE cable standard?
For parallel port to IDE devices, known as parallel IDE, I am wondering if there is a parallel cable standard? Or if standard parallel cables should work?
Background:
A friend bought an Imation LS-120 ...
16
votes
4
answers
3k
views
What is the earliest computer technology to be referred to as "Artificial Intelligence"?
It seems that in recent years, when people talk about "AI", they are usually referring to neural net-based technologies (ChatGPT being the most well known example at the moment). But ...
- 261
4
votes
2
answers
586
views
Rufus FreeDOS option for CF is not bootable
When I try to prepare a bootable FreeDOS on my CF disk my old 386SX laptop (AMI Bios from 1990) is not able to boot => "missing operating sytem". If I select "Use a fix for older ...
- 267
1
vote
1
answer
194
views
Interfacing with the Commodore 64 IEC Serial Port using Assembly
I'm struggling a bit to find relevant documentation on this subject when it comes to using just assembly. All I've found is either irrelevant or for BASIC. My goal is to be able to send and receive ...
- 21
10
votes
1
answer
1k
views
Did the IBM 1401 have much better code density than the 360?
Reading an old thread https://groups.google.com/g/alt.folklore.computers/c/53C2adEQ5jE I see a surprising claim:
I told an IBM salesman once that IBM had so bollixed up the architecture
that our ...
- 58.4k
14
votes
1
answer
2k
views
How did Altair 8800 interrupts work?
I'm playing around with building an Altair 8800 emulator in my free time in C#. I've read through the Operator's Manual many times in the past, and I'm refreshing my memory of late.
I'm struggling to ...
- 243
4
votes
0
answers
318
views
How does the Apple IIgs color compare to the Apple Macintosh color?
There has been an interesting discussion of how to convert Classic Macintosh Color to sRGB, which begs a second question. How does color on the IIgs compare to that of Classic Macintosh? I'm asking ...
- 2,352
11
votes
2
answers
1k
views
Where to obtain 3c509b empty boot ROM chip?
I'm planning to write iPXE to boot ROM of my 3c509b to enable HTTP booting on my old computer.
What is the type of the ROM chip and where would you obtain it? It's 28 pin connector, please see picture ...
- 213
23
votes
3
answers
3k
views
Why were OS/360 PL/I procedure calls so expensive in terms of stack space?
In 1977, Guy Steele published a paper entitled Debunking the “expensive procedure call” myth or, procedure call implementations considered harmful or, LAMBDA: The Ultimate GOTO. The paper was the ...
- 333
12
votes
1
answer
517
views
How much did it cost to develop the 8-bit era graphics chips?
I'm interested in the development cost of different kinds of chips in the 70s and 80s, both for its own sake and because it aids in the understanding of historical events; in technology and business, ...
- 58.4k
6
votes
4
answers
5k
views
Is the substitution "ss" for "ß" on mainframes due to the SS being the largest customer of IBM punched cards outside the USA? [closed]
When I was a child, my German teacher (in a non-German speaking country) told us that the typed form for the letter "ß" in use in mainframes at that time was "ss" instead of "...
- 566
11
votes
3
answers
3k
views
Classic Mac OS colors to modern RGB
I want to find a way to convert RGB colors used by classic Mac OS to RGB colors that are understandable to modern image editors and to web browsers.
The two palettes that are subjects of my interest ...
- 113
3
votes
0
answers
241
views
Were the Apple II patents, obstacles to cloning?
The Apple II was a simple design relative to its retail price, so attractive to cloners. This naturally led to many lawsuits, at least one of which actually established new copyright law. https://en....
- 58.4k
1
vote
0
answers
287
views
Was hardware scrolling patented?
One of the most valuable graphical features on early computers that had it, was hardware scrolling, that allowed the horizontal position of the screen to be adjusted by one or more pixels, thereby ...
- 58.4k
4
votes
0
answers
205
views
Did Atari lobby against FCC regulation change?
In the 1970s, FCC limits on RF emissions applied to 'anything that plugs into a TV', and were stringent and difficult to pass. Atari went to extraordinary lengths regarding this when designing their ...
- 58.4k
9
votes
1
answer
679
views
Which generations of PowerPC did Windows NT 4 run on?
In a blog entry at The Old New Thing, Raymond Chen states that Windows NT first started supporting the 603 and 604 series of PowerPC processors. Was there a specific firmware version which was needed ...
- 383
4
votes
1
answer
410
views
Isometric fantasy action RPG game for the PC from the late 1990s
Please, help identify an old computer game.
Year: 1995-1998 (possibly earlier, but no later than 2005).
Genre: action RPG (or related)
Theme: Fantasy.
Platform: PC (Windows 95-98).
Control: keyboard (...
- 49
21
votes
1
answer
996
views
How did "Super Wonder Boy (in Monsterland)" defeat the Multiface One?
The Multiface One was a memory dumper for the ZX Spectrum 48K with a button that generated an NMI to run code in its ROM that could dump the machine state to mass storage (CMT/cassette tape, diskette, ...
- 24.6k
4
votes
1
answer
513
views
How to use thinkpad x230 with PCjr 4863 monitor?
I understand it is probably more trouble than it is worth, but I am keen on using my 4863 IBM monitor as a second display for my x230. So far I've looked into converting its VGA signal to a CGA output,...
- 41
5
votes
1
answer
384
views
Why does the VIC-20 have its cartridge area at a higher adress than the I/O area?
Why did the designers of the Commodore VIC-20 chose to put the main cartridge ROM area at $A000, beyond the character ROM area at $8000 and the I/O area at $9000? Flipping the two around, with the ROM ...
- 703
7
votes
2
answers
3k
views
How does 2M for DOS (2 MB formatted floppy disks) achieve what it does?
This is the program and technique in question:
https://dbpedia.org/page/2M_(DOS)
Also described here:
https://en.wikipedia.org/wiki/2M_(DOS)
And here is the unintelligible explanation from the website:...
- 1,463