All Questions
5,415
questions
2
votes
1
answer
254
views
Motivation for DOS 3.3 using I/O hooks rather than ampersand-hook
AppleSoft BASIC is designed so that if it encounters an ampersand while processing a program, it will jump to address $03F5, allowing code there to examine what follows and process it suitably. While ...
- 32.3k
22
votes
7
answers
4k
views
Disk compression risks in MS-DOS
Continuing my nostalgia reading of Dan Gookin's DOS For Dummies, there is a section that literally advises against compression programs like DriveSpace and calls it a solution to a problem not some ...
- 1,595
2
votes
0
answers
253
views
Installing Windows 2000 from a USB drive on semi-modern hardware [closed]
I have an HP computer that currently has Windows XP on the hard drive, and I was thinking whether I could install Windows 2000 on the computer. I assumed it might work because Windows 2000 uses the ...
11
votes
5
answers
2k
views
What cable is needed to connect a drive to an older IDE controller socket with all 40 pins?
For testing a retro PC, I bought an old T-9004E Controller PCI IDE (CMD PCI0640B).
My IDE cables have one pin blanked off in the center, whereas this controller presents all pins. I cannot insert my ...
- 1,203
56
votes
4
answers
8k
views
Why is Ctrl-V the Paste shortcut?
We now casually use the Ctrl-C to Copy.
We also use Ctrl-X to Cut. I understand this choice. We cannot reuse Ctrl-C and the 'X' represents a cross. Crossing something out on a sheet of paper was ...
- 835
15
votes
1
answer
1k
views
How are the randomizer values on the Apple II maintained?
Looking at a comment on this question, it reminded me of how there are two memory locations in the Apple II zero page that are used for random number generation: 0x4E and 0x4F (78 and 79, respectively)...
- 15.1k
11
votes
1
answer
2k
views
Which version of BASIC uses RANDOM for seeding the random number generator (RNG)?
Which version of BASIC uses RANDOM as the pseudo-random seed command?
I believe that the following is correct, given the linked-to articles:
Atari BASIC uses RANDOMIZE
C64 BASIC uses RND(-<n>)
...
- 2,888
4
votes
1
answer
486
views
Initial contents of CPU registers at OS/2 1.x program startup
What are the initial contents of CPU registers at OS/2 1.x program startup? I know that CS, IP, DS, SS and SP are initialized based on the NE header. But what about the other registers? Are they ...
- 1,335
3
votes
5
answers
2k
views
What PC VGA connector used 2 rows of pins?
I remember that 20 years ago (around the year 2000) I came across a few computers with a weird monitor connector. They weren't old computers, but rather budget mainstream computers of the time period. ...
- 1,305
7
votes
1
answer
1k
views
What are the most historically relevant implementations of Prolog? And what platforms?
Does anyone know what are the most historically relevant implementations of Prolog, in the sense of being extensively used, and producing representative programs written in this language? And what ...
5
votes
1
answer
219
views
Boot and run OS/2 1.x from floppy to run a few command-line tools
How (by doing which steps) can I boot and run OS/2 1.x from a boot floppy, without installing it to a hard drive? As a way to do this, is it possible to go to the command prompt from within the ...
- 1,335
3
votes
1
answer
509
views
Why did it take 2 hours to switch to a standby VAX? [closed]
According to this section of an excellent book on the history of Novell,
I had actually started a business attempting to do some phases of what we are doing here at Novell. My plan was to develop to ...
- 55.2k
3
votes
2
answers
298
views
Atom BASIC, anyone here used it or can emulate it?
I'm reading over "Atomic Theory and Applications" (best name EVAR) but having never used the Atom a couple of things are confusing me.
For one, did the Atom have a "full screen" ...
- 17.8k
7
votes
2
answers
920
views
Looking for EMS emulators that work on XT machines
EMS memory can be used to make UMB because it's mapped to upper memory as page frames. Quarterdeck QRAM(QRAM.SYS) is a driver that changes page frames to UMB. Therefore, UMB can be created by ...
- 349
31
votes
6
answers
10k
views
How could early UNIX OS comprise so few lines of code?
I start my journey to become a hardware / software specialist with an internship in two weeks time and decided to start studying the C language early.
I came across this video, Learn C Programming ...
- 5,385
4
votes
1
answer
749
views
Is there an util that maps part of HDD to upper memory to create UMBs?
I know this question may sound a little odd...
My Juko XT is a "1MB" XT machine. And I actually saw that number in its POST process. However, 384KB of its physical memory are not mapped to ...
- 349
4
votes
0
answers
163
views
IMPI Instruction set: is there any reference?
I've had an IBM 9404 B-10 for some time and I'm curious about its assembly language. I'm fully aware the AS lines were designed with portability in mind as much IBM didn't seem to provide assembly ...
- 623
20
votes
2
answers
479
views
What is the history of SysV i386 calling convention for struct return?
I would like to understand historical roots of the quirk in the SysV calling convention for the 32-bit x86, which was inherited by the ELF standard, and so remains used on Linux to this day. Consider ...
- 301
14
votes
1
answer
795
views
What sequence of instructions is the equivalent to `fcomip` on i486?
Do you perhaps happen to know, what would be the easiest way to modify my AEC-to-x86 compiler (you can run the core of it in browser: https://flatassembler.github.io/compiler ) to be able to target ...
- 327
10
votes
2
answers
468
views
Why did Windows 9x allow ring-3 software to change IDT?
I was researching how old Windows 9x viruses, such as Win95.CIH, got ring 0 access, and it's shown that one of the approaches was to get the Interrupt Descriptor Table, hook the interrupt handler and ...
- 101
1
vote
1
answer
250
views
What cultural problems did TSMC Camas run into in 1995? [closed]
According to a speech made by Morris Chang in Arizona, transcribed at https://interconnect.substack.com/p/globalization-is-dead-and-no-one
When I started TSMC back in 1987, I had a dream. Probably ...
- 55.2k
8
votes
4
answers
1k
views
How do you run a program automatically when CP/M 2.2 loads?
Following my question on booting CP/M automatically on RC2014 Z80, I'd like to run a program after CP/M starts, similar to how autoexec.bat works on DOS.
I see that CP/M 3 has PROFILE.SUB which would ...
- 679
2
votes
1
answer
137
views
Why does Z80 RC2014 ROM image 88 not have CP/M or BASIC boot options?
While trying to boot to CP/M automatically on my RC2014 Z80, I encountered a problem getting SCM to show a CP/M boot option. According to the docs, ROM address 4000 (88 on the ROM label) is SCM with ...
- 679
27
votes
6
answers
6k
views
Did anyone ever run out of stack space on the 6502?
Unlike its main rival the Z80, the 6502 had a size limit of 256 bytes for the hardware stack. That sounds like a very tight limit, but in my experience, it was never actually an issue; by the time you ...
- 55.2k
17
votes
3
answers
2k
views
Why was the VIC-II restricted to a hard-coded palette?
The MOS VIC in the VIC-20 and the MOS VIC-II in the C64 were capable of outputting 16 colours drawn from a hard-coded palette.
It's clear that the palette size was fixed at 16 colours as a memory-...
- 6,951
6
votes
2
answers
188
views
6502 Assembly on Apple IIe: GETLN fails with 'syntax error' under ProDOS
I'm writing a text adventure in assembly for the Apple IIe (using Merlin). I'm also using ProDOS 8 v2.0.3. At some point, I have a subroutine to read user input from the keyboard using the GETLN1 call....
9
votes
1
answer
767
views
How did Ridge Racer the arcade game store its music?
For both Daytona USA and Sega Rally (released around the same time but produced by SEGA), the arcade machines had sort of a synthesizer soundtrack with no CD-ROM involved. Only the home ports of those ...
- 93
6
votes
1
answer
252
views
What is the "Special Cleaning Mechanism" in some Sony HD Floppy Disks?
I recently bought a pack of Sony IBM formatted high density floppy disks, the same pictured below. There's a "Special Cleaning Mechanism" logo displayed on the box, and the only information ...
- 131
4
votes
1
answer
133
views
Tandy 1000 TDYSPKR utility
I've seen reference to a TDYSPKR (.EXE or .COM?) tool that sets audio output options on the early Tandy 1000 series of computers (1000, 1000A, 1000SX, 1000TX, maybe others). Apparently it can toggle ...
- 178
36
votes
4
answers
2k
views
How did Multics make library calls available as shell commands?
I was reading Pouzin's comments on the early Multics shell, and I'm a bit confused about this passage:
In the same vein, I also felt that commands should be usable as
library subroutines, or vice ...
- 17.8k
9
votes
4
answers
1k
views
Testing "8-bit readiness" with an emulator or pre-packaged kit
I'm working on a project that intends to implement a dynamically typed language on 8-bit systems. (That is, a CPU with 16-bit pointers and a maximum of 64 kB of RAM. Some language tricks are involved, ...
- 193
12
votes
1
answer
197
views
Layout of pre-APM Apple partition map
Page 3-25 of Inside Macintosh: Devices describes the format of a partition map entry. The definition of the pmSig field says:
The partition signature. This field should contain the value of the ...
- 8,240
2
votes
1
answer
182
views
How to fix the inaccurate mouse movement in the Eye of the Beholder for C64 under VICE? [closed]
I'm trying to play the C64 and C128 versions of the Eye of the Beholder by using the VICE emulator on Windows 11, but the mouse movement is too inaccurate and it constantly flutters on a moving ...
- 573
6
votes
1
answer
391
views
Help me identify a vertical shooter from the 80's, please
Just reaching you guys because I'm completely unable to identify the game, and I haven't seen it in any compilation neither in Mame, etc. The following data are based just in my memories from the 80's....
- 61
24
votes
3
answers
3k
views
How were Amiga games cracked circa 1987?
I remember getting my Action Replay MKIII cartridge on my A500 in 1992, and from there I could remove protections (manual/code & physical) of a lot of games.
The MKI & MKII existed before 1991 ...
- 10.2k
12
votes
1
answer
610
views
Why did the Atari 800 have a flying RF lead?
The Atari 800 had a nice range of output sockets: four joystick ports at the front:
Along the right hand side, a serial interface (SIO) port, an S-video type output, and a power jack socket:
...
- 2,888
4
votes
1
answer
203
views
What series of AS/400 is the 9406 F2?
I am considering the acquisition of an old IBM AS/400 midrange computer. The provider has stated the model is "9406 F2".
I have dived into the AS/400 information provided by IBM in their own ...
- 623
29
votes
3
answers
4k
views
How did the X-Men game for Sega Genesis have its state survive a console reset?
The Sega Genesis system had a rather interesting game. X-Men (1993) was based on the popular cartoon version of the comic book series. But it had what was still one of the most unique (and unintuitive)...
- 423
13
votes
4
answers
2k
views
When was the CHS (cylinder - head - sector) system invented and what was before it?
There is some information about the CHS (Cylinder/Head/Sector) addressing system and its design flaws and limits. As long as CHS was not compatible with Zone Bit Recording, which became very popular ...
- 303
21
votes
7
answers
4k
views
References for the complexity of the COBOL language
One thing that struck me about the design of COBOL was that it was surprisingly complex, particularly for the era. As in, if I were trying to squeeze a compiler into a few tens of kilobytes of memory, ...
- 55.2k
3
votes
1
answer
225
views
Can this bottle of "Lubricating Oil" be used to lube up Nintendo 64 sticks?
I have two original Nintendo 64 controllers. A year or so ago, I finally opened them up and replaced the old, worn-out analogue sticks with new ones.
They work and I can play games, but it "...
- 47
3
votes
2
answers
286
views
How can the current date be accessed from DOS/VS assembler?
In assembler on an old /370-125 running DOS/VS I can access the TOD (Time of day) with GETIME, i.e. the time since midnight. But I want to be able to print the date.
- 140
1
vote
1
answer
229
views
is there a tool to convert .dsk to a .rom file? [closed]
So over the span of about 2 months I've been trying to get a USB drive together with all the tools to run an old game my uncle made. It was make for a really old computer(I think like a TRS-80 or CoCo ...
- 19
3
votes
0
answers
234
views
VisiCalc V1.0 is not working on modern computer as expected
I am trying to run Visicalc on the modern laptop (Lenovo Thinkpad X1 Extreme Gen.2). I created bootable flash drives with DOS 6.22 and Free DOS, booted from them and ran visicalc (vc.com file).
All ...
- 183
1
vote
4
answers
436
views
Are rainbow books the only CD standards?
Rainbow books are the most common CD standards.
Have there ever been CDs (or DVDs or Blu-Rays) that use different standards?
Maybe Gamecube discs or PSP discs?
- 3,557
5
votes
1
answer
224
views
Z80 Bus Control by External Device: /BUSRQ or /RESET?
I'm designing a Z80 system from scratch. My approach is to only have one memory device, a big SRAM, that covers the entire 64 KB memory block.
A sub-system on the board will be a microcontroller (MCU)....
- 153
16
votes
2
answers
2k
views
What was the last terminal to include a physical bell?
Drew asks:
… what was the latest terminal produced which rang a physical bell rather than beeping through a speaker?
- 18.9k
5
votes
0
answers
155
views
Solderless UHF adapter for audio
The BBC Micro came with an on-board ASTEC UM1233, which has no audio input (or output). It is purely video only.
On page 31 (or page 43 of the PDF) of Making music on the BBC computer1, by Waugh, ...
- 2,888
56
votes
6
answers
7k
views
Did Microsoft really reserve secret APIs in Windows?
In the nineties when the antitrust case was building against Microsoft, various accusations of abuse of monopoly power were leveled against the company, some of which were proven true.
One of the more ...
- 55.2k
7
votes
2
answers
1k
views
How to use all memory on an IBM PC with 8086
I'm developing software for the IBM PC with an 8086 processor. I want my program to use all available memory.
I know that I can use DOS int 21h function AH=48h to allocate all available conventional ...
- 1,335