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Questions tagged [operating-system]

For general questions regarding operating systems on retrocomputers.

57
votes
13answers
12k views

Were later MS-DOS versions still implemented in x86 assembly?

Recently, Microsoft published the source code of old MS-DOS versions on GitHub. What is odd in my opinion is the use of x86 assembly language for everything. The assembly language would not be my ...
3
votes
1answer
175 views

Can anyone help provide more information regarding an operating system called I/OS by Infosoft in the early 1980's?

The title pretty much says it all. I'm looking for information about an operating system called I/OS by a company called Infosoft in the early 1980's. I think it might have been a CP/M variant and ...
43
votes
9answers
7k views

Why was preemptive multitasking so slow in coming to consumer OS's?

Preemptive (rather than cooperative) multitasking was a highly-touted feature for PC's in 1996, with its inclusion in Windows 95 for the first time. It was also highly-touted for 2001 Macs when ...
16
votes
1answer
2k views

Where does the hierarchical directory structure originate from?

Windows, Macintosh, Unix/Linux: today, they all support a hierarchical directory structure. The differences are in the details (mount points vs drive letters), but all use a hierarchical directory ...
22
votes
2answers
3k views

The origins of fork()

Is fork() older than C? What are its origins? I might think that fork() was created along with C (1970s) but I recently read a reference to a 1963 paper where fork() was mentioned.
6
votes
2answers
460 views

What system pioneered displaying masking characters for password entry and why?

On the mainframe OSes I was familiar with, and on UNIX to that day, when there is a prompt for a password in "text mode" (a command line session), the echo is suppressed, and there is no visual ...
3
votes
2answers
181 views

68k macintosh lowmem system globals

While digging through a classic Mac 68k disassembly I got to the point where I need to know more about the "Boot Globals" residing in lowmem's system global variables. BootGlobPtr lives at $DDC, that'...
4
votes
2answers
543 views

How hard would it be to port Amiga OS4 to x86 or ARM?

This question was raised on Facebook a few hours ago. Some say it's possible, others say impossible. What do you experts say?
4
votes
1answer
477 views

The history of context switch

I wonder which was the first operating system that had context switch and what are famous examples of OS that didn't have context switch?
13
votes
3answers
742 views

How did the original Apple Macintosh and Atari ST use protected mode?

The Macintosh, ST, and Amiga were all 68000 CPU systems released in 1984-85, along with their respective new Operating Systems. While this was 5 years before protected mode became commonplace on Intel ...
16
votes
5answers
3k views

What is the best choice for DOS for a 1990 80386 PC?

I plan to install Windows 3.0 and PC/GEOS on top of DOS. Plus I will install numerous games from the 1984-1992 timeframe. Some of the later games will require >640K RAM and make use of an EMM driver. ...
8
votes
2answers
1k views

Was it Microsoft that started the war between Application and OS vendors?

I think there is a long history of application vendors going to great lengths to complain or litigate against Operating System vendors to compete fairly. Specifically, I am talking about "fairness" ...
8
votes
2answers
367 views

What operating systems allowed arbitrarily-sized disk blocks?

According to my limited experience with IBM clone mainframes, and as far as I can remember, at least in one OS the permanent storage disk space was allocated to users (and the scratch space — to ...
86
votes
16answers
19k views

Does “Disk Operating System” imply that there was a “non-disk” Operating System?

In the 1980's at primary school we saw MS DOS and DR DOS competing before Windows 3.1 and subsequent releases took over that space. At home we had Apple II's which booted up to a BASIC prompt. On ...
68
votes
8answers
7k views

What key factor led to the sudden commercial success of MS Windows with v3.0?

Microsoft Windows was originally introduced in 1985, ostensibly to compete with the Apple Macintosh, and other computers shipping with graphical shells by that time. However, early versions of Windows ...
21
votes
2answers
4k views

Which original retrocomputer OS's are still maintained and updated today, for original hardware?

I would like to know which original Operating Systems that run on retrocomputers are still being actively maintained and updated. This only applies to retrocomputer OS's that may still be used on ...
3
votes
0answers
177 views

Using a modern microcontroller to explore early home computing concepts [closed]

I'm working on a project to write a small OS based loosely on the functionality of CP/M. I want to better understand a few things about the early home computing market, as well as to understand ...
10
votes
1answer
309 views

How are File Timestamps recorded in classic Mac OS?

When I save a file it has a 'Created At' and 'Updated At' Value saved as well. I would like to know HOW these values are saved? Are they saved as an integer representing a number of seconds since 1904?...
11
votes
2answers
278 views

Creating an System Extension (INIT) for classic mac os

I have some old macs that I would like to remove their clock batteries so that I don't have to worry about them leaking and destroying logic boards. That being said I do want to operate them from time ...
25
votes
3answers
3k views

What was the first operating system to feature a separate kernel?

Kernels are programs that abstract the hardware of a computer to some extent, allowing other programs to use standardised system calls (e.g. malloc) to perform hardware tasks (e.g. writing to memory, ...
10
votes
1answer
422 views

How POSIX-compliant is Xenix?

Xenix was the most popular Unix flavour of the 80's. However, it was designed before the POSIX standards came to be, and its final version was released shortly after the first POSIX specification was ...
73
votes
18answers
15k views

Why was BASIC built into so many operating systems?

There are a lot of retro-computers with BASIC as an integral part of the operating system. The IBM 5100 was one of the first computers with a separate memory space for BASIC, followed by the Commodore ...