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Questions tagged [ibm-pc]

For questions about the early IBM PC, clones and compatible systems.

93
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21answers
33k views

Was there ever any reason to wait 30 seconds to restart a c.1995 PC?

I owned a PC in the mid-to-late 90s, and while everyone said when you turn it off and back on again, count to 30. But it also had an instant reset button down below. Was there ever really any risk ...
44
votes
10answers
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 ...
42
votes
9answers
11k views

Why did the IBM PC need a sound card?

The original IBM PC and later variants used an Intel 8253 or 8254 as a sound chip. Why did users add sound cards such as the Adlib or Sound Blaster. I remember voice output with programs like ...
41
votes
2answers
10k views

Who set the 640K limit?

We all know that "640K should be enough for everyone". But who actually set this limit? The quote is often attributed to Bill Gates, but it doesn't seem like a decision for an Operating System vendor ...
35
votes
2answers
6k views

Did IBM encourage Bill Gates to retain the rights over PC-DOS?

As is well-known, Microsoft's negotiations with IBM to deliver PC-DOS 1.0 with the original IBM PC resulted in: IBM licensing the OS from Microsoft, as opposed to purchasing it outright. Microsoft ...
33
votes
7answers
8k views

How did Apple fail to tap the business and scientific markets?

Currently reading an excellent book called Blue Magic: The People, Power and Politics Behind the IBM Personal Computer, which is just what it says on the tin; highly recommended to anyone who wants to ...
30
votes
17answers
9k views

What were the real competitors to the early IBM PC?

As I understand it, PC was not really competitive with Home computers until the 90’s. The PCs rise in popularity in the 80s must have been mainly in the business world. So during that time, what ...
30
votes
4answers
4k views

What was the IBM PC cost saving for using the 8088 vs 8086?

The decision to use the 8088, a version of the 8086 with the data bus restricted to 8 bits, in the original IBM PC, seems strange on the face of it, certainly hurt performance and intuitively shouldn'...
27
votes
5answers
2k views

Does every retrocomputer and console with NTSC composite output have 'artifact color' ability?

Artifact color is heavily associated with the Apple ][, since that is the only method the machine had to produce a color display. I was looking at the fantastic demo for IBM PC + CGA, 8088MPH, and I ...
26
votes
10answers
15k views

How to get started writing C for the IBM PC in 1980-81

Suppose it's late 1980 to early 1981, you've got some software you want to write for the IBM PC which will be released later in 1981, want to get started ASAP, and believe C is the right language for ...
26
votes
3answers
5k views

Why separate cursor keys?

The original IBM PC keyboard didn't have separate cursor keys; the numeric keypad doubled as such. It wasn't long, however, until a new keyboard was introduced that did have separate cursor keys (so ...
24
votes
4answers
6k views

Windows 98 with 2GB of RAM

I have assembled a retro-gaming PC out of an old Shuttle SN45G with a Windows 98/Windows XP dual boot. The motherboard can handle 2GB of RAM, but apparently Windows 98 can only handle 1Gb. Windows ...
24
votes
2answers
2k views

How did MS-DOS assign drive letters in the case of more than two floppy disk drives?

The IBM PC BIOS had provisions for up to four floppy disk drives, by virtue of returning the number of floppy disk drives in a two-bit field plus a none/some flag (allowing for reporting values of 0, ...
23
votes
8answers
3k views

What were the early PC applications requiring a hard disk?

I had to wait about 5 years before hard drives (HDs) became affordable enough to begin moving off of floppies. During this time, I remember my desire for an HD being based on convenience. All the ...
22
votes
2answers
1k views

Why did connecting the IBM PC 3.5" FDD backwards cause the problems it did?

When the 3.5" FDD was introduced for the IBM PC and compatibles (or possibly earlier), someone made a decision to make the data cable between the controller and drive unkeyed. This, of course, meant ...
21
votes
3answers
3k views

Does an ISA card have a fixed memory address?

A PCI card does not have a fixed memory address, the PCI card specifies how much memory it wants, and the OS will assign whatever address it wants for this memory, and will set this address in the PCI ...
19
votes
5answers
5k views

What makes a floppy disk bootable?

A lot of web sites describe how to create a bootable floppy disk using an existing image (via dd). But what about the image makes it bootable? I'm interested in making my own bootable floppy images ...
19
votes
2answers
2k views

How did an IBM 5150 with 16KB RAM work?

I keep reading that when it was first released, there was a variant of the IBM PC model 5150 that had only 16KB of RAM installed. From a hardware perspective, this would clearly work - the 5150 ...
19
votes
2answers
1k views

The almost-was Atari IBM PC

One of the more remarkable events in the history of personal computers was IBM contemplating basing their PC on Atari technology. That this was seriously considered, everyone agrees, but it's hard to ...
16
votes
2answers
3k views

First commercial DOS game?

What was the first commercial game sold for use on IBM/MS/PC DOS after the IBM August 12, 1981 release.
16
votes
2answers
2k views

How do CGA emulators for Hercules graphics work?

HGC cards on IBM PCs used to be able to run CGA software by using a CGA emulator. How exactly did those programs work? What were the limitations?
16
votes
5answers
4k 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. ...
15
votes
4answers
759 views

Were there VLB cards other than video cards and SuperIO controllers?

VESA local bus was an expansion bus used to overcome speed limitations imposed by ISA bus. In theory VLB could reach 1280 Mbit/s (with 40 MHz CPU) which was way more than ISA's 66.7 Mbit/s. The speed ...
15
votes
3answers
1k views

How did DoubleDOS work?

Back in the MS-DOS days, there was a program DoubleDOS that you could run that would split your machine in half and multitask two separate DOS programs. While it didn't particularly work well for ...
14
votes
5answers
3k views

What PC “Clone” technology standards were introduced by clone manufacturers?

IBM famously created the PC standard with the introduction of the first IBM PC in 1981. IBM also extended the standard with the introduction of the PC/AT (1984) and the PS/2 line (1987). However, by ...
14
votes
3answers
15k views

How can I connect a DIN plug keyboard to USB?

I have a wonderful IBM Model M keyboard, which has the best key action of all keyboards I ever used. The problem is it has the big round 5-pin DIN connector used in AT PCs. I have some PS/2 to USB ...
13
votes
2answers
1k views

Which communication protocol is used in AdLib sound card?

By "AdLib sound card" I mean AdLib Music Synthesizer Card released in 1987. Wikipedia says that AdLib uses frequency modulation synthesis to produce sound, but does it use MIDI communication protocol ...
12
votes
5answers
2k views

Adding the third floppy drive?

I've seen a few computers with more than two floppy drives, most with two 3.5" and one 5.25". My question is how was this achieved? I've heard that it could be done with a second controller card, but ...
12
votes
2answers
1k views

What was the first C compiler for the IBM PC?

When did a C compiler first become available for the IBM PC? I have fond memories of Turbo C, but that didn't become available until the mid to late eighties; it definitely wasn't the first one. ...
11
votes
6answers
1k views

Why did tactile-feedback keyboards lose popularity?

IBM spoiled me for hardware quality. I've gone through many computers, including a TRS-80, Heathkit H-89, Commodore Vic-20 and C-64, and countless PC's but my first original IBM PC will always be my ...
11
votes
3answers
1k views

What specific technical advance(s) allowed PCs to play “Full-screen full-motion” video?

In the early 1990s, the new buzzword for PCs was "Multimedia", and the gold standard for multimedia performance usually talked about was "full-screen full-motion" video playback. Many will remember ...
11
votes
1answer
639 views

Can the IBM PCjr be upgraded to support the better features of the Tandy 1000?

It is well known that the IBM PCjr was a commercial failure and that the Tandy 1000 series of computers not only matched the features of the PCjr (other than maybe the wireless keyboard), it also ...
10
votes
3answers
2k views

Restore corroded AT motherboard with dead CMOS battery

I have acquired a nice MS-DOS PC from EET Computer (I couldn't find any information about them). It actually works, but I have two errors on boot: Floppy disk drive controller failure; CMOS Battery ...
10
votes
3answers
2k views

Only “Drive A:” detected with two floppy disk drives

I am trying to repurpose an old Acer Aspire M1641 to copy/format bulks of 3.5'' floppy disks. I think it's one of the last generations of computers to have a 34 pin floppy disk drive header as it also ...
10
votes
2answers
825 views

How did the IBM PC handle multiple physical devices serving memory at the same physical address?

I'm trying to figure out how the IBM 5150 PC handled the case where multiple physical devices (memory chips) were mapped to the same address within the 8088's physical address space. The closest I've ...
9
votes
10answers
2k views

Which pointing devices were used by early laptop computers?

I've started reading this article on the history of the ThinkPad. In it, the TrackPoint (pointing stick/"nipple" mouse) is heralded as an important innovation in the design of portable computers at ...
9
votes
3answers
739 views

IBM PC expansion card latency

In the IBM PC and early successors and compatibles, it was commonplace for most of the computer's memory to be on cards in general expansion slots. (e.g. the original IBM PC could take 64K on the ...
9
votes
2answers
673 views

Transferring files between Commodore PET and IBM PC

Suppose you have two early eighties computers, a Commodore PET with 8050 disk drive and an IBM PC with its 5.25" disk drive. Is there a way to transfer files between them? Not machine code programs, ...
9
votes
2answers
1k views

Unused RAM Chips on x86 machines

On classic x86 machines the upper 384 KB of system memory contains video RAM and BIOS ROM Besides other things. Those areas overlay over conventional RAM, so that you can't use all upper memory, but ...
8
votes
2answers
4k views

Windows 98 / XP Dual boot

I have acquired an old Shuttle X PC (Windows XP, Mini-DTX form factor HTPC) that works fine. As I can't do much with this form factor (I can't fit a modern motherboard in the case) and that the ...
8
votes
3answers
657 views

Does the 25-pin IBM PS/1 serial port connector contain two serial ports?

I got my hands on an IBM PS/1 computer and it provides a 25-pin serial port connector. Whith the help of an adapter I can get a 9-pin serial port on COM1 and transfer data that way. I would like to ...
8
votes
2answers
249 views

Is it safe to provide 5V to CMOS RAM from PSU instead of CR2032 battery?

I have a motherboard which stores BIOS settings in a DS12887 chip with internal battery. The battery is long dead, and the pin of chip's socket is not connected to any power supply so the chip doesn't ...
8
votes
1answer
538 views

Looking for a specific BASIC music program from the 80s

When I was a kid, we had a PC-XT with a lot of GW-Basic programs on it. I am trying to track down one in particular -- it was a music player of sorts. A menu (all monochrome text as I recall) and you ...
7
votes
4answers
403 views

Cost of expansion slots

Among other early computers, the Apple II and IBM PC made the consequential decision to provide internal expansion slots. How much did this add to manufacturing cost? Intuitively, it seems like it ...
7
votes
4answers
591 views

When did the tower form factor appear and when did it become popular?

Essentially, my question is there in the title. Tower cases are commonplace these days, and probably are the "default" form factor for personal computers (or at least were, before they were surpassed ...
7
votes
1answer
195 views

How did Drive Overlay programs break BIOS disk barriers on older PCs?

I was just reading a thread on Vogons about OnTrack and EZ-Drive setup, and it occurred to me that I have no idea how they work. Please explain why the barrier existed and then how the overlay ...
7
votes
2answers
483 views

How to repair paint on IBM PC?

I have an IBM XT 286 which has essentially the same case as the original IBM PC. It has a few minor blemishes, some places where the paint has been chipped off, and some tiny spots of rust. How should ...
6
votes
4answers
2k views

How do I create a boot menu to select between Windows and DOS?

I was not a PC user before Windows 98. But I remember one of my friends was using a boot menu in his 486 machine to select between Windows/DOS. The menu was like: 1. EMS 2. XMS 3. Windows If we ...
6
votes
2answers
496 views

Who were the first engineers to “cleanroom” the IBM PC BIOS?

In the first season of the AMC show Halt & Catch Fire, the protagonist "Cameron Howe" is introduced. Cameron portrays a rookie engineer who is recruited for being extraordinarily talented, and is ...
6
votes
5answers
406 views

Where are the authoritative specs for legacy PC/AT devices still in use in today's PCs?

For example, the 8250/16550 chip used to handle serial communication is still simulated by modern chipsets and is enumerated by ACPI as PNP0500/PNP0501. You can find datasheets for these chips. ...