Questions tagged [ibm-pc]

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

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7
votes
1answer
242 views

Meaning of KP_Begin and VK_CLEAR names of numpad 5

The key "5" at the standard keyboard numpad ("keypad" in XFree86) is named KP_Begin in XFree86 and VK_CLEAR in Windows virtual key space. What are these names originated in? Are ...
14
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1answer
663 views

Was there any software on the IBM PC that specifically took advantage of the NEC V20?

Back in the day I remember friends upgrading their IBM PCs (and compatibles) with a NEC V20 CPU. While this was mostly to get a bit more performance out of their machines over the stock Intel chip, I ...
14
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7answers
3k views

Cost of PC vs. Amiga 500 in Europe

Based on Commodore sales figures, and other historical claims, the Amiga achieved its peak popularity in 1990-91, with European sales being the leader. By 1990, with the rapid fall in PC clone prices, ...
0
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0answers
150 views

What was the first PC-compatible computer to have a DRAM controller?

The original IBM PC used a timer from the 8254 PIT and a channel from the 8237 DMAC in order to refresh RAM with dummy reads (and I think used NMI to signal parity errors.) I'd like to know when PC's ...
23
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1answer
2k views

What is 'Adaptive Tile Refresh' in the context of Commander Keen?

The question Did John Carmack really invent "Adaptive Tile Refresh"? asks about the origins of the scrolling and drawing techniques used to allow an MS-DOS PC to provide a NES console-like ...
29
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1answer
7k views

Did John Carmack really invent "Adaptive Tile Refresh"?

John Carmack is credited with making fast-paced arcade games like Commander Keen possible on an IBM-PC that had no specialized graphics controllers suited for those, thanks to the "Adaptive Tile ...
1
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0answers
297 views

What old LCD monitor am I thinking about?

I once had a PC with an LCD monitor and I'd like to remember what model that monitor was. Here's what I remember: It was basically a beige rectangular box with right angles on all corners. Only the ...
17
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3answers
3k views

In x86 real mode, how does BIOS know what hardware is present?

I know that BIOS is obsolete, hence why I'm asking here :-) BIOS needed to do things like start loading the OS, for which it (usually?) would have needed things like a hard disk driver. However, BIOS ...
13
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2answers
2k views

If a PS/2 device on a 32-bit x86 sends a byte to the IO port 0x60 and you read it, what happens next?

I'm writing a hobby OS and the first thing I want to do is access PS/2 devices (it's a somewhat legacy, 32 bit OS, so I figured it's relevant to ask here?). I can see my PS/2 devices and I want to ...
30
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6answers
6k views

Why did the monsters have "infinite invisible pillars" of hitboxes vertically in all versions of the DOOM engine?

Even in the last version of the DOOM engine, v1.9, used for Final DOOM, there is this strange limitation in which all the monsters have an invisible, infinitely tall "pillar" above and ...
8
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2answers
2k views

Why did the BIOS load the MBR at 0x7c00?

The IVT is at 0x0000-0x03ff while the BDA is at 0x0400-0x04ff but boot sectors are loaded at 0x7c00. What was at 0x0500-0x7bff that caused this convention? I'm also curious why some MBRs relocate ...
20
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3answers
5k views

Why doesn’t my VGA-to-HDMI converter work with my 286 PC?

I have a Commodore PC 30-III with a Cirrus ISA VGA card in it. I wanted to connect to an HDMI display by using a mini VGA-to-HDMI converter The converter doesn't generate any output. The machine ...
15
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4answers
2k views

How was the real-time clock implemented in the original IBM PC and PC/XT?

I know that the IBM PC/AT added a battery backed real-time clock chip that independently maintained time whether the system was powered or not. I've also seen many of those big DS1287 clock chips on ...
-1
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3answers
321 views

Why did PCs for the longest time have a default "memory test" on boot which caused them to take a long time to start? [duplicate]

Not just "really back in the day", but even as late as "only a few years ago" (meaning 15-20 years), every time I started my PC, it would slowly "count through" the ...
50
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6answers
8k views

Why did some old MS-DOS games lack the ability to exit them?

While playing around in DOSBox-X, I'm reminded of some DOS games which appear to entirely lack the ability to exit/quit/close them. One prime example of that is "Paratrooper" from 1982. I've ...
38
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4answers
9k views

What caused older computer fans to be so much louder than they are today?

I had one of those bulky IBM 486 PCs in the mid-1990s. Desktop form factor. I think it was probably made somewhere in 1992. It made a lot of noises, pleasant ones to me, such as mechanical hard drive ...
15
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7answers
5k views

Are there any good, non-abandoned PC emulators?

Mission: I'm trying to simulate a classic ~286/386/486/Pentium inside my modern PC (running Windows 10) in the most authentic way possible. Just a quick note to say that I (Sarah Walker) have decided ...
10
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3answers
3k views

What was that old FPS game where you shot rats in a sewer?

In the 1990s, I played an obscure shareware (I believe) FPS game for the PC (MS-DOS) which was closer in technology to Wolfenstein 3D than DOOM. It was rather dark, so I assume it had some sort of ...
25
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1answer
4k views

Did the original MS-DOS Quake not have a menu item for freelook, and if so, why?

I know that Quake (the 1996 MS-DOS game) is a "full" 3D engine, and always had some kind of mouse support. However, even the original Wolfenstein 3D from 1992 also had mouse support from the ...
22
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2answers
2k views

How does Laplink achieve "high speeds" on standard/legacy serial ports?

I have been using Laplink Pro 4.0a to transfer files between a modern Windows 10 desktop PC (via DOSBox) and several vintage DOS computers. Using a standard null-modem serial cable, in my testing it ...
39
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11answers
7k views

What's the origin of terminating strings by setting the high bit of the last character?

I was looking at a hex dump of the ROM BASIC from the original IBM PC and found some byte strings like this (ASCII dump is on the right): 50 52 49 4e d4 9d 4c 49 53 d4 9e 50 4f d3 1b 45 PRIN..LIS.....
3
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1answer
222 views

Award BIOS error code meaning

I have a faulty Asus SP-97V Pentium motherboard. It doesn't boot, but it definitely takes power and does something. I plugged a PCI diagnostics card into it, and it shows error codes C0 or C1. It ...
4
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1answer
122 views

Quadram odd IBM PC card bracket

I came across an early IBM PC ISA realtime clock/calendar card made by Quadram called the "Chronograph" (picture). It's basically the same clock feature they incorporated into their ...
14
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5answers
1k views

Glue to attach rubber feet to a PC case?

I have an old PC case. I spray painted it because it was a little bit rusty. Now I'm trying to attach a set of rubber feet to it, but I have no idea what kind of glue to use. I tried hot glue, but it ...
5
votes
4answers
1k views

9-pin vs 10-pin serial port ribbon cables

I'm (still) putting an old Pentium PC together. I just found that the connectors of my serial port's ribbon cable have one less hole than needed. The socket on the mainboard has 10 pins, but the 10th ...
2
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0answers
69 views

Soltek SL-52B2 motherboard manual

I'm looking for the manual of this motherboard. Google can't seem to find one for this exact model, only similar ones. Help appreciated, thanks!
2
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1answer
105 views

Asus SP97V motherboard not powering up

I found an Asus SP97V Pentium-I motherboard. It works with both AT and ATX power supplies. At least it's supposed to, because it actually doesn't. I put a Pentium 120 CPU, four RAM modules and a ...
7
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0answers
289 views

What are the differences between MS-DOS and DR DOS FASTOPEN?

OS/2 Museum's history of DOS mentions the FASTOPEN.EXE TSR was introduced in DOS 3.3. Its entry on DOS 4.0 adds some implementation details. It reminded me of the DR DOS FASTOPEN=nnnnn directive in ...
3
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0answers
159 views

PC AT power supply not providing correct voltage

I'm refurbishing a Pentium 120 PC with an AT power supply. It seems to work, at least nothing pops or smokes, but there's a slight problem with voltages, particularly on the motherboard connectors. ...
5
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2answers
362 views

Can I power a Windows 95-era AT PC with an ATX PSU, like this?

Is this the correct way to make the adapter? Will the "15A 120V AC ONLY" switch damage anything? The switch is illuminated. (glows when off)
11
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1answer
456 views

What was special about "Vulcan" - the CP/M database program?

The Vulcan DBMS for CP/M micros was originally developed in 8080 assembly language by a contractor working for Jet Propulsion Lab, based on an earlier JPL mainframe program. This code went on to be ...
10
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2answers
390 views

How do I terminate an ISA bus correctly?

I am stuck by designing a 8 Slot 16 Bit ISA Backplane Do I have to terminate an ISA bus? My search results are: No termination at all Some homebrew projects use active termination for all signals ...
11
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2answers
499 views

AdLib, YM3812 and Timers

For no particular reason I started reading up on the original AdLib Music Card, and it's clear that this card was little more than a stock Yamaha YM3812 music chip (aka OPL2) glued to a PC's 8-bit ISA ...
13
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4answers
3k views

CPU frequency / memory wait states at end of the 80s

According to the advertisements of the late eighties, you could find RAM having an access time ranging from 120 to 80 ns (150 to 210 cycle times). A 386SX-25 could execute a typical register to ...
5
votes
2answers
264 views

Config information on ancient 16-bit Multi I/O card

I need to build a retro machine so that I can access an HDD that required manual input of BIOS parameters. (Yes, I have that information.) The only ID I can find is ES1O/4A 280695 which yields nothing ...
13
votes
1answer
791 views

What was the intended use for the character symbols for control codes in codepage 437?

Is there a well documented or well understood explanation for what was the intended purpose for the more haphazard glyph choices in the control code range of the original IBM PC character set? Maybe a ...
10
votes
2answers
808 views

When does an IBM-compatible PC keyboard controller dequeue scancodes?

There is a not-unheard-of technique in DOS software to detect certain keypresses (like Ctrl+Break) by intercepting the keyboard interrupt (IRQ 1) and reading the scancode directly from the keyboard ...
5
votes
3answers
977 views

How can I read COM port addresses from BIOS in QuickBasic 4.5?

I have been using the following code to get comm port addresses from BIOS in QuickBasic 4.5: PRINT "Hex addresses for ports 0 to 3 from BIOS." DEF SEG = 0 FOR x = 0 TO 3 z = &H400 + ...
2
votes
2answers
455 views

What was the DRAM refresh interval on early microcomputers?

Dynamic RAM is denser than static RAM, but needs to be refreshed every few milliseconds to avoid losing data. How many milliseconds, exactly? If the answer has changed over time, then I'm interested ...
28
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5answers
4k views

What really is a sound card driver in MS-DOS?

To my knowledge, neither MS-DOS nor BIOS offers any kind of API for sound cards. Therefore the concept of a "driver" is absent, as we know it today. Apart from accessories and sample files ...
3
votes
0answers
150 views

Is there any way to obtain the abandonware 1994 original release of Klik & Play in non-English, non-"For Schools" versions?

In the mid-1990s, I purchased a Swedish boxed copy of v1.0 (I believe) of Klik & Play in a computer store. Since that, the floppies have died and I stupidly even threw away the entire big box and ...
4
votes
1answer
383 views

What does it mean when "The Good Old Days" have several seemingly identical downloads for the same game?

This happens for numerous games. If I search, for example, for "Spear of Destiny", I get this: https://archive.org/details/TGODFloppyCollection?and%5B%5D=spear+of+destiny&sin= Four ...
25
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5answers
11k views

Twist in floppy disk cable - hack or intended design?

There are many documents (e.g. this) describing the twist on two-drive floppy disk cable on IBM PC compatibles. While this is not the most proud example of clean hardware design, how much of this was ...
27
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17answers
7k views

How much did the first hard drives for PCs cost?

I would like to know how much early PC hard drives cost but have only been aable to find adjacent or unsourced data. According to the Centre for Computing History: The "IBM 5161 Expansion ...
16
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2answers
2k views

Why did the 8087 need a special socket?

The IBM PC included a coprocessor socket for the 8087 floating-point unit. Logical enough; some customers wanted to use the 8087 to make numeric calculations run faster. But why was the 8087 designed ...
3
votes
1answer
241 views

PC Task performance

What sort of performance I can expect from PC Task 4.4 on Amiga 500 + 030 50MHz MMU, 64MB RAM? Would it be possible to run Windows 3.11 / 95 and have any real use from it?
9
votes
2answers
587 views

Origin of Ctrl-Alt-Delete key combination to reset

The Ctrl + Alt + Del key combination to reset is known to me to work on older PC/MS-DOS PCs, some versions of Atari TOS, on runlevel 3 / multiuser.tager Linuxes (it can be disabled). The older of ...
32
votes
5answers
3k views

Did IBM originally plan to use the 68000 in the PC?

One of the big turning points in the history of the industry was IBM choosing the Intel 8088 over the Motorola 68000. Given that most people outside IBM considered the 68000 preferable, there has been ...
3
votes
2answers
330 views

How did databases use the 8087?

A discussion on programs that used the 8087 mentions several categories I expected, and one I did not: Database programs (dBase IV, FoxBase, Paradox, Revelation) The more I think about it, the more ...
3
votes
1answer
448 views

What were the most common applications of the 8087?

The original IBM PC had a slot for the 8087 floating-point coprocessor. This was a somewhat esoteric feature at the time – previous microcomputers had done all their floating-point in software – but ...

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