Questions tagged [ibm-pc]

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

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19
votes
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
votes
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
votes
3answers
294 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 ...
49
votes
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
votes
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
votes
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 ...
9
votes
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 ...
24
votes
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
votes
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
votes
11answers
6k 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
votes
1answer
206 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
votes
1answer
119 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
votes
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
votes
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
votes
1answer
104 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
votes
0answers
280 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
votes
0answers
155 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
votes
2answers
346 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
votes
1answer
443 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
votes
2answers
356 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
votes
2answers
473 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
votes
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
254 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 ...
8
votes
1answer
620 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
784 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
962 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
354 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 ...
25
votes
5answers
3k 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
149 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
364 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
votes
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
votes
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
votes
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
223 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?
8
votes
2answers
570 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
325 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
423 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 ...
11
votes
2answers
1k views

Was natural convection ever a consideration in orienting expansion cards?

Many computers have followed the design pattern of a backplane with expansion cards, including arguably the three most influential microcomputers ever built: the Altair 8800, the Apple II and the IBM ...
10
votes
1answer
359 views

Did the Harris 80C286 differ from Intel's 80286 in its behaviour?

The Harris company, well known for being an early second source making x86 chips under license, eventually produced a fully static CMOS 80C286 of their own design (later known as the Intersil 80C286 ...
3
votes
1answer
232 views

Where can I donate Old Mags and Media in bulk in UK?

I am taking advantage of lockdown(s) and scanning/imaging all old media to archive.org, but would like to donate the boxes when finished. A bit like Donating old Computer Shopper Magazines The Centre ...
6
votes
2answers
208 views

Are there any known 8086 systems that would dynamically switch between XTAL and EFI clocks on 8284 clock generator?

In an typical 1980s 8086 system the 8284 clock chip is typically used to generate the clock for the CPU. The 8284 has two clock sources XTAL and EFI. XTAL provides a steady clock source from a ...
2
votes
2answers
1k views

Why does changing a DOS/Windows EXE cause it to not run? [closed]

If I hex-edit an EXE for DOS or Windows, by adding or removing some text for example, it will no longer run. If I just change a single char around to a different one, it may run. Is this some anti-...
4
votes
2answers
228 views

Detecting the number of disk drives installed

When the BIOS gives control to the MBR (or the bootloader, for non-partitioned media), it passes the drive number from which the bootloader was loaded in the DL register. This number is most of the ...
11
votes
3answers
1k views

Default (as opposed to physical) read/write heads - what are they?

The Seagate U Series hard disk Product manual states that the drive has 16 "Default read/write heads" while it has 4/3/2/1 "Physical read/write heads" (depending on actual model). ...
6
votes
3answers
471 views

Who produced all-in-one / wedge style IBM compatibles?

The RetroManCave YouTube channel recently made me aware of the Sinclair PC-200 / Amstrad PC-20 and I already knew about the Tandy 1000EX / 1000HX but were there any other IBM-compatibles (or mostly ...
1
vote
2answers
328 views

Does the Sound Blaster Live! Value had hardware support for Adlib/OPL3?

As I m buying a computer without an onboard sound card, I m thinking about using my old Creative Sound card from 21 years ago and buying a pcie riser adapter instead of a modern sound card (I m ...
15
votes
7answers
6k views

Why did the IBM PC have an internal power supply?

Microcomputers run off low voltage DC, but usually came with a power supply to produce a suitable DC current from the mains AC voltage. It was usual among early home computers to supply an external ...
26
votes
3answers
6k views

Why does DOS ask for the current date and time upon booting?

In most versions of DOS, when they are started from a medium that lacks an AUTOEXEC.BAT file, the very first thing COMMAND.COM does is ask the user to confirm the current date and time: Starting PC ...