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Questions tagged [hardware]

For questions about the components of retro devices (computers, etc.)

15
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2answers
798 views

Who decides what is the memory address that the CGA video buffer will be mapped to?

In DOS, the memory mapped IO base address for the CGA video buffer is 0xB8000. So when you write to 0xB8000, you are actually writing to a buffer in the CGA card itself and not to RAM. What I want to ...
16
votes
7answers
2k views

Why did CP/M and MS-DOS used the BIOS drivers instead of their own drivers to access hardware?

Modern versions of Windows (and other modern operating systems I suppose) have their own drivers to access hardware. But as I have read, in the old days, if CP/M or MS-DOS wanted to access hardware, ...
12
votes
3answers
504 views

Why was OCS low resolution limited to 6 bitplanes?

I'm looking for information whether there has ever been an official statement by Commodore back in the days on why the Original Chipset was limited to doing 6 bitplanes only when running in low ...
7
votes
3answers
623 views

How were terminals connected to a PDP-11 computer?

This is how I think terminals were connected to a PDP-11 computer: A PDP-11 computer had only one port that you can connect the console terminal (/dev/console) to, and if you want to connect more ...
15
votes
1answer
316 views

Does anyone know the specific differences between the NES-001 (NTSC) motherboard revisions?

On each Motherboard of an NES-001 (NTSC) there is a code: NES-CPU-xx These range from 04 to 11 (I think) I would like to know if these are all of the revisions of the NES and what major differences ...
20
votes
1answer
661 views

What is the difference between the “Return” an “Enter” key in the VT100 terminal?

What is the difference between the "Return" an "Enter" keys in the VT100 terminal:
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 ...
12
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3answers
1k views

Is it possible to expand Amiga 500 rev 8 to 1.5 MB with a 1MB trapdoor expansion?

Is it possible to expand an Amiga 500 rev 8 (not an Amiga 500 plus) to 1.5 MB of Chip RAM using an A501+ expansion? It is plug and play or are modifications required? This is the board: Source: ...
19
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1answer
729 views

Are the effects of “Retro-Brighting” permanent or temporary?

As many of you know, plastics used in our beloved computers from the 70's, 80's and 90's contained a fire retardant called Bromine. This chemical (along with exposure to the Sun's ultraviolet rays) ...
21
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3answers
3k views

When you type on a computer terminal, how are the characters displayed on the screen?

Assume that the following computer terminal is connected to a large computer: When I type something on the keyboard (for example: pwd), is it the computer terminal the one that receives the ...
22
votes
3answers
2k views

Why did so many early microcomputers use the MOS 6502 and variants?

Quite a few successful early microcomputers used the MOS 6502 CPU. This included, but was not limited to, systems like the Apple I, Apple II, Commodore PET, and Ataris. A followup known as the MOS ...
13
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9answers
842 views

Do retro-microcontrollers exist?

I'm trying to learn the fundamentals of computer architecture (more here), and it occurred to me that a retro version of an Arduino or Raspberry Pi could be useful for that. Does such a thing exist, ...
18
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5answers
2k views

Can a retro-computer be a useful way to learn computer-architecture fundamentals?

I've been reading about the fundamentals of computer architecture, but I think I could get a better grasp of the basics if I could could have an actual device to play with. I had considered building ...
5
votes
1answer
159 views

Amstrad CPC 464 tape deck loads, but makes grinding scratching noise

I'm concerned about an Amstrad CPC 464 tape deck, which loads, but makes grinding scratching noise while rewinding, fast-forwarding and play. Sometimes it does load silently, but after a subsequent ...
12
votes
2answers
369 views

Is this machine the EDVAC, MANIAC, or IAS?

See the image. Different sources claim that this machine is the EDVAC, MANIAC I, or IAS. For example, the Wikipedia page on John von Neumann has a picture of him and J. Robert Oppenheimer standing ...
21
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3answers
2k views

Why did the Atari 800 designers choose such a radical system design?

The physical system design of the Atari 800 was pretty radical, when compared to the 3 other canonical home computer designs of the late-1970s: TRS-80 Model 1, PET, and Apple ][. As the photo of the ...
14
votes
3answers
1k views

How do you recognize an early production model Commodore 64?

The Commodore 64 was the most popular single retro-computer produced, probably selling something like 15 million units. Clearly, the C64 is not "rare", but early revisions from 1982 are highly prized ...
11
votes
2answers
247 views

How did the early UPC barcode readers work?

According to the history of barcodes, the idea of consumer product barcodes appeared before the microprocessor era. What was the implementation plan then? Would each store need a mini-computer in a ...
5
votes
1answer
458 views

How much did different kinds of ports cost to add to a 1980's home computer? [closed]

These days it's mostly converged on USB, but in the old days computers tended to have lots of different kinds of ports. In particular, I'm interested in: 9-pin serial 25-pin serial parallel printer ...
11
votes
2answers
580 views

How does the Amiga chipset RGA bus work?

The RGA bus is the bus that connects Agnus/Alice with Denise/Lisa and Paula. What is it used for? I guess at a minimum to write/read registers in Denise/Lisa and Paula, and I guess to feed data to ...
18
votes
5answers
2k views

Cloning circuit boards for antique computers?

Would it be feasible to create direct clones of obsolete and increasingly hard-to-find motherboards and controller boards for vintage computers? Most of the early 1980s technology was either single ...
7
votes
4answers
335 views

What was the first personal computer to use surface mount components?

Title pretty much says it all. To qualify, the computer must have been manufactured and released. No prototypes or computers that never shipped. Also, I'm looking for computers used at a home or ...
20
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4answers
2k views

Why does MP3 audio decoding overwhelm retro CPU's?

Many retrocomputers from the late 80s and early 90s had audio DAC hardware support. This includes the Amiga, Classic Macintosh, and PC's with SoundBlaster add-on cards. Despite the fact that the MP3 ...
12
votes
1answer
702 views

How did Apple's 'CYA' chip function to “Control Your Apple”?

Unlike the original Apple ][, the Apple IIGS was built from highly-integrated custom chips. Among these were the Mega II and the CYA (which, apparently stands for "Control Your Apple"). From what I ...
11
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2answers
494 views

What were the 9 VAC pins used for on the Commodore 64 User Port?

I read that pins 10 and 11 are the 9V AC +/- pins on the Commodore 64 User Port. Pin 10 is the + phase while pin 11 is the - phase. I realize the User Port wasn't as versatile as the Expansion Port (...
36
votes
5answers
5k views

Why do programmable sound generators like SID include a noise generator?

In layman's terms, please explain the reason that all the popular PSG's used in 1980s computers and game consoles provided an additional channel to generate programmable "noise". How was this "noise" ...
9
votes
4answers
1k views

What was the first mass-market, 16-bit microcomputer system?

To qualify what I mean by "16-bit microcomputer system", I am talking about a system that has not only a 16-bit (or 32-bit) microprocessor CPU, but also a 16-bit wide external data bus connected to ...
19
votes
3answers
2k views

Adjusting focus for old CRT monitors

I have an old Atari SC1224 CRT which has badly lost focus over the years. After taking the cover off, I can see various focus controls that can be adjusted by screwdriver. Question: is there a ...
14
votes
3answers
573 views

Can the CSG 65CE02 CPU be used to accelerate an Apple //e or //c?

The CSG 65CE02 is an improved 6502 microprocessor that was shipped in small quantities by Commodore around 1988. It is used in the Amiga A2232 multi-port serial controller card, and that would be the ...
10
votes
3answers
328 views

Will careful restoration of a retrocomputer's paint job enhance its value?

First off, I'm not talking about painting my plastic C64 in Ferrari Red! While this may look cool, I'm sure any value enhancement of the machine would be based purely on 'taste'. I have a NeXT Cube, ...
12
votes
3answers
2k views

How can a ST-412 MFM hard drive be integrated with a modern PC?

I have a Seagate ST-225 20MB hard drive. It used a ST-412 MFM (Modified Frequency Modulation) controller which unfortunately went to the great bit bucket some time ago. Is it possible to get this ...
15
votes
4answers
718 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 ...
10
votes
2answers
414 views

Can I use my IBM P/N 93F0502 (circa 1992) monitor in a dual monitor setup with my modern Mac Mini or Thinkpad?

I have an old IBM monitor here and I'd like to use it as a second screen to my computer (Mac mini running Fedora or Thinkpad running Archlinux). I plugged it into the electricity socket without a ...
7
votes
2answers
97 views

Will this Acculite laptop boot without HDD?

First I'd like to ask: Does anybody even know of this laptop? I was surprised to find 0 information about it online. I've was asked to see if I could get this thing to boot, but it was in rough shape. ...
16
votes
12answers
2k views

Was there a retro computer susceptible of being damaged only by issuing instructions at it?

This question... Can a USR command damage a ZX Spectrum? ... has leaded me to wonder if there was once a microcomputer that could actually be damaged by software. More specifically: Is there a case ...
87
votes
16answers
21k views

How was early randomness generated?

Many programs make use of randomness, from BASIC guess-the-number games to encryption key generators. This randomness could have been generated in many, many different ways: hardware, software, ...
7
votes
4answers
385 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 ...
54
votes
6answers
7k views

Reason for the Amiga clock speed

The Amiga used a CPU rated for 8 megahertz, but clocked at 7.14 megahertz. What was the reason for this number? I remember it was something to do with a multiple of the frequency of the video ...
9
votes
2answers
293 views

S-100 bus and device drivers

It is said that the S-100 bus provided a standard hardware format for expansion cards across many models of computers, including ones using different system software and even different CPUs. Having ...
19
votes
2answers
2k views

Wiring a Zilog Z80

I've recently got hold of an old Zilog Z80 microprocessor and I know how to clock and test it. I do not however know how to connect RAM, I/O ports, control switches (for programming instructions into ...
12
votes
1answer
401 views

BBC Master 65C102 co-processor — test memory

Out of the blue the other day, my friend found an internal 65C102 co-processor for the BBC Master in his attic, and gave it to me. It wasn't in particularly good physical condition (all the pins were ...
12
votes
1answer
429 views

What is known about the Wang VS series CPUs?

I'm trying to do research about the Wang VS series, and there's very little on these computers on the internet (as the company was effectively dead before the internet era, this is hardly shocking). ...
13
votes
1answer
134 views

Videoprocessor with custom horizontal sampling

I have a variety of videoprocessors (Micomsoft Framemeister, Micomsoft SC-512N1-L/DVI, Sync Strike) to help me get the best possible RGB picture out of my retro computers/consoles. However one issue ...
14
votes
2answers
726 views

Heating issues in Apple II?

My Apple II has been getting really hot in use, I've cleaned it, so I don't think dust is an issue. Is there something wrong with the hardware that could be affecting it? I've had Apple IIs overheat ...
24
votes
16answers
2k views

What computers had redefinable character sets?

My first computer was an Exidy Sorcerer, bought in the late '70s. It featured a full keyboard including lower case, on screen text of 64 B&W characters by 30 rows, 2 MHz z-80 processor, up to 48 ...
8
votes
1answer
230 views

6 Player X-Men Arcade Cabinet Compatibility

I've got a 6-player X-Men Arcade cabinet and I was wondering what other boards might be compatible with it. Can I use any Jamma compatible board? Will the dual monitors just mirror? Here's a link to ...
11
votes
1answer
454 views

What API did the POKEY module provide?

The POKEY module was used in many, many Atari arcade games, including most that contained the Atari Math Box. It could be used to sample potentiometers, scan matrices of switches and, more famously, ...
14
votes
1answer
428 views

What is the prototype of the Eastern Bloc videoterminal Videoton 340?

Several decades ago, the Hungarian company "Videoton" manufactured a videoterminal for which I couldn't find a Western prototype. It likely existed, as the device had been assigned a "ES" number, ...
17
votes
1answer
244 views

Did any Mockingboard game use the VIA timers or interrupts?

There were only a small number of games that supported any of the Apple II sound cards such as the Mockingboard. From those games that used the Mockingboard, did any of them utilize the on-board VIA'...
10
votes
1answer
304 views

Why does my Macintosh SE FDHD only see 2 of the 4 megabytes of RAM?

I have a whole bag of 30pin SIMMS so I thought I would see about upgrading the 1 MB of RAM in my Mac SE FDHD to 4 MB. The original RAM had four sticks of OKI M41256A. These SIMMs have 8 chips each. ...