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Questions tagged [hardware]

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

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18
votes
2answers
2k views

Why does the VIC-20 have 5KiB of RAM?

Why does the VIC-20 have 5 KiB of RAM? Why not a multiple of 4 as any other systems, e.g 4 KiB or 8 KiB. Is there a technical reason for that?
10
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2answers
1k views

Small RAM 4 KB on the early Apple II?

Most of the reference material for the Apple II that I have seen refers to the 4116 RAM chip which held 16x1 kbit. This provided 16, 32 or 48 KB in banks of 8 chips. The Apple II motherboard layout ...
20
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3answers
2k views

What does it take to recreate microchips like 68000 and 6502 in their original process nodes nowadays?

I am trying to figure out what type of machines could be used to reconstruct these chips nowadays. It doesn't need to use exactly the same machines used to build them, it's just that the product ...
5
votes
0answers
81 views

IBM terminal schematics

I'm searching for the electronics schematics for IBM terminals 3477 and 3486. I've already googled for it without success. I've to mend this hw and the power side seems ok but doesn't function, so I ...
3
votes
1answer
127 views

Did the IBM Game Control Adapter have I/O port aliases?

I was taking a look at the logic diagram in the manual for the original IBM game port adapter card: In the upper-left corner of the schematic, there is the circuitry responsible for decoding the I/O ...
5
votes
1answer
159 views

How did this coordinate capture peripheral work? [duplicate]

From an 80s Royal Air Force recruitment video, a peripheral is shown and it is used to capture coordinates off a map, onto a computer, for the flight plan to be written on a casette, for loading on ...
21
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5answers
2k views

Were there any LSI-11 like home computers outside of Russia?

In my childhood I had one of these: https://en.wikipedia.org/wiki/Electronika_BK Note, that the CPU of this is based on LSI-11. This is rather surprising because PDP-11 took a room (I was lucky ...
11
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4answers
1k views

Amiga 500 OCS/ECS vs Mega Drive VDP

Superficially the Amiga 500 and Mega Drive are similar. Both run a Motorola 68000 CPU at similar clocks and both have dedicated hardware for sprite and other graphics operations Comparing the arcade ...
14
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4answers
1k views

How powerful was Knuth’s computer?

The Art of Computer Programming, volumes 1–3, was written in the late 1960s, with vol 3 finalized in Sept 1972 after a delay of “almost 3 years” because of rapid development of the subject matter. I ...
13
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1answer
991 views

Upgrades for the TRS-80 Model 100 portable

The TRS-80 Model 100 portable officially allowed for RAM expansion to 32k and an external acoustic coupler for the model. What other upgrades and peripherals exist for the Model 100? I had one of ...
38
votes
4answers
7k views

When did computers stop checking memory on boot?

I remember my old 8088 used to do this (640K OK) but can't remember seeing anything like this since. Does this still happen and it's just not visible? If not, when did it stop, and why? (Imagining ...
4
votes
3answers
185 views

Are there standard DIN pinouts for cassette and video ports on early Japanese 8-bit computers?

I have several different Japanese 8-bit computers, and they use similar DIN connectors for video and cassette I/O: Composite video: 180° 5-pin DIN: Fujitsu FM-7, NEC PC-8001mkII Color TTL (digital) ...
33
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3answers
3k views

Why did the VIC-II and SID use 6 µm technology in the era of 3 µm and 1.5 µm?

In short, 3 µm looks like it was the "standard" process size at the time, and it was available to Commodore before the chips were designed. Therefore it looks like using the larger 5 to 7 µm process ...
12
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3answers
3k views

What happened to ZIP RAM?

I have several retro machines and add-on cards for the Amiga that use ZIP RAM. This vertically mounted chip design enjoyed a brief popularity in the early 1990s, in between the original DIP DRAM and ...
12
votes
1answer
325 views

How did restarts resolve parity errors triggered by broken core-rope wires?

In his account of the history of the Apollo Guidance Computer, Don Eyles describes the role of a parity bit as follows (p. 80): ... if one of those hair thin wires in our woven core-rope memory ...
6
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10answers
1k views

Was it possible to send data over the phone-line without a modem?

Was it possible to send data over the phone-line without a modem? Clarification Was it possible to send data over the phone-line without a modem, either by connecting computers directly to the ...
6
votes
3answers
360 views

Single-stepping the Altair 8800

I've just been watching a rather interesting series of videos about the MITS Altair 8800. It has a button on the front panel to single-step the CPU one instruction at a time... Except that, on closer ...
6
votes
1answer
206 views

Digital PCB Plans for Retro Computers

I use software like Fritzing or Autodesk EAGLE to draw my Raspberry Pi or Arduino projects and was wondering if there is a source for PCB plans of for example an Amiga 500 in a format readable for ...
6
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7answers
3k views

Were any external disk drives stacked vertically?

There was a time when floppy disk drives were big, expensive devices that in many cases, instead of being components of a computer, would be separate machines connected by a cable, in some cases with ...
5
votes
3answers
577 views

How did 2-chip CPUs work?

The 1970s saw a big transition from CPUs built from thousands of discrete components, to CPUs implemented on a single chip, with the occasional use of bit-slice components along the way. There were, ...
4
votes
2answers
289 views

Reference material for building a DIY Stack Computer from Logic Gates

I've been following Ben Eater's series of videos about designing a small computer from discrete logic gates, I'm curious if there is a similar tutorial/book/reference for building a stack computer. I ...
9
votes
3answers
413 views

What are the Ultra-Highres registers in ECS and AGA for?

The Amiga custom chip set, in its ECS and AGA versions, seems to contain some registers for what is called an "Ultra-HighRes/DUAL" mode: DFF078 SPRHDAT W Ext. logic UHRES sprite pointer and ...
1
vote
3answers
248 views

When was Tantalum first used in computing?

I know that nowadays Tantalum is very common in computer components, specifically capacitors, due to its desirable electrical properties. I'm curious when it was first used specifically in the ...
14
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6answers
1k views

How much data could a home computer store on an audio cassette?

The use of audio cassettes for storing data for home computers was a great example of repurposing an existing invention. Cassettes were sold in a variety of capacities, and labelled with their audio ...
7
votes
2answers
467 views

First computer to have interactive text on a CRT?

What was the first computer to have interactive text on a CRT ? That the text on screen responded to key-presses without significant delay . I remember seeing some very early radar-installation CRT'...
7
votes
3answers
621 views

What were the first chips with hardware support for SPI?

The SPI four-wire serial bus is a very common interface between chips and other small devices these days, but was originally developed by Motorola in the mid-1980s. What were the first Motorola and ...
12
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3answers
349 views

Pair Am386 with i387

I've got a motherboard with a Am386/DX processor. I've also got an Intel 387 coprocessor. Is it possible to use the Intel 387 that I've got together with the Am386 or do I need a coprocessor from AMD?...
8
votes
6answers
765 views

Low-cost sound chip

I want to make a homebrew 8-bit computer and I want to include a sound chip in it. It needs to be as cheap as possible (under 5$) and I also want it to be possibly controlled by an Arduino or ATmega-...
9
votes
2answers
538 views

8086 pinout and address space limit

It is tempting to say - and I have said - that Intel made a mistake in the design of the 8086 and 8088, in going from 16 bit addresses to only 20 bits; if they had even shifted the segment registers ...
4
votes
1answer
136 views

Was there any VIC-20 expansion to bring memory beyond the default maximum of 40 KiB?

The Commodore 64 was very flexible in terms of how RAM could be controlled. ROMs and I/O devices could easily be swapped out by setting bits in the first two addresses of memory. The VIC-20's ROMs and ...
6
votes
2answers
1k views

Why have computers used so many different video connectors? [closed]

Over the years and with the large variety of hardware I've dealt with I've used quite a few of different video inputs and outputs. While I usually have no issue just plugging cables into devices, I ...
16
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5answers
5k views

Why plastic cases?

Early computers of the 'all in one' form factors, such as the Commodore PET, the early IBM microcomputers and later models of the TRS-80, as well as the 'box' form factors such as the Altair, used a ...
55
votes
12answers
11k views

How big is a mainframe?

If you read about the history of computing, you'll hear how the first computers were "huge". You will often come across assertions that in the early days of commercial computing, a single computer ...
13
votes
2answers
575 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 ...
22
votes
10answers
4k views

Why was hardware diversification an asset for the IBM PC ecosystem?

The IBM PC was cloned very early on, and many third parties made hardware peripherals. This required users to run an OS, install drivers, manage IRQs and hardware bus addresses, etc. Why was this a ...
16
votes
6answers
4k 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 ...
21
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9answers
2k views

Why did CP/M and MS-DOS use the BIOS 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, ...
2
votes
1answer
93 views

What's the required battery voltage within a DALLAS DS12C887+ RTC? [closed]

I am having some difficulty getting a board that has a Dallas Real Time Clock DS12C887+ to behave. Not sure if the problem is the RTC or not but am in the investigative stage and got the cross hairs ...
24
votes
4answers
3k 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 ...
3
votes
1answer
111 views

how can I connect a scanner with Centronics 50 output to USB?

How can I connect a Legacy scanner with a Centronics 50 output to a laptop with USB ?
1
vote
1answer
101 views

Atari 1040STFM PSU Hissing, high pitch sound when on

I have an Atari, which is working correctly, but the power supply makes this hissing noise as soon as it is turned on. What may cause it?
8
votes
1answer
249 views

Anyone have more information on the “Hammerstein TV Games” 1st gen console?

I have what appears to be an early games console (supported games are variations on the theme of "pong", or ball and paddle games) manufactured in South Africa. Does anyone have more information or ...
8
votes
3answers
430 views

Why do Early DRAMs (e.g. 4116) have a negative Column Address Set-up Time?

Early DRAMs have a multiplexed address bus. Briefly speaking, to access a word, one needs to... Put the row address on the bus, and latch it using the falling edge of /RAS signal. Put the column ...
2
votes
1answer
129 views

Software Failure after RAM upgrade Amitek Hawk

I have Amitek Hawk for my A1200, the board came with wrong RAM and apps were crashing with 8003 Guru error. After contacting the seller I was told by mistake wrong SIMM was shipped and I received a ...
7
votes
1answer
823 views

What is this Amiga 2000 mod?

I got an Amiga 2000, board Rev. 6 Does anyone know what is is? (click to enlarge)
8
votes
2answers
3k views

Was the IBM 5100 ever used for codebreaking?

There's a rumor that there's something embedded in the IBM 5100 which makes it useful for codebreaking. What is the legitimacy of that claim?
4
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3answers
188 views

How did console flexowriters connect to their computers?

Several early computers (e.g., KDF9, LGP30) used Friden Flexowriters for console functions. What was the nature of the connection between the Flexowriter and the computer? Was this something we ...
0
votes
3answers
324 views

The earliest a home-computer or home-robot could be interfaced with a commercially available camera?

What was the earliest date a home-computer or home-robot could be interfaced with a commercially available tv-camera or digital-camera . Although I'm asking this question for the purpose of computer-...
9
votes
5answers
1k views

Largest practical motherboard for early computers

The power of a computer is often effectively determined by the size the RAM can be expanded to. In many cases, this was even more important than CPU speed: Memory-limited workloads In the early days, ...
2
votes
0answers
145 views

Would anyone have made a mechanical, or electronic camera for their computer or robot? [duplicate]

Would anyone have made a mechanical, or electronic camera for their computer or robot ? Parameters Of The Question As a home-project [ Although, any example of a mechanical-tv-camera or mechanical-...