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Questions tagged [hardware]

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

19
votes
2answers
3k 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 ...
59
votes
5answers
13k views

Is it safe to turn on a 40-year old TRS-80?

My father is a retired programmer. When I was in high school in the late 1970s, he purchased a TRS-80 model 1 (on which I learned to program in BASIC). At some point in the early 1980s it, together ...
40
votes
5answers
15k views

Why did CPU designers in the 70s prioritize reducing pin count?

A lot of 70s era microprocessors were packaged in DIP packages with 40 pins. This was a reasonably good fit for 8-bit processors: 16 address lines, 8 data lines, 2 power and clock are all absolutely ...
34
votes
4answers
7k views

What determines the color of every 8th pixel on the Apple II?

On the Apple II there's an interesting way to add a little color to the bitmap, since the high bit select the palette used for the three-and-a-half pixels represented by the byte. Like this: 0: Black,...
25
votes
9answers
5k views

Graphics chips in 1980

Suppose you were trying to build a computer with a color graphics display in 1980, you have limited engineering resources and time to market is critical, so you want to get as many of the parts off ...
14
votes
1answer
479 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, ...
104
votes
4answers
23k views

It's now safe to turn off your computer

One thing I remember very well from my childhood is the screen you got at the end of a shutdown process ond old computers: I don't know if this was a Windows 95/98/2000/ME only thing but I wonder why ...
18
votes
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 ...
44
votes
2answers
5k views

Why did the IBM 650 use bi-quinary?

The IBM 650, announced in 1953, was the world's first mass-produced computer. It represented numbers in decimal, which is understandable, both because it needed to work with exact money amounts, and ...
26
votes
7answers
11k views

Why did computers use a power supply with a socket?

Most home electrical appliances use a fixed power cord and have a on/off switch near the front. I was in many government electronics labs and that cord and socket was not used i.e HP test equipment. ...
18
votes
2answers
1k views

Power cycling old hardware

For those of us that use an old computer daily, is it safer for the hardware if the machines are turned off every night, or should they be left on? I assume that powering up is more stressful for the ...
17
votes
6answers
3k views

Can removing a cartridge from an NES (or any other cartridge-based game system) damage the hardware or software?

On some cartridge-based video game systems (NES, Game Boy Color, etc.) it is possible to remove the cartridge while the game system is still powered on. What kind of damage can this behavior do to ...
28
votes
1answer
2k views

How do Amiga 600 CPU accelerators work?

The Amiga 1200 has a trapdoor expansion for CPU accelerators. The Amiga 500 has a side expansion port and its CPU is socketed. But Amiga 600's expansion port is only useful for memory expansion ...
27
votes
3answers
1k views

What are the differences between a PAL and NTSC C64?

A lot of programs released for the Commodore 64 contained different software for the PAL or NTSC computer. Why did they have different versions of the hardware? Did the software have to be different ...
22
votes
5answers
2k views

How do you open an SE/30? (a.k.a. what is a “pull-apart tool”?)

I have been trying to work out how to open a Mac SE/30, in order to have a better look at its internal condition. I have the repair manual, and in the "Take Apart" section it references a "pull-apart ...
12
votes
1answer
521 views

Why was the audio output of the SID6581 so variable between chips?

Each of the SID6581s I have tested sound different, particularly when it comes to filter cutoffs and distortion. What are the causes of these variances?
11
votes
8answers
2k views

Why did common floppies never advance past 1.4 MB in size?

The chronology of some early floppy standards was: 80 kB, 160 kB, 360 kB, 720 kB, 1.2 MB, finally 1.44 MB. (There were less common sizes such as 250 kB, 800 kB, ...
11
votes
3answers
690 views

z80 crashes after executing some instructions

I'm building my own Z80 computer but I'm having a very strange problem. Consider this code: ld a,0xaa out (00),a jp a That works as expected, outputting 0xaa on port 0x00. Now consider this code: ...
23
votes
3answers
2k views

Main board of the original Game & Watch (Ball)

The Game and Watch was a series of single-title games consoles created by Nintendo from 1980 until 1991. Each machine contained a custom LCD screen (containing images related to the software), some ...
15
votes
2answers
938 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 ...
12
votes
3answers
3k views

What is the benefit of increasing Amiga chip memory?

For example, an Amiga 500+ has 1MiB of chip memory, but it can be expanded to 2MiB. What would be the advantage?
12
votes
5answers
2k views

Can I run Windows 98 and games from the same era on an AMD Duron CPU?

I have acquired an old motherboard with a socket 462 and a AMD Duron (I think its a "Spitfire" model 3). The copyright on the CPU is from 1999 and it apparently doesn't require a dedicated CPU fan as ...
11
votes
2answers
714 views

What was the A1200 Flash ROM support meant for?

Question inspired by this answer's last paragraph: https://retrocomputing.stackexchange.com/a/1307/2155 The Revision 1 A1200 schematics show that the system originally had support for a two internal ...
9
votes
2answers
417 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 ...
8
votes
4answers
666 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
317 views

How can I edit CMOS hard drive geometry settings on a 1991 PC?

First, I am NOT asking how to use the BIOS Setup utility. I'm asking how to OVERRIDE the built-in settings my BIOS Setup supports for the HD geometry. I have a 1991 NCR PC with a 386SX, on-board IDE, ...
1
vote
2answers
288 views

Didn't people 'back in the day', ever try 'Object-Tracking'( combined with RC ), via their retrocomputers, as 'Home-Projects'

Didn't people 'back in the day', ever try 'Object-Tracking'( combined with RC ), via their retrocomputers, as 'Home-Projects' ( I'm referring to a time range from say 1975 to 1985 ) ( Also, if ...