Questions tagged [8-bit-microcomputers]

For generic questions about 8-bit microcomputers. For specific computers please use the appropriate specific tag.

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What were MECC's specifications for a school computer in 1978?

It is well-known that one key moment for Apple was selling 500 Apple IIs to the Minnesota school system in 1978. I came across this video which discusses the background to that, including a reminder ...
rwallace's user avatar
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3 votes
2 answers
361 views

Can anyone tell me more about flippy games?

I remember having a number of Mastertronic tape games for the Amstrad CPC 464 that could be used on a Spectrum too by using the other side of the tape. These were called flippys I believe. Was this ...
Robbie Dee's user avatar
15 votes
6 answers
3k views

Which 8 bit computer could display the most colors?

Which 8-bit computer could / can display the most colours on screen? Please take into account undocumented/newly discovered video modes and other hacks. For example, static sprites supposedly allow ...
user1095108's user avatar
1 vote
0 answers
226 views

Why is my crystal oscillator (4 pin DIP 4 MHz unbranded from ebay) producing unusable clock signal waves? [closed]

I was trying to make a Z80 computer (I tried with Intel 8088 and failed because I am dumb) so I bought a 4-pin 4 MHz crystal(from here:ebay listing) and I tried to check the crystal by connecting it ...
Dragonite Brian 1024's user avatar
14 votes
1 answer
2k views

How did Altair 8800 interrupts work?

I'm playing around with building an Altair 8800 emulator in my free time in C#. I've read through the Operator's Manual many times in the past, and I'm refreshing my memory of late. I'm struggling to ...
ConnieMnemonic's user avatar
7 votes
1 answer
305 views

Is there really any implementation of a Ada compiler/cross-compiler/interpreter for 6502?

I found some Ada compilers for CP/M machines but no luck for 6502-based C64/Apple II/BBC Micro. I'm not sure if Abacus Ada on C64 exists or how much a subset it implements for Ada. There is, though, ...
Schezuk's user avatar
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9 votes
4 answers
1k views

Testing "8-bit readiness" with an emulator or pre-packaged kit

I'm working on a project that intends to implement a dynamically typed language on 8-bit systems. (That is, a CPU with 16-bit pointers and a maximum of 64 kB of RAM. Some language tricks are involved, ...
Jim Pivarski's user avatar
1 vote
2 answers
153 views

Dump Mask ROM on MAB8421

I am trying to find a way to dump the rom contents of several MAB8421 microcontrollers. I know that on many 8048 MCUs, you can use the external access pin to dump the rom, but the 8421 doesn't have ...
c0metdrag0n's user avatar
9 votes
3 answers
738 views

BASIC : POKE and PEEK prohibited on the same line?

Having been raised on an 8-bit Commodore, I was never afraid of PEEKs and POKEs. I remember trying to accomplish something on a computer, in BASIC, using PEEKs and POKEs, and discovering that this ...
Nimloth's user avatar
  • 2,068
34 votes
8 answers
4k views

What made some 8-bit BASIC interpreters especially slow?

Most 8-bit systems had a BASIC interpreter that ran at a rate roughly commensurate with the CPU type, speed, memory bandwidth and interrupt status. Some systems, however, had interpreters that ran at ...
scruss's user avatar
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7 votes
1 answer
319 views

Anyone have the 1975 edition of "An Introduction to Microcomputers, Vol 2"?

I'm looking for references to the EA9002, an ill-fated design if there ever was. Practically the only place I can find it detailed is Osborne's Introduction to Microcomputers, where it was chapter 11 ...
Maury Markowitz's user avatar
28 votes
9 answers
6k views

Fastest 8-bit microprocessor for multiply-accumulate?

I'm wanting to identify which 8-bit microprocessor would have the best performance for a multiply-accumulate operation. By "operation", I mean the minimal implementation for 16-bit operands ...
Brian H's user avatar
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3 votes
1 answer
357 views

What was the first personal computer store in Australia?

In the US, the personal computer revolution was kickstarted by mail order, which is the channel through which the Altair was sold. However, it did not take long for the new industry to be augmented ...
rwallace's user avatar
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8 votes
1 answer
404 views

What was a MicroAce?

I am familiar with the original ZX80 and its "cousin", the Jupiter Ace, a similarly specc'ed machine but running Forth rather than BASIC. However, a colleague at work stated that there had ...
paxdiablo's user avatar
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21 votes
5 answers
4k views

How did old computers address far more than 64K of memory despite only having a 16 bit address bus?

I have an old Sharp PC-G830 pocket computer from the '80s that has 32K of RAM and 256K of ROM. I also have a simple single board computer I built with 128K of RAM and a few megabytes of ROM from a ...
Shades's user avatar
  • 321
8 votes
1 answer
421 views

Looking for an 8-bit microcomputer with a hardware-accelerated database

In some old video on YouTube a few years ago, I noticed a curious computer from the end of the 70s - early 80s. In the rack (half height), typical of minicomputers of those years, there was a 14" ...
Wheelmagister's user avatar
10 votes
3 answers
2k views

Was there ever a microcomputer with a full-size keyboard and a hex numpad?

I'm aware of some early/super hobbyist microcomputers that came with ONLY a hex numpad (that is, no letters beyond F/no punctuation). I'm also aware of home microcomputers that had the usual decimal ...
Muzer's user avatar
  • 1,792
0 votes
1 answer
172 views

How the technology keeps improving [closed]

How does the technology keep improving despite having everything discovered already? I mean the same sized chips and electronics are used from year to year but with every new version of the main board ...
Borislav Stefanov's user avatar
33 votes
1 answer
8k 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 ...
scrØllbær's user avatar
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2 votes
4 answers
483 views

Cheapest way to store and load small dataset in the 80s?

An extra, costly floppy drive would overkill when transferring a page of letter, storing game level data, or distributing a piece of BASIC program, and non built-in ones have to be paid. A tape ...
Schezuk's user avatar
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9 votes
0 answers
234 views

Systems that used the Rockwell R65C00/21 or R65C29

The Rockwell R65C00/21 and R65C29 are described in an October 1984 datasheet ("R65C00/21 dual CMOS microcomputer and R65C29 dual CMOS microprocessor," Document no. 29651N64, rev. 2) which is ...
JRN's user avatar
  • 1,265
26 votes
9 answers
5k views

How common was programming in C targeting 8-bit processors in 1983?

How often was C used to program firmware for 8-bit processors in the early 80s? I'm reverse engineering a firmware binary for a device built around a Hitachi 6303 processor, manufactured in 1983. Even ...
ajxs's user avatar
  • 836
4 votes
2 answers
323 views

Looking for NEC RA87 “Relocatable Assembler Package”

I admit, I am pushing my personal envelope (punching above my weight, beyond my pay-grade etc. etc.) on the trailing edge of technology. So please be kind! I would like to write new firmware for a NEC ...
Birdman's user avatar
  • 41
7 votes
1 answer
2k views

The proper way to shift a byte using a Z80

In a nutshell, why can I not shift a byte using this way? LD A, 11110000b ; I want this to be 00001111b LD C, 4 SRA C OUT (0), A ; doesn't give correct number What is the proper way of shifting a ...
Shams M.Monem's user avatar
8 votes
3 answers
649 views

Uh, oh, I've woken up in 1973. Can I get a job in computing? [closed]

I've woken up in 1973. Until I can figure out how to monetize my knowledge of coming political, economic, and social trends, I need to support myself somehow. So... I walk into one of the major ...
SlowMagic's user avatar
  • 205
15 votes
4 answers
3k views

Benchmark test that was used to characterize an 8-bit CPU?

I was curious if there was a benchmark test that was available to compare CPUs that are 8-bit. People always like meaningless analysis to justify some decision, and I was curious if there was a ...
b degnan's user avatar
  • 1,099
23 votes
11 answers
5k views

Did any European computers use 10-line fonts?

Most 8-bit computers implemented hardware text mode, and most of those used 8x8 fonts. This was logical for American computers; the title safe area on NTSC is about 200 scan lines; font height 8 gets ...
rwallace's user avatar
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10 votes
2 answers
964 views

Did any 8-bit CPUs use dynamic memory for registers?

According to https://jamiestarling.com/project-8088-the-8088-cpu-pinout/ One thing to note – the 8088 registers are made from dynamic memory cells – they have to be refreshed. The minimum clock speed ...
rwallace's user avatar
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18 votes
4 answers
2k views

How was the main mechanic of the game Qix implemented?

Qix was a quite unique Taito arcade video game that saw ports to nearly any home computing platform of its time. At first glance, the game mechanics seem to be targeted at low-performance hardware - ...
tofro's user avatar
  • 34.1k
26 votes
8 answers
6k views

Why did 8-bit Basic use 40-bit floating point?

Nowadays floating point is usually either 32 or 64 bits, sometimes 16, occasionally 128. But of course, the Basic interpreters on the 8-bit machines, having to implement floating point in software ...
rwallace's user avatar
  • 60.3k
-3 votes
2 answers
498 views

How can 8bits = 1byte but also = 255 bytes at the same time? [closed]

I don't understand why 8bits is defined as being equal to 1byte or 1octet but at the same time the maximum capacity of an 8bit bus or 8bit databus would be 255 bytes because 128 64 32 16 8 4 2 1 1 1 ...
6502Assembly4NESgames's user avatar
9 votes
1 answer
1k views

What kind of 256 color palette did the Enterprise 64/128 have?

The Enterprise 64 or 128 Home Computer apparently had a palette of 256 colors. However, that is pretty unusual and doesn't fit evenly into the typical 3 channels for RGB. Wikipedia doesn't provide any ...
scrØllbær's user avatar
  • 1,109
12 votes
10 answers
3k views

Were there any bitmap-based 8080 computers?

Does anyone know of any bitmap-based 8080/8085 (or, failing that, Z80) computers? Background: In the late 70s and early 80s, there were a few hobby computers with bitmapped displays. For example, the ...
tobiasvl's user avatar
  • 1,489
23 votes
21 answers
6k views

8-bit home computers without BASIC

All the 8 bit home computers I'm aware of, had BASIC in their ROMs. A notable exception was Jupiter Ace, a British home computer which used Forth. Were there any other 8-bit home computers that came ...
Krackout's user avatar
  • 1,528
34 votes
1 answer
2k views

When and where did the $ convention for hexadecimal literals originate?

I found this question asking about the origin of 0x to denote hexadecimal to be interesting. However, when I cut my teeth programming on 8-bit 65xx systems in the early 80's everything I saw used a $ ...
Geo...'s user avatar
  • 10.2k
6 votes
2 answers
1k views

What was the first microcomputer capable of working with Japanese kanji?

Apparently the first microcomputer capable of working with the Chinese language in Chinese characters was the Microprofessor II (or MPF-II-C), a Taiwanese Apple II clone from 1982. Now I'm 99% sure ...
hippietrail's user avatar
  • 6,636
7 votes
6 answers
1k views

Would some BASIC interpreters for microcomputers be considered operating systems?

As software for micros developed, you could use the BASIC interpreter just to CLOAD and RUN assembly language programs. Those might call BASIC ROM routines (say, for converting ASCII input to binary ...
Jeffrey Henning's user avatar
2 votes
1 answer
128 views

TMS9918ANL question

I am working on setting up a TMS9918ANL Video Display Processor. I was wondering if there is any way I can test to see if it is working without having the DRAM hooked up (I have a while before the ...
benjamin black's user avatar
3 votes
1 answer
326 views

What bug in first version of game Karateka for Apple 2e cause this game reset in Apple 2c?

If I try to start the first version of the game Karateka for Apple IIe on an Apple IIc, the Apple IIc will restart after reading the game from disk after a few seconds. Later versions of Karateka for ...
Châu's user avatar
  • 515
3 votes
4 answers
901 views

"SAP" microcomputers vs real microcomputers

In Paul Malvino's "Digital Computer Electronics", he labeled 3 theoretical microcomputers which he called the SAPs or "Simple As Possible"s. The point of these 8-bit microcomputers was to teach ...
Nip Dip's user avatar
  • 341
28 votes
10 answers
7k views

Why did 8-bit computers choose BASIC dialects as "de facto" command-line interface, instead of contemporary Shell/Lisp dialects?

While all three clans of languages predated 8-bit computers, they shares features like 1) imperative programming, 2) English-alike keywords, 3) Prompt-Command-Parameters pattern interface. Why was ...
Schezuk's user avatar
  • 3,762
20 votes
4 answers
6k views

Were there any 8-bit CPUs with 24-bit addressing?

Or was that something that didn't appear until later CPUs (around the time of the 286 maybe)? Also, how would I go about researching this on my own? It's not exactly something I can look up on ...
Anthony's user avatar
  • 455
30 votes
2 answers
5k views

Zilog Z80 freezes while binary counting up to 65 536 (2^16)

A few days ago, I got Z80A CPU from eBay. So I tried to run it with classic 555 timer as a clock signal generator. I connected the 8-bit data bus of the CPU to the ground to "simulate ROM" (00 for NOP)...
Nogard's user avatar
  • 533
2 votes
4 answers
376 views

What 8bit home computers did not have a supplied intro tape [closed]

As per the title, we are obviously referring to machines that had cassette audio tape as their default medium even if other media was supported via expansion. To be clear I mean what was "in the box" ...
AndyF's user avatar
  • 584
21 votes
9 answers
7k views

Intel 8080-based home computers

I'd like to build an FPGA replica of a home computer based on the Intel 8080. I am not looking to design my own computer, since I would like to tap into an existing software base. Were there any ...
Cactus's user avatar
  • 2,700
21 votes
3 answers
4k views

What LISP compilers and interpreters were available for 8-bit machines?

What LISP or LISP-like language compilers and interpreters were available for 8-bit microcomputers? Criteria for "8-bit" include that it should certainly run and execute non-trivial programs given no ...
cjs's user avatar
  • 25k
5 votes
5 answers
1k views

Did any assemblers work like this?

Once you get past the stage of manually entering numeric machine code, the most primitive programming tool is a machine code monitor. Intended primarily as a debugging tool, this works with a target ...
rwallace's user avatar
  • 60.3k
14 votes
10 answers
3k views

Which microcomputer manufacturers developed their own Local Area Network systems? [closed]

With the advent of microcomputers, there was a large number of manufacturers entering the home computer market. The ability to network these computers together wouldn't be very useful (or affordable) ...
Kaz's user avatar
  • 8,056
80 votes
14 answers
19k views

Back in the late 1980s, how was commercial software for 8-bit home computers developed?

When hobbyists wanted to write software for e.g. the Commodore 64, they either used the built-in BASIC interpreter (with all its limitations) or some native tools, like compilers for other languages ...
Felix Palmen's user avatar
  • 1,502
20 votes
4 answers
5k views

Unlicensed home computer ports of arcade games

During the 1980s, it was quite common to see unofficial ports of popular arcade games released on home computer systems. For instance, Acornsoft (the software division of Acorn Computers) released ...
pmarflee's user avatar
  • 707