The 8-bit era

The MOS 6502 microprocessor was introduced in 1975, followed by the Zilog Z80 in 1976. These microprocessors powered the homecomputer boom in the late 1970s and early 1980s. Both were 8-bit processors with a 16-bit address bus, resulting in a 64 kByte address space for memory and memory-mapped I/O.

A brief history

Some of the 8-bit homecomputers from that era:

  • Tandy TRS-80 (Z80, 1977)
  • Acorn Atom (MOS 6502, 1980)
  • Commodore VIC-20 (MOS 6502, 1980)
  • Sinclair ZX-81 (Z80, 1981)
  • Acorn BBC Micro (MOS 6502, 1981)
  • Commodore 64 (MOS 6502, 1982)
  • Sinclair ZX Spectrum (Z80, 1982)
  • Acorn Electron (MOS 6502, 1983)
  • MSX, various brands (Z80, 1983)
  • Acorn BBC Master 128 (MOS 6502, 1986)

In 1987, Acorn introduced the first ARM-powered 32-bit homecomputer: Acorn Archimedes (ARM2, 1987). ‘ARM’ originally stood for Acorn RISC Machine, but that was later changed to ‘Advanced RISC Machine’ when Apple invested in ARM development.

My first homecomputer

In the summer of 1982 I got the Acorn BBC Model B - an 8-bit home computer that was developed specifically for the BBC Computer Literacy Project. It was quite expensive - NLG 1999 back then (corrected for inflation that would be EUR 1950 in 2022!).

Next year, in the summer of 1983, I had saved up enough money to buy a 5.25” floppy drive (NLG 450), an Intel 8271 disc controller chip (NLG 100), plus an EPROM with Disc Filing System software and other required parts and of course a couple of floppy discs (about NLG 100). Each floppy disc would hold up to 200 kilobytes of data.

I used that machine for several years - at least until 1990 when it was stored in the attic as I started playing with Intel PCs.

In 2018 I re-discovered my BBC Micro and decided to bring it back to life and see if I could recover my old data. Assuming that the machine or floppy drive would need major repairs after all these years, I bought a refurbished Acorn BBC Micro from Mark at RetroClinic via his eBay store to have at least one “known good” reference machine.

He mentioned that most Beebs only needed their ‘RIFA’ capacitors replaced in the power supply so he shipped a replacement kit. And indeed - I now had a “new” BBC Micro, as well as my original Beeb in full working order!

Around that time I also discovered and joined the StarDot forums - a great community with a huge amount of knowledge of all things Acorn.

This started my interest in #RetroComputing and a little #RetroGaming ;-)