Back then, a PC was extremely expensive and inaccessible to most people, and that is why microcomputers were so popular in their day. Its most common use, however, was as a video game system and they were never used as computers beyond a gaming environment, although there were people who used them for certain office tasks. , they were not their common use.
There was neither Intel nor AMD in the CPU
We can divide 8-bit microcomputers into two different categories depending on the CPU they used, on the one hand those which used the MOS 6502 and on the other, those who made use of the Zilog Z80. The latter was an upgraded version of the Intel 8080 or what you might call a clone.
Both were 8-bit processors with 16-bit addressing, so that microcomputers could not have more than 64 KB of RAM. Which of them was the best? Despite the fact that both were 8-bit processors in terms of philosophy, they were completely different from each other and controversies over which of them is the best continues to this day.
While the Z80 was considered a more professional processor, it could run CP / M, an operating system of the time considered the precursor to MS-DOS. We are not going to argue here whether we are talking about a copy or an inspiration, only that the CP / M was designed to work on the 8080 and its clones, which gave computers with this processor the possibility to run said operating system. .
The 6502 had a different path, it was the CPU used by early Apple computers and early Atari computers and consoles. We can’t forget Commodore either, since he was the owner of MOS after all. Unable to run CP / M because of the 6502, each of these manufacturers created their own software libraries, but they weren’t very successful beyond games. The only one that managed to stand out was Apple in the early years, but as history tells us, they were relegated to the PC.
And what about graphics and sound? This is where each of the microcomputers differed from each other, as it was possible to identify whether a game was available for a Spectrum, Commodore 64, Amstrad CPC or any other computer by its looks and sound. It stood out and gave each of them a mark of identity, meaning that each had distinctive material in this regard.
BASIC as a universal language
The BASIC programming language has become the universal language of microcomputers for develop programs. And it is that each of them at startup presented a very simple text editor which was used to write code in this language which was then compiled in the same microcomputer to save it in the storage unit. This is why many programs weren’t stored on tapes or magnetic disks, but you could find them in magazines and books as written code.
The most well-known BASIC dialectic was that of Microsoft, which was originally written for the Intel 8080 and therefore compatible with the Z80, but was only used on the MSX platform since other brands used their own interpreter. There were also two incompatible versions for 6502 of Microsoft BASIC, one for Commodore and the other for Apple. All this meant that the platforms were not compatible with each other in terms of software.
Storage unit in microcomputers: the cassette
The bands, was the standard storage unit used in the vast majority of microcomputers. Although it is possible to use magnetic disk drives, as storage drives they were very expensive hardware drives. It was also possible to use cartridges, but being based only on ROM, they were readable.
Cassettes were ideal because they were cheap and it was very easy to write data to them, the drives were the same as used to replicate commercial tape drives, where the classic mini jack was used as the data bus for recording. communication. Of course, it was very slow and loading the data from the cassette was tedious, so the data was transferred from the cassette to the RAM.
It must be taken into account that a tape is a continuous storage unit, unlike a disk unit, we cannot search for a specific data in a specific position. The band unit therefore passed and its content in bits was reproduced via the audio output, but with the difference that each of the microcomputers did not interpret it as sound, but as lines of data after digitization which were stored in RAM and once there. the program could be executed.
