Sinclair computers were designed to be cheap. 100 pounds for a computer in 1982 was like a joke. The Commodore PET which was less featured costed over 500 to 800. Hence the rubber keys and stuff. But it sill was a great computer.
And it is the king, commercially, in the UK, Spain, Portugal, Italy, the Czech Republic, Slovakia and the former USSR.
All you have named was developed for the ZX Spectrum. I can remember 3, 3 1/2 and 5 1/4 disk interfaces and drives, microdrives, a 9600 bps modem, a network interface which would allow the interconnection of 85 machines, three different soundcards, a nice speech box (the Currah microspeech), interfaces to most printers (at that time, of course), analogue and digital joysticks, mice, light guns, memory expansions, optical pens, tablets, etc. The last "official" Spectrum model, the ZX Spectrum +3, released in 1987, featured 64Kb ROM and 128Kb RAM, a 3" disk drive, a slot for a second one, the Yamaha AY chip for sound, printer port, joystic port, a RS232 port, a MIDI port, RGB-Peritel monitor output and a proper keyboard... It ran CP/M natively and was considered one of the most powerful 8 bits computers, only put down by the Amstrad CPC 6128 (which had almost the same things but a way better BASIC and a way way way better picture processing unit). The difference is that, when it was released, the +3 costed around 250⬠and the CPC6128 around 1000â¬.
take a glance:
http://www.homecomputermuseum.de/comp/detail/75.jpg
And that if we talk about "official ones". In eastern countries and the USSR a lot of clones were developed in some kind of "build it yourself" basis (hence making the computer even cheaper). My favourite model has to be the Pentagon, which had a Z80B running a 7 Mhz (instead of the normal 3.5 Mhz) plus 128Kb ROM and 1 Mb RAM, the powerful TR-DOS operating system or ROM, the ability to run CP/M stuff, interfaces to connect 3 1/2 or 5 1/4" disk drives, the Covox soundcard (with its own memory to play nice MODs), etcetera. Of course, it was fully backwards compatible. It was just some kind of Spectrum on stheroids
The thingo is still being manufactured in Russia. If you want, they put the thing together for you in a nice AT case.
The best thing is that the ZX Spectrum retro-community is the biggest in the internet. Check the dimmension of
http://www.worldofspectrum.org . The emulators are awesome (Spectaculator emulates almost ANYTHING).
The good ZX Spectrum +3 was so well designed that with just a slight ROM change (you remove the ROM supplied and place an EPROM) you can even conect a hard disk drive using a normal IDE cable, a PC disk drive or even a CDROM.
The magic behind the ZX Spectrum is that it was cheap, easy to use, and easy to hack. Most people who owned a ZX Spectrum began playing with software and/or hardware soon. I like to call it "the computer geek creator".
It was cheap and used cheap parts, but my +2A still works, after almost 18 years
Btw, just for the trivia: The BBC chose Acorn to build their "official computers" instead of Sinclair, which was also a candidate. Some rumours say that Acorn paid some nice amounts of money to some BBC directives
