It's linked ...ish...but not also..Timex released the ZX81 types, the predecessor, and screwed up a small scale release of the spectrum variants, too little too late, forget Timex, wrong path there.
Spectrum is a quantum leap forward from zx81. Really ERASE timex from your mind. think sinclair, and spectrum.
And jetpac aint rare. Oh you mean RARE....Ultimate Play The Game...yeah - classic. get it.
You just gotta GET spectrum to appreciate it, this is what the aim is here, not just to get a machine to go - thats piss easy. It's was never the best computer of it's time, it was the affordable one, and it exploded for gamers. If you want to compare spectrum to commodore, most of the time the commodore game looked and sounded better, but maybe only 1 kid in 5's parents could afford commodore, so spectrum was HUGE, tempramental, made on a shoestring budget.....and still being played today, and as a gamer, you need to tick this box.
You need focus grasshopper, put your feet up and enjoy this... Dramatisation of the Cambridge computer scene from the BBC, amazing film, it's a stretch of the truth for drama, but you'll learn shit loads of facts too.
http://www.youtube.com/watch?v=XXBxV6-zamMMicro men
Enjoy
http://www.imdb.com/title/tt1459467/