Sci-fi from the time of TOS often used real computer hardware. Check out "The B-205 in Movies & T.V." link on this page:
Only computer-savvy viewers, who were very rare at the time, knew that those photogenic panels of blinking lights were already obsolete by the mid-Sixties. That's what made used units affordable as studio props.
And some of that stuff still looks really good to me. It's ironic given how primitive they were, but late-1950s institutional computers, from certain angles, are gorgeous.
went another way of course, building most of their computers from scratch with varying results. Spock's built-in unit at the Briefing Room table is nice and sleek, but the judicial computers in "The Menagerie" and "Court-Martial" are boxy and clunky, and other desktop units throughout the series seldom look very good.
I'd say the best-looking computers were the M-5 in "The Ultimate Computer" and the Beta 5 in "Assignment Earth," while the worst was Landru in "Return of the Archons."
One of McCoy's little computers was actually a slightly modified portable radio if I'm not mistaken. It's at the bottom of this image:
There's a 7-part feature here on the "PC Props of Star Trek
" that illustrates a lot of things:
Having to portray things way beyond current technology prevented Star Trek
from using much real hardware. Sometimes a great look was achieved, but at their worst, Star Trek
computers looked a lot less real than the used business machines on other shows, but no more futuristic.