Please forgive me ... I have to comment on this and I'm gonna sound like a condescending asshole :-) ....

1> The term software was alive and well in 1985. It first appeared in the 1950s.

2> Mainframe computers were typically run off large magnetic tape drives at the time. Many used LARGE (physically) harddrives too. Punch cards were still around, but were pretty much a dead technology by then.

3> Largest storage devices ... 3.5" floppy drives were available at the time ... many machines being released in '85 had them. Plus, hard drives were making their way onto the desktop.

4> In the 80s, everyone bought computers from Commodore, Atari, Tandy, and Sinclair (in the West at at least). Alot of clones of these computers made their way into the USSR.

Apples and PCs were kind of rare in homes at the time due to price ... they mainly showed up in schools. Also, the Apple II, Apple's first successful computer, debuted in the late 70s IIRC ... the Mac did come out in 1985 (and it was impressive at the time though quite expensive compared to other 16 bit computers with vastly superior AV systems (like the Amiga and Atari ST) but wasn't exactly a big seller compared to the others I mentioned.

5> Using an off the shelf operating system to control a nuclear arsenal would have been ridiculous at the time (in my opinion, it'd still be retarded to use one today).

6> Speed isn't everything when it comes to control of weapons. Reliability is.

7> A Russian system in 1985 could easily control a nuclear arsenal. They had access to a lot of Western technology ... they could have integrated that into their system. However, I think "keep it simple stupid" applies to weapons ... you want to make a frigging rock solid, simple system to control weapons ... Russia certainly had this at the time, and if it was designed properly, they'd have absolutely no need to upgrade anything.

I'm not trying to be condescending ... you'd be amazed what older technology is capable of doing when a systems engineers and programmers know what they are doing. MANY businesses still use mainframes purchased in the 80s to manage/store their critical data today. It's mainly due to reliability. Sure, they could probably use a frigging Raspberry Pi these days to do the task of a giant piece of equipment performed in the 80s, but why risk that when a machine you've been using for 40 years never fails and does exactly what you need it to do?