That said, a lot of that hardware, especially rugged, would easily last for a few decades.
We'd have to use cassettes for data storage once again.
Getting enough food and water that wasn’t dreadfully contaminated alone would be the preoccupation of generations. By the time anyone had ideas about rising from barbarism, what we think of as civilization now would be rusted, eroded, and overgrown.
All of that assumes the most optimistic of assumptions regarding global wildfires, teratogenic effects, and nuclear winter. We wouldn’t be using magnetic tapes, we’d be using rocks and sticks and animal hides.
Remember we actually detonated a large number of nukes on the surface with minimal impact on global radiation exposure.
While relatively small by modern standards Yoshitaka Kawamot was less than 1km from the hiroshima blast and survived. Yes, these nukes may be 100+x as powerful but destruction is far from 1:1 with yield sizes.
15,000 warheads concentrated where humans live, on the fraction of the 27% of Earth that isn’t water. Be reasonable.
It all boils down to supply chains and the economy, basically. Electronics capable of working with today's data storage media is incredibly complex, and manufacturing replacements will require large and insanely expensive fabs. Those fabs themselves are full of precise tools and exotic materials, every one of which requiring other specialized fabs, using tools requiring other fabs... The whole pipeline from dirt to CPU involves many thousands of people directly, and itself can only exist in an advanced civilization like ours - where lots of other people do everything from agriculture to catering to logistics to law and law enforcement. To build a CPU, you first need to build a civilization like ours. And to build a civilization like ours, you need cheap energy sources - it literally wouldn't be possible without them.
> GP claimed civilization would be unable to rise again, implying thousands of years of knowledge would disappear.
Our best bet to retain all that knowledge after total civilizational collapse is to form orders - not unlike medieval monks - whose sole purpose would be to make exact paper copies of that knowledge. Otherwise, after computers eventually die, a lot of that knowledge would disappear (because it wouldn't be used), and what would stay would get increasingly distorted over time.