Coding ...
Getting a development environment setup for a machine can be fairly
intensive. Especially if the machine had a few vendors that provided
environments. Once you are setup, nothing teaches you more about the
machine than trying to wring something useful out of it. ;-0
My favorite example .. the TCP/IP stack that I wrote for DOS. It is
part of a long process to put a BBS on my PCjr. I missed the
opportunity 20 years ago to have a dialup BBS, so I'm making up for it
with a multi-user Telnet BBS.
Getting the development environment setup, writing code that works and
is stable, and wringing the performance out of it has put me a lot
closer to the machine that just powering it on once in a while. Given
your collection, you could spend a few lifetimes doing software.
Mike