I have an old PC in the ceiling still connected to power and fully operational. I test it every two or three weeks.
It has DOS 6.2, Multimate, Wordstar, Symphony and Dataflex plus a lot of other generally useless junk and 1 MB of memory. However it has enough capacity to do all the essentials of a computer still. It has the princely capacity of a 20MB MFM hard drive with 15 MB unused.
It has a 2MHz processor and it can start up from cold. I can enter my accounts on the spread sheet or look up an address in the DB in less than a minute and shut down. Slightly less than the time it takes Windows XP to load on a 3.3 Ghz machine!
What the hell do we need TB's for except to collect more data than you can ever use
Barry