My Dad bought us an IBM PCjr with 256KB of RAM, which was kind of elite in 1984. But he wanted more. So, he purchased a pair of thick memory expansion board th

My Dad bought us an IBM PCjr with 256KB of RAM, which was kind of elite in 1984. But he wanted more. So, he purchased a pair of thick memory expansion board that brought it up to an unheard-of 640KB of RAM. Of course, these slabs generated an impressive amount of heat, so we had to set up a series of cooling fans, or else computations would go awry and weird bugs would appear in programs as it overheated. It had all manner of strange behaviors, and IBM engineers on the support contract would dutifully visit and give us stacks of floppies containing custom builds of MS-DOS to try and help us out when he called about problems with his mods. Today, incidentally, I’m a sysadmin.