It's a pity that people think these sorts of tricks are amazing in any way. This is the sort of stuff you have to do when you have a very small amount of available memory and need to make something as powerful as possible.
You are likely to still see the same sort of stuff going on when working with microcontrollers. Now, if you want to read about something really cool, read about drum memory and optimizing code so that instructions are ready for execution when the drum they are on has rotated to the right spot: http://www.columbia.edu/cu/computinghistory/650.html
The only reason you're able to make a statement like "This is the sort of stuff you have to do when you have a very small amount of available memory..." is because people like Gates came up with it first. It's only common knowledge now because the trailblazers made it so.
The real pity is not appreciating the incredible creativity of those who laid the groundwork for everything we take for granted today.
I have been programming for a very long time and have been involved in all sorts of nasty tricks to fit things in memory (self modifying code, code that uses subroutines from the OS to save having duplicates in its own base, code that relocates itself while running, storing tiny amounts of code in 'free space' inside the BIOS, temporarily storing code in screen memory because there's nowhere else to go and you hope the user won't notice the funny image on screen, etc.)
Not to make light of his accomplishments, but Bill Gates is only 55: A mere whipper-snapper compared to some of the grey beards that many of us have worked with over the years. Gate's blazed many a trail, but this wasn't one of them.
This is a great quote: "I have often felt that programming is an art form, whose real value can only be appreciated by another versed in the same arcane art; there are lovely gems and brilliant coups hidden from human view and admiration, sometimes forever, by the very nature of the process. You can learn a lot about an individual just by reading through his code"
You are likely to still see the same sort of stuff going on when working with microcontrollers. Now, if you want to read about something really cool, read about drum memory and optimizing code so that instructions are ready for execution when the drum they are on has rotated to the right spot: http://www.columbia.edu/cu/computinghistory/650.html