[chrisseaton]

I read it - I did't find an explanation of what it was that he was building, just how he was building it.

[saagarjha]

Think of it of decompression software bundled along with a compressed version of the program you actually want to run. So execution starts in the uncompression part, it unzips all the code into memory, and then starts running the program you actually cared about.

[abiogenesis]

See https://en.wikipedia.org/wiki/Executable_compression . They have been around since forever.

[icedchai]

Packers were common in the 80's and 90's to save disk space. I mostly remember them from Amiga warez and demos.