Author is talking about manually typing in by hand the hundreds (or even thousands) of lines of code from magazines like COMPUTE!: https://www.google.com/search?q=compute%21+magazine+code+lis...

It's interesting how different people view the past. I also used to spend hours and days typing in all that BASIC code but I don't look back on it with romantic nostalgia. We were forced to do that simply because modems and floppy disks were expensive in the 1980s.

The reason magazine subscribers endured it was because most of us were kids (which means we had more free time than money) and the reward was usually a "free" game when it was done. We just mindlessly type in endless PEEK and POKE syntax which was just gibberish to get a video game out of it. (Some of the code listings were for "serious" things like spreadsheets but the vast majority was for games.) I certainly didn't learn programming or patience by typing in PEEK/POKE for seemingly-random memory locations.

To help reduce the inevitable typos and frustrating mistakes made by readers, the later magazines had a "checksum" utility to help: https://en.wikipedia.org/wiki/The_Automatic_Proofreader

And after that, magazines also offered to mail floppy disks with all the code listings for an extra price. (The selling point was "No Need To Type In The Code!")

These days, we complain when other programmers "cargo-cult" code by copy-pasting from StackOverflow (or LLM these days) without truly understanding it. Well, that's what us kids did in 1980s ... just cargo-culted the whole BASIC code listing to play a game. Sure, there were a small minority that actually studied the magazine's BASIC code line-by-line to really understand it but none of us in our computer club did that.

Just last week, I spent several hours reading the rsync C Language source code line-by-line so I could write a custom patch to add nanoseconds to the file creation dates. Dissecting that took a lot more patience and focus than typing in code listings from a magazine.