Comment by reaperducer

That is interesting, it was before my time, and I never heard of this

It was necessary because both RAM and disk space were so severely limited, and because almost every computer came with an assembler.

Many CP/M programs were expected to run in as little as 32K RAM, and 130K of slow-ass floppy disk. Or worse – From a cassette tape. If you had 64K of RAM and a 360K disk, you were something special.

Unlike today, most programs were optimized for the bottom of the market, not the top. You wanted your program to run on as many system as possible so you could sell more copies. You didn't just shrug your shoulders and tell people to upgrade their hardware. The failure was yours, not your customers'.

There simply wasn't room for any kind of external configuration file, or a program to generate that configuration file. Common functions could be accessed via a command-line parameter, but even that logic eats valuable bytes.

Today people complain about the MacBook Neo having just 8,000,000,000 bytes of RAM, saying you can't do anything in such a limited space.

Meanwhile, in 1978, people could write an entire rudimentary IDE in 2,048 bytes.