[arp242]

The first edition of MSX Computer Magazine from 1985 has them, and I doubt they were the first or invented it: https://www.msxcomputermagazine.nl/archief/bladen/msx_comput...

Perhaps it was less common in other countries? Things were a lot less global back then and things operated more on a local level.

[pimlottc]

We mostly had Family Computing magazine. I looked up an issue from 1985 with one of my favorite type-by-hand games, Hit or Miss [0], and no sight of a helpful checksum.

To be honest, the idea of it would have blown my mind back then; the idea that your BASIC code is just a text file that can be processed by other programs is something that would never have occurred to me.

https://archive.org/details/FamilyComputingIssue041983Dec/Fa...