[stevesimmons]

I learnt assembly language programming on a Vic20 in 1983, using this Vicmon machine code monitor:

http://commodore.software/downloads/download/211-application...

I like this explanation of "monitor", from https://www.atarimagazines.com/creative/v9n12/272_A_monitor_...

"The novice machine language programmer often does not have an assembler. Without an assembler, the programmer must assemble the program by hand, and then enter it by hand. Even a small program could require hundreds of POKEs followed by hundreds of PEEKs to verify that everything has been entered correctly.

A good monitor gets around these problems. It allows the programmer to examine memory locations sequentially. As each location is examined, the operator has the option of changing it or looking at the next one. A good monitor program also allows the operator to list a range of memory all at once. A third monitor feature allows the operator to move a range of memory to a new location in the computer. A final feature in a good monitor is the ability to execute and return from a machine language program."