Did the term "multitasking" come from the computer realm?

Using Google Books, I found several instances of multi-task in print prior to 1966. Here's the earliest I found, in a description of a lawn mower from a 1954 issue of Chambers's Journal:

Last month a multi-task appliance for turf maintenance was described here, but it was pointed out that its size and cost made it more suitable for use on large areas of grass—e.g. sports grounds, parkland, etc.

I believe this shows that the term multi-tasking did not orginate specifically as computer jargon, but was present prior as engineering jargon.

This earlier use probably did not carry the meaning of performing multiple tasks at the same time, but rather meant, simply, able to perform multiple tasks.

As a matter of fact, the word multitasking did originate in the computer realm, but it is older than you estimate.

According to the OED, the first citation of the word is from 1966, in a magazine called Datamation:

Multi-tasking is defined as the use of a single CPU for the simultaneous processing of two or more jobs.

The more general sense of multitasking, then, arose from this computing term.