I've always assumed BSD used ^Z as the suspend character for this reason.
Yes, Kulp's Job control for the PDP-11 was based on his ITS experience. Joy picked it up from Kulp.
The other big gift to UNIX from ITS was Eric Shienbrood's more(1) command [discussed elsewhere].
This brings us back to the topic -- the need for more(1) as either built-in like ITS or as command [UNIX] is lost with today's infinite scroll buffers.
To pull the thread back to the list topic
2. Fix a filesystem without fsck.
Much less, what was fsck(1) original name at CMU ;-) or why tjk wrote the first version.
4. Edit a driver and recompile the kernel to change partition sizes.
Doing the same with adb(1) on the kernel binary
as well as understanding disk geometry and calculating the HEAD/CYL/SEC to block numbers properly.
6. Wonder whether something with a serial port is a DTE or a DCE.
How about knowing what DTE and DCE mean in the first place.
Along with why CTS/RTS (HW) flow control was really needed at high speed.
Why the UNIX community tended to migrate to aftermarket DH11, instead of DZ-11s - particularly for UUCP
8. Adjust jumpers on a peripheral
How about having the proper jumper sizes. Or realizing the DIP switches were not actually toggling properly so the address was wrong.
9. Insert or remove wires for IRQ bus continuity
Know what a BUS GRANT card does.