we soon discovered that while the floppies stated that they were single sided and the drives were only single side that careful use of a hole punch to add the required holes in the card cover
This was one of the causes of unreliability, the inserts in the single sided disks were typically from batches that had failed testing for double sided. Didn't stop us doing it though!
I also remember writing a program that allowed two machines to connect via serial cables
I thought Kermit was around by then but double checking it may not have been (it launched in 1981). I was using a 380Z from around 1979-1982.