At the time I was a hardware engineer and I installed and upgraded so many System/34/36/38s I couldn't count them all. It was, by modern standards, dinosaur-era hardware but I loved working on them every time.
To add the 2nd frame onto a S/38 - the L-shaped frame on the left, held more I/O cards and I think four more 62ED disk drives (64MB each, IIRC) - there were data cables that ran from the far corner of the 2nd frame to the extreme lower right corner of the card cage in the main unit. The cables ran through every cable channel and card gate in the system, and if the weren't run exactly the way IBM wanted them to be run, they'd come up about a half an inch short and you'd have to re-run them again.
To add the 2nd frame onto a S/38 - the L-shaped frame on the left, held more I/O cards and I think four more 62ED disk drives (64MB each, IIRC) - there were data cables that ran from the far corner of the 2nd frame to the extreme lower right corner of the card cage in the main unit. The cables ran through every cable channel and card gate in the system, and if the weren't run exactly the way IBM wanted them to be run, they'd come up about a half an inch short and you'd have to re-run them again.
Miserable? Nah. Good times.