IBM 8" Floppy Cartridges?

I've dealt with some companies that only had a System/3x, and others that also had mainframes. In the latter group, I never heard of any plans to use the System/3x as a backup for any of the mainframe workload, though I suppose in some circumstances that might have been possible. One company ran some of their COBOL and Fortran programs on their local System/36 because they got shorter turnaround time running them locally than by submitting RJE jobs to the remote mainframe. They used RJE for the jobs that were too large or too computationally intensive for the System/36. I think they also did some of their COBOL development on the System/36 for programs eventually intended to run on the System/370, though obviously you can't do that if the COBOL program will use mainframe facilities unavailable on the System/36.