I think CMS finally added tree structured directories, but it was after I was using it regularly so I never used them much. > Also, if I remember correctly, th

I think CMS finally added tree structured directories, but it was after I was using it regularly so I never used them much. > Also, if I remember correctly, the drives addressed by letters were virtual drives In most cases they were virtual drives (attached to your virtual machine) that were mapped to a set of contiguous cylinders on a physical drive. (But you could allocate a virtual drive that consisted of an entire physical drive if you wanted to, which could be useful if you wanted an entire device to be managed by some guest operating system that was running in a VM/370 virtual machine.)