Parameter | Open System | IBM z System (Mainframe) |
Storage Type | FBA (Fixed Block Architecture) | CKD (Count Key Data) |
Connectivity | Fibre Channel/SCSI etc | ESCON/FICON |
Character sets | ASCII | EBCDIC |
Extent Size | 16 MiB, 1GiB | 21 cylinders (or) 1113 cylinders |
Base | Used by many OEMs | IBM proprietary |
Note: Whether Flash or HDD, it’s still an emulated track for zOS or FB environments