| Platform SDK: Files and I/O | 
The TAPE_SET_MEDIA_PARAMETERS structure describes the tape in the tape drive.
typedef struct _TAPE_SET_MEDIA_PARAMETERS {
  DWORD BlockSize; 
} TAPE_SET_MEDIA_PARAMETERS, *PTAPE_SET_MEDIA_PARAMETERS; 
There is no longer a requirement that block sizes be powers of 2.
  Windows NT/2000: Requires Windows NT 3.1 or later.
  Header: Declared in Winnt.h; include Windows.h.
Tape Backup Overview, Tape Backup Structures, GetTapeParameters, SetTapeParameters