Changes
/* Extended Disk Parameter Block (DPB,CSA,ALT) for Drive A/B */
48h 2 Checksum accross [05h..47h]
== XDPB - Extended Disk Parameter Block (DPB,CSA,ALT) for Drive A/B ==
00h 2 SPT Records per Track (CPM/Data=36, IBM=32)
02h 1 BSH Block Shift (3) (records per block = 1 SHL N)
