Module dpb 

Disk Parameter Block Module

This contains disk parameter blocks (DPB) for CP/M disks. There is no standard for storing a DPB on a CP/M disk; all we know is the BIOS must generate it somehow. As a result, we end up with the strategy of keeping a few likely DPB’s on hand to try heuristically.

Structs

DiskParameterBlock

The Disk Parameter Block (DPB) was introduced with CP/M v2. This allows CP/M to work with a variety of disk formats. The DPB was stored somewhere in the BIOS. The parameters are interdependent in a complicated way, see verify function. Fields are public, but should be changed by hand only with caution.

Constants

A2_525

CPM1

DSDD_525_OFF1

This covers Kaypro 4 disks. Kaypro sector id’s are sequenced by cylinder, but we still regard SPT as the count of sectors on only one side. 32*(DRM+1) uses half the blocks mapped by AL0. The remainder are reserved OS blocks.

NABU

SSDD_3

SSDD_525_OFF1

This covers Kaypro II disks. 32*(DRM+1) uses half the blocks mapped by AL0. The remainder are reserved OS blocks.

SSDD_525_OFF3

This covers upgraded Osborne1 disks

SSSD_525

This covers standard Osborne1 disks

TRS80_M2