Volume Parameter Block (VPB)

- Creates Logical association b/w PDO & LVDO
- Only exists for Dev Objs that represent physical or virtual media, that can be mounted.
- There is no physical association b/w the PDO & LDO representing a mounted vol, as would typically happen in an attach operation, this is typically done for filters to intercept the requests to the target dev obj.
- Has information abour volume Serial number, Volume Label and Volume label length
- IN a mount op. the only connection b/w PDO and LVDO is VPB
- I/O M is aware of this logical association & always checks the VPB on receipt of a Create/Open call for an on-disk obj. to determine the FS vol dev obj in which the req should actually be directed.
- Each File Obj (FO) struct represents a successful open Op. on an on-disk obj, points to the VPB struct belonging to the PDO on which the opened on-disk obj resides.