Software & Apps Windows What Is the Disk Parameter Block? Disk Parameter Block Definition (DPB) by Tim Fisher General Manager, VP, Lifewire.com Tim Fisher has 30+ years' professional technology support experience. He writes troubleshooting content and is the General Manager of Lifewire. our editorial process Facebook Twitter LinkedIn Tim Fisher Updated on February 18, 2020 Windows The Ultimate Laptop Buying Guide Tweet Share Email The disk parameter block, also known as DPB or media parameter block, is one component of the volume boot record and contains details about a disk's volume. Some of the volume details stored in the disk parameter block include the volume label, the volume serial number, volume size, and other information about the structure of the volume. Disk Parameter Block Structure and Location Offset Length (Bytes) Description 00h 1 Drive number; 0=A, 1=B 01h 1 Driver unit number 02h 2 Bytes per sector 04h 1 Sectors per cluster, minus 1 05h 1 Shift count to convert clusters into sectors 06h 2 Reserved sectors at beginning of drive 08h 1 Number of FAT copies 09h 2 Number of root directory entries 0Bh 2 Number of first sectors containing user data 0Dh 2 Number of clusters plus 1 0Fh 2 Number of clusters used by first FAT 11h 2 First sector of root directory 13h 2 Driver header address 17h 1 Media ID 18h 1 00h if disk is accessed; FF if not 19h 4 Pointer to next DPB 1Dh 2 Starting cluster for free space search 1Fh 2 Number of free clusters; FFFFh if unknown More from Lifewire What Is a Volume Boot Record? Active@ Partition Manager v6.0 What Is the Master Partition Table? What Is a Volume Label of a Drive? Vol Command Examples and Options What Is the Windows Boot Manager (BOOTMGR)? Volume Serial Numbers Erase or Format Your Mac's Drives Using Disk Utility How to Resize a Mac Volume With Disk Utility Disk Utility Can Create a JBOD RAID Set for Your Mac Use Disk Utility to Create a RAID 1 (Mirror) Array How to Use Disk Utility in macOS Use Disk Utility to Create a RAID 0 (Striped) Array How to Find a Drive's Volume Label or Serial Number How to Partition a Hard Drive What Is the Volume Boot Code?