Tables and Formats used by DOS & BIOS

These topics contain information about various structures and formats that are used in x86 systems with MS-DOS.

Disk drives and filesystem

• DOS BACKUP Control Information
• Boot Sector (since DOS 2.0)
• Disk Partition Table (Fixed disk boot record)
• DIRECTORY - DOS Directory Structure
• DBT - Disk Base Table (BIOS INT 13)
• DTA - Disk Transfer Area (partially undocumented)
• DPT/DPB - Drive Parameter Table / Disk Parameter Block
• Drive Status Bytes Found in BIOS Data Area
• FAT - File Allocation Table
• FCB - Standard DOS File Control Block
• DOS File Attributes
• DOS Default/Predefined File Handles
• Common Floppy Disk Formats
• Media Descriptor Byte
• System File Table (Undocumented)
• XFCB - Extended DOS File Control Block

Devices

• Device Driver Attribute Values (brief)
• Device Command Codes (Device Request Header)
• Device Driver Header
• Device Request Header Format
• Device Status Word

Display

• Box Drawing Characters
• Color Definitions
• Video Information Tables
• Video modes and corresponding number of pages

Machine

• BDA - BIOS Data Area - PC Memory Map
• BPB - BIOS Parameter Block
• EBDA - Extended BIOS Data Area EBDA (PS/2)
• Floating Point Formats
• Machine Identification Byte
• BIOS System Descriptor Table (PS/2)

Keyboard

• Keyboard Flags Bytes 0 and 1
• INT 9 - Hardware Keyboard Make/Break Codes
• INT 16 - Keyboard Scan Codes

Executables

• .EXE - DOS EXE File Structure
• MCB - DOS Memory Control Block Format
• GDT - Global Descriptor Table
• PSP - DOS Program Segment Prefix Layout

Miscellaneous MS-DOS

• BCB - Batch Control Block (undocumented)
• Code Page and Country Codes
• DOS Country Codes (DOS 2.x)
• DOS Error Codes
• VERSION - Versions of DOS