{| class="wikitable"
|-
! Field !! Bytes !! Name !! Notes
|-
| rowspan="10" | System || 0 || User number || User number, #00..#FF
|-
| 1..8 || Filename || Unused characters are filled with space
|-
| 9..11 || Extension || Unused characters are filled with space
|-
| 12..15 || Zero || Contains all zeroes
|-
| 18 || File type || #16, unprotected ASCII version 1
This is only a summary. All details are in [[Firmware Guide]] chapter 9, page 4.
=== Expansion of the AMSDOS Header ===
Some OS and DOS expanded the classic AMSDOS header:
1. [[FutureOS Header]]:
* Contains and icon or information text
* File length is 24 Bit
* Defined Loading and Autostart (expansion) RAM configuration
* Additional file types
[[Category:Disc Operating System]]
[[Category:Programming]]