# C9 — File format magic numbers

For C9, offset is 0; extension is com; format is <https://en.wikipedia.org/wiki/COM_file_(CP/M)> CP/M 3 and higher with overlays, recorded from its source on 2026-08-03.

- **Hex signature:** C9 _(unconfirmed — we could not tie this to the quote below)_
- **Offset:** 0 _(unconfirmed — we could not tie this to the quote below)_
- **Extension:** com
- **Format:** <https://en.wikipedia.org/wiki/COM_file_(CP/M)> CP/M 3 and higher with overlays

## What the source says

> <https://en.wikipedia.org/wiki/COM_file_(CP/M)> CP/M 3 and higher with overlays [ 27 ]

## Source

- https://en.wikipedia.org/wiki/List_of_file_signatures

Last verified: 2026-08-03. Review by: 2027-08-03.
Part of [File format magic numbers](https://referencesource.org/file-format-signatures/).