Why do Photoshop files start with 8BPS?

Question

From pretty much the beginning of time Photoshop files have begun with 8BPS. (I have verified this back to version 2.5) It must have had some meaning at some point.

The 8B I thought might refer to bits/channel, but it makes no difference saving it 16 or 32. PS is probably PhotoShop, but might not be. Something to do with the way Mac saved files?

Answer 1

8B is shorthand for Adobe. I guess "eight bee" sounds a little bit like Adobe; more so if you're Italian - "Otto Bee".

And PS is "Photoshop". So, 8BPS is "Adobe Photoshop".

8B crops up in quite a few places in Adobe file extensions or internal types. Wikipedia has a list.

Answer 2

That is just the Signature to identify the file as a Photoshop file. From the Specification:

Signature: always equal to '8BPS' . Do not try to read the file if the signature does not match this value.

See the Photoshop File Format Specification for more detailied information.