[LeoPanthera]

The most common Macintosh archive format was (eventually) StuffIt, but StuffIt Expander couldn't open a .sit file which was missing its resource fork, and when you downloaded a file from the internet, it only came with a data fork.

So a common hack was to binhex the .sit file. Binhex was originally designed to make files 7-bit clean, but had the side effect that it bundled the resource fork and the data fork together.

Later versions of StuffIt could open .sit files which lacked the resource fork just fine, but by then .zip was starting to become more common.

[amatecha]

I could be remembering wrong, but didn't later versions of stuffit compress to a .sit file that had no resource fork, so it would stay fully-intact on any filesystem? I may be imagining that, but I remember hitting a certain version where "copying to Windows" would no longer ruin my .sit files... haha

[EkriirkE]

I don't remember there ever being a resource fork, but I Think around v4 it started allowing you to drag-n-drop any file to decompress, ignoring the missing/required finder info from previous versions

[LeoPanthera]

It's been a long time, but I don't think that's exactly true. The resource fork simply became optional, assisted by later versions of MacOS, which let applications open files which didn't have one.

[amatecha]

Ahh hmm OK, I'll have to check into this some time. I feel like the filesize would stay the same (suggesting no loss of data), but it's totally possible I'm misremembering considering how long it has been, hahah :)

[LeoPanthera]

It's quite plausible that the "file size" simply didn't include the resource fork.