Opening somthing.rar also reads the data in somthing.r01 through somthing.r15 etc
Oh so it’s just kinda a part of the rar specification then? How did that work on CDs or floppies, if presumably you’d have had to swap out to insert the next part?
Yes, it asks for the next part if it’s not in the same folder with the same name, doesn’t really make a difference what it’s stored on. Multipart zip and tar also exist.
So the first file acts as a sort of index? From the earlier comment I thought it was autodetecting the presence of the numbered files and expanding what it found.
It’s going to have some metadata to that effect yes, like a file index or number of parts or total extracted file size. I don’t know the details, I’ve used them I haven’t read the spec. rar is Rarlab’s proprietary format so there might not even be a public spec.
They’re normally all the same size except for the last part, so it’s not that file 1 is just an index.
