So there’s three options: index at the beginning, index at the end and no index. Index at the beginning means it’s easy to look up, but impossible to add anyth

So there’s three options: index at the beginning, index at the end and no index. Index at the beginning means it’s easy to look up, but impossible to add anything. No index, which is tar, means it’s impossible to tell what’s in it without reading the entire file. Index at the end, which is zip, means you have to do slightly more work to find the index, but then you can read it without reading the rest of the file, and move it further along the file if you want to extend the file and you can edit it or add to it. And if you want compression tar is just a compressed blob and the only thing you can do is read it from beginning to end. That’s just not very helpful unless the only things you want to do are packages a bunch of things and unpack all of them. A major use case but one met perfectly fine by hundreds of formats.