I'm just wondering what this byte actually looks like. My textbook says that it's dependent on OS but often ctrl + Z.

Ok, fair enough. But as I see it, there are only 256 possible distinct values for a byte, and all are listed in a chart of ASCII codes, in which some of the ones 31 and lower are still mysterious to me.

But, if you want to interpret those bytes as numbers rather than characters, you can't exclude any of the possible 256 values. int, for example, needs all 256 possibililities if it's going to store its 4 billion plus possible values in 4 bytes of memory.

Do we actually need more than 4 bytes to store an arbitrary integer on disk so that there's available space to tell us when we've reached the end of the file?

Could someone explain the mechanics of this?

What I'm not seeing is how a file can at the same time leave all 256 options open for storing a numeric value in a byte and at the same time have some specific byte value that definitively signals the end of a file.