If I use the extreme byte size of 1 gb vs 1 mb for instance, on the hardware level, what is the difference? What does a byte size do if a constant stream of data is just getting written to the disk>?
The difference is in how much data is read/written at once.
Programs rarely work with true constant streams – they usually read and write data in pieces: read 1 kB from input, write 1 kB to output, read 1 kB from input, write... So the
It also depends on the storage media. Disks are not streams and aren't byte-addressed, whether magnetic or flash-based – they only allow reading block-sized pieces (where the block size depends on the hardware; many disks have it as 512 bytes or 4 kB). If the OS tries to read 100 bytes, the disk has to read the whole block anyway, and then discard the data. (It's even worse when writing: not sure with magnetic disks, but at least with flash, if you write 100 bytes the disk has to read the entire block, update it in memory, then write it.) So the block size used by