Origin of "partition" in storage devices
Maciej W. Rozycki
macro at orcam.me.uk
Mon Jan 31 22:53:41 CST 2022
On Mon, 31 Jan 2022, Fred Cisin via cctalk wrote:
> File sizes were stored as the last 4 bytes of each DIRectory entry, with a
> signed 32 bit number. So, a file could be from
> -2,147,483,648 to 2,147,483,647
> Unfortunately, they never successfully finished the implementation, so copying
> a negative size file to the drive did not increase the free space. Since they
> didn't make THAT work, perhaps they should have used an UNSIGNED 32 bit
> number, to permit files up to 4,294,967,295
Consider the file seek operation however: with the file size limited to
the 31-bit positive range of the signed 32-bit data type you can move the
file offset backwards and forwards through the entire range with a single
operation using the same data type. It would not be possible if the data
type was unsigned and all the 32 bits used for the file size.
Maciej
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