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.


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