Re: [Freedos-user] Re : Support for 4k byte

[dmccunney <den...@gm...>]

On Wed, Feb 8, 2012 at 4:10 PM, Bertho Grandpied <y31...@ya...> wrote:
 dmccunney <dennis***> wrote :
>
>> (albeit much of the additional space is lost slack at  the user files level ...)
>
> Slack space will be a real issue?  I don't see how.
>
> There would be a net loss for partitions sizes and file systems comprised of less than
> 4K bytes per cluster. You are right, not a big problem, in general. I was repeating what
> I read, without too much thinking.

Slack space was an issue under FAT12/16, because the minimum unit of
disk MS-DOS would read/write in one operation was the cluster, and
there was a hard limit to the number of clusters possible.  (65,536
under FAT16.)  Cluster size varied depending on volume size, with a
2GB volume and a 32KB cluster being the top end.  Only one file could
be on a cluster, so it was possible to have a one byte file that would
require 32KB on disk.  Disks were smaller and more expensive, and
various schemes were used to minimize slack space to store the most
data possible.

FAT32 removed the limit on the number of clusters, but the concern
wasn't slack space: it was allowing larger logical volumes on drives.
Partitioning to create multiple 2GB volumes seen as separate drives
got old fast.

Current hard drives are huge and cheap, and getting bigger and
cheaper.  I wouldn't call slack space a problem in particular there
days, let alone in general.  The amount of storage lost to slack apace
simply isn't big enough to be worth addressing.

> Czerno
______
Dennis