Re: 3.5" Disk archiving

["Tom Zuchowski" <tzuchow@attglobal.net>]

"Jeff Blakeney" <CUTjblakeney@sentex.net> wrote in message
o3tl4v07ov1emf8vciblvdvnoo47kapu2j@4ax.com">news:o3tl4v07ov1emf8vciblvdvnoo47kapu2j@4ax.com...
> On Wed, 12 Feb 2003 19:07:05 +1300, Roger Johnstone <rojaws@es.co.nz>
> wrote:
>
> >The warning: "Disk archives are an old archive format, are often larger
> >than file archives, and many people consider them inconvenient. Disk
> >archives are meant only for those occasions when there is no other way
> >to archive something (such as old DOS 3.3 disks)."
>
> Disk archives, when done using the method I described in my previous
> post in this thread, are only fractionally larger than a file archive.
> It is even possible for a disk archive to be smaller than a file
> archive if there are a large number of files involved.

(This reply applies to ShrinkIt. It may apply to GSHK as well, but I am not
sure about that.)

I wrote this subject up many years ago for the help files on Genie. I wish I
had that available to post here, as I did it in a very clear manner at that
time.

Quite often, disk archives are larger than the UNCOMPRESSED file contents of
the original disk!

Having done about a zillion disk archives for Genie when I was a librarian
there, I have to say that it will be a very rare occasion when a disk
archive is as small as a file archive. Here is why: ShrinkIt archives the
ENTIRE disk, including all of the "empty" sectors. Erasing a file does not
remove it from the disk, but merely deletes it from the disk catalog. If the
disk has seen activity where files have been erased, many of those "empty"
sectors will have old data in them. This erased data becomes a part of the
archive, increasing its size. For DOS 3.3 disks, the problem is even worse
as DOS itself becomes part of the archive.

The only way to avoid this is to format a fresh floppy, copy all of the
files onto it, and archive it before any files are erased. For DOS 3.3,
further savings can be realized by using Copy II+ or equivalent utility to
make a DOS-less disk.

Tom Zuchowski