[arachne] Re: Comprrressing ramdrives

Arachne at FreeLists---The Arachne Fan Club!

On Wed, 05 May 2004 15:15:14 +0200, Bart Buitinga wrote:

> Just another speedy idea:
> Use a disk compressor (not win9+ drvspace because it won't run in DOS)
> to create an empty volume, mount it, install arachne, unmount, unattrib
> it if necessary, zip it and write a batch to put it on a ramdrive.

> When?  If low on XMS (if 4 / 8 MB total mem) and already using disk
> compression.

At least with Stacker (3.12 shipped with DR-DOS) you don't have to
use hard disk compression, you can force Stacker to load always with
STACKER.INI; I don't know whether it is possible with MS DBLSPACE/
DRVSPACE, because I never used them.

Then, you can create empty volumes any time (with CREATE.EXE).

> Additional questions: Which compressor would make best compressable
> empty volumes? (Dos6 drvspace volumes won't compress more than about 40%
> and that's just lousy)

Well, Stacker doesn't physically wipe the whole STACVOL.xxx file,
just stores the necessary information that it is empty, so most of
it may contain random garbage (the previous contents of the clusters
allocated for the Compressed Volume File). Similarly, formatting
a hard disk parition doesn't wipe the files, just clears the File
Allocation Table and Root Directory (internally, the CVF contains
such data structures as well). I wouldn't expect MS DriveSpace to
behave much differently, and 40% compression for random data wouldn't
be particularly lousy ;-)

I tried creating a 6 MB empty STACVOL.DSK on a 'fresh' RAMdisk
(just after booting) and it was almost all-zeroes. PKZip squeezed
it to about 6 KB, saying 100% compression ;-) BTW, Stacker seems
to require 512-byte sectors (which can be forced on RAMdisks, of
course).

Michal


Arachne at FreeLists
-- Arachne, The Web Browser/Suite for DOS and Linux --

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