[arachne] Re: Comprrressing ramdrives with Stacker

[Bart Buitinga <bartbuitinga@xxxxxxxxx>]

Arachne at FreeLists---The Arachne Fan Club!

All done.

Empty stacvols can be compressed 99% whereas drvspace seems to have some 
obscure resistance against it. And to compress a ramdrive nothing else 
is needed than the SCREATE RD: command, and provided stacker.com was 
loaded from config.sys with no options, claiming one spare driveletter, 
mounting the new volume would require STACKER SP:=RD:STACVOL.DSK to be 
entered ("DEVICEHIGH=STACKER.COM @" enables mounting with STACKER @RD: , 
hiding the hostdrive completely)
Stacker.com (version 2) can be loaded high (although it complains about 
this unknown treatment), is about 44KB in size and reports exactly 
double diskspace, but reports 3.2:1 after unpacking archn169.exe.

PKZipping the a169 install results in a 1.153.915 Bytes zip (the 
original sfx is 1.005.710 Bytes), with pkzip 2.06

Comparing the zippability of compressed ramdrive volumes there's a funny 
conclusion to be drawn: Since those high compression rates (99/100%) can 
only be achieved after a reboot, deallocated RAM must get as polluted as 
deleted diskspace. Even after reinstalling xmsdsk, stacvols won't 
compress to the same degree, so they must contain whatever the previous 
RAM installation left there. (In fact you can see at the progress 
counter that pkzip slows down at the same place, then maybe that place 
and another one, getting slower after more work has been done in the 
same area, with or without ramdisk)

After a single run unpacking archn169.exe since reboot the _next_ 
ramdrive stacvol will compress to 67%

This calls for another standard: Freshly installed ramdrives are to be 
filled with a repetitive textfile, which is then deleted before screate.
The empty stacvol created on this drive compresses again to 100% even 
after having had previous installs in RAM.

(For filling diskspace I use the following:

**fill.bat**
echo.>wipethis
:x
type wipethis>>wipethis
goto x

which results in diskspace being completely filled with cr/lf until 
interrupted with ^C, then a file called wipethis has to be deleted 
before compressing the RD: )

Recomparing with Drvspace vols (Created on now "cleanfilled" HDD space) 
now also show 100% compression with pkzip, but stacker still wins for 
better flexibility and controllable compression factor "estimate" which 
may be set to 3 for a plain Arachne install (but lower when caching 
graphics or binaries on the RD).

So for those who have Stacker 2.0, your simms will triple if you:
1. add DEVICEhigh=STACKER.COM in config.sys
2. apply the following batch in which SP: is the spare drive mentioned 
by Stacker at boot:
XMSDSK 6000 RD:
SCREATE RD:
STACKER SP:=RD:\STACVOL.DSK

But then again: Is Stacker shareware? (I just found it on a HDD with 
ms-dos 5.0 and win3.1, and it claims to be registered to one abc.xyz)

Regards,

B

Michal H. Tyc wrote:
> 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).

I'm not really sure about the version number, but the Stacker I used to
play with had som utilities like screate and scheck (possibly sdefrag).
I can hardly imagine that the same limitations that M$ used to
"stabilise" Dos6.2 would also have affected Stacker, so probably
screate RD: would be sufficient.
> 
> 
>>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 ;-)

For the initial Arachne install, there would be no problem if the
remainder of the compressed volume would be unaffected after copying
Arachne. What puzzles me is that M$-drvspace volumes too, contain only
dots (zero's in the hex window) and pkzip "implodes" the fresh and empty
file from 6 to 4 MB only, as do Arj and Winzip, btw. I think Stacker
will win this contest, and since it's there on two MFM drives at the
bottom of the pile, just waiting to be dug up, I think I'll be back soon...

Bart

> 
> 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 --
> 
> 
> 



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

• References:
  • [arachne] Re: Comprrressing ramdrives
    • From: Michal H. Tyc

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