Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!cpqhou!scotts
From: scotts@cpqhou.UUCP (Scott Shaffer)
Newsgroups: comp.sys.ibm.pc
Subject: Re: > 32MB partitions wanted
Keywords: partition large 32
Message-ID: <562@cpqhou.UUCP>
Date: 8 Mar 90 06:00:00 GMT
References: <10365@ttidca.TTI.COM> <217@metapyr.UUCP> <202@vela.acs.oakland.edu> <12961@udenva.cair.du.edu>
Lines: 52

In article <12961@udenva.cair.du.edu>, news@udenva.cair.du.edu (netnews) writes:
> 
> compaq 3.31 does also, but i think it uses 32 bit FATs as opposed to 16 bits
> like the rest of the world. 

This is not the case actually.  All the 3.31s use 16-bit FATs, just like
you would expect.  The thing they change is the sectors per cluster size
in order to make the big disk fit.  This is not efficient, but it works.
DOS 4.0 uses the same strategy, but allows up to 2GB (3.31 is limited to
a wimpy 512MB, which HAS been reached by the 615MB drives).  It does this
by raising the sectors per cluster size.  For a 2GB partition, that would
mean 64spc, or 32KB clusters!  And, since a cluster is the REAL minimum
size for a file, that little 10 byte batch file actually takes 32KB from
your disk (but then again, if you've got 2GB, would you notice?).  This
can be a problem.  I was once told of a man who had filled his 10MB
drive and went out and bought a new 20MB to replace it.  Well, he backed
up the 10MB drive and restored it to the 20MB.  Much to his surprise,
he only had 5MB free!  Was his disk bad?  No, the sectors per cluster
size had doubled, and with a lot of small files this resulted in a lot
of unused space being taken up by the small files.

> i use 4.01 DOS..
Good man.  I use it too, but I have to say I just did it out of the
habbit of upgrading...   But what did I get?  DOS 4.0 has a better
command line interpreter, DOSHELL (better known as DOS HELL), a new
command called MEM (interesting really, the neatest thing I've seen
in DOS in a while), and the ability to put a little more in extended
memory (not much though).
> 
> question:  many people complain about 4.01 having problems, but the only
> problem i ever saw was with a cheap shareware program. what are these
> supposed incompatibilities?
>
Well, I don't know if any incompatibilities, besides the ones that come
up because somebody hard-coded the line that says:
if (_dos_major_ver != 3) then throw_up();

I do know that DOS 4.0 takes a LOT more base memory than 3.31.  That is
why some network companies recommend it, because with thier drivers
and DOS 4.0 there isn't enough memory left to run any apps.  

Oh yeah, I just remember that LapLink 3 says it won't work with DOS 4,
but then again it doesn't understand 16-bit fats (ie. it wont work with
big 3.31 partitions either).

+==========================================================================+
| Scott Shaffer    |  Compaq Computer Corporation @ Houston TX             |
| Systems Engr     | (These opinions do not necessarily reflect those of my|
| SW Development   | employer, friends or any living person.)		   |
+==========================================================================+
"Unix is a registered bell of AT&T trademark laboratories."
			from a University of Utah Research Paper