[comp.sys.ibm.pc.misc] How do FAT tables differ between DOS 3.2 and DOS 4.x?

frank@odetics.com (Frank Merrow) (11/20/90)

Hi,

My machine was purchased long enough ago that DOS 3.2 was the best available
at the time.  Even though I have a 40Meg drive I have never been able
to get at more than 32Megs of it.  I was considering purchasing DOS 4.x to
get at the extra 8Megs, but I got to looking at the way the drive is currently
defined.  Since the 32Meg partition has (almost exactly) 16K clusters in it
seems likely that the DOS 3.2 limitation was 16K clusters in a partition.

THE QUESTION:

I have LOTS of small files.  If DOS 4.x allows larger partitions by giving
me 4k (or more) clusters instead of the 2k I have now, I will likely NOT
get ANY benifit out of the larger partition.  Does DOS 4.x get at the extra
space with a bigger FAT table (more clusters) or by bigger clusters?  Also
my "Mace Utilities" dates from this time as well.  Does anyone know off hand
if an "older" version of Mace can handle DOS 4.x partitions, or will I need
to update/repurchase?

Frank
frank@odetics.com or uunet!odetics!frank

plim@hpsgwp.sgp.hp.com (Peter Lim) (11/22/90)

/ frank@odetics.com (Frank Merrow) /  6:15 am  Nov 20, 1990 / writes:

> My machine was purchased long enough ago that DOS 3.2 was the best available
> at the time.  Even though I have a 40Meg drive I have never been able
> to get at more than 32Megs of it.  I was considering purchasing DOS 4.x to
> get at the extra 8Megs, but I got to looking at the way the drive is currently
> defined.  Since the 32Meg partition has (almost exactly) 16K clusters in it
> seems likely that the DOS 3.2 limitation was 16K clusters in a partition.
> 
What do you mean 16K clusters ? The last time I use DOS 3.2 was about
3 years ago. I seems to remember that DOS 3.2 allocates 2K per cluster
for hard disk size > 16 MB and (<= 32 MB). ie. 16 bit FAT. For
hard disk size <= 16 MB, DOS chooses 12 bit FAT and you get 4 K per cluster.

For DOS 4.x, my experience is that with partition > 32 MB <= 128 MB, you
get 2K cluster; > 128 MB <= 256 MB, you get 4 K cluster; and > 256 MB and
<= 512 MB, you get 8 K cluster.


> THE QUESTION:
> 
> I have LOTS of small files.  If DOS 4.x allows larger partitions by giving
> me 4k (or more) clusters instead of the 2k I have now, I will likely NOT
> get ANY benifit out of the larger partition.  Does DOS 4.x get at the extra
> space with a bigger FAT table (more clusters) or by bigger clusters?  Also
>
Seems like you should be okay if you have <= 128 MB disk. My experience
is with HP's MS-DOS 4.01. So, your mileage might vary --- I say this
because nobody seems to agree on what is the largest disk DOS 4.x can
accomodate (so .... something is unknown).


> my "Mace Utilities" dates from this time as well.  Does anyone know off hand
> if an "older" version of Mace can handle DOS 4.x partitions, or will I need
> to update/repurchase?
> 
Never use MACE, but I would try the old version with data which I don't
mind losing.


Regards,     . .. ... .- -> -->## Life is fast enough as it is ........
Peter Lim.                     ## .... DON'T PUSH IT !!          >>>-------,
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