2 large hard drive questions

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djc

I just installed a 250GB drive (WD WD2500JB). No problems with BIOS or OS
(xp sp2) recognizing and using the drive, supports 48bit LBA.

However,

1) I noticed that Disk Manager in Windows XP SP2 reports the disk as 232.88
GB? I know that the 'marketing' number on the box of the drives is not exact
and when you do the actual math there are differences between the
'marketing' number and the 'real' number (largely due to manufacturers using
1000 instead of the proper 1024 bytes = 1 KB). I can't think of how to work
this out at the moment to see if that is all my descrepency is, or if there
is something else wrong here. I'm used to working with 20-40 GB drives where
these differences did not amount to much so I know when going to such a
large drive they will be compounded. Is my 232.88 GB correct? and how do I
do that math?

2) What about the 'allocation unit size' (If I remember correctly this is
the same as the 'cluster' size, correct me if I'm wrong please) when
formating a partition on the drive? I have always left this at the default
value for NTFS partitions. Now that I'm dealing with such a large drive does
this setting become more important? how significant is it? what should I set
it to?

any input is apprecated... my A+ skills are pretty rusty.

Thanks.
 
1.Open My Computer and right click the drive in question , select properties. In the center you will
see capacity of about 250,056,740,000 bytes 232 GB (thats what I have for my 250).

2. I am pretty sure NTFS uses the 4k cluster size no matter the size of the drive. When you run the
disk defragmenter and do an analyze it will tell you the cluster size in the report.
 
djc said:
I just installed a 250GB drive (WD WD2500JB). No problems with BIOS or OS
(xp sp2) recognizing and using the drive, supports 48bit LBA.

However,

1) I noticed that Disk Manager in Windows XP SP2 reports the disk as
232.88 GB? I know that the 'marketing' number on the box of the drives is
not exact and when you do the actual math there are differences between
the 'marketing' number and the 'real' number (largely due to manufacturers
using 1000 instead of the proper 1024 bytes = 1 KB). I can't think of how
to work this out at the moment to see if that is all my descrepency is, or
if there is something else wrong here. I'm used to working with 20-40 GB
drives where these differences did not amount to much so I know when going
to such a large drive they will be compounded. Is my 232.88 GB correct?
and how do I do that math?
Click to expand...

232.885591685771942138671875 GB is the actual number. WD refers to MB as
1,000,000 bytes and states the formatted capacity of this specific hard
drive as 250,059 MB.
Another words multiply 250,059 times a million, or 250,059,000,000 gives the
capacity in bits. Divide this by 1024, 3 times, gives you the term in
actual GBs used by the PC.
2) What about the 'allocation unit size' (If I remember correctly this is
the same as the 'cluster' size, correct me if I'm wrong please) when
formating a partition on the drive? I have always left this at the default
value for NTFS partitions. Now that I'm dealing with such a large drive
does this setting become more important? how significant is it? what
should I set it to?
Click to expand...

Yep, cluster size. If partitioning with XP's disk manager or XP install
setup CD, just leave it alone when done. It will format it automatically.

If you want a smaller cluster size, make a more suitable size partition for
XP for both the same identical partition for boot and system. Mine is 26GB
as an example. Use the remainder of the space for another partition that
may use predominantly large files of your own device.
 
thank you Jonny and David. That definitely clears up the 232.88 GB for me.

However, on the cluster issue, I was wondering what effect cluster size
would have on these big drives. I did install my OS on its own partition,
about 40GB and then formated the rest of the drive on another partition
using disk manager. Thats when I thought about whether or not I should use
the default cluster size, as I usually do, or not? It didn't matter much in
the past with smaller drives but I was thinking that in the same way the
manufacturers use of 1000 instead of 1024 is *much* more apparent now with
the *big* drives that this too (cluster size), may be much more significant
now? maybe using a smaller size gains you significantly more usable space
now? If I remember correctly the smallest unit of storage on the formated
disk is equal to the cluster size, which is a component of file system,
rather than physical hard drive. So if for example you have a 16K cluster
size and you save a 17K file to the partition, it actually takes up 32K of
space.

If my memory is correct, I think I just answered my own question. I would
think smaller cluster size *would* have a much bigger impact now, in
general. It does depend on the types/sizes of files being saved on the
partition.

Am I remembering correctly? what do ya think?
 
I just checked my 250 which I just did a plain format using NTFS from Disk management and it says
that the clusters are 4 K. Your recollection is correct to the way clusters are used. The use of
partitions is strictly personal now, I personally use 4 different disks and each has 1 partition. 2
40's, 250, and 320.
--
Dave Vair
CNE, CNA, MCP, A+, N+

djc said:
thank you Jonny and David. That definitely clears up the 232.88 GB for me.

However, on the cluster issue, I was wondering what effect cluster size would have on these big
drives. I did install my OS on its own partition, about 40GB and then formated the rest of the
drive on another partition using disk manager. Thats when I thought about whether or not I should
use the default cluster size, as I usually do, or not? It didn't matter much in the past with
smaller drives but I was thinking that in the same way the manufacturers use of 1000 instead of
1024 is *much* more apparent now with the *big* drives that this too (cluster size), may be much
more significant now? maybe using a smaller size gains you significantly more usable space now? If
I remember correctly the smallest unit of storage on the formated disk is equal to the cluster
size, which is a component of file system, rather than physical hard drive. So if for example you
have a 16K cluster size and you save a 17K file to the partition, it actually takes up 32K of
space.

If my memory is correct, I think I just answered my own question. I would think smaller cluster
size *would* have a much bigger impact now, in general. It does depend on the types/sizes of files
being saved on the partition.

Am I remembering correctly? what do ya think?
Click to expand...
 
With NTFS, if it ain't broke, don't fix it.

4K cluster size is fine for windows partition.

Now, just go have some fun with the PC. Pondering any further tweaking is
worth much less in the gains seen.
--
Jonny
djc said:
thank you Jonny and David. That definitely clears up the 232.88 GB for me.

However, on the cluster issue, I was wondering what effect cluster size
would have on these big drives. I did install my OS on its own partition,
about 40GB and then formated the rest of the drive on another partition
using disk manager. Thats when I thought about whether or not I should use
the default cluster size, as I usually do, or not? It didn't matter much
in the past with smaller drives but I was thinking that in the same way
the manufacturers use of 1000 instead of 1024 is *much* more apparent now
with the *big* drives that this too (cluster size), may be much more
significant now? maybe using a smaller size gains you significantly more
usable space now? If I remember correctly the smallest unit of storage on
the formated disk is equal to the cluster size, which is a component of
file system, rather than physical hard drive. So if for example you have a
16K cluster size and you save a 17K file to the partition, it actually
takes up 32K of space.

If my memory is correct, I think I just answered my own question. I would
think smaller cluster size *would* have a much bigger impact now, in
general. It does depend on the types/sizes of files being saved on the
partition.

Am I remembering correctly? what do ya think?
Click to expand...
 
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