cluster-sector question

What are the advantages and disadvantages of 2 sectors per cluster vs. 4
sectors per cluster?

under fat, fat16, fat32 there are limits to the number of clusters the OS
can address, higher for each version
if there is one sector per cluster maximum disk size is (Example only I cant
remember what it actually is) 2 GB
64 sectors per cluster 128 GB
Cluster sizes are determined when creating the disk volume
changing the default cluster size for a given disk size is not usually
efficient, and may if the disk is large enough make the later parts of the
disk inaccessible
Large cluster sizes are efficient when the files are large 900MB video in
64sector clusters very little head movement to find the next cluster
Small cluster sizes are efficient where file sizes are generally small,
Windows boot files, batch files since a 1kb batch file can then occupy a 1
kb disk cluster, no slack space
A solution is to partition a large drive into two or more volumes, 1 or more
small enough to be efficient to store small docs on, and 1 or more large
enough to store large files efficiently,

--
-
Adaware http://www.lavasoft.de
spybot http://security.kolla.de
AVG free antivirus http://www.grisoft.com
Etrust/Vet/CA.online Antivirus scan
http://www3.ca.com/securityadvisor/virusinfo/scan.aspx
Panda online AntiVirus scan http://www.activescan.com
Panda online AntiSpyware Scan
http://www.pandasoftware.com/virus_info/spyware/test/
Catalog of removal tools (1)
http://www.pandasoftware.com/download/utilities/
Catalog of removal tools (2)
http://www3.ca.com/securityadvisor/n...aspx?CID=40387
Trouble Shooting guide to Windows http://mvps.org/winhelp2002/
Blocking Unwanted Parasites with a Hosts file
http://mvps.org/winhelp2002/hosts.htm
links provided as a courtesy, read all instructions on the pages before
use
Grateful thanks to the authors/webmasters
_
"b11_" wrote in message
...
What are the advantages and disadvantages of 2 sectors per cluster vs. 4
sectors per cluster?

Small clusters waste less space, but need a larger index (FAT) to manage
them, and that means more index accesses and updates for a given volume of
data.
--
Jeff Richards
MS MVP (Windows - Shell/User)
"b11_" wrote in message
...
What are the advantages and disadvantages of 2 sectors per cluster vs. 4
sectors per cluster?

So 2 clusters per sector waste less space then 4 cluters per sector?
__________________________________________________ ____________
"Jeff Richards" wrote:

Small clusters waste less space, but need a larger index (FAT) to manage
them, and that means more index accesses and updates for a given volume of
data.
--
Jeff Richards
MS MVP (Windows - Shell/User)
"b11_" wrote in message
...
What are the advantages and disadvantages of 2 sectors per cluster vs. 4
sectors per cluster?

On Mon, 22 May 2006 17:32:02 -0700, b11_
put finger to keyboard and composed:

So 2 clusters per sector waste less space then 4 cluters per sector?

Yes. On average you will save 1 sector per file, ie (4-2)/2. If you
have 10,000 files, then you will save about 5MB.

BTW, that should be sectors per cluster.
__________________________________________________ ____________
"Jeff Richards" wrote:

Small clusters waste less space, but need a larger index (FAT) to manage
them, and that means more index accesses and updates for a given volume of
data.
--
Jeff Richards
MS MVP (Windows - Shell/User)
"b11_" wrote in message
...
What are the advantages and disadvantages of 2 sectors per cluster vs. 4
sectors per cluster?

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

So 2 sectors per cluster waste less space then 4 sectors per cluster?

__________________________________________________ _________
"Franc Zabkar" wrote:

On Mon, 22 May 2006 17:32:02 -0700, b11_
put finger to keyboard and composed:

So 2 clusters per sector waste less space then 4 cluters per sector?

Yes. On average you will save 1 sector per file, ie (4-2)/2. If you
have 10,000 files, then you will save about 5MB.

BTW, that should be sectors per cluster.
__________________________________________________ ____________
"Jeff Richards" wrote:

Small clusters waste less space, but need a larger index (FAT) to manage
them, and that means more index accesses and updates for a given volume of
data.
--
Jeff Richards
MS MVP (Windows - Shell/User)
"b11_" wrote in message
...
What are the advantages and disadvantages of 2 sectors per cluster vs. 4
sectors per cluster?

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

"b11_" wrote in message

What are the advantages and disadvantages of 2 sectors per cluster vs. 4
sectors per cluster?

Just some pertinent information that was easier for me to just copy/paste some
portions of it right out of my Partition Magic help files.

After you read and understand it is why that you will find it's best to keep
your FAT32 OS primary partition(s) under 8 GB not only for best 4k cluster
size efficiency, but it's so much faster to defrag it, etc; you don't need anymore
than 8 GB anyway for the OS partition.

Then you take all of your Non-OS partitions and that is where you would
make all those larger according to your HD's size (but always under 128 GB)
...and use them for storage partitions - and the cluster efficiency may be bigger
yes but for storage drives and what it's used for it's not a big deal and not that
much is lost comparatively, and to me is a non-issue.

Rick
(gone on vacation ..now

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~

(copy/paste)

Making Efficient Use of Disk Space

If you have a large hard disk and want to use the FAT file system on all or
most of the disk, you can prevent wasted space by using several small FAT
partitions.
All data on a FAT partition are stored in allocation units called clusters.
Each cluster is made up of a fixed number of disk sectors. (sectors meaning
the smallest addressable section on a disk. It is used to record one block
of a program or data. Each head on each track is typically divided into 17
or more sectors)
The FAT file system supports disk or partition sizes up to 2 GB, but only
allows a maximum of 65,525 clusters. Therefore, whatever the size of the
hard disk or partition, the number of sectors in one cluster must be large
enough so that all available space can be included within 65,525 clusters.
The larger the available space, the larger the cluster size must be.

However, using a large cluster size wastes disk space. Even if a data file
(or the last portion of a data file) is much smaller than the cluster size,
the computer must still use a complete cluster to store the data. The rest
of the cluster space goes unused.
The following table shows the minimum cluster size and typical wasted space
for various partition sizes.

Partition Sizes Min Required Cluster Size % Wasted Space (approx.)
16-127 MB 2 KB 2%
128-255 MB 4 KB 4%
256-511 MB 8 KB 10%
512-1,023 MB 16 KB 25%
1,024-2,047 MB 32 KB 40%
2,048-4,096 MB 64 KB 50%

You can prevent wasted disk space by using smaller partitions, because
smaller partitions use smaller cluster sizes. For example, a 1,024 MB
partition has a cluster size of 32 KB. If you saved a 2 KB file to this
partition, an entire 32 KB cluster would be used to save the file, wasting
30 KB of space. However, if you divide your storage space into 120 MB
partitions, these partitions would only use 2 KB clusters. When you save
the same 2 KB file, the file would fit neatly into a 2 KB cluster, with no
wasted space.

About Resizing Clusters
Use Resize Clusters to change the cluster size on FAT and FAT32 partitions.
Reducing cluster size may help you reclaim wasted space on your hard disk.
All files on FAT and FAT32 partitions are stored in allocation units called
clusters. Each file is allocated at least one cluster, resulting in wasted
space in clusters containing small files. The size of a partition
determines cluster size. Larger partitions have larger clusters, and,
therefore, more wasted space.

Default Cluster Sizes
A partition's cluster size is set by the DOS FORMAT operation, based on the
size of the partition, as shown in the following tables.

DOS and Windows default FAT cluster sizes

Partition Size (MB) FAT Type Sectors Per Cluster Cluster Size
0-15 12-bit 8 512
bytes
16-127 16-bit 4 2 K
128-255 16-bit 8 4 K
256-511 16-bit 16 8 K
512-1,023 16-bit 32 16 K
1,024-2,047 16-bit 64 32 K
2,048-4,096 16-bit 128 64 K*
*Only available with Windows NT.


Windows 95 OEM Service Release 2, Windows 98, Windows Me, and Windows
2000/XP default FAT32 cluster sizes

Partition Size (GB) Sectors Per Cluster Cluster Size
0.256-8.01 8 4 K
8.02-16.02 16 8 K
16.03-32.04 32 16 K
32.04 64 32 K



FAT (File Allocation Table)
The FAT file system is used by DOS, Windows 3.x, and Windows 95 (in most
installations). The FAT file system can also be used by Windows
98/Me/NT/2000/XP.
The FAT file system is characterized by the use of a file allocation table
(FAT) and clusters. The FAT is the heart of the file system; for safety,
the FAT is duplicated to protect its data from accidental deletion or
corruption. Clusters are the FAT system's smallest unit of data storage;
one cluster consists of a fixed number of disk sectors. The FAT records
which clusters are used, which are unused, and where files are located
within the clusters.

The FAT file system supports disk or partition sizes up to 2 GB, but only
allows a maximum of 65,525 clusters. Therefore, whatever the size of the
hard disk or partition, the number of sectors in one cluster must be large
enough so that all available space can be included within 65,525 clusters.
The larger the available space, the larger the cluster size must be.
In general, large clusters tend to waste more space than small clusters.

The FAT file system also uses a root directory. This directory has a
maximum allowable number of entries and must be located at a specific place
on the disk or partition. OSs that use the FAT file system represent the
root directory with the backward slash character (\), and initially display
this directory at boot-up.
The root directory stores information about each sub-directory and file in
the form of individual directory entries. For example, a file's directory
entry holds information such as the filename, the size of the file, a date
and time stamp that indicates when the file was last changed, the starting
cluster number (which cluster holds the first portion of the file), and the
file's attributes (for example, hidden, system, and so forth).


FAT 32 (File Allocation Table 32)
FAT32 is a file system that can be used by Windows 95 OEM Service Release 2
(version 4.00.950B), Windows 98/2000/XP. However, DOS, Windows 3.x, Windows
NT 3.51/4.0, and earlier versions of Windows 95 cannot recognize FAT32, and
are thus unable to boot from or use files on a FAT32 disk or partition.
FAT32 is an enhancement of the FAT file system and is based on 32-bit file
allocation table entries, rather than the 16-bit entries used by the FAT
system. As a result, FAT32 supports much larger disk or partition sizes (up
to 2 terabytes).

The FAT32 file system uses smaller clusters than the FAT file system, has
duplicate boot records, and features a root directory that can be any size
and can be located anywhere on the disk or partition.


NTFS (New Technology File System)
The New Technology File System (NTFS) is accessible by Windows NT/2000/XP.
NTFS is not recommended for use on disks less than 400 MB because it uses a
great deal of space for system structures.
The central system structure of the NTFS file system is the master file
table (MFT). NTFS keeps multiple copies of the critical portion of the MFT
to protect against corruption and data loss.
Like FAT and FAT32, NTFS uses clusters to store data files; however, the
size of the clusters is not dependent on the size of the disk or partition.
A cluster size as small as 512 bytes can be specified, regardless of
whether a partition is 500 MB or 5 GB. Using small clusters not only
reduces the amount of wasted disk space, but also reduces file
fragmentation, a condition where files are broken up over many
noncontiguous clusters, resulting in slower file access. Because of its
ability to use small clusters, NTFS provides good performance on large
drives.