

NOVELL TECHNICAL INFORMATION DOCUMENT

DOCUMENT PROCESSING INFO:  FAX - this TID replaces FYI.M.1208 (drdos fax 
document #5208)
TITLE:  FDISK and Cluster Size
DOCUMENT ID:  TID800069
DOCUMENT REVISION:  A
DATE:  18AUG94
AUTHOR:  DPARTRID;KBANTA
ALERT STATUS:  Yellow
DISTRIBUTION:  Public
INFORMATION TYPE:  Issue
README FOR:  NA
NOVELL PRODUCT CLASS:

Desktop Products

NOVELL PRODUCT and VERSION:

DR DOS 6.0

CATEGORY:

Disk Utilities

ABSTRACT:

This document discusses the relationship between partition size (set through 
FDISK) and cluster size.

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THE ORIGIN OF THIS INFORMATION MAY BE INTERNAL OR EXTERNAL TO NOVELL.  NOVELL 
MAKES EVERY EFFORT WITHIN ITS MEANS TO VERIFY THIS INFORMATION.  HOWEVER, THE 
INFORMATION PROVIDED IN THIS DOCUMENT IS FOR YOUR INFORMATION ONLY.  NOVELL 
MAKES NO EXPLICIT OR IMPLIED CLAIMS TO THE VALIDITY OF THIS INFORMATION.
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ISSUE

The cluster (or file allocation unit) size that FDISK will select depends on 
the size of the partition (or logical drive) being created.

The following table shows the cluster sizes that correspond to various 
partition sizes.

PARTITION SIZE         FAT SIZE   SECTORS/CLUSTER  CLUSTER SIZE
up to 15.9 MB           12 bit           8              4K
16 - 127.9 MB           16 bit           4              2K
128 - 255.9 MB          16 bit           8              4K
256 - 511.9 MB          16 bit          16              8K
512 - 1023.9 MB         16 bit          32             16K
1 - 2 GB                16 bit          64             32K

It is theoretically possible for FAT size and cluster size to vary from this 
table.  For example, it is possible for a partition up to 8 MB in size to 
have 12 bit FAT and 2K clusters, which would give more efficient usage of 
space. However, the FDISK utilities in DR DOS 6.0, Novell DOS 7, and MS DOS 
6.x all comply to the table listed above.


A more detailed discussion of DOS partitioning, cluster sizes, and the 
implications thereof can be found in TID800066 (Selecting FDISK Partition 
Size).

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