Hardware Reference
In-Depth Information
Another thing to note is that this drive conforms to the SATA 3Gbps specification and is capable of
an interface transfer speed of 300MBps. As you can see, that is entirely theoretical because the true
media transfer speed of this drive varies between about 56MBps and 118MBps, averaging about
80MBps overall. The interface transfer rate is just that: what the interface is capable of. It has little
bearing on the actual capabilities of the drive.
The use of zoned recording enables drive manufacturers to increase the capacity of their hard drives
by 20%-50% or more compared to a fixed-sector-per-track arrangement. All modern drives use
zoned recording.
Partitioning
Creating a partition on an HDD enables it to support separate file systems, each in its own partition.
Each file system can then use its own method to allocate file space in logical units called
clusters
or
allocation units
. Every HDD must have at least one partition on it and can have up to four primary
partitions, each of which can support the same or different type file systems. Four common file
systems are used by PC OSs today:
•
FAT (file allocation table)
—The standard file system supported by DOS and Windows 9x/Me.
FAT is also the default file system used by Windows 2000 and later on flash or other
removable drives. FAT partitions support filenames of 11 characters maximum (8 characters +
a 3-character extension) under DOS, and 255 characters under Windows 9x (or later). The
standard FAT file system uses 12- or 16-bit numbers to identify clusters, resulting in a
maximum volume size of 2GiB.
•
FAT32 (FAT, 32-bit)
—An optional file system supported by Windows 95 OSR2 (OEM
Service Release 2) and later.
FAT32 uses 32-bit numbers to identify clusters, resulting in a maximum single volume size of
2TiB (32GiB recommended) and a maximum file size of only 4GiB.
•
exFAT (aka FAT64)
—An optional file system supported by Windows XP
(
http://support.microsoft.com/kb/955704
)
and by Vista SP1 and later.
exFAT uses 64-bit numbers to identify clusters, resulting in a maximum recommended volume
(and file) size of 512TiB.
•
NTFS
—The native file system for Windows NT and later that supports filenames up to 256
characters long and volumes (and files) up to (a theoretical) 16EiB. NTFS also provides
extended attributes and file system security features that do not exist in the FAT file systems.
Because NTFS is native to Windows 2000 and later (and required for Vista or later boot volumes),
NTFS is by far the most common file system in use on nonremovable drives. NTFS, however, is not
very compatible with non-Windows systems, has a high amount of overhead, and in general is not
designed for removable drives where a “surprise removal” may be common. Because of this the FAT
file system is the standard for removable (that is, flash) drives and is accessible by nearly every OS,
which makes it the most compatible format for external drives in a mixed OS environment. When
formatting removable drives, Windows XP and later will default to FAT for drives that are less than
or equal to 2GiB, FAT32 for drives that are greater than 2GiB but less than or equal to 32GiB, and
NTFS or exFAT (FAT64) for drives that are larger than 32GiB.
Partitioning normally is accomplished by running the disk partitioning program that comes with your
OS. The name and exact operation of the disk partitioning program varies with the OS. For example,
