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Title: Guide to buying Hard Drives
Author: Kevin Price
Article:
Apart from being one of the most essential parts of your
computer, <a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives">hard
drive storage</a> is constantly updating, in terms of both
capacity of disk space and in physical size. When it comes
time
to upgrade your disk storage, there are a number of factors
for
you to take into account. Once you've made basic decisions
about
size, connectivity, speed and data transfer rate, and
whether
you want an internal drive or external, you can search
through
Myshopping.com.au to find the most suitable brand, and
model,
and compare the prices of different vendors.
<b>How A Hard Drive Works</b>
Your hard drive has a number of magnetized platters
connected
to a spindle. The spindle spins the platters at a very fast
speed while a series of read/write heads scan over them
both
looking for and writing information. This information is
transferred via a cable system, or through a wireless
connection
to a hard disk controller, which in most systems is built into
the motherboard, or in some systems installed as an add-in
card.
The information that comes from your hard drive through its
controller is then made available to the components of your
computer. The effectiveness of your hard drive (its
performance)
depends on how much of its capacity remains unused, how
well
organised the data is (known as fragmentation) and its data
transfer rate, which in turn is dependent on its connection
type
and the drive's spin rate.
<b>Internal Hard Drives</b>
Most computers from, the most basic home models up to
the most
powerful servers, have an internally installed hard drive.
Technology today ensures that they are all generally fast,
reliable, and offer dependable storage ability. Most modern
computers have installation slots and cabling to enable you
to
install additional hard drive. This allows you to increase your
storage capacity without giving up your existing hard drive.
<a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_Internal__f
s_1207_e__">Internal Hard Drives</a>
<b>External Hard Drives</b>
These drives are essentially the same drives as ones
installed
inside computers, but cased inside a protective, portable
case.
This is a good solution for people who work remotely and
need to
transport large amounts of data. If an external hard drive is
your choice, make sure your computer is compatible with
the
interface that the hard drive uses. An add-in card, such as a
FireWire card can help to increase your computer's
capabilities.
You can compare different brands of external hard drives
simply
at Myshopping.com.au and search on the connection type,
or other
specifications. <a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_External__f
s_1206_e__">External Hard drives</a>
<b>Laptop Hard Drives</b>
There have been many advances in miniaturization of
hardware
components for laptop computing, and hard drive
technology is
not left out of this loop. Laptop hard drives function in
exactly the same way as internal hard drives on other
computers,
only they are designed to provide maximum storage and
efficiency
in the smallest possible package. For added flexibility, some
laptop computers come with removable hard drives that can
be
easily installed and removed. However, before you buy a
hard
drive for your portable computer, check that the hard drive's
specifications will meet the standards of your computer, as
many
laptop hard drives are proprietary, and are not compatible
with
other brands and models. <a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_Notebook__f
s_930_e__">Laptop Hard Drives</a>
<b>Size</b>
Your hard drive stores your operating system, its programs
(games and applications), your working data, and your
digital
music and movies. Most new computer purchases have a
minimum of
80 GB of hard disk space; many have considerably more.
Hard
drive space is one of those things, once you have it, you'll
find ways to fill it soon enough. There is no real rule of
thumb, but consider the cost per gigabyte of storage as a
way to
guide your purchase. If you work with large files, such as
music, video and graphics, it pays to have a big storage
space
for your work. It may pay you to have two hard drives, one
that
houses all your programs and applications, and another for
storing your work and projects.
You may want to compare the price of say a 160GB drive
against
two separate 80 GB drives. If one drive fails all is not lost.
Today's hard drives however, are fairly robust pieces of
equipment and providing they are not abuse, will serve you
well
for a long period of time. <a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_up_to_32_GB
__fs_873_e__">up to 32 GB Hard Drives</a> <a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_32_GB_64_GB
__fs_874_e__">32-64 GB Hard Drives</a> <a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_64_GB_100_G
B__fs_875_e__">64-100 GB Hard Drives</a> <a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_100_GB_more
__fs_876_e__">100 GB and more Hard Drives</a>
<b>Interface</b>
One key distinguishing factor between hard drives is the
way in
which they connect to your computer. There are a number
of basic
types of connection schemes used with hard drives. Each
connection type has a range of differences in performance.
<b>IDE (INTEGRATED DRIVE ELECTRONICS)</b>
This is by the most common connection methods. Because
the hard
drive controller is on the drive itself rather than on the
motherboard, it helps to keep costs down. There different
IDE
standards available. Mostly, you will want to purchase the
fastest possible standard that your computer can support.
Most
computers will support a standard that is faster than what
the
computer currently supports, so you can buy a faster drive,
and
update your computer at a later time. The different IDE
standards, in order from most basic to fastest, are:
<li></li><i>ATA (Basic).</i> Supports up to two hard drives
and
features a 16-bit interface, handling transfer speeds up to
8.3
MB per second.
<li></li><i>ATA-2 or EIDE (Enhanced IDE).</i> Supports
transfer
speeds up to 13.3 MB per second.
<li></li><i>ATA-3.</i> A minor upgrade to ATA-2 and offers
transfer speeds up to 16.6 MB per second.
<li></li><i>Ultra-ATA (Ultra-DMA, ATA-33 or DMA-33).</i>
Dramatic speed improvements, with transfer rates up to 33
MB per
second.
<li></li><i>ATA-66.</i> A version of ATA that doubles
transfer
rates up to 66 MB per second.
<li></li><i>ATA-100.</i> An upgrade to the ATA standard
supporting transfer rates up to 100 MB per second.
<li></li><i>ATA-133.</i> Found mostly in AMD-based
systems (not
supported by Intel), with transfer rates up to 133 MB per
second.
<a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_IDE_EIDE__f
s_1219_e__">IDE / EIDE Hard Drives</a> <a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_Serial_ATA_
_fs_1221_e__">Serial ATA Hard Drives</a> <a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_Ultra_DMA_1
00__fs_4743_e__">Ultra DMA 100 Hard Drives</a>
<b>SCSI (SMALL COMPUTER SYSTEM INTERFACE)</b>
This is the hard drive interface standard used by many
high-end
PCs, networks and servers, and Apple Macintosh
computers, except
for the earliest Macs and the newer iMacs. While some
systems
support SCSI controllers on their motherboards, most
feature a
SCSI controller add-in card. SCSI drives are usually faster
and
more reliable, and the SCSI interface supports the
connection of
many more drives than IDE. While SCSI drives come in
many
different standards, many of them are not compatible with
one
another. So it's important be know that your computer
supports
the drive you plan to install. The different SCSI connections
are:
<li></li><i>SCSI-1.</i> A basic connection using a 25-pin
connector, supporting transfer rates up to 4 MB per second.
<li></li><i>SCSI-2.</i> Uses a 50-pin connector and
supports
multiple devices with a transfer rate of 4MB per second.
<li></li><i>Wide SCSI.</i> These drives have a wider cable
and a
68-pin connection that supports 16-bit data transfers.
<li></li><i>Fast SCSI.</i> Uses an 8-bit bus but transfers
data
at 10 MB Per second.
<li></li><i>Fast Wide SCSI.</i> Doubles both the bus (16-
bit)
and the data transfer rate (20 MB per second).
<li></li><i>Ultra SCSI or Ultra Wide SCSI.</i> Uses an 8-bit
bus
and transfers data at 20 MB per second.
<li></li><i>SCSI-3.</i> Features a 16-bit bus and transfers
data
at 40 MB per second.
<li></li><i> Ultra2 SCSI.</i> Uses an 8-bit bus and transfer
data at a rate of 40 MB per second.
<li></li><i>Wide Ultra2 SCSI.</i> Uses a 16-bit bus and
supports
data transfer rates of 80 MB per second.
<a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_SCSI__fs_12
20_e__">SCSI Hard Drives</a> <a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_Ultra320_SC
SI__fs_4749_e__">Ultra320 SCSI Hard Drives</a>
<b>FIREWIRE (IEEE 1394)</b>
The FireWire standard is becoming popular in portable hard
drives because it can be connected and removed without
having to
reboot the computer. It supports data transfer rates of 50
MB
per second, which means it is ideal for video, audio and
multimedia applications. FireWire requires a dedicated add-
in
card and the hard drives in use require an external power
source, but the interface can support up to 63 devices
simultaneously. <a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_FireWire__f
s_8568_e__">FireWire Hard Drives</a>
<b>USB 1.1 (UNIVERSAL SERIAL BUS)</b>
Pretty much all computers today include USB ports on their
motherboards. (On older model, you can install an add-in
card.)
USB controllers can be used to connect external hard
drives, and
can support as many as 127 devices simultaneously either
through
USB port hubs or linked in a daisy chain fashion. USB
controllers do delivery power to devices connected to them,
but
many hard drives still use an external power source. USB is
limited by its data transfer speed, the maximum rate being
about
at 1.5 MB per second. <a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_USB__fs_121
5_e__">USB Hard Drives</a>
<b>USB 2.0 (HI-SPEED USB)</b>
A more recently introduced and far better connection
standard
that offers backward compatibility and data transfer rates of
up
to 60 MB per second. USB 1.1 system can use a USB 2.0
device; it
will need a USB 2.0 controller card to achieve the higher
transfer rates. <a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_USB_2_0__fs
_1209_e__">USB 2.0 Hard Drives</a>
<b>FIBRE CHANNEL</b>
Fibre Cabling is mainly used for high-bandwidth network
servers
and workstations, providing very fast data transfer rates (up
to
106MB per second), and connection at long cabled
distances,
although it is expensive and you need to install a special
interface card.
<b>Spin rate</b>
Data transfer rate is crucial to how well your computer
performs for you. Apart from the connection types above,
the
performance of your hard drive depends on its spin rate,
measured in RPM. Higher RPM generally means faster data
transfer
rate. The lowest spin speed that is acceptable in computing
today is 5400 RPM. The common standard at present is
7200 RPM.
But higher speeds are available in SCSI drives, and it is one
area of computer system technology that is constantly being
developed. <a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_3600_RPM__f
s_6917_e__">3600 RPM Hard Drives</a> <a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_4200_RPM__f
s_6854_e__">4200 RPM Hard Drives</a> <a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_5400_RPM__f
s_6842_e__">5400 RPM Hard Drives</a> <a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_7200_RPM__f
s_6755_e__">7200 RPM Hard Drives</a> <a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_10000_RPM__
fs_6933_e__">10000 RPM Hard Drives</a> <a
href="http://www.myshopping.com.au/PT--
57_Hard_Drives_15000_RPM__
fs_6785_e__">15000 RPM Hard Drives</a>
A larger capacity hard drive will not necessarily make your
system function any faster unless you are low on available
disk
space with your existing drive. But a drive with Ultra
ATA/100
or ATA/133 and a 7200 RPM spin rate will pretty much
guarantee
an improved hard drive performance.
Other considerations
<b>CACHE</b>
Cache (pronounces 'cash') is additional temporary memory
that
acts as a buffer between the system and the drive.
Frequently
accessed data is stored in the cache for quick access.
Cache
sizes vary from 512 KB up to 16 MB on some SCSI drives.
The
larger cache you have on your drive, the faster your drive
will
transfer data. If you are working with large files, such as
video, images and audio files, it pays to have the largest
cache
you can get (8MB or more).
<b>SEEK TIME</b>
The data on your disk is stored in tracks and sectors and
when
you instruct your hard drive controller to retrieve some data,
it goes looking. The seek time is a measure of how long it
takes
the hard drive to find a specific track on a disk. Seek times
can vary slightly from disk to disk and a drive with a faster
seek time will always perform better.
<b>INTERNAL AND EXTERNAL TRANSFER RATES</b>
These two rates tell how fast a drive actually reads the data
and passes it along to the system. Internal Transfer Rate
refers
to the time it takes for a drives heads to read data from the
platter and pass it to the drive's cache. The External
Transfer
Rate (sometimes called the Transfer Rate or the Burst
Transfer
Rate) is a measure of the time it takes to send the data from
the cache all the way to the computer's memory. Naturally
faster
transfer rates provide better performance.
<b>S.M.A.R.T. (Self-Monitoring Analysis and Reporting
Technology)</b>
This is a nice built-in feature in some hard drives that can
help alert you to a potential hardware problem. Your
computer's
BIOS must support this in order for the SMART function it to
work, however the drive itself will still work in a system
without it.
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