The image shows a close-up of the rear view. The USB port is on the left followed by two FireWire ports, the power connection, and on/off switch. Mouldings that can interlock allow several OneTouch drives to be stacked one upon another.

There are two main types of external hard disk drives: models designed to be used on a desk and those designed to be portable.

Note that most portable and desktop external hard disk drives come with bundled backup software.

Desktop external hard disk drives have the highest capacities of the two types, and therefore also the lowest cost per gigabyte (GB). They require an external power supply, which is not a problem for desktop use.

You should use a portable drive if you want to carry it with you with a laptop PC or transfer files from one computer to another. Portable drives are based on laptop hard drives. They don't require an external power adapter, are smaller and lighter, less spacious , but more expensive than desktop drives. However, some portable drives have to be connected to two USB ports via a special cable in order to be able to draw sufficient power.

It's possible to purchase external hard disk drives (HDDs) that connect to a computer via the Serial ATA (SATA), eSATA, USB, or FireWire interfaces. More information on the external form of SATA called eSATA is provided further down this page. The SATA interface is more commonly used to connect internal hard disk drives, but some PC motherboards provide an external SATA (eSATA) port.

Most external hard disk drives use a USB 2.0 (USB Hi-Speed) interface. All new and fairly recent computers have external USB 2.0 ports. The theoretical maximum rate of data transfer is 60MB/s (megabytes per second), which, as is usual with these standards, is never reached in practice.

There are two versions of the FireWire interface - FireWire 400 (50MB/s) and FireWire 800 (95MB/s). At the time of writing (August 2006), some external drives provide a FireWire 400 connection, usually in addition to a USB 2.0 connection. A FireWire 400 connection is usually faster than a USB 2. 0 (USB High Speed) connection, but USB 2.0 is the best option to use if you need to copy very large files.

A FireWire 800 connection is faster still, but at the time of writing (November 2007), very few external hard drives or computers provide a FireWire 800 port. An example of an external drive that provides such a port is the Lacie Little Big Disk drive that can be powered via the FireWire cable or by an external power supply. A PCI adapter card that adds FireWire 800 support to a PC can be purchased for around £30.

The SATA 150 interface transfers data at a theoretical maximum rate of 150MB/s, but an external SATA hard disk drive can't get anywhere near that maximum rate.

Make sure that you purchase an external drive with an interface that your computer supports. If you have an elderly computer that only has USB 1.1 ports, you have to buy a PCI adapter card that has USB 2.0 or Firewire 400/800 ports. It is installed in a PCI slot on the PC's motherboard.

eSATA (external SATA) external hard drives are the fastest of all, but unless you have a very recent desktop or laptop PC, you will have to add eSATA ports by using a PCI expansion card ( for a desktop PC), or an ExpressCard or CardBus expansion card (for a laptop PC). You can make use of the Google search box provided at the top of this page (with its Web radio button enabled) to locate information and vendors for them. If you need an eSATA CardBus card for a laptop PC, for example, you could try using a search term such as: esata + cardbus.

Due to the current fast interfaces (USB and FireWire), external hard disk drives are no longer as slow as they used to be in comparison to internal IDE/SATA and SCSI hard disk drives. However, internal hard disk drives still perform about twice as fast as external ones, particularly when very large files, such as digital video files, are being accessed or transferred.

It is also possible to use an ordinary IDE hard disk drive as an external drive by installing it in a special enclosure that uses a USB or FireWire port. See the Q&A on this site called: How to make an ordinary internal IDE hard disk drive into an external drive.

An example of a hard-disk enclosure is the Cooler Master X Craft 360, which takes one 3.5" SATA hard disk drive, and has eSATA and USB 2.0 (Hi-Speed) ports. It was priced at £30 in December, 2007 and received a four-star Most Wanted award from Computer Shopper in October 2007.

External Hard Drive Charts - "This page is updated on a regular basis and provides a unique resource for everybody who is looking for a desktop [external to the PC] hard drive - whether it is for home or for business use." -

http://www.tomshardware.co.uk/charts/hard-disks/...

External SATA (eSATA) technology

"eSATA - Initially SATA was designed as an internal or inside-the-box interface technology, bringing improved performance and new features to internal PC or consumer storage. Creative designers quickly realized the innovative interface could reliably be expanded outside the PC, bringing the same performance and features to external storage needs instead of relying on USB or 1394 interfaces. Called external SATA or eSATA, customers can now utilize shielded cable lengths up to 2 meters outside the PC to take advantage of the benefits the SATA interface brings to storage. SATA is now out of the box as an external standard, with specifically defined cables, connectors, and signal requirements released as new standards in mid-2004. eSATA provides more performance than existing solutions and is hot pluggable." -

http://www.sata-io.org/esata.asp

Bye Bye Tape, Hello 5.3TB eSATA -

http://www.tomshardware.co.uk/bye-bye-tape-uk,review-2148.html

Silicon Image Brings Virtualization to eSATA: Silicon Image Simplifies ESATA Storage - http://www.tomshardware.co.uk/...review-2303.html

The security of data stored on external hard disk drives

The major problem presented by external data storage drives is one of security. For that reason, the industry now offers external storage drives that feature a variety of security mechanisms that range from providing the encryption of all data content to access protection provided by a fingerprint scanner.

For example, Lock Box is the name of a drive from MicroSolutions that makes use of a fingerprint sensor. Access can only be achieved by people with fingerprints that the drive recognises. For more information on it, enter the names in the Google search box at the top of this page. For general information, use a search term such as: security + "external hard disk drives" (as is).

Click here! to go to the information on this site on computer security.

External hard disk drives can easily be used as removable system back-up devices, or to transfer data between non-networked computers.

Like most speaker systems, the large 3.5 inch external hard disk drives - whether USB or FireWire - require more power than they can draw via their connection to the computer, so they are supplied with an external power supply unit. Therefore they are usually more expensive than internal hard disk drives, which take their power directly from the computer's power supply unit. However, the smaller 2.5 inch drives are able to draw their power from the system via their USB or FireWire connection, do not require an external power supply unit, and are therefore cheaper than the larger external drives, but are still more expensive than equivalent internal drives because of their special casing.

i.Link is the Sony version of FireWire, which is technically identical to it but uses an external mains power supply instead of taking power through the computer, thereby making it an excellent choice for a notebook owner who doesn't want to run the portable computer's battery down by using a power-hungry external device.

External 2.5 or 3.5 inch hard disk drives are really just internal drives placed into an external case and provided with a USB 1.1, USB 2.0, or FireWire interface. Read and write speeds are adversely affected by the necessity for the extra interface compared to drives using the internal motherboard's IDE interface.

USB2 external drives are backward compatible with the USB1 standard, so a USB 2.0 drive will work on a USB 1.1 connection, which, you should note, is much slower than a USB 2.0 connection. USB 2.0 and FireWire are the fastest external interfaces. In some cases, a FireWire interface, as with Archos and LaCie drives, can outperform USB 2.0.

If your computer doesn't have a motherboard that supports USB 2.0 or FireWire, you can obtain a PCI add-on card for about £20/$30. - For examples see the end of the following page of this site - USB and FireWire.

Because USB and FireWire devices can be connected to a computer while it is switched on (hotplugged), besides being useful for creating back-ups that can be stored off-site, external hard drives are very handy for transferring data between computers that are not networked. Windows should detect the connection and load the drivers for the drive automatically.

Click here! to find out how to partition/activate and format a new external hard drive in a Windows 95/98/Me and a Windows XP/Vista system on this page. Use your browser's Back button to return to this point on the page.

External hard disk drives can usually be obtained from the same vendors that sell the internal drives, but some manufacturers specialise in external drives.

The main manufacturers of external hard disk drives are:

Maxtor - http://www.maxtor.com/

Seagate - http://www.seagate.com/

Western Digital - http://www.westerndigital.com/

Buffalo - http://www.buffalo-technology.com/

Archos - http://www.archos.com/

LaCie - http://www.lacie.com/ and http://www.lacie.co.uk/

EZQuest - http://www.ezq.com/

IOGEAR - http://www.iogear.com/

Five-star and four-star external hard disk drives as reviewed by Computer Shopper

Visit http://www.pcpro.co.uk/shopper to read the full reviews of the following hard drives under PRODUCT REVIEWS, or enter the make and model in the site's Search For: box. If there is no review available, to locate information and reviews, try entering the make/model in the Google search box at the top of this page (with its Web radio button enabled).

Click on the make/model link to visit the manufacturer's website

Computer Shopper (issue 244) reviewed the following portable and desktop external hard disk drives in March 2008:

1. - Maxtor OneTouch 4 Mini 160GB portable external hard disk drive - Four stars - Budget Buy award - 160GB capacity - USB 2.0 (USB Hi-Speed) interface - Priced at £57 in March 2008.

2. - Iomega eGo USB 250GB Blue portable external hard disk drive - Five stars - Best Buy award - 250GB capacity - USB 2.0 (USB Hi-Speed) interface - Priced at £91 in March 2008.

3. - Buffalo DriveStation Combo TurboUSB 500GB desktop external hard disk drive - Five stars - Best Buy award - 500GB capacity - USB 2.0 (USB Hi-Speed) and FireWire 400 interfaces - Priced at £92 in March 2008.

Computer Shopper reviewed the following portable and desktop external hard disk drive in December 2007:

Buffalo Drive Station TurboUSB 500GB - Four stars - 500GB capacity (465GB formatted using the NTFS file system) - USB 2.0 Hi-Speed connection from host computer that also powers the drive - Buffalo claims that it is up to 37% faster than other USB drives due to its TurboUSB mode - Inexpensive - Fast overall performance - Priced at £88 in December 2007.

Computer Shopper reviewed the following portable and desktop external hard disk drive in November 2007:

Buffalo MiniStation TurboUSB Portable Hard Drive 120GB - Four stars - 120GB capacity (111GB formatted using the NTFS file system) - USB 2.0 Hi-Speed connection from host computer that also powers the drive - Buffalo claims that it is up to 64% faster than other USB drives due to its TurboUSB mode - Priced at £59 in November 2007.

Computer Shopper reviewed the following portable and desktop external hard disk drives in July 2007:

1. - Western Digital: Passport Portable (Black) 160GB USB 2.0 Hard Drive - Five stars - Best Buy award in July 2007 - 160GB capacity (149GB formatted) - USB 2.0 Hi-Speed connection from host computer that also powers the drive - Bundled backup software: EMC Retrospect Express HD 2.0 - Warranty: Two years - Priced at £70 in July 2007.

2. - Maxtor: OneTouch III Mini Edition 160GB - Four stars - Portable external hard disk drive - 160GB capacity (149GB formatted) - USB 2.0 Hi-Speed connection from host computer that also powers the drive - Bundled backup software: Maxtor EasyManage - Warranty: Two years - Priced at £87 in July 2007.

3. - Buffalo DriveStation Combo 500GB - Five stars - Best Buy award in July 2007 - Desktop external hard disk drive - 500GB capacity (465GB formatted) - USB 2.0 Hi-Speed/FireWire 400 connections - External power adapter - Bundled backup software: Memeo AutoBackup 2.0 - Warranty: Two years - Priced at £100 in September 2007.

4. - LaCie d2 eSATA II 3Gbits Hard Drive 500GB - Five stars - Best External Hard Disk award in the Computer Shopper 2007 Awards - Desktop external hard disk drive - 500GB capacity (465GB formatted) - eSATA connection - External power adapter - Bundled backup software: LaCie Backup Software - Warranty: Two years - Priced at £115 in December 2007.

Computer Shopper gave the following external hard disk drive a four-star review in March 2007:

1. - Trekstor DataStation maxi t.u 250GB - Four stars - External portable hard disk drive - 250GB capacity (232GB formatted) - USB 2.0 Hi-Speed connection - Priced at £79 in March 2007.

****

Computer Shopper gave the following external hard disk drives (and one hard-drive enclosure) five-star and four-star reviews in February 2007:

1. - Buffalo DriveStation Duo 500 GB - Four stars - External desktop hard disk drive - 500GB capacity (465GB formatted) - USB 2. 0 and FireWire 400 connections. Priced at 157 in February 2007.

2. - Akasa Integral Fusion - Four stars - External hard disk drive enclosure that accommodates a 3.5" PATA hard drive - A memory-card reader that supports most types of memory cards and a two-port USB hub.

3. - Iomega Desktop Hard Drive 320GB - Four stars - External desktop hard disk drive - 320GB capacity (298GB formatted) - USB 2.0 and FireWire 400/FireWire 800 connections.

4. - Trekstor DataStation pocket x.u 120GB - Five stars - External portable hard disk drive - 120GB capacity (111GB formatted) - USB 2.0 connection - USB powered.

****

Computer Shopper gave the following external hard disk drives five-star reviews in December 2006:

1. - Western Digital 500GB My Book Pro Edition - Five stars - Best Buy award - USB 2.0, Firewire 800, and Firewire 400 ports - 500GB (465GB formatted disk space using the NTFS file system) - Priced at £133 in March 2007.

Storage With Style: WD MyBook Pro Edition (external hard drive) -

http://www.tomshardware.co.uk/2006/12/05/storage-with-style-uk/

2. - Western Digital Passport 120GB - Five stars - Budget Buy award - 120GB (111GB formatted disk space using the NTFS file system) - USB 2.0 - USB powered - No FireWire port - Priced at £62 in April 2007.

****

Visit http://www.pcpro.co.uk/shopper to read the full reviews of the above-mentioned hard drives under PRODUCT REVIEWS, or enter the make and model in the site's Search box.

ARTICLES ON EXTERNAL HARD DRIVES

External Hard Drives Buyer's Guide -

"We assess 25 of the hottest external hard disk drives from Cavalry, Iomega, LaCie, Maxtor, Seagate, Western Digital, and more." -

http://www.informationweek.com/news/storage/portable/...

Four Sub-Terabyte External Hard Drives -

"We received four different external hard drive products by Buffalo, Maxtor, Seagate and SimpleTech. All four offer 750 GB to 1 TB of storage, and come with sophisticated features and backup packages." -

http://www.tomshardware.co.uk/sub-terabyte-external,review-29954.html

The Terabyte Drives Redefine External Storage -

"We looked under the hood of two amazing storage mammoths by LaCie and Maxtor." -

http://www.tomshardware.co.uk/...review-1582.html

****

Serial ATA (SATA) external hard disk drives (HDDs)

At present [May 2004], it's possible to buy a proper SATA external hard disk drive, or a controller card that can connect an ordinary IDE PATA or an ordinary SATA hard disk drive to the motherboard, or, if the motherboard has a free SATA header, a cheaper bracket containing an SATA port that connects to it and to which the external drive is then connected via the back of the computer's case.

Such an external SATA drive is the somewhat expensive 200GB CMS Velocity.

Highpoint Technologies has on offer a cheaper solution that it calls an "external SATA" or e.SATA controller card. For example, it's possible to use a Rocket 1511 Host Adapter and a RocketMate e.SATA 1100 HD Enclosure to connect both an ordinary IDE PATA drive and an ordinary SATA drive up on a computer as an external SATA drive.

"The Rocket 1511 Host Adapter is a single channel External SATA controller card that can support SATA or IDE hard disk drives. The external channel is ideal for removable storage applications, and is designed for use with RocketMate external disk enclosures. The Rocket 1511 supports high speed transfer rates up to 150MB/s. Its single External SATA channel supports one SATA, or IDE hard disk, via the RocketMate external disk enclosure." - http://www.overclock.co.uk/

And if the motherboard already has an SATA interface, the cheaper Highpoint Rocket B11 bracket can be used instead of the controller card.

Theoretical and actual bandwidths

Interface	Theoretical bandwidth	Bandwidth achieved in practice
USB 1.1 (old)	12 MBit/s [1.5MB/s]	1 MB/s
USB 2.0	480 MBit/s [60MB/s]	25 MB/s
FireWire 400 (IEEE 1394A) / i.Link	400 MBit/s [50MB/s]	30 MB/s
FireWire 800 (IEEE 1394B) / i.Link	800 MBit/s [100MB/s]	60 MB/s
Serial ATA (SATA) 150	1500 MBit/s [187.5MB/s]	120 MB/s

The bandwidth of each of the interfaces, which is a theoretical or actual measure of the data transfer speeds of an interface, is shown in megabits per second (MBit/s), and megabytes per second (MB/s). There are eight bits in a byte, so dividing MBits/s by eight converts it to MB/s.

FireWire and eSATA external hard disk drives

USB 2.0 is the most common standard used for external hard drives. It is fast enough for most uses, but if you have to work with very large files, such as DV movies, a FireWire 400 hard drive is faster. A FireWire 800 hard drive is faster still, but, at the time of writing (May 2006), very few hard drives or computers support the standard. The new External SATA (eSATA) hard drives are the fastest of them all, but are currently more expensive and more difficult to buy than FireWire 800 drives. If you don't have a motherboard that supports eSATA, which is approximately 99% of current motherboards, you can add support by installing a PCI expansion card.

External SATA (eSATA) hard disk drives

External SATA, or eSATA technology appears to be making its presence felt in the market. eSATA enclosures are becoming more widely available, and some motherboards offer built-in support for the technology. The hard drive enclosures operate much like USB and FireWire enclosures, but with much faster data transfer speeds. An enclosure for four drives containing 750GB Barracuda 7200.10 units provides a massive 3TB (3000GB) of disk space.

ExtremeTech has an overview of eSATA technology and a review of a LaCie eSATA enclosure. - http://www.extremetech.com/article2/0,1697,1953878,00.asp

External USB and FireWire hard disk drives are slower than internal IDE PATA and SATA drives. However eSATA technology extends internal SATA technology so that it can be used external drives, which are just as fast as internal SATA drives.

Motherboards are now coming out that provide an eSATA connector that you connect to an eSATA drive or to an IDE PATA or SATA drive enclosed in an eSATA enclosure. You can also purchase PCI adapter cards that fit in a PCI slot on a motherboard to provide an eSATA connector.

The eSATA cable connector and port have been designed to make the cables easy to insert and remove. Internal SATA connectors are rated to be inserted and removed approximately 50 times. eSATA connectors are designed to be removed up to 5,000 times. Moreover, in order to meet emmissions regulations, an eSATA cable has an extra layer of shielding.

eSATA SATA II Drive Enclosure for 3.5" SATA II 3Gb/s Hard Drives -

"With data transfer rates of up to 300 MBytes/sec, Serial ATA II 3Gb/s SATA II hard drives are the new high performance choice for external storage! This drive case turns your 3.5” SATA II hard drive into an external drive supporting up to 3Gb/s data transfer, letting you backup information, move large files, or archive data with incredible speed and reliability. Aluminum construction helps keep your drive running cool and makes the case lightweight and easy to transport." -

http://www.firewire-1394.com/esata-3-5-hard-drive-case.htm

WD ships eSATA external hard drive -

http://www.reghardware.co.uk/2007/02/05/wd_ships_esata_my_book_hdd/

The safest way to upgrade RAM: Use the UK and US Crucial Memory Advisors

Paul Mullen, the highly-respected computer guru of the Helpfile at ComputerShopper.co.uk - "I have recently been buying my memory only from Crucial Technology. I would rather pay the extra cost than waste time trying to track down the obscure program faults that bad memory can cause."

The memory requirements of the versions of Windows Vista

Most of the versions of Windows Vista require more RAM memory to run optimally on a computer that doesn't use memory-hungry applications than Windows XP. A video-editing application is an example of memory-intensive software. Only Windows Vista Home Basic has a recommended minimum amount of memory of 512MB, which is the same amount recommended for Windows XP. Windows Vista Home Premium, the most popular version, and Windows Vista Ultimate require a recommended minimum of 1GB (1024MB) of memory, which is twice the amount of minimum memory recommended to run Windows XP. For more information on computer memory, read the RAM pages of this site.

UK - Crucial Memory Advisor - UK

USA - Crucial Memory Advisor - USA

For example, if your computer has an Asus motherboard, open the menu, scroll down to ASUS, and click GO. If, say, you have a Dell computer, scroll down to DELL, and do likewise. You will be taken to the relevant information on Crucial's website.

If you don't know the make and model of the motherboard installed in your computer, here is a good free utility - Belarc Advisor - that creates an analysis of the hardware and software on a personal computer. Look under FREE DOWNLOAD - http://www.belarc.com/. Another utility that also provides detailed information on the memory itself is CPU-Z.

External IDE hard disk drive enclosures with USB and/or FireWire ports

External enclosures for standard IDE hard disk drives that provide them with a FireWire or a USB interface - or both - are available.

An old or new 3.5" IDE hard disk drive can be installed in such an enclosure so that it can be used as an external drive via a USB or FireWire port, or both, depending on the type of enclosure. The installation of the IDE drive in the enclosure is a simple matter. No technical expertise is required.

Everything necessary except the hard disk drive itself is included in the package - the installation instructions, a 6-6-pin FireWire cable, USB cable, power supply, fitting screws, etc.

The enclosed IDE drive can then be used for any number of purposes, from backing up to storing video, image, and music files. It can also be shared between computers, using it as a data pool. If it has both USB and FireWire interfaces it can be used on almost any PC or Apple Mac. Even if the computer's motherboard doesn't have USB 2.0 ports, it should also run from a USB 1.1 port.

Using an ATA IDE drive in this way is a much cheaper alternative to buying an external USB or FireWire hard drive.

USB-to-IDE converters cables/adapters

You can buy a USB-to-IDE converter that allows you to connect an IDE hard drive or CD/DVD optical drive to a USB port. If necessary you could probably connect it to USB header on the computer's motherboard so that you can install the drive in a bay in the PC's case instead of as an external drive.

To locate vendors, you can enter a search term such as usb + ide + converter (as is) in the Google search box provided at the top of this page (with its Web radio button enabled).

How to configuring and install a hard disk drive

The method of configuration and installation depends on the type of hard drive being installed. The methods differ for the three main types - IDE ATA, SATA, and SCSI. IDE ATA hard drives are still manufactured, but are in the process of being replaced by SATA hard drives in home PCs.

There is usually a diagram on an IDE ATA hard drive itself (of the kind illustrated in the image below), showing the jumper settings to configure it as a master or slave device. The configuration table is fixed to the top or bottom of the drive.

The illustrated configuration information on a Maxtor hard disk drive

The Master, Slave, and CS Enabled (Cable Select) jumper settings are clearly shown on the Maxtor drive shown above.

Note that due to political correctness that is offended by the words Master and Slave, new drives will probably be using the terms Primary and Secondary instead, but I will continue using the clearer Master and Slave. A PC with four drives would have a primary master, a primary slave, a secondary master, and a secondary slave, but if Primary and Secondary replace the traditional terminology, the four drives will be called a primary primary, a primary secondary, a secondary primary, and a secondary secondary, which is somewhat absurd.

The Cap Limit setting shown in the image above automatically sets the drive to a system's maximum size capacity, because many systems cannot run huge drives. This particular DiamondMax Plus drive (5400RPM, 2MB cache, 12.6ms disk access time), has a capacity of 300GB that unmodified Windows 9x systems, which run the FAT16 or FAT32 file systems, won't be able to run as a single (unpartitioned) volume. Windows XP/Windows Vista, running its NTFS file system, can run such a drive unpartitioned if the motherboard's BIOS setup program allows it. Windows XP was released in October 2001. Nevertheless, you need to install Service Pack 1 (SP1) or Service Pack 2 (SP2), which incorporates it, to be able to use drives larger than 137GB. Needless to say, Windows Vista supports drives larger than 137GB.

For more information on what you need to know in order to upgrade a hard drive on a particular PC, visit this Upgrade Checklist on this site.

If the BIOS doesn't allow it, reflashing it with the latest BIOS file from the PC manufacturer or motherboard manufacturer's site might fix the problem. Otherwise, installing a new PCI IDE adapter card of the kind made by Promise, or a new motherboard that has a BIOS capable to recognising such a large hard drive is the only remedy.

In fairly recent PCs, the connectors for the drives on an IDE cable are "keyed," which means that they are designed so that they can only fit into the sockets on the motherboard (or adapter card) and on the drives themselves in the correct way. If you try to plug a cable's connector in the wrong way, it won't fit. A different system was used before the connectors were keyed. The page provided at the end of this section provides details of both types of connection.

I prefer using the sound Master/Slave settings to configure drives, but the easiest way to configure and install an IDE ATA 66/100/133 HDD, which has to be installed using an 80-conductor ribbon cable (not an old-style 40-conductor cable), is to set the drive's jumpers to the Cable Select setting. When jumpered for Cable Select, the cable plus the jumpering determines which is the master drive and which is the slave drive. The master drive will go to the black connector on the 80-conductor ribbon cable, and if a slave is used, it will be connected at the ribbon's middle (grey) connector. The ribbon's blue connector fits to the motherboard.

As long as two hard drives on the same cable are jumpered to the Cable Select setting, you can swap them from the master to slave positions on the ribbon cable. But, if you swap a drive set as Master to the position on the cable for a Slave drive, you have to change the jumper setting to Slave or the drive won't be recognised by the system.

This page - How to Build a PC - Page 3 (a set of six pages on this site) - contains information on how to configure and install IDE ATA and SATA hard disk drives. It also includes information on installing CD/DVD and floppy disk drives.

Note that if your PC has an elderly motherboard that only supports the original SATA standard, a SATA II drive, which has a theoretical data transfer speed of 300MB/s, will work at the slower SATA 150MB/s data transfer speed. However, to do so, some SATA II drives require a jumper on the back of the drive to be set. The jumper, which will be stored on inactive pins at the back of the drive, will have to be placed across two pins that will be indicated by a diagram on the drive. Setting the jumper makes it possible for the drive to operate at the slower speed. You can consult your PC's or its motherboard's user manual to find out if it supports SATA or SATA II. If your PC only supports SATA and you have an SATA II drive, look for a diagram on the drive that shows you how to set its SATA jumper.

Partition and format a hard disk drive in a Windows 95/98/Me system, or by using the Disk Management feature in Windows XP/Windows Vista

Read Partition Planning here - http://aumha.org/a/parts.htm - if you want advice on choosing a partitioning strategy that best suits your computing needs.

Windows 95/98/Me

Note well: back the system up, or implement whatever your back-up routine is before you attempt to partition of format a hard disk drive. Because if the process goes awry for any reason, such as a power failure, you might have to reinstall Windows, which would mean a loss of data if no back-up is available to be restored.

In a MS DOS/Windows 95/98/Me system, you would use the FDISK utility to partition a hard disk drive, and the DOS format [drive letter followed by a colon (C:)] command to format a whole drive or a partition on a drive. (Enter the word command in the Start => Run box to bring up a DOS window within Windows, and enter format /? to bring up the information on the format command.)

Click here! to go to some very useful information on FDISK on this page. Use your browser's Back button to return here.

Unless you use a Windows program such as Partition Magic, you can only partition the drive from full MS DOS mode (not MS DOS running within Windows), but you can format the non-boot partitions from My Computer (on the Windows Desktop or in Windows Explorer) by right-clicking on the the drive's graphical entry and then clicking on Format.

In an emergency, you can access partition information and format the boot partition (usually the C: drive) containing Windows (or any other partition) of a Windows 95/98/Me system from a start-up floppy disk by using the usual DOS format and FDISK commands.

Windows XP

When you first install Windows XP on a computer from its installation CD, the system has to boot from the CD, which means that the CD/DVD drive must be set as the first boot device in the BIOS. An unpartitioned and unformatted hard disk drive will have to be partitioned and formatted from the Windows CD before Windows can run its setup routine.

To partition and format a new hard disk drive (which could also be an external HDD using a FireWire or a USB connection) from within Windows XP, click Start => Control Panel => Performance and Maintenance => Administrative Tools => Computer Management. From the list in the left pane, click Storage to expand the list, and then click Disk Management.

Or just enter diskmgmt.msc in the Start => Run box.

You can also use the command prompt (command line).

MS Knowledge Base articles:

1. - How To Use Disk Management to Configure Dynamic [Hard] Disks in Windows XP - This step-by-step article describes how to use the Disk Management snap-in to configure dynamic [hard] disks. - http://support.microsoft.com/?kbid=308424

2. - How to enable 48-bit Logical Block Addressing support for ATAPI disk drives in Windows XP - This article describes the Microsoft Windows XP Service Pack 1 (SP1) 48-bit Logical Block Addressing (LBA) support for ATA Packet Interface (ATAPI) disk drives that can increase the capacity of your hard disk to more than the current 137 gigabyte (GB) limit. - http://support.microsoft.com/?kbid=303013

For more detailed information, enter Create a partition or logical drive in the Search box of Start => Help and Support, or make use of the Google search box at the top of this page (with its Web radio button enabled).

****

Non-destructive partition management: Copy, move, resize, split, or merge partitions partitions on the fly

If you want to add and remove, merge or resize partitions without destroying the data on them, you have to make use of a third-party utility that is designed for the purpose, because the Windows disk management utilities are very limited, even in Windows XP and Windows Vista. You can use utilities such as Partition Magic, BootIt NG, and the free but difficult-to-use Ranish Partition Manager.

Windows Vista

To open Disk Management in Windows Vista, click the Start button and enter diskmgmt.msc in the Start Search box, or click the Start button => Computer and then select Manage. Expand the Storage section and select Disk Management.

Read Can I repartition my hard disk? on Microsoft's site.

The new version of Disk Management allows you to resize partitions on the fly without the loss of data. Just right-click on any partition and select Extend Volume or Shrink Volume.

QTParted, a free partitioning utility that works very much like Partition Magic

You can use the QTParted partitioning utility from Knoppix Linux, which runs from a bootable CD/DVD. Download the ISO image free of charge from http://www.knoppix.org/ and use CD/DVD burning software to burn it to a recordable CD/DVD. Your PC's BIOS setup program should be set to boot from a CD/DVD drive in order to boot into Linux at startup without interferring with an installation of Windows XP/Vista. You would place the Knoppix Linux CD/DVD in its drive and reboot the PC. The PC will boot into Knoppix Linux, which looks like Windows. From the Start menu go to System and choose the program QTParted, which looks and works very much like Partition Magic, which costs around £40. It can be used with Windows XP/Vista on NTFS partitions.

How to initialize, partition, and format a new hard disk drive from within Windows XP and Windows Vista

With the ATA, SATA, or USB hard drive connected to the motherboard, PCI adapter card, or USB port, enter diskmgmt.msc in the Start => Run box to bring up Disk Management.

To open Disk Management in Windows Vista, click the Start button => Search and enter diskmgmt.msc in the Search box, or click the Start button => Computer and then select Manage. Expand the Storage section and select Disk Management.

The drive should be given a space there with the other drives, and you should be able to partition and format if from there by right-clicking on its space. You have to initialise (US: initialize) it in Disk Management before you can format it, but it will be listed there.

Here is what Windows XP's Help and Support says about initialising a disk:

"To initialize new disks: Open Computer Management (Local) [under All Programs => Administrative Tools]. In the console tree, click Disk Management. Right-click the disk you want to initialize, and then click Initialize Disk. In the Initialize Disk dialog box, select the disk(s) to initialize. The disk is initialized as a basic disk. To open Computer Management, click Start, and then click Control Panel. Double-click Administrative Tools, and then double-click Computer Management. You must be logged on as an administrator or a member of the Administrators group in order to complete this procedure. If your computer is connected to a network, network policy settings might also prevent you from completing this procedure. New disks appear as Not Initialized. Before you can use a disk, you must first initialize it. If you start Disk Management after adding a disk, the Initialize Disk Wizard appears so you can initialize the disk."

Note that from within Windows XP, the Disk Management tool can only format partitions and drives that are larger than 32GB as NTFS. In other words, you have to choose the NTFS file system, not the FAT32 file system, in order to be able to format drives that are larger than 32GB.

Using Disk Management to make an existing partition into smaller partitions

Disk Management allows a user to make an existing partition into smaller partitions. To achieve that, back up the data on an oversized partition, delete it completely, and then create two or more smaller partitions where the one oversized partition used to be. Then restore the backup to one of the new partitions - if it has enough space in it. Make sure that you create a partition that is big enough to hold the backup with about 1GB or more of free space.

Windows XP Disk Management Tool -

Visit the following article on how to use Disk Management for creating, formatting, or deleting partitions or drives, for changing drive letter assignments and paths, for setting up disk-mirroring and RAID, etc. -

http://www.informationweek.com/showArticle.jhtml?articleID=180207718

Disk Management in Windows Vista

The Disk Management feature in Windows Vista can perform all of the functions of the version in Windows XP, but it can also resize partitions on the fly without destroying data. Read Can I repartition my hard disk? on Microsoft's site.

Deleting and creating partitions or logical drives

Note that you can also use the command prompt (command line) to delete and create partitions/logical drives. To find out how to do so, go Start => Help and Support and enter create a partition or delete a partition in the Search box. You will be offered these two options: Using a Windows interface and Using a command line.

Right-click with the mouse on the drive's graphical entry to choose the operation (partition or format) that you want to perform. For Windows XP, the best choices are a 4KB cluster size and the NTFS file system. If you use the FAT32 file system, use the option called default.

You can easily remove the logical drive or partition by using the Delete Logical Drive option.

If there is an unpartitioned, unformatted space on the drive it will be represented by a box that you can partition by using Create Logical Drive and then Format. Windows give a new logical drive a drive letter automatically, but there is also an option that allows you to choose the drive letter.

But the best way to do perform those actions in an emergency with Windows XP is to boot the system from the Windows XP CD. You may have to enable the CD-ROM drive as the first boot drive in the boot order in the BIOS setup. You do this by choosing the Windows Setup option after the system has booted from the CD. It asks you if you want to reformat the boot partition.

****

Note that the system recovery discs for Windows XP systems of some vendors/ PC manufacturers only function on a FAT32 file system, apparently because they don't want to incur additional support costs from having ignorant users running into trouble if they enable the extra security measures that Windows XP running the NTFS file system allows. Therefore, if you convert a drive from FAT32 to use NTFS, you won't be able to use the system recovery disc (disk).

Disk Management in Windows Vista

How to copy/transfer data files from and old to a new hard drive

The first version of Windows 95 used the FAT16 file-allocation table, which could only address a HDD or a partition on a HDD of only 2GB in size, because 16 bits of information can only be arranged in a file system to address that much data at a time.

The FAT32 system used by Windows 9x systems (Windows 95 OSR2 to Windows Me) uses 32 bits of information at a time, and, because of technical rather than limitations on the size of the file system, it can only properly address drives of up to 64GB in size.

But HDDs of 80GB and larger are now common, and tools such as Defrag and the DOS Chkdsk were not designed to handle drives of a capacity larger than 64GB, so loss of data is likely if they're used on volumes or partitions larger than that limit.

Note that the Chkdsk HDD utility that is part of Windows XP and Windows Vista (the equivalent of the ScanDisk utility that comes with Windows 9.x systems), can be used with any of the latest large hard disk drives.

Chkdsk can only be used from the Command Prompt (Start => All Programs => Accessories) or from Start => My Computer => right-click the drive that you want to check, and then in the menu that comes up click Properties => Tools => Error-checking, or by running Windows XP's Recovery Console. Click here! to visit information on it on the Recovering Windows XP page on this site.

In Windows Vista, click Start => Computer => right-click the drive that you want to check, and then in the menu that comes up click Properties => Tools => Error-checking.

You should use Windows XP or Windows Vista, which both use the NTFS file system (not FAT32 unless you upgrade from a system using FAT32 and do not convert to NTFS), or divide the drive into multiple partitions with capacities under that limit. The NTFS system can easily address the whole volume of any hard disk drive now available, or that will become available for a long time to come.

If you want to copy the contents from one drive to a drive with a larger capacity installed in a Windows XP or Windows Vista system, you should not use the Xcopy utility that Windows 9x systems have, because the drive letters are allocated differently from the way that Xcopy expects them to be.

You should use the data-transfer utility that came with the retail boxed hard disk drive, or download it from the drive manufacturer's site if it's an OEM product.

Western Digital calls its data-transfer utility Data Lifeguard, and Maxtor calls its utility MaxBlast. Both of these utilities are versions of StorageSoft's EZ Drive, and both utilities can partition and format a HDD. Indeed, it would be much better to use such a utility than to use even the updated version of FDISK, the DOS tool for partitioning a HDD.

Note that FDISK, the DOS partitioning utility that comes with DOS and Windows 9x, cannot be used with Windows XP and Windows 2000, which have their own partitioning and formatting utilities that are run from their setup CDs.

Click here! to go to some very useful information on FDISK on this page. Use your browser's Back button to return here.

You can also use XXCopy (free for personal use) from http://www.xxcopy.com, because it supports all of the versions of Windows. There are articles on XXCopy on the Tips page of this site.

Windows XP: Files and Settings Transfer Wizard

"...I was pleased to find that my new Windows XP based computer includes a Files and Settings Transfer Wizard that even this skeptic finds truly wizard. In just a few steps you can move all your precious files and even more precious settings from one machine to another. Even if you don’t have a new computer, use the Files and Settings Transfer Wizard to create a backup copy of your files and settings, which can then be used to restore your detailed configuration data if you ever need to reinstall Windows XP. Even if you don’t have a new computer, use the Files and Settings Transfer Wizard to create a backup copy of your files and settings, which can then be used to restore your detailed configuration data, if you ever need to reinstall Windows XP". -

http://www.microsoft.com/windowsxp/expertzone/columns/crawford/november12.asp

Click here! to read the page devoted to the Files and Settings Transfer Wizard on this site.

Using "Windows Easy Transfer" in Windows Vista

Windows Easy Transfer allows you to copy all your files and settings automatically to an extra hard disk drive or other storage device and then install Windows Vista. It saves the files and settings on your upgraded PC and then reinstalls them after Vista has been installed. Unfortunately, all of your applications will have to be reinstalled from their CD/DVDs in order to register then with the Windows Registry.

Maximum file size

Note that although its maximum supported volume is two terabytes, the FAT32 file system has a 4GB file-size limit. (One gigabyte (GB) = 1024 megabytes (MBs) and one terabyte (TB) = 1024GB.) If you download a DVD video file to a FAT32 system that exceeds this size limit you will be in trouble. The only solution is to upgrade to Windows 2000 or Windows XP, and either do a clean installation, which will install the superior NTFS file system by default, or upgrade from Windows 9.x and convert from FAT32 to NTFS, which does not suffer from such a file-size barrier because its maximum file size is so immense that there are currently no drives capable of storing anywhere near that much data on a home computer.

NTFS can have over four billion (four thousand million) files on a single partition, and it supports single files as large as sixteen terabytes (16,384GB).

See this article on this site: Windows files systems: FAT32 versus NTFS

The FDISK utility

The FDISK utility is provided by Microsoft to partition and format hard disk drives in Windows 95/98/Me.

Visit this MS Knowledge Base article - 255867 - How to Use the FDISKTool and the Format Tool to Partition or Repartition a Hard Disk, here:

http://support.microsoft.com/?kbid=255867

Note well that if you have a HDD of 64GB or more, if you are using the MS FDISK utility to partition it, you have to use the latest update of the FDISK.EXE file.

To read an article called FDISK Does Not Recognize Full Size of Hard Disks Larger than 64 GB,access the MS Knowledge Base here:

http://support.microsoft.com/?kbid=263044

The updated version of FDISK has never been issued through the Microsoft Update facility.

Fdisk.exe (FDISK) Unable to Partition Drives Larger Than 512 Gigabytes -

http://support.microsoft.com/?kbid=280737

You should also read the following related document that deals with the DOS file, Format.com, which displays the size of the HDD incorrectly:

http://support.microsoft.com/?id=263045

Note that even the updated version of FDISK doesn't allow you to enter partition sizes that are larger than 99,999MB (approximately 100GB) unless you enter the partition size as a percentage of the drive size. In any case, there is some annoying display corruption when partitions are larger than 99,999MB. It also can't use 48-bit addressing, which is needed to access drives that are larger than 137GB. HDDs of 137GB and larger raise several other problematic issues.

You are therefore advised to use the formatting and partitioning utility that is provided by the manufacturer of a HDD, such as Maxtor's MaxBlast, or WesternDigital's Data Lifeguard.

Western Digital made a diskette/download of Data Lifeguard - version 10 - available that often crashes at the end of the data-copying process. At the time of writing, there wasn't a fix available on WD's site, but the older version, 2.8, works on HDDs of up to 137GB.

Click here! to visit FDISK-related sites listed on the first of the four Links pages on this site.

You can look up many more MS Knowledge Base articles on the Diagnostics page of this site.

How to erase the contents of a hard disk drive properly

Formatting a hard drive does not erase the data recorded on it, it merely removes the file system's reference to the data so that it cannot be accessed by the system. In Windows 9.x systems, the file system - usually FAT32 - is changed, and in Windows NT/2000/XP it is usually the NTFS file system that is changed.

The data of a formatted hard drive can be read or recovered by disk-editing or specialised forensic software.

If you want to erase the data permanently, you have to use special software that overwrites the data many times, because it can still be recovered after several overwritings. The US Government's Department of Defense standard requires that erased data has to be overwritten 7 times (US DoD seven pass extended character rotation wiping - DoD 5200-28-STD), but some programs can erase it 35 times or more.

The more data that is overwritten, the longer the process takes.

You should always erase sensitive private data on a hard drive if you are selling it or the computer it is installed on.

Overwriting the data once is sufficients for practical purposes, but a low-level program must be used that writes to every sector of the drive. The free erasing tools from http://www.hddguru.com/ do that.

Eraser from http://www.heidi.ie/eraser/ is a free utility can perform a user-selected number of overwritings, the US Department of Defense standard number (7), or the Guttman number of 35 overwritings.

You can find other free tools by using a suitable search term in the Google search box provided at the this page (with its Web radio button enabled). Try entering: overwrite hard disk drive or erase hard disk drive.

If you have particularly private data on a hard disk drive, the only certain way to make sure that it can never be accessed is to destroy the drive. Here are some ways to do that:

Removing hard drive data - the YouTube way -

"Forget "Format c:" or that silly disk erasing software; get physical" -

http://www.computerworld.com/action/article.do?...

28-bit and 48-bit addressing - the 137GB limit of 28-bit addressing

Older computer motherboards that have 28-bit IDE controllers are limited to installing drives with a maximum capacity of 137GB.

To overcome this limit for drives larger than 137GB, many HDD manufacturers were providing a Promise 48-bit PCI controller card with each drive.

The new SATA (serial ATA) hard disk drives also use 48-bit addressing in order to exceed the 137GB limit. - See immediately below for more information on serial ATA drives.

Hard disk drives are not created equal

Like humans, not all hard disk drives are created equal.

There are several features that have to be taken into consideration in deciding what is the best value for money in buying a hard disk drive at any point in time.

The first of these is if the drive comes as a kit, or as a bare drive without any of the following items. A hard-drive kit typically includes the drive itself, the conversion holder to fit a 3.5" drive - the usual size - in the 5.5" bay of the typical tower or desktop case, a printed installation guide, the installation software (which should contain a utility to reorganise the drive letters of the other IDE devices if an additional drive is installed), and a ribbon cable.

As mentioned earlier on this page, ATA/66 - and higher drives (ATA 100/133) require a special new cable to operate at the higher data transfer rate.

Unlike the case with the older ATA ribbon cables, which only require the correct side of the ribbon to be attached to Pin 1 on the motherboard, with the new 80-conductor ribbon cables, the position on the cable of a drive, and the end that connects to the motherboard and the drive itself is obligatory. The blue end connector must be connected to the motherboard, the black end connector must be connected to the master drive, and the grey connector in the middle of the cable must be attached to a slave drive.

See this Build a PC page on this site for information on the installation of a hard disk drive.

For confirmation of this information visit this PC Guide page:

http://www.pcguide.com/ref/hdd/if/ide/confCable80-c.html

INSTALLING A NEW HARD DISK DRIVE ON A "PROMISE" PCI ADAPTER CARD

If you plan on connecting the new drive to a PCI controller card made by Promise, install both at the same time. In most cases, the system will automatically detect the card, the card detects the drive and you are up-and-running. In a few cases, it is necessary to go into BIOS setup and set it to boot from an SCSI device, because even though your drive may be an IDE ATA, the adapter card makes it appear to the computer as though it is an SCSI drive. There is more information on SCSI drives further down this page.

The features of an IDE (ATA) hard disk drive

The other aspects that you have to consider are features of the drive itself - its capacity or size in gigabytes (GB), the Revs per Minute (RPM) that it is capable of reaching, the size of its data cache/buffer, and the average time it takes to access (read and write) data.

In short, the higher the RPM and the cache/buffer size, the better.

The current RPM categories are 4,200, 4,500, 5,200, 5400, and 7,200, the current cache/buffer categories are 128KB, 256KB, and 512KB, 2MB, and the access times vary from 8 to 12 milliseconds (ms).

Many advertisements for hard disk drives do not provide these specifications, so search for the advertisements of a supplier that does before deciding on a make and model. Computer magazines are packed with advertisements. Some will contain all of the relevant information, including the warranty period, which varies from manufacturer to manufacturer, from one year to five years.

Click here! to go down to information on what to look for in an IDE/SCSI hard drive further down this article. Use your browser's Back button to return here.

SCSI hard disk drives

SCSI hard disk drives (and CD/DVD drives) are often called scuzzy drives.

Those of you who want to record sound and video CDs should investigate SCSI hard disk drives. Burning CDs requires the fast and consistent throughput of data. SCSI drives are superior to IDE drives in this respect, and, as such, are more expensive, but ATA 2 and 3 IDE drives - the types that arrived before ATA 33 and 66 - are quite capable of getting the job done, albeit not as quickly.

SCSI hard disk drives require an SCSI Controller, which can be built into the motherboard, or added in the form of an ISA or PCI adapter card. Many SCSI devices, such as scanners, printers, back-up drives, etc., can be daisy-chained to the controller, with the first and last device in the chain having to be terminated at the connection points that could connect another device, with a jumper-like device called a terminator, so that the controller can determine where the daisy chain begins and ends.

Each device in the chain is allocated an ID number via the SCSI BIOS. Thus, SCSI devices are more complicated to install compared to IDE devices. Like IDE drives, SCSI drives come in different versions.

The table below shows the main SCSI standards from the lowest - SCSI-2; Fast SCSI - 8-bit Narrow - to the highest - Serial Attached SCSI (SAS) - and the SCSI devices that use them.

Type	Speed	HDD/peripheral devices
Serial Attached SCSI (SAS) - (Serial SCSI)	600 MB/sec now, but 1,200 MB/sec eventually	Hard disk drives - The SAS controller can run both SATA and SAS hard drives, but an SAS drive cannot be run from an SATA connection. Click here! for more information on Tom's Hardware Guide.
Ultra320 SCSI (16-bit Wide)	320 MB/sec	Hard disk drives
Ultra160 SCSI (16-bit Wide)	160 MB/sec	Hard disk drives
Ultra2 SCSI (16-bit Wide)	80 MB/sec	Hard disk drives
Ultra Wide SCSI (16-bit Wide)	40 MB/sec	Hard disk drives and tape drives
Ultra SCSI (8-bit Narrow)	20 MB/sec	CD-R, CD-RW, tape, removable storage (Jaz), and DVD drives
SCSI-2 and Fast SCSI (8-bit Narrow)	10 MB/sec	Scanners, Zip drives, and CD-ROM drives

The SCSI standards are broken down into normal (8-bit) mode and wide (16-bit ) mode; the latter being twice as fast as the former.

The technology of latest generation of SCSI hard disk drives is called the Ultra320 16-bit wide standard, which has a data transfer rate of 320MB/s, which is much faster than the highest data transfer rate (133 MB/s) of the latest IDE ATA 133 (UDMA 133) hard disk drives. Even the Ultra160 SCSI standard with its data transfer rate of 160MB/s is faster than the IDE ATA 133 standard. As with IDE drives, SCSI drives are backward compatible. An Ultra320 drive will use the Ultra160 mode of operation if the hardware or the controller card's BIOS do not support the Ultra320 mode of operation.

The Ultra320 standard is twice as fast as the Ultra160 (16-bit) standard, which is twice as fast as the Ultra2 (16-bit) standard, because of the employment of a similar kind of double-data-rate (DDR) and dual-channel DDR technology that is used to increase the effective speed of RAM.

Note that cheap SCSI controller cards often come bundled with SCSI scanners, etc. These are usually cut-down versions that do not have a BIOS. Such a bundled card will be fine for use with the peripheral it came with, but if you want to connect more than one SCSI device, you should obtain a card that has its own BIOS that can be accessed, enabled, and disabled.

The installation of SCSI drives is more complicated than an IDE drive, so, if you don't know how to do it, make sure that you buy a boxed product that comes with an installation manual. You can also search the web by using the Google search box at the top of this page to find tutorials on SCSI configuration and installation.

Note that it is possible to buy a separate case, which looks like like a PC tower case, to house SCSI devices. It contains an interface card and one or more fans. You install all of your SCSI devices to it, and then link the case to your PC as you would any other external SCSI device. You can install up to 15 SCSI drives daisy-chained to an SCSI interface card.

To find more about SCSI, visit these sites/pages. -

How SCSI Works - http://computer.howstuffworks.com/scsi.htm

How to Install SCSI Devices - PCSupportAdvisor.com/

Click the title to read: How To Install and Troubleshoot SCSI Hard Drives.

You can also find plenty of information on SCSI by entering a suitable search term in the Google search box at the top of this page (with its Web radio button enabled). If it contains more than one word or reference, place them between double quotation marks, or use the other search techniques, such as inserting + signs between the words.

What to look for in an IDE/SATA/SCSI hard disk drive

Here is how the specifications for some IDE/SATA/SCSI hard disk drives as they would appear in an informative advertisement.

Manufacturer	Model	Capacity	RPM	Cache	Seek Time	Interface
Maxtor	D540X	160GB	5,400	2MB	8.5 ms	ATA Ultra 100
Maxtor	DiamondMax+	80GB	7,200	2MB	8.5 ms	ATA Ultra 133
Western Digital	Caviar	120GB	7,200	2MB	8.5 ms	ATA Ultra 100
Hitachi	Deskstar 7K250	250GB	7,200	8MB	8.5 ms	ATA Ultra 133
Maxtor	DiamondMax+	300GB	5,400	2MB	12.6 ms	ATA Ultra 133
Samsung	SpinPoint SP1614C	160GB	7,200	8MB	8.9 ms	SATA 150
Seagate	Barracuda 7200.8	400GB	7,200	8MB	8.0 ms	SATA 150
Samsung	SpinPoint SP2504C	250GB	7,200	8MB	8.9 ms	SATA II 300
Hitachi	Deskstar T7K250	250GB	7,200	16MB	8.5ms	SATA II 300
Hitachi	Deskstar 7K80	500GB	7,200	8MB	8.5 ms	SATA II 300
Hitachi	Deskstar 7K1000	1,000GB/1TB	7,200	32MB	8.5 ms	SATA II 300
Seagate	Barracuda 7200.10	750GB	7,200	8MB or 16MB	N/A ms avg	SATA or Ultra ATA/100
Seagate	Cheetah 15K.4	146GB	15,000	-	3.5 ms avg	Serial Attached SCSI (SAS)
Seagate	Cheetah 73LP	73GB	10,000	4MB	5.0 ms	SCSI Ultra 160
Hitachi	Ultrastar	146GB	10,000	8MB	4.7 ms	SCSI U320 68Pin

MB stands for megabytes, which is approximately 1000 kilobytes (KB). With regard to hard disk drives, only their data cache is measured in MB.

GB stands for gigabytes (1GB is approximately 1000MB), which is a measure of the data capacity of a hard disk drive, DVD discs, or RAM and flash memory. All current hard disk drives have their capacities measured in gigabytes.

TB stands for terabytes, which is approximately a 1000GB. The Hitachi Deskstar 7K1000, listed in the table above, has a capacity of 1TB. DVD discs currently have their capacity measured in GB. RAM and flash memory is currently measured in MB and GB.

RPM stands for the number of revolutions per minute that a magnetic platter inside a particular drive spins at.

SATA stands for serial ATA - a drive that uses a serial ATA interface, the original version of which is SATA 150. The latest version of the standard is SATA II 300.

Warranty. - You are advised to check for the warranty provided with a new HDD, as this can be for one, three, or five years, depending on the drive.

Click the name in the Manufacturer column in the above table to visit the company's website.

The 300GB DiamondMax Plus drive shown above has only 2MB of cache, a slow access time of 12.6ms, and runs at only 5,400RPM because it is designed primarily for its storage capacity for use on systems that do not require high performance accesses. Consequently, it stays cool and will probably last longer than a drive running at 7,200RPM.

Note that an SCSI drive of the same capacity as an IDE drive costs many times more than the IDE drive. In January 2003, the 73GB Seagate Cheetah SCSI drive above costs £530/$880, while the 80GB Maxtor DiamondMax+ IDE drive costs only £105/$175. An SCSI drive with a capacity of only 9GB (the Quantum Atlas V) costs £120/$200. And the 146GB Hitachi Ultrastar SCSI drive shown in the table above costs £490 in November 2003, yet a 160GB Maxtor DiamondMax Plus 9 ATA 133 drive only costs £102. Moreover, IDE ATA and serial ATA (SATA) drives with a capacity of 300GBs are now available.

SCSI drives have not reached the same high capacities as IDE drives, while the speeds of IDE drives are rapidly approaching the high data transfer speeds and access times of SCSI drives. The difference in speed is expected to be narrowed even further when serial ATA (SATA) drives reach their full potential.

In October 2003, the Raptor WD360 250GB HDD from Western Digital was the only IDE ATA drive that runs at 10,000RPM. Is it likely that more 10,000RPM IDE drives will become available in the months or years to come? - Probably not until SCSI drives run faster than that, because manufacturers like Maxtor and Hitachi would not want to ruin their own business in fast SCSI hard drives by making comparably fast ATA hard drives available.

It is now May 2006, and, so far, Western Digital is the only manufacturer of hard drives that run at 10,000RPM. The fastest IDE ATA drive currently available is the Western Digital Raptor X that spins its platters at 10,000RPM. The downside of using such a fast drive is the extra cost compared to standard 7,200RPM drives, and the extra noise they make.

In February 2003, for the price of five Ultra320 SCSI hard drives with a capacity of 147 GB, you can currently buy fifteen state-of-the-art IDE hard drives with a capacity of 200 GB.

Because SCSI drives are used in mission-critical systems, they typically still come with five-year warranties, whereas most IDE drives now only have one-year warranties instead of the three-year warranties they used to have.

It is now possible to obtain IDE drives with 8MB of cache (8192KB) compared to the previous maximum of 2MB (2048KB). SCSI drives are available with 4MB of cache. - The cache size is increasing as drive capacity is increasing remorselessly.

Note well that HDDs with a high revs-per-minute rating (7200RPM+) get much hotter than drives with a lower rating (5400RPM). Therefore, be sure to install a drive with a high rating in its bay so that it has space around it. Do not cram it in between other drives. If you have odd problems with the system, consider buying and installing a cooling unit for such a drive. If you don't require fast drive access speeds, buy a drive with a 5400RPM rating. They are less expensive, and may well last longer.

Since the shakeout that took place in a declining PC market, the advertisements in PC magazines are providing less information than ever in order to reduce costs. Most of the above information is no longer provided by advertisers that used to provide it when the PC market was at its height a few years ago. You should try looking at the advertisers' websites for this information before making a purchase, otherwise you run the risk of getting less for your money than is necessary. If performance is an issue for you, why purchase a drive that runs at 5400 RPM when you can purchase a drive that runs at 7200 RPM for almost the same price? If all of the above information for a particular drive is not on a website try e-mailing the company for it.

As a measure of the decline, you only have to compare the information that advertisers provided in Computer Shopper a few years ago with the severely reduced number of advertisers and the information they provide now. The magazine itself is half its former size, has reduced editorial content, yet costs more than it did at its peek.

In practice, on desktop PCs, there is little difference in the performance of UDMA (ATA) 100 and UDMA (ATA) 133 drives with the same or similar revs per minute (RPM), cache, and access times, but there is a significant difference in performance between drives spinning at 5,400, 7,200, and 10,000 RPM.

The faster the platters within a drive spin, the better the performance, and the higher the price.

Just for your information, although neither of the following items are in production, with a 500MHz processor, a UDMA 33 (ATA 33) HDD is fast enough to run office applications and access the Internet without any noticeable delays of the kind that would be experienced if the processor was running at 200MHz and the HDD was using PIO mode 4 - the ATA 2 mode that came out prior to ATA 33.

My Internet computer has a motherboard that supports UDMA 33 (ATA 33) as its highest mode. The system has two HDDs - a 20GB UDMA 100 Quantum Fireball, with a 2GB ATA 2 (PIO mode 4) Seagate drive that contains a clone of the main drive - created with the free version of XXCopy - several folders of which are backed up according to a schedule using Karen Kenworthy's free Replicator.

The UDMA 100 Quantum Fireball drive works very quickly in the UDMA 33 mode supported by the motherboard. When I eventually purchase a motherboard that supports UDMA 100, or higher, I will be able to use it, because all UDMA (ATA) IDE drives are backward compatible with all of the earlier UDMA drives.

Note that the motherboard, the drive itself, and the BIOS must support a particular mode if the drive is to function in that mode, otherwise the drive will run in highest mode supported by all three of the above mentioned factors.

Note that it would be wise to read the postings about hard disk and CD drives that appear in your motherboard's newsgroup before you make a purchase.

See the Newsgroup page on this site for more information on newsgroups.

For a full list of UDMA (ATA) modes, see the table a little further down the page...

If you want to upgrade your hard disk drive, choose one that has a cache of 2MB and 7,200 RPM, and remember that while they are expensive at present, the prices will fall as bigger, better, and faster drives, using new technology that will probably require a new kind of motherboard, become available.

For your information, ATA stands for Advanced Technology Attachment.

DMA stands for Direct Memory Access (see the table below) - modes of data transfer that increase performance by avoiding having to use the processor as much as possible.

Enabled or disabled in the BIOS, all of the DMA modes use a dedicated DMA Controller on the motherboard.

How to Activate DMA on Hard Disk Drives and CD/DVD drives in Windows XP

Follow this clicking path:

Start -> Control Panel -> System -> Hardware -> Device Manager -> IDE ATA/ATAPI Controllers -> Right click on the Primary IDE channel and Secondary IDE channel entries -> Properties -> Advanced Settings tab -> set the Transfer Mode to DMA if available for both devices.

IDE drives also support the non-DMA modes of operation - PIO modes 0 to 4 - which can also (usually but not always) be enabled/disabled in the BIOS, the drivers for which will be installed by Windows automatically if the DMA modes are disabled in the BIOS and their drivers have been uninstalled.

In all of the Award BIOSes that I have seen, the IDE settings appear in the Integrated Peripherals section.

In the AMI BIOS that I have, there are no individual settings for the two IDE channels. The IDE mode of operation is automatically set at the highest one available for each drive. This means that with this particular BIOS program I cannot choose the mode of operation for any of the the HDDs installed on the motherboard that uses it.

In most Award BIOSes, the UDMA modes, and the IDE PIO modes 0 to 4 can be set to Auto, or can be set individually.

Uninstalling non-Microsoft IDE Busmaster DMA drivers usually means having to use the same utility that installed them in its uninstall mode, but often video and sound card drivers, etc., can be uninstalled using the Add/Remove Programs icon in the Control Panel, or by using the Remove button in Device Manager to remove the whole device.

All of the IDE drivers will have been loaded into memory at start-up, so removing them will only take effect on the next start-up, when Windows will re-detect the driverless devices and attempt to provide them with drivers.

Note that you can purchase external hard disk drives that are connected via a parallel port, USB, and FireWire ports.

These removable drives are connected externally with the appropriate cables, via a parallel port, USB, or FireWire ports. As such they are ideal for system back-ups, since they can easily be removed off site as insurance against fire and theft.

The official terms for the different modes of ATA IDE hard disk drives (aka UDMA and Ultra DMA drives) - from the earliest - PIO Mode 0 (ATA 1) - to the latest - ATA 133 (Ultra ATA Mode 6) - and some of their technical details are as follows:

DMA Transfer Modes

Data Transfer Rate (max.)