The image shows a close-up of the rear view. The USB 2.0 port is on the left followed by two FireWire ports (FireWire 400 and FireWire 800), which means that it can be connected to a PC or an Apple Mac. Beside them is the power connection and the on/off switch. Mouldings that can interlock allow several OneTouch drives to be stacked one upon another. The latest OneTouch drives also come with a stand that allows the to be positioned vertically on a desktop.

Note that USB 3.0 is now available. It is much faster than its predecessor, USB 2.0. The best USB 3.0 external hard drives are up to four times faster than USB 2.0 models. Visit the USB section of this website for more information on the new USB standard. The first USB 3.0 external hard drives were made available in October 2009, but most existing desktop and laptop PCs don't have USB 3.0 ports and you have to make sure that USB 3.0 is a specification of a new computer, because the new standard's adoption is taking place slowly. USB host controller adapter cards for desktop PCs are available that add USB 3.0 ports. PC Card USB 3.0 host controllers for laptop computers are also available.

Buffalo ships world's first USB 3.0 hard disk drives this month [October 2009] -

http://www.engadget.com/2009/10/07/...

Three External (and Fast) USB 3.0 [Hard Disk] Drives Compared -

"The first USB 3.0-based external hard drives aim at eliminating the USB 2.0 bottleneck (that hovered around 30 MB/s) with enough bandwidth to outperform the fastest mechanical disks. A-Data, Buffalo, and WD do battle for maximum performance." -

http://www.tomshardware.co.uk/usb-3.0-superspeed-external-drive,review-31952.html

Visit the following page for information on how to test for USB support and on the USB settings in the BIOS setup program. -

http://www.usbman.com/Troubleshooter%20General.htm

There are three current interfaces that can be used to connect external hard disk drives - USB, FireWire and eSATA (dealt with on this page).

USB 2.0, FireWire, Or eSATA: Which Interface Should You Use? : USB/FireWire/eSATA: 2.5” And 3.5” Storage Options -

"Adding external storage to your PC can be a mess if you aren't familiar with the various interfaces in play. Should you go for compatibility with USB 2.0 or is FireWire a better choice? What about eSATA, which matches native hard drive performance?" -

http://www.tomshardware.co.uk/usb-firewire-esata,review-31793.html

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

External hard drives come in all kinds of shapes and sizes - tower units, horizontal desktop units, and portable units.

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.

Desktop units with 1 terabyte - 1TB (1000MB) - of storage space are now common. (Remember that the hard-drive manufacturers use 1,000KB = 1MB and 1,000MB = 1TB, whereas the true mathematical figures - 1,024KB = 1MB and 1024MB = 1TB - are used by software developers (Microsoft, etc.). Therefore, a hard drive always has more disk space according to the manufacturers than is reported by Windows XP/Vista/7.

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 a growing number of PC motherboards now 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 2008), 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 Quadra (eSATA 3Gbits, FireWire 800, FireWire 400, USB 2.0) 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. Note that FireWire PCI Express adapter cards are now available, such as the Belkin FireWire 3-Port PCI Express Card.

Just as there is little performance increase between SATA I 150 and SATA II 300 hard drives, it doesn't make much difference if a FireWire 400 or FireWire 800 port is used because of the speed limitations imposed by the mechanical nature of hard drives. The platters can only revolve and the data can only be picked up and transferred across cables at a maximum rate that can't be exceeded just by using an interface that provides bandwidth that exceeds those mechanical limitations. You can design a motorway so that it has a speed limit of 700MPH, but there is no point in doing that if the cars themselves can't exceed 250MPH.

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 usually installed in a PCI slot on the PC's motherboard. (At the time of writing in August 2008 there were no USB 2.0 PCI Express adapter cards, but FireWire PCI Express adapter cards were available, such as the Belkin FireWire 3-Port PCI Express Card.)

All ATX motherboards have had the PCI 2.x or PCI-X slots that accommodate the current PCI adapter cards for many years. If you buy a PCI Express adapter card for a desktop PC, you must make sure that you have the type of free PCI Express slot on the PC's motherboard that the card uses. PCI Express slots come in three sizes - x16, x8, and x1. The motherboard's user manual will tell you which slots it has. The motherboard manufacturer's website provides manuals in the PDF format.

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). (eSATA PCI Express adapter cards are also available for desktop PCs that have the required free PCI Express slot on the motherboard.) 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.

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 Storage: Terabyte [1,000MB] Drives Compared : Value-Added External Terabyte Storage -

http://www.tomshardware.co.uk/-external-hard-drive,review-31383.html

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

More information on eSATA hard disk drives is provided further down this page.

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/7 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/

LaCie - http://www.lacie.com/

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

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

Paul Mullen, who was 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 best way to choose RAM memory for a brand-name desktop or laptop computer, or memory for a paricular make/model of PC motherboard is to make use of the Crucial Memory Advisors (provided under the brief guideline on the minimum memory requirements for Windws XP, Windows Vista and Windows 7). If the Crucial memory you receive does not work, you are guaranteed a refund and standard shipping is free.

The memory requirements of the versions of Windows Vista and Windows 7

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. Note that if you are using a 64-bit version of Windows, up to 4.0GB, it requires twice the amount of memory as a 32-bit version, which can only use a maximum of about 3.5GB. For more information on computer memory, read the RAM pages of this site, which includes information on the lower memory requirements of Windows 7.

UK - Crucial Memory Advisor - UK

USA - Crucial Memory Advisor - USA

How to Use the Crucial Memory Advisor

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.

Computer storage devices rated and reviewed by Expert Reviews

Expert Reviews - storage reviews - http://www.expertreviews.co.uk/storage

The above page on the Expert Reviews website provides reviews on the following storage devices:

Internal hard disk drives
External hard disk drives
DVD/Blu-ray drives
Network attached storage
USB flash drives

ARTICLES ON EXTERNAL HARD DISK DRIVES

Two Portable 500GB Drives Benchmarked (And Dropped) -

"If you're the sort of power user who's hard on technology, especially out in the field, then ruggedized mobile storage might be apropos. Today, we're looking at a pair of portable disks that can take drops and spills, while serving up 500GB of capacity." -

http://www.tomshardware.co.uk/ruggedized-resistant-hdd,review-31827.html

Comparing External RAID Housings : Backing Up Data To A Hard Drive -

"External RAID via eSATA and USB - Thanks to the intelligent SATA controller, which, alongside the port multiplier also provides a virtualization layer, multiple drives can now be addressed simultaneously in a single housing via either eSATA or USB 2.0. The operation of an external RAID cluster in the DAS [Direct attached Storage] devices is thus possible. To operate a RAID configuration, it is necessary for the housing to be used with at least two drives." -

http://www.tomshardware.co.uk/SansDigital-Superbox-FantomDrive,review-31247.html

Convenience Storage By Buffalo And Toshiba : Data Mobilization By Buffalo And Toshiba -

"The latest external 2.5" drives by Buffalo and Toshiba come with easy-to-use backup software, but they lack features. More interesting is their capacities of 500 GB and 320 GB." -

http://www.tomshardware.co.uk/Storage-Buffalo-Toshiba,review-31227.html

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

External SATA (eSATA) hard disk drives

eSATA is part of the SATA standard, but it isn't just internal SATA extended into an external enclosure. The eSata standard is a standard of its own that defines the interconnect (the design of the connectors) - the signalling requirements and user features such as shielded cables and hot-plug connections. The connector for an eSATA cable is different from a standard SATA 150 or SATA 300 cable, so you can't use a standard motherboard SATA cable.

External SATA or eSATA is supported by many makes/models of ATX desktop PC motherboards, which provide an eSATA port on the ports panel. If a motherboard doesn't provide an external eSATA connector, some motherboards provide an option (often as an optional extra) to install eSATA ports in the form of a cabled bracket containing them that fits into an expansion slot at the back of the case.The cable is connected to an SATA header on the motherboard.

If neither of those options are available, PCI/PCI-X and PCI Express eSata controller cards are available that you install in a PCI slot (which all motherboards have had for may years), or in a PCI Express slot. The contoller is usually installed in a PCI Express x1 slot. Most recent motherboards provide at least x1 slot. Your PC's motherboard's user manual will tell you which ports it provides for adapter cards. If you don't have a manual, the motherboard's manufacture provides them in the PDF format. You can use the free CPU-Z utility to identify the PC's motherboard (make/model).

You can locate vendors for the above-mentioned controller cards by entering a search term such as esata controller card in the Google search box at the top of this page (with its Web radio button enabled).

eSATA is currently the best option to use for an external hard drive, because it is actually (not just theoretically) much faster than USB 2.0 (USB Hi-Speed) and FireWire 400.

Five eSATA Drives Reviewed -

"We gathered five eSATA hard drives, perfect for data backups and portability, and pitted them against each other with performance tests. In doing so, we also exposed the gap between eSATA and USB 2.0, since each drive is also capable of the latter."

http://www.extremetech.com/article2/0,1697,2173840,00.asp

Seagate 500 GB External Hard Drive Goes eSATA : 500 GB -

http://www.tomshardware.com/reviews/....

eSATA External Hard Drive [PDF document] -

"An eSATA PCI host adapter card is included with your Seagate eSATA drive in order to provide the necessary connection between your computer and the drive. Before using the drive, please install the PCI card by following the instructions in the enclosed Quick Install Guide." - http://www.seagate.com/docs/pdf/datasheet/disc/ds_ext_esata.pdf

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 I 150	1500 MBit/s [1.5 GBit/s or 150MB/s]	118 MB/s
Serial ATA - SATA II 300	3000 MBit/s [3.0 GBit/s or 300MB/s]	118 MB/s

eSATA has the same figures for SATA 150 or SATA 300, depending on the version of SATA being used by the motherboard.

Click here! to view the theoretical bandwidth (not the bandwidth achieved in practice) of all of the computer storage standards. The page contains the bandwidths of all of the other computer standards, such as PCI, AGP, PCI Express, etc.

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.

Note that data transfer rates are limited by mechanical hard drives themselves, not by the interfaces. The fastest modern desktop hard drives transfer data at a maximum of about 118MB/s, which is well within the capabilities of even the older IDE ATA/133 specification. An analogy would be a highway that allows speeds of 700MPH, but cars that can only reach a maximum speed of 270MPH.

All of the facts and figures of SATA and eSATA are provided here:

Serial ATA - http://en.wikipedia.org/wiki/Serial_ATA

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. You can now buy external hard drives that support all four of the current standards - eSATA 3Gbits, FireWire 400, FireWire 800, USB 2.0 (Hi-Speed).

Have a look at this page to see which standards are supported by the models of external hard drives made by Lacie:

http://www.lacie.com/products/range.htm?id=10033

If that link doesn't work, visit http://www.lacie.com/ to access the products.

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 as 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 ATA or SATA drive enclosed in an eSATA enclosure. You can also purchase PCI/PCI-X and PCI Express x1 adapter cards that fit in a PCI or PCI Express x1 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

External IDE hard disk drive enclosures with USB, FireWire, eSATA ports

External enclosures for standard IDE ATA and SATA hard disk drives that provide them with USB 2.0, eSATA, and FireWire ports are available. So, if you have any old IDE (PATA) hard drives taken from a PC that you have upgraded, etc., you can make use of it as an external backup drive. Note that you probably won't be able to find an enclosure with all three types of ports.

The image below shows the back view of an enclosure that accepts an IDE or and SATA hard drive and can be connected to either its USB 2.0 or eSATA port.

A hard disk drive enclosure that allows an IDE or SATA drive to be connected to a USB 2.0 or eSATA port

An old or new 3.5" IDE or SATA hard disk drive can be installed in such an enclosure so that it can be used as an external drive via a USB, FireWire, and eSATA ports, depending on which types of ports the enclosure provides. The enclosure shown above does not provide a FireWire port, but other makes/models do. The installation of the IDE or SATA 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, eSATA cable, power supply, fitting screws, etc.

The enclosed IDE/SATA 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.

Using an ATA IDE (PATA) or SATA drive in this way is a much cheaper alternative to buying an external (USB, FireWire, eSATA) hard drive.

Enclosures that accept only SATA hard drives are already the dominant type. Soon, the manufacturers won't be manufacturing enclosures that accept IDE drives, because there will be little demand for them as that standard dies out.

USB-to-IDE and USB-to-SATA converters cables/adapters

You can buy a USB-to-IDE or a USB-to-SATA converter that allows you to connect an IDE or SATA hard drive or CD/DVD optical drive to a USB port. You can also buy a single converter that can be used with both IDE and SATA drives. 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. You can use it for doing malware scanning from a known uninfected PC on the drives of other PCs, transfer files from an old PC's hard drive to a new PC's hard drive, etc.

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

Here are a few examples that I found:

USB to IDE Converter -

"This is brilliant. My computer died, so I bought a new one. Plugged my old hard drive into the USB2.0 using this gizmo, et voila, instantly recognised." -

http://www.amazon.co.uk/Dynamode-USB-IDE-Usb-Ide-Converter/dp/B000IGE8DG

TeckNet VS408 USB 2.0 to IDE/SATA Cable for 2.5-Inch/ 3.5-Inch / 5.25-Inch Drive With Power Adapter -

http://www.amazon.co.uk/TeckNet-2-5-Inch-3-5-Inch-5-25-Inch...

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 hard disk drive using an eSATA, 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 on configuring hard disk drives:

1. - How to use Disk Management to configure basic disks in Windows XP -

http://support.microsoft.com/kb/309000

2. - 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

The following page provides information on the difference between basic disks and dynamic disks.

Logical Disk Manager - http://en.wikipedia.org/wiki/Logical_Disk_Manager

3. - 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 (137GB) limit. - http://support.microsoft.com/?kbid=303013

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.

Note that no PC that has a fairly recent motherboard (from about 2002/2003), which runs Windows XP SP1 or higher (including Windows Vista) will have the 137GB limitNote that no PC that has a fairly recent motherboard (from about 2002/2003), which runs Windows XP SP1 or higher (including Windows Vista), will have the 137GB limit, because it will have a 48-bit controller. All motherboards with SATA-drive connectors (that support SATA) have 48-bit controllers.

How to work with partitions in Windows Vista/XP when Disk Management doesn't work - http://www.vistarewired.com/2007/04/07/...

Review: 3 partition managers take on [Windows] Vista's built-in tools -

"Partitioning your hard drive can be useful for trying out a new OS or managing several terabytes of data." -

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

To locate more information on this subject within Windows XP, enter Create a partition or logical drive in the Search box of Start => Help and Support. Alternatively, make use of the Google search box at the top of this page (with its Web radio button enabled).

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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, but this free program is probably the best of them all:

Partition Logic - "Partition Logic is a free hard disk partitioning and data management tool. It can create, delete, format, defragment, resize, and move partitions and modify their attributes. It can copy entire hard disks from one to another. Partition Logic is free software, based on the Visopsys operating system. It boots from a CD or floppy disk and runs as a standalone system, independent of your regular operating system. It is intended to become a free alternative to such commercial programs as Partition Magic, Drive Image, and Norton." - http://partitionlogic.org.uk/

You can also use the following free program developed for Linux. It is also available on the Knoppix Linux boot CD, where it began, but has now been hived off as an individual utility.

Gnome Partition Editor - GParted Live -

"GParted is an industrial-strength package for creating, destroying, resizing, moving, checking and copying partitions, and the file systems on them. This is useful for creating space for new operating systems, reorganizing disk usage, copying data residing on hard disks and mirroring one partition with another (disk imaging)." -

http://gparted.sourceforge.net/

And here is a well-reviewed free partition manager:

EASEUS Partition Manager Home Edition (four stars - doesn't work with 64-bit Vista) -

http://www.download.com/Easeus-Partition-Manager/3000-2248_4-10863346.html

Windows Vista

To open Disk Management in Windows Vista, click the Start button and enter diskmgmt.msc in the Start => Start Search box, or click the Start button => right-click 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.

Full click path: Click on the Start button, right-click the mouse with the mouse pointer on Computer and select Manage. Expand the Storage section and select Disk Management. Now just right-click on any partition and select either Expand or Shrink to change the size of the partition.

How to work with partitions in Windows Vista/XP when Disk Management doesn't work - http://www.vistarewired.com/2007/04/07/...

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.

You can also download QTParted from http://qtparted.sourceforge.net/ for use in a Linux system, but you can only use it in a Windows if it is part of a live distribution of Linux, such as Knoppix.

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

To open Disk Management in Windows XP, enter diskmgmt.msc in the Start => Run box.

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 and right-click with the mouse pointer over Computer and then select Manage in the menu that presents itself. Expand the Storage section and select Disk Management.

The boot drive (usually C:) should be given a space there with the other drives (additional hard drives and CD/DVD 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 to use the NTFS file system. In other words, you have to choose the NTFS file system option, not the FAT32 file system option, 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.

If you enter Disk Management in Vista's Start => Help and Support, you will be able to read the information that Vista itself provides on it.

At the time of writing this (August 2008), there were no other Microsoft articles on Disk Management on the web. However, if you want to search for what is available, copy and enter disk + management + vista (as is) into the Google search box at the top of this page (with its Web radio button enabled).

Deleting and creating partitions or logical drives in Windows XP and Windows Vista

Note that you can also use the Command Prompt (command line) to delete and create partitions/logical drives in Windows XP/Vista.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. In Windows XP, you will be offered these two options: Using a Windows interface and Using a command line. In Windows XP/Vista to bring up the Command Prompt, enter cmd in the Start => Run box (XP) and the Start => Start Search box (Vista).

In Disk Management within Windows, 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/Vista, the best choices are a 4KB cluster size and the NTFS file system. Note that those options are greyed out for the boot drive, which is usually the C: drive, because you cannot format the drive that Windows is running from or delete its partition.

You can easily remove any other 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 gives a new logical drive a drive letter automatically, but there is also an option that allows you to choose the drive letter.

The Disk Management feature in Windows Vista (but not in Windows XP) 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.

But the best way to perform those actions in an emergency in a Windows XP/Vista system is to boot from its installation CD/DVD (if your PC came with one, or you purchased your own). You may have to enable the CD/DVD drive as the first boot drive in the boot order in the BIOS setup, because the system won't boot from a CD/DVD unless its drive is the first boot device in the BIOS. 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.

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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 that is the case and you convert a drive from FAT32 to use NTFS, you won't be able to use the system recovery CD/DVD.

That could still be the case with brand-name PCs that have Windows Vista preinstalled by the manufacturer and that come with a recovery CD/DVD. In any case, you can easily check which file system is being used by the hard drive(s) installed in a system. In Windows XP, open My Computer and in Windows Vista open Computer. You might have to right-click on an empty space in the window, click on View in the menu that comes up, followed by Details, and then click on the bar that shows the attributes (Name, Types, Total Size, etc.) to enable File System.

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

The first version of Windows 95 used the 16-bit FAT16 file system, which could only address a hard disk drive (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 250GB 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 in Windows 95/98/Me (Windows 9x) systems.

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 9x systems), can be used with any of the latest large hard disk drives.

In Windows XP, 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.

If you want to transfer files from one computer to another, 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. You can also use the Files and Settings Transfer Wizard in Windows XP or Windows Easy Transfer in Windows Vista. More information on them is provided below.

Note that FDISK, the MS DOS partitioning utility that comes with DOS and Windows 9x, cannot be used with Windows 2000/XP/Vista, which have their own partitioning and formatting utilities that are run from their setup CD/DVD or from within those versions of Windows.

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 them with the Windows Registry.

Click here! to go to the information on Windows Easy Transfer on the Using Windows Vista section of this site.

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/Vista 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 and the more times it 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?...

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.

SCSI and serial Attached SCSI (SAS) hard disk drives

SCSI hard disk drives (and CD/DVD drives) are often called scuzzy drives. Just as parallel IDE ATA has develped into a serial standard - serial ATA or SATA, there is now serial SCSI called serial attached SCSI or SAS.

SCSI/SAS drives are hardly ever used in desktop PCs, because the extra performance they deliver, which has been severely reduced by the SATA standard, is not required by the typical home or office user. Moreover, solid state drives (SSDs) that use flash memory, might take over from both SATA and SCSI/SAS drives. Google is reported to be planning on using SSD drives in its servers.

Google Plans To Use Intel SSD Storage In Servers -

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

SATA drives are up to 1TB (1,000GB), while SCSI/SAS drives are still around 300GB. The cost per gigabyte (1GB - 1,000MB) of SCSI/SAS is about four times as much as the cost per GB of SATA disk space. SATA bit error rates are ten times that of SCSI/SAS, which is a critical statistic for servers and mission-critical systems, because errors during a RAID rebuild can cause loss of data. With SCSI/SAS you might be able to get away with using RAID 5, but with SATA you should seriously consider RAID 6. Moreover, the MTBF (mean time between failures) of SCSI is reported to be two to four times that of SATA. However, that statistic has been called into question recently in the Google and CMU whitepapers. SATA is point-to-point (uses a single cable per drive to attach it to the motherboard), while SCSI is a shared, parallel bus in which all of the drives are linked togeher. Therefore, with SCSI, a cable or drive problem can bring down all of the drives. However, note that this is not an issue with SAS, which is point-to-point (uses a single cable per drive connected directly to the motherboard). In fact, SATA and SAS drives can use the same cables.

SCSI/SAS hard disk drives require an SCSI or SAS Controller, which can be built into the motherboard, or added in the form of a PCI or PCI Express adapter card. Note that some motherboards have controllers that support both SATA and SAS drives. SCSI hard drives usually come with a controller card, because not many motherboards have an SCSI controller.

Many SCSI (not SAS) 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 (bottom of the table) - 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 dated April 7, 2006.
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 (with its web radio button enabled) 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

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

You can also find plenty of information on SCSI and Serial Attached SCSI (SAS) 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.

Direct Memory Access (DMA)

DMA stands for Direct Memory Access - modes of data transfer that increase performance by avoiding having to use the processor as much as possible. Therefore, using DMA improves performance by relieving the processor of work.

With some motherboards, DMA access for IDE hard disk drives can be enabled or disabled in the BIOS.

All all of the DMA modes use a dedicated DMA Controller on the motherboard. It can be enabled or disabled for the IDE channels (connectors). Older motheboards have two IDE channels that support four IDE hard drives or CD/DVD drives. Most new motherboards have six SATA channels (connectors) for SATA disk drives and usually provide one IDE connector for up to two IDE drives.

Note that the Transfer Mode cannot be set to DMA for SATA drives in Windows XP/Vista. It is enabled in the BIOS. There are usually two BIOS settings to set to enabled, one for the SATA interface and one for the SATA DMA (Direct Memory Access).

Note that the following information on DMA (Direct Memory Access) only applies to IDE ATA hard drives and IDE ATAPI CD/DVD drives. For SATA drives SATA DMA is a setting that can be enabled or disabled in the BIOS setup program, not in Windows. If you have purchased a PC that has SATA drives, it will have been enabled by default, but you will probably have to enabled it for a new motherboard that supports both IDE ATA and SATA drives. Consult the motherboard's user manual for motherboard-specific information.

Note that some motherboards have settings in the BIOS that can enable and disable DMA for IDE channel(s) (connector(s).

To activate DMA (Direct Memory Access) on IDE Hard Disk Drives and CD/DVD drives in Windows XP/Vista, follow this clicking path:

In Windows XP, click Start -> Control Panel -> System -> Hardware -> Device Manager. Click on the + beside IDE ATA/ATAPI Controllers. Right-click with the mouse on the Primary IDE channel and the Secondary IDE channel entries in turn, in each case clicking Properties -> Advanced Settings tab. Set the Transfer Mode to DMA if available for both devices.

In both Windows XP and Windows Vista, to bring up the Device Manager, enter devmgmt.msc in the Start => Run box in XP, and in the Start => Start Search box in Vista.

If the system refuses to start up, press the F8 key repeatedly at startup after the memory count until the boot menu appears and choose the Safe Mode boot option. You can then access the DMA setting and disable it. If DMA can be enabled or disabled in the BIOS, you can disable it there.

From a system performance point of view, it important to make sure that you enable DMA properly, which is not as straightforward as you might think. You can simply enable DMA for a particular drive in the Device Manager, but there is a DMA setting in the registry too. There are several articles on this subject in Microsoft Knowledge Base on this subject.

The following article on Microsoft's site explains DMA in Windows XP.

DMA Mode for ATA/ATAPI Devices in Windows XP -

http://www.microsoft.com/whdc/device/storage/IDE-DMA.mspx

How do I enable DMA mode on CD and DVD burner drives? -

"DMA (Direct memory access) mode is a high performance mode for transferring data to and from devices, in particular, to CD and DVD burner devices. The burner devices can function in either DMA or PIO modes. DMA mode allows the processor to transfer large pieces of data with very little software overhead - therefore requiring low CPU utilization. In this mode, high speed burning can be performed in background with other programs running. PIO mode requires CPU processing for every few bytes sent to the device, so that CPU utilization becomes very high when trying to burn at high speeds." -

http://www.onthegosoft.com/dma_setting_nt.htm

Windows [Vista] Help and How-to - Turn Direct Memory Access (DMA) on or off [IDE ATA/ATAPI controllers] -

"Direct memory access (DMA) is usually turned on by default for devices such as hard disks and CD or DVD drives that support DMA. However, you might need to turn on DMA manually if the device was improperly installed or if a system error occurred." -

http://windowshelp.microsoft.com/Windows/en-NZ/Help/...mspx

The use of DMA became available with UDMA2 (ATA 33) hard disk drives, which support busmaster IDE drivers. If you have an earlier hard disk drive that supports only the PIO modes of operation up to PIO 4, you should not enable the DMA option for that drive, because it will not be able to use a busmaster IDE driver, and as such will cause problems that will probably involve having to boot in Safe Mode to disable the DMA setting, or remove the IDE busmaster drivers in order to reinstall the proper ones.

IDE ATA hard disk drives have reached UDMA5 (ATA 133). UDMA2 = ATA 33 - UDMA3 = ATA 66 - UDMA4 = ATA 100 - UDMA5 = ATA 133.

Any UDMA2 (ATA 33) or higher IDE ATA hard disk drive will support DMA - as long as it is also running on a motherboard that supports the UDMA2 (ATA 33) or higher modes of operation.

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.

The modes of the IDE ATA standard

The official terms for the different modes of IDE ATA 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.)	Cable	Cable Conductors	CRC
PIO Mode 0 (ATA 1)	3.3MB/s	40-pin IDE	40	No
PIO Mode 1 (ATA 1)	5.2MB/s	40-pin IDE	40	No
PIO Mode 2 (ATA 1)	8.3MB/s	40-pin IDE	40	No
PIO Mode 3 (ATA 2)	11.1 MB/s	40-pin IDE	40	No
PIO Mode 4 (ATA 2)	16.6MB/s	40-pin IDE	40	No
Ultra ATA Mode 2 (ATA 33)	33.3MB/s	40-pin IDE	40	Yes
Ultra ATA Mode 3	44.4MB/s	40-pin IDE	80	Yes
Ultra ATA Mode 4 (ATA 66)	66.6MB/s	40-pin IDE	80	Yes
Ultra ATA Mode 5 (ATA 100)	100MB/s	40-pin IDE	80	Yes
Ultra ATA Mode 6 (ATA 133)	133MB/s	40-pin IDE	80	Yes

The data transfer rate is measured in megabytes per second (MB/s). The 80-conductor cable has to be used for a drive that supports Ultra ATA Mode 3 and higher modes. The 40-conductor cable can only be used with drives up to Ultra ATA Mode 2, but the 80-conductor cable can also be used with those drives. Ultra ATA 33 introduced CRC (Cyclical Redundancy Check), a feature that provides data-protection verification. Ultra ATA 66 and Ultra ATA 100 and Ultra ATA 133 use the same process, and support all previous DMA transfer modes. There are no Ultra ATA Mode 3 hard disk drives; it is only a mode that ATA 66 and higher drives support. There are only ATA 33/66/100/133 hard disk drives.

Windows XP: How to enable Ultra DMA 66 mode

Note well: always back-up the Registry (or the system) before making changes to it.

Enter regedit in the Start => Run box to open the Registry Editor.

Navigate to the HKEY_LOCAL_MACHINE\System\ CurrentControlSet\Control\Class\{4D36E96A-E325-11CE-BFC1-08002BE10318}\0000 key, select it in the left hand pane, right-click an empty space in the right-hand pane, and, by clicking New => Key, create a new DWORD Value and name it EnableUDMA66. Right-click on it and give it a Binary Value of 1.

In my Windows XP Pro Registry, (the laptop computer has an IDE hard drive) there are three CurrentControlSet entries - ControlSet001, ControlSet002, ControlSet003 - so you would have to make that entry three times.

Enabling Ultra DMA 66 (ATA 66) also enables DMA 100 (ATA 100) and DMA 133 (ATA 133).

How to find out the DMA transfer mode being used in Windows 95/98/Me/XP

If things go wrong with the IDE ATA drivers, etc., Windows can revert to using the earliest and slowest PIO Mode, called MS-DOS Compatibility Mode in Windows 95/98/Me, which slows the system down considerably. Read this MS Knowledge Base article on the problem in those versions of Windows: MS-DOS Compatibility Mode Problems with PCI IDE Controllers - the NOIDE Registry entry. If there is a message under the Performance tab of System Properties (accessed from the Control Panel) saying that Windows 95/98/Me is using MS-DOS Compatibility Mode, then the computer has this problem. If you want to know which mode of DMA is being used in those versions of Windows, the information is provided on the start-up screen. Press the Pause/Break key when system information appears in order to hold it, because the information flashes by.

In Windows XP this Knowledge Base article discusses the problem: IDE ATA and ATAPI Disks Use PIO Mode After Multiple Time-Out or CRC Errors Occur.

To find out what DMA mode is being used in Windows XP, open the Device Manager (enter devmgmt.msc in the Start => Run box), click on IDE ATA/ATAPI controllers, then right-click on Primary IDE Channel, select Properties, then Advanced Settings. Look at these settings: Transfer Mode (DMA if available) (PIO is the alternative setting) and Current Transfer Mode (Ultra DMA Mode 5 appears in its box on my laptop that has an IDE hard drive). The Secondary IDE Channel on my system is used for an IDE/ATAPI DVD writer, which uses Ultra DMA Mode 2. This information does not apply to Windows 95/98/Me.

Information pages on hard disk drives and how to install, partition, format and troubleshoot them

Hard disk drives - problems and solutions

Click here! to go to the section of this site devoted to hard disk drive problems and their solutions.

If you want to find out exactly how a hard disk drive works visit the first link. It is not a complicated business installing a hard drive, especially an SATA hard drive. Click here! to go to the information on this site on how to install IDE and SATA hard drives. If you require more information, the other links go to relevant articles and a PDF file download on how to install hard drives. Some of them provide extra information such as how to partition/format and troubleshoot them.

You can find many other pages by making use of the Google search box at the top of this page (with its Web radio button enabled). For example, the search term install + sata + hard + disk + drives (as is) will bring up many links.

How Hard Disks Work -

http://computer.howstuffworks.com/hard-disk.htm

How To Install and Troubleshoot Serial ATA (SATA) Hard Drives -

http://www.seagate.com/ww/v/index...

Western Digital Serial ATA [SATA] Hard Drive Installation Guide - 001

http://www.wdc.com/en/library/sata/2779-001006.pdf

How IDE Controllers Work -

http://computer.howstuffworks.com/ide.htm

Hard Disk Drives [IDE ATA] - How to install them:

http://www.tweak3d.net/articles/howtoinstallhd/

Hard Drive Upgrade Install Guide [IDE ATA] - http://www.harddriveupgrade.com/