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