System Type

Current home computers use a Serial ATA interface. However, computers that are more than a year old may have an ATA interface. The best way to determine the type of drive required is to review the documentation that came with the computer; it should mention if the computer uses Serial ATA (SATA) or ATA (also known as IDE). If the documentation is not available and you plan to perform the upgrade yourself, then the next best option is to look at the hard drive connectors on the motherboard. An ATA connector will have a ribbon cable (approximately 50 mm wide) with many ridges going between the drive and the motherboard. A SATA connector will be a much thinner cable (approximately 8 mm wide). See images below for examples.

ATA Drives

Ultra ATA models can be Ultra ATA/33, /66, or /100, and in some cases Ultra ATA/133. These drives are all downward compatible with previous ATA interfaces, and will work in these slower modes, as well as the mode for which they were designed. The drive you choose will operate at the fastest mode supported by your computer's hard drive controller. If you have an Ultra ATA/66, /100, or /133 controller, the 40-pin port on the hard drive controller will normally have a blue plastic cover over the pins. The cable for these modes needs to be a 40-pin, 80-conductor ribbon cable, also called an Ultra ATA cable. If you have an Ultra ATA/33 or standard ATA (either IDE or EIDE) controller, it will have a black cover over the pins, or none at all. You can use a standard 40-pin, 40-conductor ATA cable with these types, or if you are not sure, the Ultra ATA cable will work with either and offers superior electrical performance.

Serial ATA (SATA) Hard Drives

Serial ATA interface hard drives are designed for easy installation. A SATA drive has its own dedicated data cable that connects directly to a SATA host adapter or a SATA port on your motherboard, and unlike Parallel ATA (PATA) drives, SATA drives do not need jumpers to be configured as a "slave" or "master".

First generation (SATA I) SATA drives have a burst transfer rate of 150 MB/sec (1.5 Gbit/sec), while second generation (SATA II) SATA drives have a burst rate of 300 MB/sec (3.0 Gbit/sec). The jumper block adjacent to the SATA interface connector on SATA 300-MB/s drives can be used to force the drive into SATA 150-MB/s mode for use with older SATA controllers that only work with SATA 150-MB/s drives.

You can use both SATA and PATA drives in the same system as long as both interface types are supported. Older computers may not have any SATA ports, in which case an add-on SATA host adapter can be added in order to use a SATA drive. This makes it easy to add Serial ATA compatibility to your existing system without removing existing Parallel ATA disc drives.

SCSI Drives

You may have an additional or exclusive SCSI controller on your system. This controller is also sometimes called a host adapter. These SCSI controllers come in a variety of types, or SCSI revision levels. Each type has its own unique hard drive requirements. You could have a Narrow SCSI ribbon cable (approximately 61mm wide) with a 50-pin controller and drive, which is recognised by the rectangular-shaped connector with two rows of 25 pins each coming out of the hard drive. You could also have a Wide SCSI ribbon cable (approximately 42mm wide) with a 68-pin connector coming out of the hard drive. This is characterised by a trapezoidal "D" shaped female connector coming out of the hard drive. This could be a variety of different SCSI interfaces, including Fast SCSI-2 Wide, Ultra Wide, Ultra2 LVD, Ultra160 LVD (also called Ultra 3), or Ultra320 LVD. The drive model you need would depend on your hard drive controller. Each of these types uses an additional power supply connector on the hard drive.

Hot-Swappable SCSI

On some systems, known as hot-swappable computers, you have drives that only have one connector coming from the drive. This is a single connector attachment, also called SCA or SCA2. The data and power connection are all combined into one connector, which is 80-pin and trapezoidal or "D" shaped. These models are designed to be connected to a tray or in a drive cage, and they simply slide into the front of the hot-swappable computer cabinet, and push into a connector fixed to a backplane board in the rear of the computer case.

Apple Systems

If you have an Apple computer, or an Apple-compatible computer, the drive model depends on the model of the Apple computer. These will vary, and the drive you choose depends on the SCSI revision level or the ATA level your system is capable of using. Please consult your Apple technician or dealer, or call our Disc Pre-sales department at 00-800-4732-4283 for clarification as to which drive your Apple-compatible system is capable of using.

If you are still unclear as to which model your system requires, try to get all the information you can. The model number and manufacturer of your current hard drive, the approximate capacity of your current hard drive, the computer manufacturer, and possibly the model of the computer can help us answer your questions faster. You can contact a Seagate Disc Pre-sales representative by telephone at 00-800-4732-4283 or by email.