Hard Drives 101

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Hard Drives 101

Glossary

Active partition - A partition on a hard disk drive that is set as the bootable partition. Generally it contains the operating system (OS) to be used on the computer. Only one partition on a computer can be set as an active or bootable partition on a hard disk drive.

ATA - "Advanced Technology Attachment." The interface used to connect such devices as hard disk drives, CD-ROM drives, and other types of drives in IBM compatible computers.

BIT - Abbreviated as "B." A bit is short for Binary digIT and is a single unit of information that can have a value of either ON or OFF.

Byte - A Byte equals eight (8) bits. The byte is the basis for measurement of most computer data as multiples of the byte value. A "megabyte" is one million bytes or eight million bits or a "gigabyte" is one billion bytes or eight billion bits. 1 gigabyte = 1,000 megabytes 1 terabyte = 1,000 gigabytes

Capacity - This is the maximum amount of data a device such as a hard drive can hold.

CD ROM Drive – A drive that reads data from or inserts data on to a removable compact disk. CD Rom Drives can come in many varieties, from the standard CD Rom drive that can only read and transfer data from a compact disk to the hard disk drive, to the CD Burner that can transfer data on to an empty compact disk, to a DVD ROM drive that can read data from a digital video disk (DVD). CD ROM drives can also be a combination of any or all of these. Compact disks can hold considerably more data than floppy disks.

Defragmentation - The process of reorganizing a hard disk drive's data to help increase the proficiency of accessing the data. Hard disk drives that are severely fragmented will take longer to access the data because it is spread across the drive and not located in a central area. Microsoft's offers a defragging utility (software) with their Operating Systems (e.g. 98, 2000, XP)

Disk access time - The time it takes for the computer to process the data request from the processor and then retrieve the required data from a storage device.

Disk partition - A single partition on a hard drive. Partitions help enable users divide a computer's HD into different drives and/or into different portions. This is done (typically) to run more than one operating system on the same drive.

Floppy Disk Drive – A drive that reads from or inserts data on to a small removable disk. The disks that are inserted into the floppy disk drive hold up to 1.44 megabytes of data.

Gigabyte - Abbreviated as GB, a gigabit is a method of measuring data transmission. A gigabit is equal to 109 or 1,000,000,000 bits. Short for , GB is equal to 1,073,741,824 bytes, however the IEC defines a GB equal to 109 or 1,000,000,000 bytes. Therefore, a GB could be either of these values; many hard disk drive manufacturers and computer manufacturers will define what they consider a Gigabyte to equal in the fine print.

Hard Disk - A rigid circular disk located inside a computer hard disk drive. Referring to the magnetic media that uses a hard metal disk to store data. A hard disk can typically hold much more data and is much faster, but is non-removable, or "fixed" to your computer.

Hard drive - The computer's main storage media device, also called a "hard disk drive" or abbreviated as "HD" or "HDD". A hard drive consists of one or more hard disks inside of air sealed casing.

RAID - Short for Redundant Array of Inexpensive Disks, RAID is an assortment of HD drives connected and designed in ways to help protect against storage loss caused by malfunctions. This design is commonly used on servers and high performance computers.

SCSI - "Small Computer System Interface." Pronounced "Scuzzy" this is the second most commonly used interface for disk drives. SCSI is capable of supporting eight devices, or sixteen devices with Wide SCSI, which is more than most other interface types.

Storage - The term used to describe the location where information is held for later use. There are two types: internal storage is a device such as a hard disk drive. External storage may be a device such as a tape drive that utilizes removable diskettes to store information.

Parts of a Hard Drive

The inners workings of a hard drive are intricate and fascinating. Fortunately, computer users don’t really have to know how everything in a hard drive works in order to use one, but it’s nice to have the information anyway.

The hard drive contains platters, which are thin magnetically coated disks that spin when the hard drive is operating; such as the way a record spins on a record player. The platters in a hard drive hold the data that comes from the various data sources, and the data is stored in different sectors on the platters. Since these platters are magnetically coated, making them sensitive to static electricity, it is always wise to be grounded when handling your hard drive. The platters sit on a spindle, which is the rod that spins them, and an access arm (like the needle on a record player) moves back and forth across the platters to read and write data. A small electrical motor that is contained within the hard drive runs the whole operation. The speed and efficiency of a hard drive is measured by how fast the access arm writes to and reads data from the platters, as well as by how much data the platters can hold. Today’s hard drives are extremely efficient and fast. The devices contained within a hard drive are considered fairly fragile, so they are enclosed in a strong metal casing for protection. Protruding from this metal casing will be the connector that is attached to the hard drive. This connector is where you plug in the cable that connects your hard drive to your motherboard.

How a Hard Drive Works.

The hard drive in your computer works something like a regular tape recorder. Although this is a rather simplistic analogy, what it means is that the hard drive will read and record data that is input by you, the computer user, or by software that is input into the computer through your CD Rom, floppy disk drive, or by downloading from the Internet or sharing files with other users on a computer network. Your computer’s hard drive is stationary and permanent; it records and maintains important files, folders, and programs such as your documents, your games, your anti-virus software, and most importantly, your computer’s operating system. The hard drive records and maintains these things by using magnetically coated platters with read/write heads, and a motor. These are all encased in hard metal housing for maximum protection. Though hard drives hold an incredible amount of data, they are not large in actual size, and desktop hard drives fit quite easily into a standard 3 ½-inch computer drive bay.

When personal computers first came on the market, many of them did not have hard drives. All data was stored on a disk that could be inserted into a removable disk drive, such as a floppy disk drive. Today’s computers, however, need drives and disks that are capable of storing immense amounts of permanent data, and this can only be accomplished by using internal hard drives. Data on hard drives is recorded in kilobytes, megabytes (1 megabyte is equal to about 1000 kilobytes), and gigabytes (1 gigabyte is equal to about 1000 megabytes). Most computers today use hard drives that are capable of storing anywhere from 20 gigabytes to 120 gigabytes, and manufacturers are constantly working on producing hard drives with higher storage capacity. For example, only about 8 or 9 years ago, most hard drives stored less than 1 gigabyte of data.

What Makes a Good Hard Drive? or Which Hard Drive Is Right For You?

There are several manufacturers that make hard drives, and the hard drive is always included when you buy a complete computer system. Hard drives, however, come in many different varieties, and depending on what you plan on doing with your computer, you need to have a hard drive that fits with your particular needs. No matter what you will be using your computer for, your hard drive needs to be reliable. Most hard drives today are made to top industry standards, and they have warranties, so shopping for the right hard drive, or a computer with the right hard drive, should not be difficult. So what makes a good hard drive?

The RPM, or revolutions per minute, of a hard drive, or more specifically of its platters, is something that you want to consider. How fast the platters in your hard drive spin define its RPM. The faster your hard drive’s RPM, the faster your computer will boot up and the faster the applications will start and run. Most of today’s hard drives come in 5400 RPM or 7200 RPM. Though at 7200 RPM your hard drive will work faster, it will also heat up faster and use more power. The heating problem is negligible if you are using a good reliable computer fan. If you are using a laptop computer, using more power usually means slightly shorter battery life. Again, this is not usually a major problem. Though 7200 RPM hard drives costs more, most people prefer them if they can afford it.

A good hard drive will also have a low “seek time”. The seek time is the time it takes for the hard drive to “seek” and read or write data. For a hard drive, seek time is measured in milliseconds. Most of today’s hard drives have a seek time of 4 ms to 9 ms, with 4 ms being the seek time for the more expensive higher-end hard drives. Anywhere in between 4 ms and 8.5 ms is optimal, but you need to keep in mind that the lower the seek time, the faster the hard drive will process information.

A good hard drive, especially for today’s computer users, should have plenty of storage space for data. A 20-gigabyte hard drive is sufficient to run a computer, but only for the most basic functions. Today, most hard drives should be at least 40 gigabytes to be able to handle what a computer user needs to do. The more data storage space a hard drive has, the more applications and programs can be run quickly and efficiently. The more gigabytes a hard drive has, the more it costs, but prices for hard drives have gone down considerably in the last few years, so even the higher-number hard drives are reasonably priced.

If you are wondering which hard drive would be best for you, you need to ask yourself a few questions. For what purpose will you be using your computer? How important is it to you that your computer works at an optimum speed? How many programs will you be loading into your computer, and what types of programs will they be?

Obviously, if you will be using your computer only for Internet access, writing and reading email, and producing some documents, you do not need the most expensive hard drive. As long as your hard drive has enough storage capacity to hold and run your operating system, your Internet service provider program, and perhaps a good word processing program along with some other basic programs, your computer should run efficiently, and you won’t get error messages saying that you are running out of space. Though a 20 gigabyte hard drive is probably sufficient for these tasks, it’s still better to get at least a 40 gigabyte hard drive, just in case. Even though you may start out thinking that you do not need your computer for more than just basic tasks, it’s nice to know that your hard drive has sufficient storage capacity if you want to broaden your horizons, such as playing some of the new computer video games, storing pictures, or downloading and storing some of your favorite music.

By far, elaborate graphics and videos will be the largest files on your computer, and they need a lot of storage capacity. If you will be using your computer to play a lot of video games, or to store video files or create detailed graphics, you need a hard drive that can handle these things easily. Graphic artists and video game programmers, for example, need faster hard drives with a lot of storage capacity in order to be able to do their work efficiently. People who use their computers for video or graphics presentations at work also need a hard drive that can handle the workload. For this reason, if you will be using your computer for these types of tasks, you will want to have a hard drive with 80 gigabyte capacity, or even larger. You also want a hard drive with 7200 RPM and a sufficiently low seek time. You can look at it this way: if you don’t want your computer to let you down in the middle of an important presentation, or you don’t want your computer to freeze up after you have spent a lot of time producing some elaborate graphics, you need to have a hard drive that is more than capable of handling these large files. Spend the money for a higher-end hard drive and save yourself a lot of grief in the long run.

If you are like many computer users these days, your needs are somewhere in the middle of using basic functions and using huge files, applications, and programs. You need a hard drive that can handle your operating system, your Internet service provider program, and all of the programs that you may decide that you need or want, such as games, word processors, and photo editing programs. What type of hard drive you decide on depends on your needs and your budget. Although hard drives are considered permanent drives, they can be replaced – or you can even use more than one hard drive in your computer. If you find that you are going to be doing more with your computer than you thought, and you are worried that your hard drive cannot handle the increased workload, you can either add another hard drive or replace the one you are using with one that is faster and has more storage capacity.

If you would like help in determining which hard drive would be best for you, talk to someone who is knowledgeable on the subject. Be sure that you are not talking to someone who is simply trying to sell you his or her company’s most expensive hard drive – if you are, you’re most likely going to get a biased opinion. Talk to knowledgeable friends or computer specialists, and they should be able to help steer you in the right direction.