Thursday, July 4, 2013

How a Hard Drive Work - Computers - Hardware

Hard Drive is a storage device (storage) that record data quickly becomes magnetic pulses on a platter / disc rotating metal.

When a CPU is the brains of a PC, then the hard drive serves as the heart, pumping vital data to the entire system. As a component that drives the virtual computer, the hard drive is also something mysterious. Most people can not see the inside of a hard drive, obstructed by aluminum cover, though perhaps people are very familiar with the files and programs are stored, copied, moved, and deleted from your hard drive.

The hard drive provides data storage in which all modern computers need it. A hard drive stores information by placing a magnetic field through the surface of a disk coated magnetic material moving around.

The main principle of a hard drive is the use of magnetism to store information. A hard drive stores digital data as magnetic point on the surface of a disk. A bit (composed as a bit of your data) suggests a value of 0 when the disk is magnetized in one direction, and the value 1 if the opposite direction.

Each individual in a hard disk drive is named as a platter (plate / metal disks). A large-capacity hard drives usually contain some 3.5-inch diameter platter and use both sides as a storage medium. Drive itself has a motor that rotates at a speed of 4500 to 15,000 rotations per minute.

Hard drives use a recording device called the head to write and read data from any surface of the platter. Drive to position a head, use an arm that can move, with a microscopic distance above the surface of the platter on each side. So for the hard drive that has five platter will have ten heads that depend on ten motor arm.

Other elements in the head reads the data recorded by sensing the magnetic field on magnetic mentioned every bit as it passes through the element is read.

Drives record data on a concentric circles called tracks, and divide each track into segments known as sectors. You can imagine that the tracks can be interpreted as a bookshelf where each segment is defined as the books in it. When the operating system needs a file located on a track and a particular sector, then it sends the request to the hard drive to get data on that particular address.

How hard drive works

When an operating system sends data to your hard drive for recording, the drive is processing the data using a complex mathematical formula that adds an extra bit in the data. Bit it did not take place: In the future, when the data is taken, these extra bits allow the drive to detect and correct errors caused by random variation of the magnetic field inside the driver.

Then, the drive is moving the head through the appropriate track from the platter. Time to move the head is called the "seek time". While at the top right track, the drive to wait until the platter spins up to the desired sector under the head. The amount of time is called "drive latency". The shorter the time seek and latency, the faster the drive completed its work.

When the electronic components of the drive determines that a head is above the appropriate sector to write data, the drive sends electrical pulses to the head. Pulse generates a magnetic field that changes the magnetic surface on the platter. Variation that is now representing a recorded data.

Reading the data requires some process of recording. Drive to position the reader of the head above the appropriate track, and then wait for the right sector to rotate on it. At a certain magnetic spectrum that represent your data in the appropriate sector and track just above the head reader, electronic components drive detects tiny changes in magnetic field and convert it to bits. When the drive is over in check process and correct errors in bits if necessary, it then sends the data on the operating system.

Interface? What is it?

Hard drive in a simple interface is the hardware that manages the exchange of data between your computer and your hard drive. You usually encounter one type of interface on the PC are outstanding: Advanced Technology Attachment, also known as the ATA interface (or IDE, integrated device electronics). Hard drives that use this interface usually come with a variety of flavors, such as Ultra ATA, Ultra DMA or EIDE, depending on the vendor you visit. The second most popular interface is SCSI (small component system interface), which is widely used on the drive for the Apple Macintosh computer servers and the old kind.

The first ATA interface supports a maximum transfer rate of 8.3 MB per second. ATA-2 increases the maximum throughput to 16.6 MB per second. Although not yet a formal standard, Ultra DMA and Ultra DMA-33-66 have generally been accepted by the industry to be the hard drive interface with maximum transfer speed, in order, 33MB per second and 66MB per second. Seagate recently announced it has started shipping drives Barracuda ATA III with Ultra ATA-100 interface are its main target to replace the SCSI interfaces on the server RAID (redundant array of independent disks).

Cheap Hard Drive Offers Encouraging Usage

IBM PC-XT type hard drives come with the beginning of the first mass-produced: a drive with a 5.25 inch diameter platter 10MB capacity - the * wow * is very large at that time. Twenty years later, the latest hard drives with 3.5-inch diameter platter can store up to 70GB of data. Drive 2.5-inch smaller on the notebook can store up to 25GB of data. And a diameter of 1 inch Microdrive is designed for digital cameras, players, and hand-held computers that can accommodate up to 1GB of data. Along with the transition size reduction drives and larger capacity has lowered the cost per megabyte of storage dramatically, so that any large-capacity drives can be possessed by ordinary computer users.

You can buy hard drives designed specifically for three distinct uses: desktop PCs, notebook computers, and servers. Attributes that distinguish them not at capacity - although more is good - but on other factors that determine performance: speed motor drive, on-board memory, interfaces, drives, and power consumption.

Drive Specific for specific task

Price becomes the most important thing on the consumer desktop market. A computer system that is built from the ground may include a speed 5400-rpm drive with an IDE interface, the curve represents the sweet spot of price-versus-performance (price-performance), a price below U.S. $ 300 for a decent amount of storage space a lot. High-performance workstations is usually accompanied by 7200-rpm drive, and in the next year 10,000-rpm speeds are common.

In the notebook computer market, the most important thing is power conservation. Drive slow spinning hard drives reduce power consumption of laptop batteries. Storage resources on the drive notebook left behind than on the drive to the desktop, because the size of a small platter.

In the server market, most important goal is performance. On a commercial server that handles the on-line sales, for example, the drive must be able to handle many requests for data in different sectors as quickly as possible. Here, you will be more to see the drive with SCSI interface (which is in the set-up in a line of RAID) rotates at a speed 10,000-rpm, and drives the rotary speed of up to 15,000-rpm has started to reveal itself. Drive has several drawbacks, such as the heat generated higher and more noisy than regular drives.

Price is always cheaper and cheaper

In the past three years, the price of hard drives has plummeted while capacity is increasing. Remind vendors that they have eliminated the unnecessary costs of the drive with the integration of electronic components, reducing component count, and increase reliability. With 150 million drives that will be marketed this year and the estimated 200 million more in the next two years, which have very large market is likely to continue to grow.

Valuable desktop systems under U.S. $ 1000 typically offer drive 8GB or larger, which is the minimum value that should you get on most systems. For middle-class desktop with a price range around U.S. $ 1500, a 40GB hard drive capacity is more frequently encountered. But one vendor estimates, in the next five years, the proportion of the price allocated to computer hard drives will increase slightly. Fees for other components will go down while the cost for the hard drive constantly awake. It's not a bad news: As capacity increases, cost per megabyte tends to decrease.

When you are satisfied with your current desktop systems, but only want to increase the storage capacity of your disk, just add a new hard drive. Unless you buy a drive for a great server who sat in the office, drive popular now able to provide satisfactory performance (with a rotational speed 5400 up to 7200-rpm) and sufficient capacity (20GB - 40GB) for the money you spend. At this writing, the on-line computer store you can find the hard drive from Max-tor Diamond Max 30GB with prices below U.S. $ 200. While with the money of U.S. $ 260 you can get a Max-tor drive capacity of 40GB. IBM sells the drive capacity of 75GB, which is intended for enterprise servers with prices ranging from U.S. $ 500.

When you buy a new drive, you can see that the vendors and shops usually sell out "maximum transfer rate" or "burst speed" from their drive. The value does not mean anything, they just describe the specifications of the drive interface. Usually these values <



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