Introduction to Hard Disk

Hard disk is a non volatile store device inside the computer that stores the data on it in the digital form. All the programs and data is stored on the hard disk. It is the most popular storage medium that is used for the desktop computer, laptop, video recorders and the gaming consoles. It is made up of the base, spindle motor, head set, voice coil and media. Data is recorded electromagnetically on the concentric circles or the tracks on the disk. H.D.D consists of several platters and each platter has read/write heads. The platters are coated with the ferromagnetic material.

Modern technology uses glass or ceramic platters. The magnetic layer on the platters has the magnetized domain, which is used to store the data that comes from the read/write heads. The platters are the actual disks that store the data. Read/Write heads are attached to the single accesses arms. Each platter has the same number of the tracks. The disk accessed time is measured in the milliseconds and the disk rotating speed varying from 4500 to7200 rpm.

The rotating motor is responsible for the movements of the head arms all over the HDD. Typical desktop HDD stores the data ranging from 120 to 300 GB with the media transfer rate of 1Gbps. The main components of the HDD include the following.

• Platters
• Spindle Motor
• Read/Write head
• Head Actuator

The major manufacturers of the HDD are Seagate, Maxtor, Quantum and Conner Peripherals. There are different types of the HDD like SCSI, ATA, SATA, IDE, ESDI and fiber channel. HDD are classified into the desktop, server and laptop hard disks. Desktop includes IDE and SATA interface, laptop includes IDE, SATA and SCSI and server includes ATA, SATA and SCSI interfaces of the HDD. SAS is a new type and is being used widely.

To keep your business profitable and productive the performance of the HDD is very important. SCSI HDD is more suitable choice in more cases for the databases and web servers with the high usages of the HDD.

External HDD is used to transfer the huge amount of data that cannot be transferred over the network. The quality of the HDD is determined by the capacity, spindle speed, seek time, aerial density, transfer rate and the interface speed.