Hard Disk or sometimes called Hard Drive, is the main storage space inside your Laptop. It is a permanent storage component unlike the RAM. It is possible for your computer to function without a hard disk, however it would be basically useless to you as you would not be able to use an Operating system or have any programs to use.
Hard disks use circular hard platters to store data on. They are in pristine condition with a mirror like finish to them. These platters are locked away inside a steel casing as unclean air can easily ruin a hard disk. On each of the platters, there is a thin layer of magnetic film. Data storage on hard disks is very similar to that of a cassette tape. Data is stored in many 1’s and 0’s. These binary digits are arranged in different ways to represent different characters. When these are read back by the head, the data is retrieved and processed.
Measuring the Speed of a Hard Disk
There are various ways of measuring the speed of the hard disk. The main ones are the maximum data transfer rate, the spindle rotation speed and the seek time.
- Maximum Transfer Rate: This is the highest amount of data that can be transferred per second. Common forms of hard disks come with an ATA format. The speed rating of an ATA100 disk would be 100Mb/s. Likewise a ATA66 disk would be able to transfer a maximum of 66Mb/s.
- Spindle Rotation Speed: The rotation speed of the disk really is the basis of the other two factors of hard disk speed. The faster the rotation speed, the more data can be written per second and the quicker it is to find the correct data on the platter.
- Seek Time: The seek time of a hard disk is the average time it takes for the disk to find the data you need on the platters. A fast spinning, highly accurate and responsive disk will have a shorter seek time and will perform much better, especially when the data is scattered around the disk.
There are currently 3 connections for a hard disk, IDE (or ATA), SCSI and Serial ATA. The most common is the IDE interface. This provides an 80 pin connection to most standard motherboards. SCSI connections often require extra hardware unless its built into your motherboard. Serial ATA does away with parallel data transfer which has its problem of large wires and electrical interference.