Media devices saves and store different sizes of data. They include optical devices and disk drives. Optical drives are CDs (Compact Disc), DVDs (Digital Versatile Disc), and Blu-ray disks. Almost all computers come with some sort of Disc drive. Disc drive plays the optical devices. A standard DVD drive plays CDs and DVDs. CD (CD-R) allows custom recordings to a CD; this is similar to a DVD-R. Modern computers come with DVD-RW (DVD-/+R). This gives a re-writable ability; CDs and DVDs can be re-edited, regardless of earlier recordings. The Blu-ray disk, is the successor to double-layered/doubled sided DVD’s. At 50GB storage, it is about 3 times as large as the largest DVD. However, Blu-ray disks are expensive.
Optical devices and disk drives store information, media data (music, videos), and softwares, making them easily accessible and transferable. Disk drive capacities are generally stated in kilobyte(kb), megabyte(mb), gigabyte(gb), and terabyte(tb). High definition movies play smoothly from Blu-ray disks.
Storage and media devices allow storage of data outside of a computer. These devices are portable, but the risk of information damage is higher. They are the main methods of transferring information between computers without a network, such as the internet. Most CDs and DVDs suffer cracks on their surface if improperly kept. This can lead to loss of important data and information.
Main Storage Devices
CD-ROM: Compact disk read only memory are capable of storing 700MB of data. They are optical discs with a reflective surface.
DVD: This is capable of storing 4.7GB of data in their single layer form and 8.5GB in their double layer form. DVDs are commonly used for store-bought programs(softwares) and videos. They are also optical devices.
USB/Flash Drive: USB sticks and Flash drives are popular ways of storing data because of their ease of use and low-cost. Their capacities range from 2GB on old units to 256GB on more expensive modern units. The average stick is 4GB or 8GB. Flash disk is a type of hard drive with no moving parts. They are better than optical devices which can easily damage.
Memory Cards: They are smallest unit of storage devices. Memory cards need special ports on the PC to work. Their capacities range from 2GB to 256GB. They have no moving parts and are very portable. Memory cards are better than other optical drives.
Interface: The mechanism that controls data transmission between the CPU and other devices on the PC is an interface. Disk storage devices, such as hard disk drives, floppy disk drives, tape drives, CD-ROM drives, DVD-ROM drives, all use a transfer interface to move data to and from themselves and the rest of the PC. The device controller and other device electronics define the form and function of an interface. Because hard disks and other storage devices work with a range of PC systems, a variety of interface protocol standards have been adopted to ensure compatibility. The interface standards that hard disk drives use are: ST506, ESDI, IDE, SCSI, and FC-AL. The first two are largely obsolete now. Most of the hard disks in use today use either an IDE or a SCSI hard disk drive interface. FC-AL is found on very high-end disk array products associated with large network servers.
Hard Disk Drives (HDD)
Hard disk is the major storage device of the computer. It stores all information that a PC processes. Hard disks come in different capacities of – 160GB (gigabytes), 500GB, 1TB (TB = Terabyte), and 2TB (TB = Terabyte). A user requires a larger hard disk space if there are many data to store on the computer. There’s no sense in buying a 1TB hard drive if you only surf the internet and do not download high-end softwares. The major components in a typical hard disk drive are: Disk platters, Spindle and spindle motor, Read/write heads, Head actuators, Air filter, Logic board, Connectors and jumpers, and Bezel. The connectors and jumpers are accessible outside of the enclosure that houses all the other components of the disk drive. The metal case and the components it encloses form the Hard Disk Assembly (HDA). The HDA is a sealed unit that is never opened.
Moving disks are very delicate. They generally have a short life span, and crash anytime. Solid State Disks (SSD) performs better than hard disk drive. SSDs have no moving parts and have a longer life span than their HDD counterparts.
Bit = One binary digit which stores either a binary 0 or 1
Byte = Eight(8) bits
Kilobyte (KB) = One(1) thousand bytes
Megabyte (MB) = One(1) million bytes
Gigabyte (GB) = One(1) billion bytes
Terabyte (TB) = One(1) trillion bytes
Petabyte (PB) = One(1) quadrillion bytes