Storage Devices

There are two types of storage primary and secondary. Main memory is usually a permanent storage device. However main memory is also sometimes referred to as memory as it is a requirement of the system.

Secondary storage is usually external devices such as a printer or filing cabinet. 

A 1956 IBM 305 RAMAC Hard Disk Drive with 5 MB of storage - weighed in at over 1 ton. Annual lease cost was about $35,000

A storage device is the computer hardware that records and / or retrieves items to and from storage media.

Hard disks can store date using longitudinal recording or perpendicular recording.

Hard Disks - The harddisks circuit board controlls the head actuator and a small motor, The motor spins the platters while the computer is running, Software requests disc access by going through the read/write head (determines the current or new location of the data), The head actuator positions the read/write head arms over the correct location to access the data.
 
A head crash occurs when a read/write head touches the surface of a platter. This will then usually destroy the disk - Always keeping a backup of your data on a disk.

Backing Up - RAID - Redundant Array of Independtent disks is a group of two or more integrated hard disks. A network attached storage (NAS) device is a server connected to a network with the sole purpose of providing storage.

Hard disk Controllers consist of a special-purpose chip and electronic circuits that control the transfer of data, instructions and information from a disk to and from the system bus. Types of controllers include - SATA, EIDE, SCSI and SAS.

Flash Memory Storage have chips are a type of solid state media and contain no moving parts. Solid State Drives (SSDs) have several advantages over magnetic hard disks. No moving parts, faster speeds.

Flash Memory Storage - CompactFlash, Secure Digital, Micro SD, SDHC, MicroSDHC, xD Picture Card, Memory Stick Pro Duo, Memory Stic Micro (M2)

Cloud Storage - Is an internet service that provides storage to computer users who use the internet.

Optical Discs start data by lasering data into the grooves on a disc. It then reads the data by interpreting the pits and lands (1s and 0s). Don't let your discs suffer from - BitRot.

Allot of data are stored on Tabe, Magnetic Stripe cards and smart cards. The only issue with these older storage devices is

Other Types of Storage are huge volumes of servers. where special hardware for heavy use, maximum availability, and maximum efficiency are used.