Storage is holds data,instructions,and information for future use. A storage medium is the physical material on which a computer keeps data,instruction,and information. Capacity is the number of bytes a storage medium can hold (how many GB or MB or TB).
A storage device is the computer hardware that records and/or retrieves items to and from storage media. There have 2 process which is reading and writing:
- Reading is the process of transferring items from a storage medium into memory.
- Writing is the process of transferring items from memory to a storage medium.
Access time measures is mean by the amount of time it takes a storage device to locate an item on a storage medium. and the time required to deliver an item from memory to the processor. If a computer access time is too long, can user stand on it?
Hard Disks
A hard disk contains one or more inflexible,circular platters that use magnetic particles to store data,instructions, and information. Hard disks can store data using longitudinal recording or perpendicular recording.
Characteristics of a hard disk include:
- Capacity
- platters
- Read/Write heads
- cylinders
- sectors and tracks
- revolutions per Minute
- Transfer Rate
- Access Time
Formatting is the process of diving the disk into tracks and sectors so that the operating system can store and locate data and information on the disk. So, how a hard disk works, please google it or youtube, it will give you a more clear picture.
RAID (REDUNDANT ARRAY OF INDEPENDENT DISKS) is a group of two or more integrated hard disks. A network attached storage (NAS) device e is a server connected to a network with the sole purpose of providing storage. An external hard disk is a separate free-standing hard disk that connects to your computer with a cable or wireless. A removable hard disk is a hard disk that you insert and remove from a drive. Internal and external hard disks are available in miniature sizes(miniature hard disks). A disk controller consists 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 and other components of the computer.
Flash Memory Storage
- Flash memory chips are a type of solid state media and contain no moving parts.
- Solid state drives (SSDs) have several advantages over magnetic hard disks:
- Faster access time
- Faster transfer rates
- Generate less heat and consume less power
- Last longer
- A memory card is a removable flash memory device that you insert and remove from a slot in a computer,mobile device,or card reader/writer.
- Compact Flash(CF)
- Secure Digital (SD)
- Secure Digital High Capacity (SDHC)
- microSD
- microSDHC
- xD Picture Card
- Memory Stick
- Memory Stick Micro (M2)
- USB flash drives plug into a USB port on a computer or mobile device.
Cloud Storage is an Internet service that provides storage to computer users. I phone users will be familiar with it because I phone has the function of I cloud which free for 5 GB. Users subscribe to cloud storage for a variety of reasons:
- Access files from any computer
- Store large files instantaneously
- Allow others to access their files
- View time-critical data and images immediately
- Store offsite backups
- Provide data center functions
Optical Discs
An optical disc consists of a flat,round,portable disc made of metal,plastic,and lacquer that is written and read by a laser. Typically store software,data,digital photos,movies,and music. It has two type of optical discs which is read only vs. rewritable. Read only optical discs is that you cannot undo what you had burn to the optical discs while rewritable optical discs you can undo it. Optical discs commonly store items in a single track that spirals from the center of the disc to the edge.
- Track is divided into evenly sized sectors.
- A CD-ROM can be read from but not written to
- Read from a CD-ROM drive or CD-ROM player.
- A CD-R is a multi session optical disc on which users can write,but not erase.
- A CD-RW is an erasable multi session disc
- Must have a CD-RW drive
- A DVD-ROM is a high-capacity optical disc on which users can read but not write or erase
- Requires a DVD-ROM drive
- A Blu-ray Disc-ROM (BD-ROM) has a storage capacity of 100 GB.
- DVD-RW,DVD+RW, and DVD+RAM are high-capacity rewritable DVD formats.
Other Types of Storage
- Tape is a magnetically coated ribbon of plastic capable of storing large amounts of data and information. A tape drive reads and writes data and information on a tape.
- Magnetic stripe cards and smart cards. A magnetic stripe card contains a magnetic stripe that stores information. A smart card stores data on a thin microprocessor embedded in the card.
- Microfilm and microfiche store microscopic images of documents on a roll or sheet film.
- Enterprise storage stores huge volumes of data and information for large businesses. Uses special hardware for heavy use,maximum availability,and maximum efficiency.
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