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Data storage

Data storage

Secondary storage is any device that can store data, in addition to the main memory. secondary storage devices are non-volatile and are typically high capacity, portable or both. 

Some factors affecting the choice is 

  • Speed (how quickly data can be accessed) 

  • Cost per storage unit (e.g., price per gigabyte or megabyte) 

  • Durability (toughness) 

  • Portability (how easy it is to move from one computer to another) 

 

HDD 

This is the main storage device in most computer systems. They use magnetism to store data on a rotating disk. A read/write head floats above the spinning disk reading and writing data. The faster the disk spins, the faster a HDDE performs. For a standard HDD they can read/write at speeds from around 80 to 160MBps. 

pros 

cons 

Relatively cheap 

Easily damaged 

Fast access and retrieval times 

Slower than SSDs 

 

Will slow and eventually break 

 

Optical storage - Blu-ray 

A laser reads from and writes to blue-ray disks. It is used to store HD movies and other HD recordings 

pros 

cons 

Can hold more data than standard DVD 

More expensive than DVDs 

portable 

Requires blue ray player 

Better sound and picture quality  

Can loose data when scratched  

  

SSD 

USB flash drives and SSDs have replaced the traditional HDD in some computers. Memory cards are used as a convenient and portable removable storage medium. A standard SSD typically starts at 320MBps and can get up to thousands of megabytes per second. 

pros 

cons 

Compact in size so portable 

More expensive than magnetic storage 

High speed of data transfer 

More vulnerable to abrupt power loss 

Low power consumption 

 

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