Secondary Storage
- Created by: NathanielBridgens
- Created on: 12-02-19 12:17
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- Secondary Storage
- What is it?
- Data and programs are stored pernamently on secondary storage
- Can be used to transfer data between computers
- Cpu cannot access programs from it directly so must be transferred to main memory first
- Magnetic Storage
- Magnetic storage is used in Hard disc Drives and digital tape drives
- Magnetic discs consist of stacks of non - removable discs coated with magnetic materials
- Data is encoded as opposing magnetic polarities on the surface of the disc, Electromagnets in the read/write heads read and write the data
- Very low cost, even Budget laptops can have 1tb or more
- Very large 1-2 TB common.
- Fast, Random Access. Can be read instantly from any part of the disc.
- Can find and supply required data in milliseconds
- Portablility, Durability and Reliability
- Not very portable, knocks may cause corrupted data
- Very durable and Reliable
- Optical Storage
- CDS (Compact Discs) Store 700MB
- DVDS (Digital Versitile Discs) Store 4.7gb
- Blu-Ray Discs store up to 50GB
- Low Capacity
- Slow
- Extremely low cost
- Portablility, Durability and reliability
- More portable than a hard disc drive but discs are relatively large
- Easily scratched and data can be corrupted Data cannot be overwritten. Stored data degrade over time
- very reliable if not Scratched
- Solid State Memory
- Solid-State memory is made of Flash memory
- Flash memory is Non-Volitile Storage.
- Flash memory uses an array of transistors, transistors use 0 or 1 and are switched from one to the other
- Data is encoded as sets of binary digits. 8 GB of solid state requires 32 Billion transistors
- SSDs (Solid State Drives)
- Provide secondary storage instead of magnetic discs
- Secure digital cards (SD cards)
- SD cards and Micro SD cards are used in portable devices such as phones, cameras and tablets
- USB flash drives
- USB Flash Drives are convenient compact forms of flash memory for sharing / transfering data
- Moderate Solid State Drive, 128-512 GB however capacity is rapidly increasing
- Very Fast Can Access data in nano seconds
- More expensive than magnetic Drives and optical drives , cost is dropping rapidly
- Portability, Durability and reliability
- Very Portable, even fitted inside phones
- limited number of erase/write cycles
- very reliable
- Solid-State memory is made of Flash memory
- What is it?
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