Storage & Memory Revision
- Created by: Joe😔
- Created on: 27-01-18 11:50
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- Storage & Memory
- RAM & ROM
- ROM stands for Read Only Memory.It is memory that cannot be changed by a program or user. Also, it is non-volatile, so it retains its memory even if the computer is turned off. It stores the BIOS.
- RAM is a volatile type of memory, whereas ROM is a non-volatile type of memory. Also, RAM stores current running applications, whereas ROM stores the BIOS.
- RAM stands for Random Access Memory and is a fast temporary volatile type of memory in which programs, applications and data are stored. For example, the OS and GUI.
- Virtual Memory
- Virtual memory is created if the RAM becomes full. Part of the hard drive is designated as temporary RAM (Virtual memory), and non-essential data stored in RAM is transferred to the hard drive.
- Categories of storage
- Magnetic
- Hard drives contain spinning magnetic discs, accessed by an arm that moves across the surface to read and write.
- Backup systems
- Network storage
- Large document files
- Hard drives contain spinning magnetic discs, accessed by an arm that moves across the surface to read and write.
- Optical
- A track of pits spirals from the centre to the edge of the disc. Read by a laser and lens, this pattern is converted into binary data stream that can contain digital text, images, sound and video.
- Storing music, video and games.
- CD 700MB
- Blu-ray 25-128GB
- A track of pits spirals from the centre to the edge of the disc. Read by a laser and lens, this pattern is converted into binary data stream that can contain digital text, images, sound and video.
- Solid State
- A grid of electrical cells divided into sections called pages and then into blocks are used to send and receive data.
- Laptop hard drives
- USB portable drives
- Smartphone and digital camera memory
- A grid of electrical cells divided into sections called pages and then into blocks are used to send and receive data.
- Magnetic
- Storage Characteristics
- Capacity
- The maximum amount of data that can be stored.
- Durability
- How long the storage device can reasonably be expected to last.
- Speed
- How quickly the user needs to be able to access the data from the storage device.
- Portability
- Whether the data needs to be moved from one place to another.
- Reliability
- Whether the data can always be accessed reliably and in the format in which it was saved.
- Price
- The cost of the storage device.
- Capacity
- Secondary storage
- Secondary storage refers to the devices used to store programs, documents and files away from the CPU and motherboard. These devices need to be non-volatile, otherwise we would need to install programs every time we wanted to use them.
- RAM & ROM
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