Fichas
Memory and Storage
Fichas del conjunto (12)
- 1Primary StorageMain Memory/RAM/ROM
- 2Secondary StorageHard drives. Secondary storage is non-volatile – it keeps its content when the power is switched off.
- 3Off-line Storage. Also Secondary.CDs/USB/Tape/DVDs
- 4RAMWhen an application or the operating system is run, it is copied from the hard disk into RAM. It can be read from and written to
Access to RAM is very fast
At any one time it will normally contain:
The Operating System (or part currently in use)
The software currently in use
The data which the software is using - 5RAM StorageWhen your computer is off, RAM is empty as it is volatile
All your programs and data are safe on your hard disk. When you switch on your computer, the startup instructions load the Operating System from your hard disk into RAM - 6Virtual MemoryVirtual memory is part of the hard drive used as an extension to RAM
- 7ROMSome data needs to be permanently held in memory, even when a computer has no power
- 8Magnetic StorageMechanical parts move over the disks surface to read and write data magnetically. Magnetic disks- Disk contains concentric circles called tracks
Each track is divided into sectors
Disk heads mounted on mechanical arms read and write the data. Advantages:
Cheap, vast storage capability, fast write speed
Disadvantages:
Lots of mechanical parts, durability an issue, sealed unit due to disk head and platter precision and not very portable . - 9Optical StrorageLasers read and write data using light. Data is stored as pits and lands burnt into a spiral track circulating outwards from the centre
A laser beam passes over the pits and lands the level of reflection is measured
From this signal, 0s and 1s can be derived from reflections or no reflections. Advantages:
Cheap, very easily portable, takes up little space physically
Disadvantages:
Less storage capacity compared to other types
Easily damaged / scratched, requires a CD reader
Slow write speeds. - 10Solid State DriveData is recorded onto solid memory chips without any moving parts. Solid-state disks use non-volatile flash memory to store information
Very fast burst read/write speeds due to data being physically close and easy to recover
No mechanical or moving parts. Advantages:
Highly durable, no moving parts, very fast read/write speeds, no noisy fan, faster start up times
Disadvantages:
Expensive at present, less storage capacity / physical size than traditional hard disks. - 11Flash MemoryLow cost, portable, no moving parts, durable
This makes them ideal for a range of offline devices:
Cameras
Mobile phones
USB memory sticks.
Large electric current used to force electrons through a barrier and trap them on the other side. They remain on the other side until “flashed” with a new current, hence the name. - 12Cloud StorageCloud storage refers to saving data in an off-site storage system maintained by a third party.
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- Descripción
- Year 10 Computing Fichas sobre Memory and Storage, creado por Oli Dent el 09/05/2018.
- Creado por
- Oli Dent
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