1.1.3 Input, output and storage Flashcards
What are input devices, and give examples.
Are peripheral devices used to pass data into the computer and allow the user to communicate with
the computer, e.g. keyboard, mouse, scanner, microphone etc.
What are output devices, and give examples.
Are peripheral devices used to report the results of processing from a computer to the user and
allow the computer to communicate with the user, e.g. printer, speaker, monitor etc.
What are the 3 types of storage devices?
Magnetic
Flash
Optical
What is magnetic storage?
Magnetic storage used magnetisable material and works by magnetic patterns being read off platters that mechanically spin at high speeds.
They tend to have a high capacity at a low cost.
They can be noisy due to parts moving at high speed and be susceptible to damage if moved quickly. They also require enough space for their moving parts.
Examples include:
- HDDs
- zip drives
- magnetic tape (often used to back up servers).
What is flash memory
Flash memory storage is a solid-state technology where data is stored on memory chips. These can have their contents erased and subsequently overwritten when an electrical charge is applied.
They have no moving parts and therefore tend to have lower power consumption and higher read/write speeds than magnetic or optical media.
They are not affected by their device moving so require less space and operate silently.
They are however prohibitively expensive.
Examples include:
- SSDs
- USB memory sticks
- Flash memory cards.
What is optical storage?
Optical storage works by using a laser and by looking at its reflection.
They tend to be cheap to distribute and fairly resilient.
Examples include:
- CDs
- DVDs
- Blu-ray discs.
What is RAM?
Random Access Memory.
RAM is where the user files, applications software and OS currently in use are temporarily stored.
The random aspect of it is that the processor can access its data locations directly and equally as quickly as any
other data location.
It operates at a much faster read/write speed than secondary storage media.
It is volatile meaning it loses its contents when the power is off.
It is editable meaning data can be written to and it allows user to alter saved contents of files in current use.
It is large and reduces buffering.
What is ROM?
Read Only Memory
ROM is generally small memory that can be read from but not written to.
A common use for it storing the OS and BIOS bootstrap program file to start up a computer quickly. It must not be
deleted or amended unintentionally therefore is best stored on a read-only medium.
It must be present in memory and immediately available when the computer is switched on therefore must be stored
on a medium which is non-volatile meaning the contents of its memory are not erased when the power is off.
ROM memory contents cannot be altered so there is no chance of the OS being accidentally or maliciously
changed.
What is virtual storage?
Uses a section of the hard drive to act as RAM when the space in main memory is insufficient to store programs being used.
Sections of programs not currently being used are temporarily moved into virtual memory through paging, freeing up memory for other programs in RAM.
