What is an embedded system?
Computers design to perform a dedicated function within a large mechanical or electrical system.
Name three examples of embedded systems
Any of:
- central heating systems
- engine management systems in vehicles
- domestic appliances, such as dishwashers, TVs and digital phones
- digital watches
- electronic calculators
- GPS systems
- fitness trackers
- MP3 player
- digital cameras
- air conditioning
- microwave ovens
- radio alarm clocks
What program controls an embedded system?
Read Only Memory (ROM)
Characteristics of an embedded system
- one dedicated function
- software inside ROM within the embedded system cannot change
- cannot run other general software on it (does not have a full operating system)
What is the function of primary storage
It is used to temporarily store the programs, instructions, and data the computer needs whilst it is in operation.
Name the primary storages
Random Access Memory (RAM)
Cache
Read only memory (ROM)
Name secondary storages
Hard disk drive (HDD)/magnetic
Optical
Solid State Drive (SSD)
What does ROM store in a computer
Instructions and data that never needs to be changed, such as the computer’s start-up instructions.
Differences between RAM and ROM
RAM is volatile whilst ROM is permanent and non-volatile.
RAM is used for the computer’s working memory for instructions, programs and data, whilst ROM is used for the computer’s start-up instructions and in embedded systems.
RAM can be written to and read from whilst ROM can be read only, so cannot be written to.
Why would increasing ROM size not improve the speed of a computer?
ROM is only required to be as large as the start-up instructions inside it. Any additional space will not make a difference. New files cannot be written into new space as it is read-only.
What is virtual memory used for?
When there is inadequate space in RAM for all current running programs and data.
