Hardware
- Created by: Aoifeowens
- Created on: 29-02-20 12:51
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- Hardware
- Central Processing Unit
- CPU
- The processor or brains of the computer this is where data is data processed and calculate patio s take place
- Fetch-execute cycle
- A computer process that locates a program instruction from internal memory, decodes the instruction and carries out the action required; this process is then repeated for the rest of the program instructions
- Control unit
- ~ decides which instruction to carry out next ~fetches it from memory ~decodes the instruction and executes the instruction ~repeats the process (fetch execute cycle)
- Arithmetic and logical unit (ALU)
- ~Carries out arithmetic calculations,+,-,/,*. ~ preforms logical comparison to assist with decision making by using the operators AND, OR and NOT.
- Immediate access store (IAS)
- ~Stores all program’s and data temporally while they are in use. ~during the fetch execute cycle, instructions are fetched from their Specific storage location in the IAS using an address. ~ each memory location has a unique address assigned to it.
- CPU
- Fetch execute cycle
- Program counter (PC)
- ~A pc stores the address (memory location reference) of the next instruction to be fetched. ~it is automatically incemented by 1 every time and instruction is fetched.
- Memory address register (MAR)
- The address of the current instruction of data being executed is temporarily stored in the MAR.
- Memory data register (MDR)
- This register will temporally store data being fetched from or written to the main memory of the CPU.
- Instructions register (IR)
- The register temporarily stores the current instruction to decode and then executed.
- Accumulator
- When calculations take place on data, the results are initially stored in the accumulator before being transmitted and stored in the main memory.
- Program counter (PC)
- Factors that influence the speed of processing
- Clock speed
- ~The clock speed measures the number of instruction cycles the CPU an deal with in a second. ~the standard unit of measurement for clock speed in in gigahertz (GHz)
- Cache
- ~Cache temporarily stores frequently used instructions and data. ~it is quicker to search cache memory than RAM, thus increasing processor speed.
- Clock speed
- High-definition storage media
- HD storage media use laser technology to store and retrieve data at high data transfer speeds to and from optical discs
- They can store over 50gb of data
- Instead of a red laser they use a blue laser, which burns much smaller pits onto the surface
- This increases the density and therefore the storage capacity.
- Solid state storage devices
- A solid state storage device is referred to as ‘flash memory’ and non volatile
- USB memory sticks are a type of solid state storage.
- They are compact, potable, have a large storage capacity and do not require a software driver to be installed.
- Memory cards
- These are electronic flash memory storage devices.
- They are used in a range of digital devices, including mobile phones.sim cards
- Smart cards
- ~Bank cards use a form of flash memory known as ‘chip and pin’. ~cards contain a small embedded integrated circuits (IC),which allows data to be written to an from the card using a smart reader.
- RAM (random access memory)
- ~memory can be read from or written to(volatile). ~stores programs and data that the user is currently using. ~the size of RAM can influence the speed of the processor ( the larger the RAM capacity the faster the processor.
- ROM (read only memory)
- ~Memory can be read from but not written to (non-volatile). ~used to store programs that the computer frequently requires.
- Central Processing Unit
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