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What is the purpose of a computer ?

To take data, process it and then output it. They were built to complete task more efficiently than humans.


What is software ?

The programs that a computer system runs. This can be subdivided into application software and system software.


What are embedded systems ?

Computers built into larger devices like dishwashers or TVs. They are used as control systems.


What can be found inside a regular PC ?

A power supply, case cooling fan, CPU heat sink and cooling fan, CPU, optical drive, RAM sticks, hard disk drive, motherboard and the graphics cards slots.


What is the CPU ?

The Central Processing Unit it processes all the data and instructions.


What are the main parts of the CPU ?

The control unit(CU), the arithmetic logic unit(ALU), the cache, the clock and buses.


What is the job of the CU ?

It's the overall control for the CPU, it executes program instructions through the fetch-decode-execute cycle. And it controls the flow of data inside and outside the CPU.


What is the job of the ALU ?

It does all the calculations, and performs the logic operations (AND, OR and NOT) and binary shifts.


What is the cache ?

It's very fats memory, faster than the RAM - it stores regularly used data to access quickly. Very expensive and have low storage capacity compared to RAM and secondary storage.


What does the clock do ?

It sends out a signal that cycles between 1 and 0, the signal is used to synchronise when instructions are done. The number of clock cycles per second is called the clock speed.


What are buses ?

Collections of wires used to transmit data between components of the CPU and to other parts of the computer system. Processors may have different buses for carrying data, instructions and memory addresses.


What are registers ?

Located in the CPU - temporarily holds tiny bits of data, very quick to read/write to.


What are the two main types of architecture ?

Von Neumann and harvard.


What is the fetch decode execute cycle ?

The process of carrying out instructions in the CPU.


What is the fetch instruction ?

The CU reads the memory address of the instruction, the instruction stored in that address is copied to one of the registers, the memory address is incremented to point to the address of the next instruction ready for the next cycle.


What is the decode instruction ?

The instruction copied from memory is decoded by the CU.


What is the execute instruction ?

The instructions is carried out.


What is RAM ?

Random Access Memory - the main memory of the computer, can be read and written to and is volatile. It's where all data, files and programs are stored while in use.


What does volatile mean ?

Temporary memory - it requires power to retain its data.


What does non-volatile mean ?

Permanent memory - it keeps its contents without power.


What is ROM ?

Read Only Memory - non-volatile memory, comes on a small factory made chip built into motherboard containing all instructions(BIOS) for a computer to properly boot up.


What type of memory do ROM chips use ?

Most commonly flash memory - a non-volatile memory that stores data in electrical circuits by trapping electrons.


What type of ROM/RAM requirements does a non-embedded system have ?

Much more RAM because they often need to write data to main memory, ROM is typically only used for BIOS which doesn't use much memory. Both are stored on motherboard away from CPU.


What type of ROM/RAM requirements does an embedded system have ?

More ROM as they don't write much data to memory, they don't have secondary storage so ROM is used to store all programmes. Both are stored on same chip as the CPU to reduce physical space needed and cost.


What affects the CPU performance ?

Clock speed, cores and cache.


How can clock speed affect the CPU performance ?

Generally clock speed is 3.5GHz (3.5 billion clock cycles per second), which determines the number of instructions processed per second - meaning the higher the clock speed the more instructions per second. Clocks can be overclocked to make them run faster - but it can cause the CPU to overheat.


How can the CPU's cores affect its performance ?

Each core processes data independently, meaning the more cores a CPU has the instructions it can execute at once.


How can cache size affect the CPU performance ?

The larger the cache the more data can be stored to be accessed more quickly than the RAM.


How can cache type affect the CPU performance ?

There are three different levels of cache memory - L1, L2 and L3, higher the level higher the storage but the slower it is. Cache is speed is determined by how far from the CPU it is, L1 is quick because its on the CPU, where L3 is slower because its on the motherboard.


How can the RAM affect the overall performance of a computer ?

If a computer has too little may not be able to keep all app data loaded so may be slower, the more it has the smoother it can run.