Computer system takes in inputs, processes them and produces an output. These outputs can also
be stored.
This is done using a combination of hardware (physical parts of a computer) + software (programs
used by a computer)
Software – computer programs containing instructions needed by CPU in order to perform a
specific task
Computer system contains a CPU, memory and other internal components such as the GPU.
Memory – physical hardware used to store data
First electronic general-purpose computer – in 1946 designed by John Mauchly and J Presper Eckert,
the ENIAC (Electronic Numerical Integrator And Computer). It could solve complex, large-scale
mathematical problems and was also used in US Army logistics.
Input is when action is performed by user on to the computer e.g. keyboard, mouse, microphone,
buttons
Processing- manipulating input data
Output – processed data in format user can understand e.g. printer, computer monitor, speakers,
LED Light
General purpose computer – PCs, tablets, smartphones, media systems in cars, games consoles
Computer systems – mobile phones, cash machines, supermarket tills, engine managements systems
in modern cars
A computer must have memory (primary storage) to hold instructions currently being executed or
data being used
CPU
The CPU executes all of the stored program instructions. It is the hardware that fetches, decodes and
executes instructions and also manages the rest of the hardware. Its purpose is to process data and
instructions.
The CPU itself is a single electronic chip consisting of the ALU, Control Unit and registers that
processes input and produces an output using the Fetch Decode Execute cycle.
Von Neumann Architecture
Desktop calculators are fixed program computers as they are only designed for one purpose. E.g.
calculators. They take inputs, process data and an output is produced.
Computer- an electronic device capable of performing processes, calculations and operations
based on instructions provided by a software or hardware program
Instruction- a single action that can be performed by a computer processor
Computer processor – CPU
Stored program computer has changeable programs