The Relationship Between Hardware and Software?

• Software provides the instructions for hardware to follow
• The control part of the processor keeps track of where the next instruction is using a Program Counter register

Fetch-Execute Cycle aka Machine Cycle occurs when each instruction is performed. There are 9 steps:

• Fetching instruction from primary storage
• Decode instruction -> op code + data address
• Copy op code into address register
• Copy data address into address register
• Copy data in the address held by the address register into storage register
• Send op code + data -> ALU
• Execute instruction on data
• Send result to accumulator ready for next instruction
• Store results in primary storage
• Electrical Pulses per Second == Clock Speed

The fetch-execute cycle

The initiation and Running of an Application

• When the computer is turned on, the OS launcher is loaded from ROM and the OS itself is loaded from the Hard Disk
• The OS continually monitors the input devices for actions
• When a program has been selected, it is loaded into main memory, and control is passed to it.
• The program sets memory for its use and performs other initialisation activities
• The program then monitors the input devices for actions

The existence of minimum hardware requirements to run some softwareMany factors affect this, including:

• Large amount of main memory
• Speed of processing
• Required peripherals
• Specialised processors
• External storage devices
• Particular I/O devices

Elements of a computer system

• Hardware: physical devices
• Software: consists of the steps, coded in a computer-understandable form
• Data: raw facts manipulated to become information
• Procedures: tasks performed by, rules put in place for the users of the computer system
• Personnel: all the people involved with the computer system
• Direct users: people who use the hardware
• Indirect users: people who are affected by the system
• Computer operators: people who look after the computer resources
• Data entry operators: people who enter data into the terminals
• Information systems managers: people who plan and oversee the computer resources
• Maintainers: people who provide technical help
• Developers: people involved in the design and development of the system