Processing is the manipulation of data by editing and updating it. It is necessary to select appropriate hardware for specific types of processing.
Hardware
Central Processing Unit (CPU)
The central processing unit(CPU) is a set of electrical circuits responsible for controlling and processing data within the computer. It is the ‘brain’ of the computer. The CPU accepts the data from any input device, changes this data according to the instructions given by the user, and then sends the results to an output device.
In a personal computer, the CPU is contained on a single integrated circuit and is called a microprocessor. In more powerful computers, the CPU may consist of more than one integrated circuit. These integrated circuits are located on a flat printed circuit board inside the computer called the mother-boarder main board.
The CPU is made up of two components: the control unit and the arithmetic logic unit.
The central processing unit(CPU) is a set of electrical circuits responsible for controlling and processing data within the computer. It is the ‘brain’ of the computer. The CPU accepts the data from any input device, changes this data according to the instructions given by the user, and then sends the results to an output device.
In a personal computer, the CPU is contained on a single integrated circuit and is called a microprocessor. In more powerful computers, the CPU may consist of more than one integrated circuit. These integrated circuits are located on a flat printed circuit board inside the computer called the mother-boarder main board.
The CPU is made up of two components: the control unit and the arithmetic logic unit.
- The control unit directs and coordinates the entire computer system. It is the organiser that directs the flow of data in the computer in the same way as traffic lights control the flow of cars at an intersection. The control unit selects and retrieves instructions from storage in sequence, interprets them and starts the required operation.
- The arithmetic logic unit(ALU) is part of the CPU that carries out all the arithmetical and logical calculations. Arithmetical calculations include addition, subtraction, multiplication and division. Logical calculations have a true or false answer and include relational operators (>, <, =, >=, <=, and <>) and logical operators (AND, OR and NOT). The ALU contains several types of registers. A register is a temporary storage area for small amounts of data or instructions needed for processing. It provides fast access to data.
- The control unit fetches the instructions from memory.
- The control unit decodes the instructions (works out what to do) and makes the data available to the arithmetic logic unit. The first two steps are called the instruction time or i-time.
- The arithmetic logic unit performs the operation on the data.
- The control unit places the result of the operation into memory or a register.
Processing Speed
All computers have an electronic clock to regulate the fetch-execute cycle. The clock generates a sequence of regular electrical pulses that the control unit synchronises with the fetch-execute cycle. The clock speed is the number of electrical pulses per second and is often measured in megahertz (mHz). The higher the clock speed, the faster the CPU can execute a particular instruction. A speed of 500 mHz means the clock is generating 500 million electrical pulses per second.
In addition to the clock speed, the system’s performance is measured using the word size, response time and CPU utilisation.
Types of processing
An information system should reflect the methods used to process information. If people are working individually and rarely share work they use a non-networked information system. However, if people work in a group and need to share data and resources, they require a networked information system. There are three types of processing used with networks to increase a computer’s performance.
All computers have an electronic clock to regulate the fetch-execute cycle. The clock generates a sequence of regular electrical pulses that the control unit synchronises with the fetch-execute cycle. The clock speed is the number of electrical pulses per second and is often measured in megahertz (mHz). The higher the clock speed, the faster the CPU can execute a particular instruction. A speed of 500 mHz means the clock is generating 500 million electrical pulses per second.
In addition to the clock speed, the system’s performance is measured using the word size, response time and CPU utilisation.
- Word size is the number of bits processed by the CPU at one time. Most computers use a word size of 8, 16, 32 or 64 bits. The bigger the word size, the faster the computer.
- Response time is the amount of time taken for the computer to respond to a command. The response time varies according to the data entered or the command issued. It is often less than one second.
- CPU utilisation refers to the amount of time the CPU is working. It is presented as a report and often compared with the disk input and output rate (called disk I/O). Systems lacking memory or power often spend more time moving data to and from a disk than actually processing the data. This is referred to as thrashing.
Types of processing
An information system should reflect the methods used to process information. If people are working individually and rarely share work they use a non-networked information system. However, if people work in a group and need to share data and resources, they require a networked information system. There are three types of processing used with networks to increase a computer’s performance.
- Centralised processing is controlled by a central computer. The central computer is a mainframe or midrange computer that performs all the pro-cessing. It allows data and resources to be shared. Centralised processing is used by organisations that require online access to a central database but are geographically spread, such as an air-line. Centralised processing is totally dependent on the central computer. If this computer malfunctions, the entire system ‘goes down’.
- Distributed processing consists of workstations connected to shared. Centralised processing controlled by a mainframe. data and resources at a local site. People do their own work on a PC or work-station but have the ability to share work and resources. Distributed processing will continue to operate even if some of the workstations are not functioning. However, security can be a problem as the data is spread out.
- Parallel processing is the simultaneous processing of instructions using multiple processors or CPUs. It is much faster than using one CPU. Parallel processing divides the processing task between a series of processors. This requires special software that can recognise how to divide up problems and bring the results back together again. Parallel processing is used by Internet search engines to convert a single query into several separate queries that can be performed simultaneously. It also has significant applications in artificial intelligence. Parallel processing performs many processes simultaneously like the human brain.
software
Each piece of application software processes data. It involves editing and manipulating data. The chapters in Part 2: Application software contain detailed information on how data is processed in different applications. The following is brief summary.
- Text and numbers are edited in many different ways such as deleting, inserting, moving and copying. In a spreadsheet, calculations are performed using formulas. Errors in text are corrected using a spell checker and a gram-mar checker. The structure of a database can be modified to take into account new requirements.
- Images are edited using graphics tools. Graphics can be positioned, cropped, resized and distorted. When you enlarge a bit-mapped graphic, you also enlarge each pixel and create a jagged staircase pattern called aliasing. Vector graphics are easily edited using a drawing program.
- Video and audio are edited using digital video production software and audio software. Editing video involves adding text, audio and graphics to the video clip. Sounds are edited in many different ways such as deleting sounds, changing the speed, adding effects such as echo, overlaying (mixing) sound files and altering the quality of the sound file.