computer & communications systems software development unit 1
TRANSCRIPT
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Computer & Communications Systems
Software Development
Unit 1
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Elements of Computer & Communications Systems
1. People
2. Procedures
3. Data/Information
4. Hardware
5. Software
6. Communications
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1. People
• People are the most important part of a computer and communications system.
• The whole purpose of a system is to benefit people and to make their jobs easier.
• Two types of people who use computer systems are – Computer professionals and – End users
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• Computer professionals are people who have had extensive education or considerable experience in the technical aspects of using a computer.
• End Users (users) are people with moderate technical knowledge of information technology who uses computers for entertainment, education or work-related tasks.
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2. Procedures
• Procedures are descriptions of how things are done - steps for accomplishing a result or rules and guidelines for what is acceptable.
• Step-by-step instructions on how to complete a task.
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3. Data/Information
• Data consists of the raw facts and figures that have no meaning or usefulness.
• Data is processed into information using set procedures.
• Information is summarised data or otherwise manipulated data that is useful for decision making.
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3.1 Storage of data and information• A computer systems data and information
storage capacity is represented by bits, bytes, kilobytes, etc.
• Computers deal with ‘on’ and ‘off’ electrical states, which are represented by 0s and 1s, called bits.
• Bits are combined into groups of 8 called bytes.
• One byte is equivalent to a character such as a letter or number or special symbol.
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• Kilobyte (KB)- equivalent to 1024 bytes
• Megabyte (MB) - equivalent to 1024 KB or approximately 1 million bytes
• Gigabyte (GB) - equivalent to 1024 MB or approximately 1 billion bytes
• Terabyte (TB) - equivalent to 1024 GB or approximately 1 trillion bytes
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3.2 Steps used in processing data into information
• There are 9 steps in the processing of data into information:
– Acquisition, Input, Validation, Manipulation/Processing, Storage, Retrieval, Output , Communication and Disposal
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4. Hardware
• There are 5 types of hardware devices:
– Input hardware
– Processing and Memory hardware
– Output hardware
– Secondary Storage hardware
– Communications hardware
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4.1 Input Hardware
• Consists of devices that allow people to put data into the computer in a form that the computer can use eg
– Keyboard
– Mouse
– Microphone
– Scanner
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4.2 Processing & Memory Hardware
• These devices are the ‘brains’ of the computer. They include:– the CPU - Central Processing Unit. The CPU is
usually the microprocessor in a computer.– Main Memory - also known as RAM (Random
Access Memory)– Motherboard, etc.
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4.3 Output Hardware
• Consists of devices that translate information processed by the computer into a form that humans can understand.
• There are three principle types of output hardware:– Screens– Printers– Sound output devices
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4.4 Secondary Storage Hardware• Secondary storage consists of devices that store
data and programs permanently on disk or tape.• Examples of secondary storage are:
– Floppy disks– Hard disks– Magnetic Tape– CD ROM– DVD ROM
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4.5 Communications Hardware• Communication hardware are used to
extend the range of computers.• Examples of communication hardware are:
– Twisted pair wire– Coaxial cable– Fibre optics– Satellite transmission– Infrared transmission– modem
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5. Software
• Software, or programs, consists of the instructions that tell the computer how to perform a task.
• There are two main types of software:– Applications Software– System Software
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5.1 Applications Software
• Is software that has been developed to – solve a particular problem, – perform useful work on specific tasks– to provide entertainment
• Application software can be either – Custom software or– Packaged software
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5.1.1 Custom Software
• Is software designed and developed fo a particular customer
• You would hire a programmer to develop this software for you
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5.1.2 Packaged Software
• Is the kind of off-the-shelf program developed for sale to the general public, such as:– Word– Excel– Access– etc
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5.2 System Software
• Controls the allocation and usage of hardware resources and enables the application software to run.
• Systems software consists of several programs, the most important being the Operating System.
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5.2.3 Operating System Software• The Operating System acts as the master control
program that runs the computer• It handles activities such as
– running and storing programs and – storing and processing data
• The OS allows applications to operate by allowing access to shared resources such as printers, modems, etc
• Examples of OS - Windows 2000, Linux, MacOSX, Unix
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6. Communications
• Communications is defined as the electronic transfer of data from one place to another.
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Developments in Computer Technology
• Smaller size - a computer with a 12’’ monitor compared with a computer that took up a whole room back in the 1960s
• More power - 1 GB RAM compared with 1 MB RAM a few years ago
• Less expense - approx $1500 for a top of the range desktop computer compared with $4000 a few years ago
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Kinds Of Computers
• There are 5 kinds:– Microcomputers– Minicomputers– Mainframes– Supercomputers– Servers
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Developments in Communication Technology
• Better communication channels• Networks• New sending and receiving devices• Online information access• Multimedia computers• Wireless pocket PCs• PC/TVs• etc
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Ethics Of Information Technology
• Ethics is defined as a set of moral values or principals that govern the conduct of an individual or a group.– Speed and Scale has serious implications for data
security and privacy of information.– Unpredictability - not as predictable as electricity,
television and cars.– Complexity - because they are so complex,
computers can become unmanageable producing massive foul-ups or out-of-control costs