Computer Application and Appreciation

1. Computer Application and Appreciation ITT 100 Paul Tate

2. What is a computer? A computer is a device or set of devices which works under the control of a stored program (which can be changed), automatically accepting and processing data to produce information.

3. Elements of a computer: Input Storage Process Output Control

4. Advantages of computers: Speed Reliability Consistency Storage Communications

5. Disadvantages of computers Violation of privacy Impact on labour force Health risks Impact on environment

6. Categories of computers Personal Computer (Desktop, Mobile) Server Mainframe Supercomputer Embedded computer

7. SYSTEMS UNIT – IS THE DEVICE WHICH MOST PERSONS CALL THE CPU. HOWEVER, THE CPU IS ACTUALLY A PROCESSOR CHIP EMBEDDED WITHIN THE SYSTEMS UNIT. • THERE ARE TWO TYPES OF SYSTEM UNITS: • TOWER • DESKTOP • THE SYSTEMS UNIT HOSTS DEVICES SUCH AS: Motherboard, processor, memory, floppy drive, hard drive, cdrom/dvdrom, network/sound/video cards, power supply, etc.

8. What is a Program: • Program – a set of coded instructions used to carry out (execute) a specific task. • One or more programs form software. Data and Information • The singular of data is datum. Data are raw facts that have not yet been processed. • E.g. if you collected all the ages of the students in this class, then you would have collected data because you have not done any processing of the ages you collected. • Information: This is processed data. • Eg. If the ages previously collected were then averaged, then the average age that was derived is called information. This is because some processing was done on the ages in order to arrive at the average age.

9. Personal Computer (PC) is also known as a micro computer. A Micro Computer is a device which has only one microprocessor (central processing unit – CPU). Types of Personal Computers: • Desktops – average computer systems found on desks – easily identified by their size. However, newer PCs are getting smaller. • Workstations – these are computer systems which are more powerful than the typical PC. This means they might have greater processing power, greater memory and greater storage. • Mobile Personal Computers – these are similar to desktop computers with the difference of moving them around. These devices are usually just as expensive as the desktop equivalent. They are typically fragile, but a few are ruggedized.

10. Mobile devices include (but is not limited to): • Notebooks (formerly called laptops) • PDAs (Personal Digital Assistants) • Smart Phones (e.g. Blackberry, IPhone) Server: • This is a very powerful computer system with vast amount of memory, hard drive storage and processing power. It provides diverse services to the computers connected to it (clients/workstations).

11. Main advantage – it manages the operations of all the clients connected to it. • Main disadvantage – if the server crashes, then all the connected clients will suffer from the loss of service. • Mainframe – this is a large single powerful computer system which provides services to dumb terminals. A dumb terminal is a computer which has no hard drive, memory or processor. Mainframes are typically much more expensive than servers and requires specialists to manage them. • Mainframes are famous for resisting virus infections; unlike the client-server model.

12. Supercomputer – this is an extremely powerful set of devices used to produce information of very complex calculations such as space exploration and aeronautics. • Embedded computers – these are microcomputers placed inside everyday devices such as microwaves, washing machines, televisions, cable boxes, dvds etc.

13. HISTORY OF COMPUTERS: • 3000 BC – ABACUS • BLAISE PASCAL – PASCALINE MACHINE (1600s) • Charles Babbage – analytical difference engine (1700s) • Punch Card (1800s) – Herman Hollerith • Generation of Computers (Electronic): • 1940s – Vacuum Tubes (1st generation) • 1950s – Transistor (2nd generation) • 1960s – Integrated Circuit (IC) (3rd generation) • 1970s – Very Large Scale I.C. (VLSIC) (4th generation)

14. Computers and how they represent data: • The smallest unit of information that a computer can process is called a binary digit (bit) • It takes usually a collection of eight bits to make up a byte (character – e.g. the letter “A”) • Construct of a Computer: • A computer is typically made up of hardware and software. • Hardware is the physical equipment that comprises the computer. • Software is the set of coded instructions that the hardware obeys/executes/carries out.

15. There are two sets of hardware: • The fixed hardware which makes up the computer (e.g. motherboard, ROM, RAM, CPU and so on) • The accessories portion such as the mouse, keyboard and speakers are called peripheral devices (add-on devices). • Software: There are 2 types of software: System Software and Application Software. • SOFTWARE WILL BE DISCUSSED LATER IN THE COURSE.

16. Computer Applications in Society • Education (websites, multimedia storage media) • Medicine (diagnosis, surgery, expert systems) • Tourism (websites, Information systems) • Trade (banking, government, commerce) • Arts and Entertainment • Social Networking (facebook, twitter) • Messaging Services (msn, yahoo)

17. DEVICES • Input devices: • Keyboard (qwerty) • Mouse (Mice) • Scanner (OCR/Images) • Digital Camera • Bar Code Reader • MICR – Magnetic Ink Character Recognition • OMR – Optical Mark Reader • Light Pen

18. Output Devices: • Speaker (sound) • Monitors/Screens/Visual Display Units: • Types of monitors (architecture): • Cathode Ray Tube (CRT) – looks like the older TVs with the back • Liquid Crystal Display (LCD) – these are the flat screen monitors. • Plasma – these have a richer colour mix technology • Colour Technologies for VDU: • Monochrome (one colour) • RGB monitor (Red, Green, Blue)

19. Printers: • 2 types: • Impact Printers – these printers are usually noisy and make contact with the paper when printing. • E.g. Dot-matrix , daisy-wheel • Non-impact printers – these do not make contact with the paper when printing. They tend to be silent. E.g. ink jet (which sprays the ink) and laser jet (which burns a laser impression on the paper). • Colour technology: Cyan (light blue), Magenta (rose pink), Yellow (CMY) • Plotter – this is a large industrial printer usually used to print things like building plans.

20. STORAGE • A computer is capable of storing data/information in two fashions: • Primary Storage and Secondary Storage • Primary Storage: • This is used to store data for online activities. • Four popular types of primary storage are: • Random Access Memory (RAM) / Main Memory / Primary Memory – this is used to temporary house data being inputted into the computer (i.e. a rough work area). RAM is volatile – which means you lose the info when power is lost. The most current types of RAM is the DDR series. DDR: Double Data Rate.

21. Read Only Memory (ROM): ROM is non-volatile. The ROM chip stores vital start up info for the computer. Type of ROM: • PROM (Programmable ROM) • EPROM (Erasable PROM) • EEPROM (Electrically EPROM) also called Flash Memory (same technology used with Jump Drives). Popular programs found on the ROM chip are CMOS and BIOS (read up).

22. Cache – This is the fastest type of memory in the computer. It is found on the Central Processing Unit (CPU). It is used to store data used only by the CPU and is not for general usage like the RAM. • Virtual Memory – this is not real memory, thus the term “virtual”. This is memory that the computer will allocate if you run out of RAM. You typically get this extra memory from a secondary device like a Hard Disk Drive.

23. Secondary Storage • This is storing data/information on a more permanent basis. There are different types of secondary storage. Two main categories are: • Magnetic (Disk or Tape) Storage • Optical Storage (e.g. Disc, Memory Cards) • Note: All data/info is stored in binary (zeroes and ones). • Note #2: When talking about secondary storage, we say that we have a storage device and a storage medium. E.g. A cassette player is the device, and the cassette is the medium.

24. When a secondary storage disk is formatted, track 0 stores the File Allocation Table (FAT). The FAT stores everything about the disk: how many files are on it, the dates they were created and modified, the size and types of the files etc. • For Compact Discs, e.g. CDROM, it is sometimes called a WORM. WORM means Write Once, Read Many (this means, store info on disc only once, but retrieve info from it as many times as possible).

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