COMPUTER STUDIES TUTORIAL FOR JUNIOR SECONDRY SCHOOL J.S.S II

TOPIC: CLASSIFICATION OF COMPUTERS: CONTENT - TOPIC: CLASSIFICATION OF COMPUTERS: CONTENT - GENERATIONS OF COMPUTERS - TYPES OF COMPUTERS - SIZEs of computers - DEGREE OF VERSATILITY(PURPOSE) note: on the last slide of this lecture is a video for the this topic just watch & pay attention to.

The development of electronic computer is divided into stage referred to as generation. Each generation of computer is associated with a specific innovation and development in computer technology over the previous stage. It is important to note that computer development came in different types and capacity. Generations of electronic computer are grouped into five innovations in technological development and advancement as at the date. The stages are 1st, 2nd, 3rd 4th and 5th generations. The generations of computers are not static, more stages are imminent as their search for knowledge and development in the area information and communication technology(ICT).

SUB-TOPIC 1:CLASSIFICATION OF COMPUTER BY GENERATIONS: 1ST GENERATION COMPUTERS These include sets of computer built between 1945-1959. The employed electronic vales (vacuum tubes) for their circuits. Examples include leo mark III, atlas series. Universal automatics computer (UNIVAC), electronic discrete variable automatic computer (EDVAC), electronic delay storage automatic computer (EDSAC). FEATURES -it uses punch card -it has valve-based machine and uses vacuum tube for storing and processing of data. -It has limited internal storage -it consumes too much electronic power and thereby generates too much heat.

2ND GENERATION COMPUTERS: This computer generation existed between (1960 - 1965). They used transistor in place of valve. They were smaller in size and faster in operation compared with the 1st generation. Besides, they were more reliable and then use English as computer language. High level language like BASIC, FORTRAN, COBOL etc. Examples are IBM 7000, series 7030, 7090, UNIVAC 1102, LEO MARK SERIES FEATURES -it uses transistors instead of valves therefore more reliable. -It is faster in operation more than the first generation computers -it uses magnetic tape as storage medium -it is smaller in size compared to first generation computer -it accepts external storage device like magnetic tape or disk.

3RD GENERATIONS COMPUTERS: The third generation computers mark the beginning of keyboards for input and video display unit (monitor) for output. It between 1966-1975. Some of the computers, its major component was integrated circuits (IC) instead of transistor used during second generation. They came in three (3) different sizes i.e. mainframe, mini, micro computers. Some of its features includes: FEATURES -Use of circuits instead of transistors used in second generation -it is more reliable than the second generation computers -it has extensive processing storage -it came in three different sizes – mainframe, mini, and micro computers.

4TH GENERATION COMPUTERS: This generation of electronic computer came into existence (1975-1990). They made use larger scale integrated circuit (LSIC). This marked the ear of micro processor with input and output devices connected to the system unit. The arrival of this generation of computer gave rise to more powerful and less expensive but realistic computers development. Examples IBM 3030 and 7700. FEATURES -it uses very large scale integrated circuit. -It has high speed and higher storage capacity -it is faster in operation and cheaper than the earlier ones -it has extensive processing storage

5TH GENERATION The present day computers are classified into this category. The fifth generation of computers are capable of performing functions of human experts solving problems that require human intelligent, judgment, insight and experience. Fight generation computers can learn, take decisions and perform other activities exclusive of human beings. It marks the era of pentium i.E. Pentium 1 pentium 2, 3, 4, and M which combine artificial intelligence with expert system. Artificial intelligence is the ability of the computer to behave like an intelligent human being while expert system is the capability of computer to the judgement and decisions like an expert in a specialized field i.E. Diagnosis and prescription of drugs like a medical doctor. FEATURES it uses very large scale integrated circuits (VLSIC) it appears to be reasoning in some type of work. It helps in planning financial management BRAIN TASK: 1. Mention at least 3 generations of computers and their features. 2. Distinguish between the first generations of computers and the Second generations of computers.

SUB-TOPIC 2: CLASSIFICATION OF COMPUTER BY TYPES When computers are classified according to type, three different groups or classes of computers are recognized. They are the digital analogue and hybrid computer. DIGITAL COMPUTER this is most common type of computer today. It is used in processing discrete data that have to do with counting. Digit is a number therefore, digital computers measure physical quantities by counting. Most applications of computer have to do with data processing. As such, the digital computer is so much in use. Many modern devices are now using digital system. Examples of such devices are: calculator, digital wrist watches, digital fuel dispenser etc.

1. State three type of computers with examples. ANALOGUE COMPUTERS: Analogue computer processes continuous data such as speed, temperature, heartbeat etc. They are mostly used in scientific measurement which may require the processing of continuous data. These are the type of specialized computers you are likely to see in the hospitals connected to patients. HYBRID COMPUTER: This type of computer combines the features of digital and analogue computers together. It can count and as well as measure. BRAIN TASK: 1. State three type of computers with examples. 2. Explain briefly the most common type of computer.

SUB-TOPIC 3: CLASSIFICATION OF COMPUTERS: BY SIZES AND DEGREE OF VERSATILITY Computer classification according to the size and capacity are grouped into four (4) categories. These are: micro computers, mini computers, mainframe and super computers. MICRO COMPUTERS: this is the smallest and most popular class of computers. Micro computers are also called personal computers (PC) or desktop computers. They are the most widely used and the fastest growing type of computers. They are accessible, relatively cheap and interactive. It is an example of general purpose computers.

CLASSES OR SIZE OF MICRO COMPUTERS Micro computers came in different sizes ranging from desktop, laptop, palmtop, notebook computers etc. DESKTOP: This category of micro computer can be set on the top of a desk “desktop”. It supports other peripherals and has a very high storage capacity and speed. LAPTOP COMPUTER :This type of computer can be placed on the lap and also in a belief case. They can be either AC powered, battery powered or both. They combine the power of the PC with mobility. NOTEBOOKCOMPUTERS:These are very high pcs but have all the capacities of a PC. Palm top: they are small enough to be held in the palm of your hand: they are equally as powerful as the desktop. WORK STATIONS: These are more powerful than the pcs. They are used by the engineers and scientists who process a lot of data. It is a kind of special purpose computer.

MINICOMPUTER This is a medium size general purpose digital MINICOMPUTER This is a medium size general purpose digital. It is a multi-user i.E. It allows many users at once and has the ability to perform many tasks simultaneously. The distinguished features of mini from micro computers are: memory size, speed of operation, faster input and output devices and higher cost. They are specially designed to solve and handle wide variety of commuting problems. It has become a popular and powerful network server to help manage large internet web sites, corporate intranet and client server networks. MAINFRAME COMPUTER These are multi-user and multi-tasking general purpose computers. They have large storage capacity and cost more than typical mini computers. They are used by large organizations such as banks, universities, central bank, national population commission etc.

SUPER COMPUTER: this can be seen as technological improvement on mainframe computers. It is used in the scientific environment such as for space studies and weather forecast. They have higher processing powers and large storage capacities. 1. Classify computers by size and degree of versatility. 2. State and discuss five general characteristics of computers.

TOPIC: THE COMPUTER SYSTEMS: CONTENT: -THE CONCEPT OF COMPUTER SYSTEMS - COMPONENT OF COMPUTER SYSTEMS -HARD COMPONENT

SUBTOPIC 1: THE CONCEPT OF COMPUTER SYSTEMS what is a system SUBTOPIC 1: THE CONCEPT OF COMPUTER SYSTEMS what is a system? A system is a group of interrelated components working together towards a common goal by accepting inputs and producing outputs in an organized transformation process. A computer is an example of a system made of input device, processing device and output device working together to produce the desire result. THE SYSTEM UNIT: system unit is the major part of a computer system. It consists of system board or power supply, system board or mother board, drives, memory and the processor. Collection of all these components inside a single case or housing is called system unit. Some people refer to it as CPU. The CPU is an acronym for central processing unit and the component parts of the system unit. The system unit came in different sizes, mini tower, full tower or desktop depending on its physical shape and architectural design.

A computer system consists of three main parts otherwise called components. These are: 1. Hardware. 2. Software. 3. Human ware. Hard ware component: computer hardware could be defined as the physical parts of the computer that we can see, feel and handle computer hardwire includes the main parts and its peripheral. The main parts are the two devices: processor and memory unit make up the central processing unit. The CPU is responsible for all the processing responsible for feeding data into the system and collecting information from the system . CPU is the brain of the computer system and sub-divided into the control unit (CU), arithmetic and logic unit (ALU) and storage of memory unit.

1.Control unit: this is the unit of the computer system that fetches instructions from the main storage, interprets them and issues all the necessary signals to the components making up the system. Control unit direct all hardware operation necessary in obeying instructions. 2.Arithmetic and logic unit: this part of the CPU is where all the arithmetic is carried out in the computer. These are adding up, subtracting, multiplication, division etc. It also carries out any logic functions that are necessary. Logic functions are decisions which have to be made such as less than <, equal to (=), greater than  etc. Its operations consist of comparisons. 3.Storage or memory unit: the memory or storage is the place in the computer where the program and the data are stored. The computer memory is divided into two, namely: 1.Random access memory (RAM) 2.Read only memory (ROM)

1. Random access memory (RAM) 2. Read only memory (ROM) 1. Random access memory (RAM) 2. Read only memory (ROM) ROM: is used by the manufacturer to store general purpose and permanent instructions as operating system and program utilities to start and test the computer. You can only read from ROM but cannot write into it as it is write protected. The information here are permanent and cannot be lost when the computer is shut down. RAM: data can be written into RAM and erased to enable fresh data to come in. This is the work area for the computer user when the program is being run. RAM is electric power dependent and stored data is lost when power goes off. Information in the RAM is said to be volatile and read faster by the computer than information stored in the external storage devices. (Read more on storage devices in chapter six.)

SUB-TOPIC 2: PERIPHERALS: The general name for all input and output devices are called computer peripherals. The peripherals are in three categories(1).Input devices (2) output device (3) auxiliary storage device. They are the devices attached to the computer system in order to transfer information into and out of the system. Input Device: These are the medium through which we can communicate textual and graphic data etc. With the computer input devices such as keyboard, joystick, scanner etc. (See book one for more information). Output Devices: These are the computer devices that bring out the result of processed data or information from the computer e.G. Video display unit or monitor, printer, speaker etc. Auxiliary/Secondary Storage Devices: The auxiliary storage devices are an additional memory or external storage device. It is otherwise called BACK STORE or BACKUP storage device. This storage device holds large amount of data, information or program on a big term basis. They are less expensive than that of main or primary memory. They also serve as an input and output device i.E. Floppy, CD ROM, ZIP DISK, FLASH DISK etc.

OVERALL -BRAIN TASK 1._____ Is not a feature of first generation computers (a)it uses punch card (b)it has limited internal storage (c)it consumes too much electricity (d)it does not generate much heat. 2. The following are examples of fifth generation computers except_____ (a)pentium I (b) pentium 2(c) pentium M (d)pentium none 3. Another for micro-computers is______ (a) compaq computers (b) micro-computers (c) mainframe computers (d) apple computers 4. Mainframe computers generate large amount of heat because; (a) they are very big (b) they consume too much electricity (c) they occupy so much room space (d) they are very small 5. The general name for all input and output devices is called____ (a)overall devices (b) computer basics (c) computer peripherals (d) group devices