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SS 1 Computer Studies (1st, 2nd & 3rd Term)

Chemistry

PARTICULATE NATURE OF MATTER

ATOMS AND MOLECULES Matter is made up of discrete particles. The main ones are atoms, molecules, and ions. An atom is the smallest part of an element which can take part in a chemical reaction. A molecule is the smallest particle of a substance that can exist alone and still retains the chemical properties of that substance. Molecules are made up of atoms. Atomicity of an element is the number of atoms in one molecule of the element. We have monatomic, diatomic and triatomic for those elements that contain one atom, two atoms and three atoms respectively in their molecules. Examples: Element                                              Atomicity Hydrogen                                             Diatomic Oxygen                                                            Diatomic Nitrogen                                               Diatomic Neon                                                    Monoatomic Helium                                                  Monoatomic Argon                                                   Monoatomic   EVALUATION Define an atom. Give two examples of diatomic molecules.   IONS An ion is an atom or group of atoms which carries an electric charge. Such groups of atoms that carry either… Read More »PARTICULATE NATURE OF MATTER

Computer-Studies

Computer Input devices and Output devices

Sections of the Keyboard The Keyboard is divided into five sections; I.            Alphanumeric keys( Alphabet and Numbers): consist of alphabet (a-z) and numbers (0-9) II.            Function keys F1-f12: they are twelve in number f1-F12 and are located horizontally on the first row of the enhanced keyboards. On standard keyboard they are labeled F1-F10 III.            Control keys- Del, Ctrl, Esc and alt: These are used in line with other keys to instruct to perform specific task. IV.            Cursor –Control and screen movement keys-Arrow, home, end, page up etc.: it allows the user to move cursor to the left, Right, up online and down one line. V.            Numeric keypad: these are usually situated at the extreme right hand corner of modern keyboard. They have only numbers.   FEATURES OF KEYBOARD 1.       Rollover Capability: The Keyboard has ‘Rollover’ capability, that is, several keys can be pressed almost simultaneously and they will be registered… Read More »Computer Input devices and Output devices

Computer-Studies

Data and Information

MEANING OF DATA Raw facts or entity which no meaning has been attached to because it has not been processed is referred to as DATA. Data could be facts about people, places, things and their activities. When data passes through some manipulation activities in order to organize them to be meaningful or to achieve a desired result it is said to be processed the result of the processed data is called INFORMATION.   TYPES OF DATA Data can take any of these forms Symbols Alphanumeric Alphabet Numeric Data can be gathered counting: using counters Observation of people, activities ,transactions or event Questioner Face to face interviews Form filling.   INFORMATION Information can be defined as any piece of fact, data or news discovered, heard or communicated to anyone verbally, or through writing or through other useful means.   DIFFRENCE BETWEEN DATA AND INFORMATION People who conduct market research surveys might… Read More »Data and Information

Computer-Studies

Output Devices II

PRINTER There are three types of computer printers: Inkjet: Inkjet printers spray a jet of special ink on the surface to create an ink under control of electric field. Ink jet is used where the volume of print out is not very large. Dot matrix: A Dot matrix printer has a print head that has a series of steel pins. It uses ink ribbon to create images on surface. LaserJet: uses xerography in line with electronically controlled laser beam to produce characters on the photo conductive surface of rotating drum. EXAMPLES OF PRINTERS Thermal Printers: These are non-impact, they are very slow. They form characters by burning them on specifically treated papers Electrostatic Printer: This form of printers work by charging paper electrically. The paper then passes through a toner solution. Particles of ink adhere to the charged areas of the paper. Dot Matrix Printers: These use a dot matrix… Read More »Output Devices II

Computer-Studies

Computer Output Devices

OUTPUT DEVICES Computer output device is a device that releases the processed data from the computer to either the user or any of the storage devices. There are many devices that produce data in different forms such as audio, Visual and hard copy. Computer output devices are type of peripheral devices connected to a computer, using cables or a wireless network. TYPES OF OUTPUT DEVICE Ø  Printer Ø  Speaker Ø  Headphones Ø  Monitor The Monitor Monitor is an output device. Monitor is also known as screen, Visual Display Unit, Cathode Ray tube (CRT) or console. A monitor looks like TV screen and it is used for viewing the result of the operation going on. This is the major function of the monitor in the computer system. Data entered into the system is visible on the screen. Although, the data appears on the screen directly, the real fact is that data… Read More »Computer Output Devices

Computer-Studies

Computer Input Devices

Sections of the Keyboard The Keyboard is divided into five sections; I.            Alphanumeric keys( Alphabet and Numbers): consist of alphabet (a-z) and numbers (0-9) II.            Function keys F1-f12: they are twelve in number f1-F12 and are located horizontally on the first row of the enhanced keyboards. On standard keyboard they are labeled F1-F10 III.            Control keys- Del, Ctrl, Esc and alt: These are used in line with other keys to instruct to perform specific task. IV.            Cursor –Control and screen movement keys-Arrow, home, end, page up etc.: it allows the user to move cursor to the left, Right, up online and down one line. V.            Numeric keypad: these are usually situated at the extreme right hand corner of modern keyboard. They have only numbers.   FEATURES OF KEYBOARD 1.       Rollover Capability: The Keyboard has ‘Rollover’ capability, that is, several keys can be pressed almost simultaneously and they will be registered… Read More »Computer Input Devices

Computer-Studies

Computer Input Devices

An Input Device is any computer hardware equipment used to feed or send data into the main storage of a computer for processing. Many input devices can be classified into two: Ø  Modality of input( e.g mechanical motion, audio, visual etc) Ø  The input is discrete (keyboard) or continuous (mouse’s position) TYPES OF INPUT DEVICES Modern Input Devices a.       Camera b.      Compact disc (CD) c.       Keyboard d.      Mouse e.      Scanner f.        Joystick g.       Barcode Scanner h.      Microphone i.         Etc. Earliest Input devices a.       Punch Card b.      Card Reader c.       Punched paper Tape d.      Magnetic Tape unit e.      Optical Character Recognition f.        Etc.   THE KEYBOARD The keyboard is an input device which is used to input data into the computer system. Keyboard remains the most vital interface between the user and the computer. It is the most common input device for entering data into the computer. Keyboard is an electronic… Read More »Computer Input Devices

Computer-Studies

HISTORICAL DEVELOPMENT OF COMPUTING DEVICES

HISTORICAL DEVELOPMENT OF COMPUTING DEVICES( 20th  Century)  These generations of computers witnessed the first set of computers that used vacuum tubes for circuitry and magnetic drum for memory and were very big taking up the whole room. They were very expensive to use and in addition made use of lot of heat. The heat generated often damage the computer.   ENIAC ENIAC (Electronic Numeric Integrator and Computer) was the world’s first general purpose, electronic, digital computer. ENIAC is called general purpose because it can be reconfigured to solve many problems and electronic because it used electronic devices that is the Vacuum tubes. It was invented by John Mauchly and J.Presper Eckert FEATURES OF ENIAC 1.      The most important of ENIAC features is that its light speed. It can perform 5000 addition cycles each second 2.      It as ability to perform digit discrimination and branch loop 3.      ENIAC cannot store programs… Read More »HISTORICAL DEVELOPMENT OF COMPUTING DEVICES

Computer-Studies

HISTORICAL DEVELOPMENT OF COMPUTING DEVICES 2

HISTORICAL DEVELOPMENT OF COMPUTING DEVICES 2 (PRE COMPUTER AGE  TO 19TH CENTURY) JACQUARD’S LOOM (FEATURES, COMPONENT AND USES) The Jacquard loom is a mechanical loom, invented by Joseph Marie Jacquard in 1801. This loom simplifies the process of manufacturing textiles with complex patterns such as brocade, damask and matelassé. The loom is controlled by punched cards with punched holes, each row of which corresponds to one row of the design. Multiple rows of holes are punched on each card and the many cards that compose the design of the textile are strung together.   CHARLES BABBAGE Charles Babbage (1791-1871) was born 26 Dec 1791, the son of London banker. Babbage put forward an idea of a machine that could do 60 calculations per second. This analytical engine stamped the foundation of the modern computing. Therefore Babbage is often considered the father of modern computers. On his 200th birth anniversary, 1st… Read More »HISTORICAL DEVELOPMENT OF COMPUTING DEVICES 2

Computer-Studies

HISTORICAL DEVELOPMENT OF COMPUTING DEVICES

HISTORICAL DEVELOPMENT OF COMPUTING DEVICES The origin of computers dates back to when our fore fathers used their early calculating devices to count. For example Counting with fingers and toes: calculations were done by our fore fathers with their toes and fingers before the invention of computers. Counting with pebbles: when counting with fingers became inadequate the early men later introduced pebbles (stone) to count the number of flocks they had. Prior to the invention of alternative means for counting, fingers ,toes ,stones and beads were used in counting in the performance of simple arithmetic calculations such as additions and subtractions etc. This simple way of counting was a difficult to use for large numbers. This early method was in place till the invention of Abacus device.   ABACUS DEVICE The Abacus device was invented to replace the manual method (finger/ stone) of counting. The Abacus dates as far back… Read More »HISTORICAL DEVELOPMENT OF COMPUTING DEVICES

Computer-Studies

Computer Hardware and Software

Definition of Computer hardware This refers to the physical units or components which make up the computer configuration. The term hardware refers to the tangible parts of a computer that can be seen and touched. Examples of hardware components Monitor Motherboard CPU( Central Processing Unit) RAM( Random Access Memory) Expansion Cards Power Supply Optical Disk Drive Hard Disk Drive Keyboard Mouse.  E.t.c The Computer Hardware is divided into two: Ø  System Unit Ø  Peripheral SYSTEM UNIT The system unit contains the most vital parts of the computer. The central process unit that does the greatest part of the processing is in the system unit. The system unit includes the motherboard that holds a microprocessor chip or a CPU, memory chips and expansion slots and cards, buses and ports. Peripheral These are devices that are attached to a computer to make it useable. They perform a specific task or operation. E.g… Read More »Computer Hardware and Software

Computer-Studies

Constituents Parts of a Computer System

A computer is a special multi-purpose electronic device (Machine) that is capable of receiving instruction (data), storing and processing it and giving a desire result as output accurately at an incredibly high speed. The computer as a system is made up of the following: 1.      Hardware 2.      Software   HARDWARE Refers to the physical units or components, which make up the computer configuration. SOFTWARE The software refers to the programmes which are processed by the Hardware. A program is a sequence of instruction that is carried out by the Hardware to solve given problems or to perform given tasks. CHARACTERISTICS OF COMPUTER The characteristics of computer are: 1.      Computation 2.      Programmable 3.      Power 4.      Speed 5.      Storage and Retrieval of information 6.      Accuracy 7.      Versatility 8.      Diligence ASSESSMENT Teacher asks the students the following questions: 1.      Explain the meaning of computer 2.      What is Hardware and Software 3.      List and… Read More »Constituents Parts of a Computer System

Computer-Studies

Logic Gate

These are gates that are formed from combination of two logic gates. There are two types of alternative logic gate: NAND GATE A NAND gate is the combination of an AND gate and NOT gate. It operates the same as an AND gate but the output will be opposite. Remember, the NOT gate does not always have to be the output leg; it could be used to invert an input signal also.   LOGIC SYMBOL FOR THE “NAND” GATE Notice the circle on output C.   TRUTH TABLE FOR THE “NAND” GATE INPUT INPUT OUTPUT A B C 0 0 1 0 1 1 1 0 1 1 1 0   NAND GATE EQUATION The NAND gate operation can also be expressed by a Boolean algebra equation. For a 2 – input NAND gate, the equation is: X = A.B This equation read X equal to A and B NOT,… Read More »Logic Gate

Computer-Studies

Logic Gate

LOGIC EQUATIONS Aside representing the functioning of a logic gate with truth table and grammatical definition, the use of logic equations can be used not only to represent logic gates and circuits, but also with the usage of some theorems and equivalences, to reduce the number of terms involved, simplifying the equation. In logic equation all Boolean variable involved is assigned a letter or symbol, very similar to the algebraic representation of unknown numerical values using letters. This approach is called Boolean algebra.   Symbolic logic uses values, variables and operations; TRUE is represented as 1 while FALSE as 0. Variables are represented by letters and can have one or two values, either 0 or 1. Operations are functions of one or more variables.   AND gate equation The AND gate operation can also be expressed by a Boolean algebraic equation. For 2 – input AND gate, the equation is;… Read More »Logic Gate

Computer-Studies

Logic Circuit

LOGIC GATES A logic gate is an elementary building block of a digital circuit. Most Logic gates have two inputs and one output. At any given moment, every terminal is in one of the two binary condition low (0) or high (1). The logic gate of a terminal can, and generally change often, as the circuit processes data. It processes one or more input signal in a logical fashion. Depending on the input value or voltage, the logic gate will either output a value of ‘1’ for ON or a value of ‘0’ for OFF. There are three basic logic gates: AND, OR and NOT. BINARY CODE Logic gates are digital circuits and they utilize a binary numbering system known as binary code. Binary code is the same language used by computer which uses only 1 or 0 as numbers. INPUTS AND OUTPUTS Gates have two or more inputs, except… Read More »Logic Circuit

Computer-Studies

Differences between primary and secondary memory

Differences between primary and secondary memory Primary storage devices Secondary storage devices 1 These devices are temporary. These devices are permanent. 2 These devices are expensive. These devices are cheaper. 3 These devices are faster, therefore expensive. These devices connect via cables and are slow, therefore cheaper. 4 These devices have less storage capacity. These devices have high storage capacity. 5 These devices refer to RAM, ROM etc. These devices refer to FDD, HDD etc. (a) BIT (Binary digit): It is the smallest possible unit of information. It can be either 0 or 1. (b) NIBBLE: Four bits form one nibble (c) BYTE: It is a unit of information consisting of fixed number of bits. It is a combination of 8 bits (d) CHARACTER: It is represented by one byte. It can be a letter, digit, punctuation mark or special characters. (e) WORD: The combination of 2 bytes or 4… Read More »Differences between primary and secondary memory

Types of Secondary Storage

SECONDARY MEMORY Secondary memory or storage is the non – volatile memory that stored externally from the computer. A secondary – storage medium is usually used for the storage of large amount of data or for permanent or long – time storage of data or programs. It is also used for storing backups. Secondary storage media can be ranked according to the following: (i)   Retrieval speed: This is the time it takes to locate and retrieve the stored data. (ii)   Size / Storage capacity: This is the ability to store data. Large storage capacity is always desired (iii) Cost per bit of capacity:  Low cost is preferred TYPES OF SECONDARY MEMORY (i)    Magnetic Disk: This is a Mylar or metallic platter on which electronic data are stored. The data are recorded as tiny invisible magnetic spots on its iron oxide coating. The access time for data stored on a magnetic disk is determined… Read More »Types of Secondary Storage

Computer-Studies

Memory Unit

 Memory is the part of the computer that holds data and instructions for processing. It stores program and instructions or data for only as long as the program they pertain to is in operation.   TYPES OF MEMORY a.    Primary Memory b.   Secondary Memory   (a) PRIMARY MEMORY This is the memory that can be directly accessed by the CPU which constantly interact with it, retrieves data stored therein, goes through instructions and execute them as per the requirement. All the information, data and application are loaded there in uniform manner. Example is RAM (Random Access Memory) which is volatile (temporary) but fast form of memory. Apart from the main large capacity RAM, there are two subs – layers of the primary memory. (i)   Processor registers within the processor, which are one of the fastest forms of data storage contain a word of data (usually 32 or 64 bits). (ii)     Processor cache,… Read More »Memory Unit

Computer-Studies

Central Processing Unit

 The main objective of the CPU is to perform mathematical calculations on binary numbers; still there are other goals of using CPU as well. The CPU comprises many hardware components like motherboard and circuits. A central processing unit (CPU) is the hardware within a computer that carries out the instructions of a computer program by performing the basic arithmetical, logical, control, and input/output operations of the system. COMPONENTS OF THE CPU As in the picture above the CPU is made up of the following: I. The control unit II.The ALU (Arithmetic Logic Unit) III.Memory Unit Two typical components of a CPU are the arithmetic logic unit (ALU), which performs arithmetic and logical operations, and the control unit(CU), which extracts instructions from memory and decodes and executes them, calling on the ALU when necessary. The Control Unit (CU) The control unit is a component of a computer’s central processing unit (CPU) that directs operation of the processor. It tells the computer’s memory, arithmetic/logic unit and input and output devices how to respond… Read More »Central Processing Unit

Computer-Studies

OVERVIEW OF COMPUTER HARDWARE

Computer Hardware This is the collection of physical elements that constitutes a computer system. Computer hardware refers to the physical parts or components of a computer such the monitor, mouse, keyboard, computer data storage, hard drive disk (HDD), system unit (graphic cards, sound cards, memory, motherboard and chips), etc. all of which are physical objects that can be touched. In contrast, software is instructions that can be stored and run by hardware. Input and Output Devices An input device is any computer hardware equipment used to send data into the storage of the computer for processing examples are keyboard, Card reader, Mouse,. Scanner, Microphone, Joystick etc Computer output device is a device that releases the processed data from the computer to either the user or any storage devices. Examples are the Monitors, printers , speaker, projector etc. ASSESSMENT 1. Revision on examination questions. Student are allowed to give corrections to… Read More »OVERVIEW OF COMPUTER HARDWARE

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