EEE206 Introduction to Computer Packages Review of Computer Systems Computer Hardware

Housekeeping Lecturers Prof L.O. Kehinde (Coordinator) Dr O.B. Akinwale Mr T.O. Olowu Mr O. Odeyomi Mr E.I. Akinboboye

Housekeeping ../2 Olawale B. Akinwale Course Website Office: PY G22, White House http://scholar.oauife.edu.ng/akinwale olawale.akinwale@gmail.com Course Website http://scholar.oauife.edu.ng/akinwale/eee206

Housekeeping ../3 Lecture Schedule Tentative mid-semester Tests Still working on it Some part of this course will be flipped Tentative mid-semester Tests 30th January 2017 27th February 2017 Tentative grading of the Course Assignments (5 marks) Quizzes (5 marks) Group Work (5 marks) Mid-semester Test (15 marks) Exam (70 marks)

Course Components Review of Computer Systems Matlab and Simulink Computer Hardware Operating Systems Application Software Programming Languages Matlab and Simulink Spice and Proteus LabVIEW orCAD

Computers Computers are automatic, electronic machines that accept data & instructions from a user (INPUT) store the data & instructions (STORAGE) manipulate the data according to the instructions (PROCESSING) store &/or output the results to the user (OUTPUT) A computer system is composed of hardware and software Hardware components are the physical, tangible pieces that we can see and touch Computer systems are not limited to the PCs and desktops, they also include your smart phones and microcontrollers

Software Program Data Example a sequence of instructions to accomplish a result a computer processes information under the direction of a program Data information to be processed by a program Example Data: for each student, the student’s registration number, examination taken and results obtained Program: instructions on how to process the results to calculate CGPA, etc.

Hardware

Digital Computers The computers that we use are digital, not analog computers Analog technology The signal is directly analogous to the information it represents The signal is continuous and in direct proportion to the source of the information In a thermometer, mercury rises in direct proportion to the temperature In an amplifier or telephone, the electronic voltage signal varies in direct proportion to the frequency and amplitude of the sound waves it represents

Digital Technology Digital technology The signal is discrete The information is broken down into pieces, and each piece is represented separately Analog information is measured many times per second (the sampling rate) and each measurement is represented as a number How music is stored on a compact disc - the disc stores numbers representing specific voltage levels sampled at specific times Can be used to digitize sound, video, graphics, etc. Our computers work with digital technology, hence the term digital computers

Storage of Programs and Data Sampling is only one way to digitize information Since our computers work ONLY with numbers, everything (not just analog information such as sound and video) must be converted to numbers Text (letters and special characters) gets converted to numbers (A = 65), using a standard coding convention called ASCII Graphics (images), gets broken down into pieces (pixels) and each colour gets a number

Binary Numbers But how do we store numbers in a computer? We could use the digits 0, 1, 2,….., 9 from the base 10 (decimal) numbering system that we are used to? We would need a unique physical representation in the computer for each of the 10 digits, 0, 1, 2,……..,9

Binary Numbers Devices that store and move information are cheaper and more reliable if they have to represent only two states A circuit conducts current (1) or does not (0) A position on a diskette is magnetized in one direction (1) or the opposite direction (0) A position on a CD is pitted (1) or is not (0) Once information is digitized, it is represented and stored in memory using the binary number system A single binary digit (0 or 1) is called a bit A single bit can represent two possible states, like a light bulb that is either on (1) or off (0) Permutations of bits are used to store values. All information is represented as combinations of the two digits 0 and 1.

Binary Numbers 1 bit 1 2 bits 00 01 10 11 3 bits 000 001 010 011 100 1 2 bits 00 01 10 11 3 bits 000 001 010 011 100 101 110 111 4 bits 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 1111 Each permutation can represent a particular item 1 bit = 2 choices, a 0 or a 1 8 bits = 1 byte = 256 different combinations of 0’s and 1’s There are 2N permutations of N bits Therefore, N bits are needed to represent 2N unique items

Binary Numbers So how do we convert decimal numbers to binary numbers? i.e. if we enter the number 9 into the computer, how is it changed to 1001 for computer storage and processing? Or when we want to display or output information from the computer, how do we convert binary numbers to decimal numbers? See the slides titled Number Systems in the Additional Material at the end of this lecture

Hardware Units of measure All done relative to a Byte (8 bits - 1 character) KB = Kilobyte - 1 thousand bytes (1024) - 210 MB = Megabyte - 1 million bytes (1,048,576) - 220 GB = Gigabyte - 1 billion bytes - 230 TB = Terabyte - 1 trillion bytes - 240

A simplified view of a computer system Central Processing Unit Main Memory Floppy Disk Hard Disk Monitor Keyboard

Hardware Devices Input Devices (Get information) Keyboard Mouse Scanner Output Devices (Give information) Screen/monitor Printer

Hardware Devices Processing Device (Arithmetic/logic/repetition) Central Processing Unit (CPU) 286, 386, 486, Pentium, K5, K6 Has three basic parts Arithmetic Logic Unit (ALU) executes all the arithmetic and logic instructions Control Unit decodes instructions and determines which is next to be executed Buses/Registers Buses are paths for information entering/exiting the CPU Registers are memory for processing information

The Central Processing Unit The CPU continuously follows the fetch-decode- execute cycle: fetch Retrieve an instruction from main memory decode Determine what the instruction is execute Carry out the instruction

Hardware Devices Storage Primary Storage (main memory) Two types Primary and secondary Primary Storage (main memory) On board memory (located on the motherboard) Very fast, but expensive RAM – Random Access Memory ROM – Read Only Memory

Hardware Devices RAM - Random Access Memory ROM - Read Only Memory Read/write capability Contents lost when computer is turned off (volatile) A program must be in RAM for it to execute 128 to 256MB for a typical desktop computer ROM - Read Only Memory Read but not write capability Permanent (non volatile) Stores the preliminary instructions to be executed when the computer is turned on, for example To check RAM To check communications with peripheral devices Bootstrap loader program

Hardware Devices Address 9278 9279 9280 9281 9282 9283 9284 9285 9286 Large values are stored in consecutive memory locations 10011010 Each memory cell stores a set number of bits (usually 8 bits, or one byte) Content Main memory is divided into many memory locations (or cells) Each memory cell has a numeric address, which uniquely identifies it

Hardware Devices Secondary Storage (secondary memory) External devices (not on the motherboard); either inside or outside the computer Store programs and data permanently Slower, but cheaper RAM - nanoseconds, Drive - milliseconds Different sizes/styles Floppy Disk - 1.4MB (portable) Zip Drive - 100-750MB (portable) CD - 650MB (portable) Jaz Drive – 1-2GB (portable) discontinued Hard Disk Drive >=20GB (not portable) Tape - 50GB (portable, very slow) Flash drives (portable)

Hardware Devices Other devices Port Modem (internal or external) For connecting peripheral devices USB, Parallel and serial ports Modem (internal or external) For communicating over telephone lines

Computer parts

Hardware There are many parts that work together to make a computer work. Physical parts of the computer, including processor and memory chips, input/output devices, tapes, disks, modems, cable, etc.

Motherboard Motherboard Main Board System Board Acer E360 Socket 939 motherboard

CPU The Central Processing Unit Processor: The chip or chips that interpret and execute program instructions and manage the functions of input, output, and storage devices.

The Computer Case Contains the major components of the computer. It helps protect them.

Monitor A display screen to provide “output” to the user. It is where you view the information your are working on.

Video Card Connects the computer to the monitor. It is a circuit board attached to the motherboard that contains the memory and other circuitry necessary to send information to the monitor for display on screen.

Keyboard & Mouse Keyboard: Used to enter information into the computer and for giving commands. Mouse: An input device operated by rolling its ball across a flat surface. The mouse is used to control the on-screen pointer by pointing and clicking, double-clicking, or dragging objects on the screen.

Touchpad A pressure-sensitive and motion sensitive device used in place of a mouse.

Disk Drives Hard Disk Drive: Magnetic storage device in the computer. Floppy Disk Drive: A device that holds a removable floppy disk when in use; read/write heads read and write data to the diskette.

CD Rom Compact Disk – A type of optical storage device. CD Rom Drive: The drive that plays CDs and reads data that has been stored on the CD.

RAM Random Access Memory RAM is a computer’s temporary memory, which exists as chips on the motherboard near the CPU. It stores data or programs while they are being used and requires power.

Printer An output device that produces a hard copy on paper. It gives information to the user in printed form.

Scanning Devices Scanner: A device that allows pictures to be placed into a computer. Barcode Reader: An input device that converts a pattern of printed bars into a number that a computer can read. They are often used by businesses to quickly input price and product information.

Sound Devices Microphone: Allows the user to record sounds as input to their computer. Sound Card: Connects the speakers and microphone to the computer. Speakers: Used to generate or reproduce voice, music, and other sounds.

Network Card A circuit board that connects the computer to the rest of the network usually using special cables.

Networks The Internet - largest of all networks. Communication standards called protocols allow for global exchange of information. Transmission Control Protocol (TCP) Internet Protocol (IP) Intranets are LANs or WANs that use these communication standards or TCP/IP. Special hardware (modem) and software (browser) are required.

End of class