9Learning About Your Computer Hardware MonitorFloppyDisk driveSystem Unit (CPU)KeyboardMouse
10Another way of looking at a computer is the Box that contains everything- the main system board (motherboard)- CPU: Central processing unit- BIOS: Basic Instruction Operating System- RAM (Random Access Memory)- System Bus- Expansion slots
18Central Processing Unit (CPU) is the “brain” of the computer.It has two components:- The Central Unit or Control Unit and- The Arithmetic Logic Unit (ALU).
19- coordinates the operation of all the other components. The ALU: CPU=Control Unit +ALUThe Control Unit:- coordinates the operation of all the other components.The ALU:- all arithmetic calculations and logical decisions.
20Program is an instruction to the CPU CPU and ProgramsProgram is an instruction to the CPUCompatibilityNot all software is compatible with any given CPU. New processors of the same family run older software. New software is not usually compatible with old processors.
21Speed is determined by the internal clock of a computer. CPU SpeedSpeed is determined by the internal clock of a computer.Speed of a computer’s CPU is measured in Megahertz.The architecture of a computer determines its speed.One cannot compare speeds across different architectures.
22CPU Control Unit Output Unit Input Unit Input Unit Memory Unit Communication devicesCPUControl UnitArithmetic & Logic UnitOutput UnitInput UnitInput UnitMemory UnitDataSecondary storageControl
23Primary Storage Section ProgramStorageAreaInputStorageAreaOutputStorageAreaWorkingStorageAreaArithmetic and Logic Unit
24Memory Unit (หน่วยความจำ) bit - the smallest unit of binary digitbyte - a group of 8 bitsword - a group of bits and may represent a number,an instruction code, or any other binary-codedinformation. Each word in memory is assignedan identification number, called an address,starting from 0 and continuing with 1, 2, 3, up to2k where k is the number of address lineเช่น 16-bit word = 2 bytes
25A Bit About Bits- In genaral using n bits, it is possible to representupto 2x2x2x2x2 ….. (n times) values, 2n- e.g., 3 bits allow us to distinguish between 8 tings4 bits > 16 things5 bits > 328 bits (1 byte) ----> 25612 bits > 409616 bits >32 bits > over 4 billion things
30Primary Storage: Computer Memory RAM (random access memory; DRAM, SRAM):is the most common memory chip.will not remain if power goes off.must move data onto a disk if it is to be saved.ROM (read-only memory):information is stored permanently on a chip.contains startup information and other permanent data.PROM, EPROM, EEPROMPROM: Programmable once!.EPROM: Erasable (via ultraviolet light) and programmableEEPROM: Electrically Erasable and programmable
31k address input linesn data input linesk address linesMemory UnitROMReadWriten data output linesn data output linesBlock diagram of RAMBlock diagram of ROM
32A program residing in the memory unit of the Instruction CycleA program residing in the memory unit of thecomputer consists of a sequence of instructions.The program is executed in the computer by goingthrough a cycle for each instruction. In the basiccomputer each instruction cycle consists of thefollowing phases :1. Fetch an instruction from memory2. Decode the instruction3. Execute the instruction
34Input DevicesKeyboardMouseTouch screenJoystickGraphics tabletTrack ballMicrophoneVideo camera…...Computers accept information from outside world using its input devices.
35Output DevicesThe information on the computer are sent to the outside world using output devices.MonitorPrinterSpeakersOtherinstruments/devices...
36LCD (Liquid Crystal Display) Screen Outputimage is stored in video memory—VRAM.monitor size is measured diagonally across screen.images are made up of dots called pixels.color depth is the amount of information per pixel.the number of pixels affects resolution of the monitor.Main Types:CRTLCD (Liquid Crystal Display)
37Peripherals with both input and output functions. Secondary StoragePeripherals with both input and output functions.This form of storage is semi-permanent.Examples include:Magnetic tape (sequential access)Magnetic disks (random access)HD: IDE, SCSIFloppy disksOptical disks (CD-ROM)
42ลักษณะการเรียงข้อมูลในเทปแม่เหล็ก Inter - record gapOne blockOne blockOne blockRecordRecordRecord1. Single record blockInter - record gapOne blockRecordRecordRecordRecord2. Multiple record blockลักษณะการเรียงข้อมูลในเทปแม่เหล็ก