Computer Based Systems Stage 2 Information Technology Studies Computer & Communication Systems

General System Concepts Definitions System Synergism Boundary Environment Interface Feedback InputProcessingOutput Interface Feedback

Systems Functions Input Processing Storage Output Control Input e.g. keyboard Processing Central Processing Unit (CPU) Output e.g. printer Control Secondary Storage e.g. fixed disk, flash drive

Systems Components Hardware Input devices Output devices Auxiliary storage Personnel Users Operators Software System software Utility software Application software Processes CPU architecture Fetch-execute cycle Data Files Database

Hardware Central Processing Unit Input Devices Output Devices Secondary Storage

Central Processing Unit Integrated Circuit (IC) Central Processing Unit (CPU) Microprocessor Buses Control Unit Arithmetic/Logic Unit (ALU) Registers

Types of Register Storage register Address register Accumulator register Instruction register Program counter register General purpose register

Central Processing Unit (continued) Word length Primary Storage –Random Access Memory (RAM) Dynamic RAM (DRAM) Static RAM (SRAM) Non Volatile RAM (NVRAM) –Read Only Memory (ROM) Programmable ROM (PROM) Erasable Programmable ROM (EPROM) Address Machine Language

Input Devices Keyboard Mouse/Trackball Graphics Tablet Barcode scanner

Input Devices (continued) Microphone Camera/Scanner Joystick/Joypad 3D Scanner

Output Devices Temporary – “Soft Copy” Permanent – “Hard Copy”

Output Devices Temporary –Monitor –Speaker

Output Devices Permanent –Printers –Plotters –CNC Machinery

Secondary Storage Magnetic storage –Magnetic Disks –Magnetic Tape Optical storage –CD –DVD Other storage Sequential and Direct Access Storage

Software Application Programs Utility Programs System Software Hardware

Operating System Services Process Management Memory Management –Allocating Memory –Virtual Memory –Memory Protection Disk and File Systems –Management of Files –Different File Systems Journaled Larger file/device sizes Case (in)sensitivity Pooling of Disk Space Networking

Operating System Services Security –Internal security –External security Graphical User Interfaces –Versus Command Line Interfaces –Recognition v. Recall Device drivers