Standard Grade Computing LOW LEVEL MACHINE CHAPTER 21

Standard Grade Computing Input Process Output TaskInputProcessOutput Making toast Bread & electricity Heat from grilltoast Foundation

Standard Grade Computing Input Process Output TaskInputProcessOutput Making toast Bread & electricity Heat from grilltoast Boiling a kettle Water & electricity HeatBoiling water Foundation

Standard Grade Computing Input Process Output TaskInputProcessOutput Making toast Bread & electricity Heat from grilltoast Boiling a kettle Water & electricity HeatBoiling water Washing clothes Clothes, soap, water WashingClean clothes Foundation

Standard Grade Computing Input Process Output TaskInputProcessOutput Making toast Bread & electricity Heat from grilltoast Boiling a kettle Water & electricity HeatBoiling water Washing clothes Clothes, soap, water WashingClean clothes Doing homework Questions & text book Reading & thinking Answers Foundation

Standard Grade Computing DATA STORAGE UNITS Bit: Binary Digit i.e. 0 or 1 Byte:8 bits e.g Kilobyte (Kb):1024 bytes Megabyte (Mb):1024Kb (= 1024 x 1024 = bytes) Gigabyte (Gb):1024Mb (= 1024 x 1024 x 1024 = bytes) Terabyte (Tb):1024Gb (= bytes) Foundation The main memory size of a computer is measured in megabytes or gigabytes. Extra memory can be bought and added to allow greater data storage.

Standard Grade Computing Data Representation Machine Code : is understood by computers and uses binary 0 or 1. NUMBERS are represented using binary (>0) General

Standard Grade Computing Data Representation General

Standard Grade Computing Data Representation General

Standard Grade Computing Data Representation General

Standard Grade Computing Data Representation TEXT (ASCII) American Standard Code for Information Interchange Each keyboard character is represented by a unique binary code An 8 bit code is used e.g. A = 65 = Understood by different text applications. Allows different computer systems to communicate successfully. General

Standard Grade Computing Data Representation Bit Mapped Graphics (B&W) Screen contains pixels Pixel either ON or OFF Coded using binary The example uses 8 bytes of storage i.e. 8 x 8 bits Increasing the resolution means more pixels General

Standard Grade Computing Storage Requirements Bit Mapped Calculation Pixels = 2500 x 1000 = pixels 1 pixel uses 1 bit of storage. = bits /8 = bytes /1024 = 305 Kb Credit 2500 pixels 1000 pixels

Standard Grade Computing Processor Structure The processor is made up of 3 parts Control Unit: carries out program instructions in order ALU: does calculations & logical operations (decisions) Registers: temporary memory locations Credit INPUT DEVICES BACKING STORAGE DEVICES OUTPUT DEVICES MAIN MEMORY PROCESSOR COMPUTER SYSTEM

Standard Grade Computing And finally WORD: Number of bits sent to the processor during each fetch operation ADDRESSABILITY: All data is placed in storage locations. Each location has a unique address Credit

Standard Grade Computing The End Remember to view this slide OFTEN for good learning!