Report

MIS 315 - Bsharah Digital Data Representation Class Handout MIS 315 - Bsharah Digital Data Representation • Data Representation Basics • Representing Numbers, Text, and Pictures • Quantifying Bits and Bytes • Circuits and Chips 2 MIS 315 - Bsharah Data Representation • Data representation refers to the form in which data is stored, processed, and transmitted. • Digital devices work with distinct and separate data. • Analog devices work with continuous data. • Digitizing is the process of converting analog data into a digital format. Digital=Distinct On / Off Analog=Continuous 3 MIS 315 - Bsharah Representing Numbers, Characters (Text), Pictures, and Sound • Numeric data – Composed of numbers that might be used in arithmetic operations. – Decimal number system has 10 symbols. – Binary number system has only two symbols (0, 1). • Character data – Composed of letters, symbols, and numerals that are not used in arithmetic operations. – ASCII, Extended ASCII, EBCDIC, and Unicode. • Picture Data – Composed of a series of dots. – Each dot is assigned a binary number for color. • Sound Data – Is characterized by the properties of a sound wave. – The wave can be represented digitally by sampling it a various points and converting those points into digital numbers. 4 MIS 315 - Bsharah Memory Capacity • Bit: – Short for binary digit (0s and 1s), the only data that a CPU can process. • Byte: – An 8-bit string of data, needed to represent any one alphanumeric character or simple mathematical operation. In this picture, one byte, 01001000, represents the letter H 55 MIS 315 - Bsharah Numeric and Character Data Representation 6 MIS 315 - Bsharah Hierarchy of Memory Capacity -Quantifying Bits and Bytes • Bit – One binary digit • Byte – 8 bits • Kilobyte (KB) – Approximately one thousand bytes, (1024 or 210 bytes) • Megabyte (MB) – Approximately one million bytes (1,048,576 bytes, or 1,024 x 1,024 or 220 bytes). • Gigabyte (GB) – Actually 1,073,741,824 bytes (1,024 x 1,024 x 1,024 or 230 bytes). • Terabyte – One trillion bytes, or 240 bytes. • Petabyte – One thousand terabytes, or 250 bytes. • Exabyte – One thousand petabytes, or 260 bytes. • Zettabyte – One thousand exabytes. 77 MIS 315 - Bsharah Circuits and Chips • An integrated circuit (computer chip) is a super-thin slice of semiconducting material packed with microscopic circuit elements. – DIP=Dual In-line Package PGA=Pin Grid Array 8 MIS 315 - Bsharah How do bits and bytes fit together with chips and circuits? • Bits take the form of electrical pulses that can travel over circuits. – The 1 bit might represent an elevated voltage, such as 5 volts, whereas a 0 bit is represented by a low voltage, such as 0. • The system board is a circuit board to which a multitude of electronic components are mounted. – Motherboard 9 MIS 315 - Bsharah Digital Processing • Programs and Instruction Sets • Processor Logic 10 MIS 315 - Bsharah Programs and Instruction Sets • Computers, portable media players, handheld computers, and smart phones all work with digital data. • Computer programmers create programs that control digital devices. These programs are usually written in a high-level programming language. – The human-readable version of a program created in a highlevel language is called the source code. 11 MIS 315 - Bsharah Programs and Instruction Sets • The procedure for translating source code into 0’s and 1’s can be accomplished by a compiler or an interpreter. 12 MIS 315 - Bsharah Programs and Instruction Sets • A collection of preprogrammed activities a microprocessor is hardwired to perform is called an instruction set. – Additions, subtractions, counting, comparisons, etc • Each instruction has a corresponding sequence of 0s and 1s. 00000100 might = Add. • The list of codes for a microprocessor’s instruction set, called machine language, can be directly executed by the processor’s circuitry. • This end product, the 1s and 0s, is called machine code. 13 MIS 315 - Bsharah Programs and Instruction Sets • A machine code instruction has two parts. – The op code and the operand. • An op code (short for operation code) is a command word for an operation such as add, compare, or jump. • The operand for an instruction specifies the data (or the address of the data) for the operation. Op Code 00000100 00000001 00100100 00011001 01010100 00100001 Operand 14 MIS 315 - Bsharah Programs and Instruction Sets • Many machine language instructions might be needed to equal a simple high-level program that counts to 100. 15 MIS 315 - Bsharah Processor Logic-What happens inside a computer chip • The arithmetic logic unit (ALU) is the part of the microprocessor that performs arithmetic operations. • The ALU uses registers to hold data that is being processed. • The microprocessor’s control unit fetches each instruction, just as you get each ingredient out of a cupboard or the refrigerator. • The term instruction cycle refers to the process in which a computer executes a single instruction. 16 MIS 315 - Bsharah Processor Logic-What happens inside a computer chip 17 MIS 315 - Bsharah Processor Logic-What role does the Control Unit play 18