M1SA.pdf

Section A: Digital Basics Data Representation Basics Representing Numbers Representing Text Bits and Bytes Compression Copyright © 2019 Cengage. All rights reserved.  Section A: Objectives (1 of 2) List three technologies that digita...

Section A: Digital Basics Data Representation Basics Representing Numbers Representing Text Bits and Bytes Compression Copyright © 2019 Cengage. All rights reserved.  Section A: Objectives (1 of 2) List three technologies that digital devices use to physically store or transmit 1s and 0s Write the numbers 1 through 10 in binary Decipher ASCII text Demonstrate how to use the terms bit, byte, megabyte, megabit, and gigabyte in the context of data storage and digital devices Copyright © 2019 Cengage. All rights reserved.  Section A: Objectives (2 of 2) Distinguish between data that would be represented by binary numbers and data that would be represented by ASCII or Unicode Explain how OCR relates to ASCII and Unicode Describe the difference between lossy and lossless compression Demonstrate how to compress a file Copyright © 2019 Cengage. All rights reserved.  Data Representation Basics (1 of 4) Data refers to the symbols that represent people, events, things, and ideas. Data can be a name, a number, the colors in a photograph, or the notes in a musical composition Data Representation refers to the form in which data is stored, processed, and transmitted Devices such as smartphones, iPods, and computers store data in digital formats that can be handled by electronic circuitry Copyright © 2019 Cengage. All rights reserved.  Data Representation Basics (2 of 4) Digitization is the process of converting information, such as text, numbers, photo, or music, into digital data that can be manipulated by electronic devices The digital revolution has evolved through four phases, beginning with big, expensive, standalone computers, and progressing to today’s digital world in which small, inexpensive digital devices are everywhere Copyright © 2019 Cengage. All rights reserved.  Data Representation Basics (3 of 4) The 0s and 1s used to represent digital data are referred to as binary digits — from this term we get the word bit that stands for binary digit A bit is a 0 or 1 used in the digital representation of data A digital file, usually referred to simply as a file, is a named collection of data that exits on a storage medium, such as a hard disk, CD, DVD, or flash drive Copyright © 2019 Cengage. All rights reserved. Data Representation Basics (4 of 4) Copyright © 2019 Cengage. All rights reserved.  Representing Numbers (1 of 2) Numeric data consists of numbers that can be used in arithmetic operations Digital devices represent numeric data using the binary number system, also called base 2 The binary number system only has two digits: 0 and 1 No numeral like 2 exists in the system, so the number “two” is represented in binary as 10 (pronounced “one zero”) Copyright © 2019 Cengage. All rights reserved. Representing Numbers (2 of 2) DECIMAL (BASE 10) BINARY (BASE 2) 0 0 1 1 2 10 3 11 4 100 5 101 6 110 7 111 8 1000 9 1001 10 1010 11 1011 1000 1111101000 Copyright © 2019 Cengage. All rights reserved.  Representing Text (1 of 9) Character data is composed of letters, symbols, and numerals that are not used in calculations Examples of character data include your name, address, and hair color Character data is commonly referred to as “text” Copyright © 2019 Cengage. All rights reserved.  Representing Text (2 of 9) Digital devices employ several types of codes to represent character data, including ASCII, Unicode, and their variants ASCII (American Standard Code for Information Interchange, pronounced “ASK ee”) requires seven bits for each character The ASCII code for an uppercase A is 1000001 Copyright © 2019 Cengage. All rights reserved.  Representing Text (3 of 9) Extended ASCII is a superset of ASCII that uses eight bits for each character For example, Extended ASCII represents the uppercase letter A as 01000001 Using eight bits instead of seven bits allows Extended ASCII to provide codes for 256 characters Copyright © 2019 Cengage. All rights reserved.  Representing Text (4 of 9) Unicode (pronounced “YOU ni code”) uses sixteen bits and provides codes or 65,000 characters This is a bonus for representing the alphabets of multiple languages UTF-8 is a variable-length coding scheme that uses seven bits for common ASCII characters but uses sixteen-bit Unicode as necessary Copyright © 2019 Cengage. All rights reserved.  Representing Text (5 of 9) 00100000 Space 00110011 3 01000110 F 01011001 Y 01101100 l 00100001 ! 00110100 4 01000111 G 01011010 Z 01101101 m 00100010 " 00110101 5 01001000 H 01011011 [ 01101110 n 00100011 # 00110110 6 01001001 I 01011100 \ 01101111 o 00100100 $ 00110111 7 01001010 J 01011101 ] 01110000 p 00100101 % 00111000 8 01001011 K 01011110 ^ 01110001 q 00100110 & 00111001 9 01001100 L 01011111 _ 01110010 r 00100111 ' 00111010 : 01001101 M 01100000 ` 01110011 s 00101000 ( 00111011 ; 01001110 N 01100001 a 01110100 t 00101001 ) 00111100 < 01001111 O 01100010 b 01110101 u 00101010 * 00111101 = 01010000 P 01100011 c 01110110 v 00101011 + 00111110 > 01010001 Q 01100100 d 01110111 w 00101100 , 00111111 ? 01010010 R 01100101 e 01111000 x 00101101 - 01000000 @ 01010011 S 01100110 f 01111001 y 00101110. 01000001 A 01010100 T 01100111 g 01111010 z 00101111 / 01000010 B 01010101 U 01101000 h 01111011 { 00110000 0 01000011 C 01010110 V 01101001 i 01111100 | 00110001 1 01000100 D 01010111 W 01101010 j 01111101 } 00110010 2 01000101 E 01011000 X 01101011 k 01111110 ~ Copyright © 2019 Cengage. All rights reserved.  Representing Text (6 of 9) ASCII codes are used for numerals, such as Social Security numbers and phone numbers Plain, unformatted text is sometimes called ASCII text and is stored in a so-called text file with a name ending in.txt On Apple devices these files are labeled “Plain Text.” In Windows, these files are labeled “Text Document” Copyright © 2019 Cengage. All rights reserved.  Representing Text (7 of 9) ASCII text files contain no formatting To create documents with styles and formats, formatting codes have to be embedded in the text Copyright © 2019 Cengage. All rights reserved.  Representing Text (8 of 9) Microsoft Word produces formatted text and creates documents in DOCX format Apple Pages produces documents in PAGES format Adobe Acrobat produces documents in PDF format HTML markup language used for Web pages produces documents in HTML format Copyright © 2019 Cengage. All rights reserved. Representing Text (9 of 9) Copyright © 2019 Cengage. All rights reserved.  Bits and Bytes (1 of 5) All of the data stored and transmitted by digital devices is encoded as bits Terminology related to bits and bytes is extensively used to describe storage capacity and network access speed The word bit, an abbreviation for binary digit, can be further abbreviated as a lowercase b A group of eight bits is called a byte and is usually abbreviated as an uppercase B Copyright © 2019 Cengage. All rights reserved.  Bits and Bytes (2 of 5) When reading about digital devices, you’ll frequently encounter references such as 90 kilobits per second, 1.44 megabytes, 2.8 gigahertz, and 2 terabytes Kilo, mega, giga, tera, and similar terms are used to quantify digital data Copyright © 2019 Cengage. All rights reserved.  Bits and Bytes (3 of 5) Bit One binary digit Byte 8 bits Kilobit 1,024 or 210 bits Kilobyte 1,024 or 210 bytes Megabit 1,048,576 or 220 bits Megabyte 1,048,576 or 220 bytes Gigabit 230 bits Gigabyte 230 bytes Terabyte 240 bytes Petabyte 250 bytes Exabyte 260 bytes Copyright © 2019 Cengage. All rights reserved.  Bits and Bytes (4 of 5) Use bits for data rates, such as Internet connection speeds, and movie download speeds Use bytes for file sizes and storage capacities 56 Kbps: Kilobit (Kb or Kbit) can be used for slow data rates, such as a 56 Kbps (kilobits per second) dial-up connection. 104 KB: Kilobyte (KB or Kbyte) is often used when referring to the size of small computer files. 50 Mbps: Megabit (Mb or Mbit) is used for faster data rates, such as a 50 Mbps (megabits per second) Internet connection. Copyright © 2019 Cengage. All rights reserved.  Bits and Bytes (5 of 5) 3.2 MB: Megabyte (MB or MByte) is typically used when referring to the size of files containing photos and videos. 100 Gbit: Gigabit (Gb or Gbit) is used for really fast network speeds. 16 GB: Gigabyte (GB or GByte) is commonly used to refer to storage capacity. Copyright © 2019 Cengage. All rights reserved.  Compression (1 of 4) To reduce file size and transmission times, digital data can be compressed Data compression refers to any technique that recodes the data in a file so that it contains fewer bits Compression is commonly referred to as “zipping” Copyright © 2019 Cengage. All rights reserved.  Compression (2 of 4) Compression techniques divided into two categories: lossless and lossy Lossless compression provides a way to compress data and reconstitute it into its original state; uncompressed data stays exactly the same as the original data Lossy compression throws away some of the original data during the compression process; uncompressed data is not exactly the same as the original Copyright © 2019 Cengage. All rights reserved.  Compression (3 of 4) Software for compressing data is sometimes referred to as a compression utility or a zip tool On laptops and desktop computers, the compression utility is accessed from the same screen used to manage files Copyright © 2019 Cengage. All rights reserved.  Compression (4 of 4) The process of reconstituting files is called extracting or unzipping Compressed files may end with a.zip,.gz,.pkg, or.tar.gz Copyright © 2019 Cengage. All rights reserved.