Tomorrow’s Technology and You 9/e and Information Technology in a Global Society for the IB Diploma Chapters 1 and 2 Slide 1 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall Information Technology in a Global Society, Stuart Gray Copyright 2011

Slide 2 Mainframes and supercomputers  Mainframes  Used by large organizations, such as banks and airlines, for big computing jobs  Communicate with mainframe through terminals  Multiple communications at one time through process of timesharing  Supercomputers  For power users who need access to the fastest, most powerful computers made Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

Slide 3 Personal computers and workstations (cont.)  Desktop computer  A PC designed to sit on a desk or table for extended periods of time  Common components: Tower with internal key components Monitor Keyboard Mouse Speakers  Has one or more power cables connecting it to an electrical outlet Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

Slide 4  Laptop, or notebook, computers are personal computers designed with portability in mind.  Generally feature a standard keyboard, and LCD screen between 14 and 17 inches and a Wi-Fi card to allow wireless acess to the Internet. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

Slide 5  Netbooks are laptop computer with lower specifications than normal, designed for maximum portability. Not designed to be primary machines for office work, but instead to provide access to the Internet and .  Tablet computers are smaller than a netbook but larger than a PDA. They are used to access the Internet and run APPs similar to a smartphone. They can have Wi-Fi or also be connected to a cell phone network. Many hospitals and other businesses use Tablets to access records in a quick and easy way.  Personal digital assistants (PDA’s) are somwhere between mobile phones and netbooks in terms of size and functionality. They are also called palm-top computers. Since the advent of the tablet computer PDA’s are not used as much although some hospitals assign them to their doctors and nurses for rapid retrieval of medical records. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

Slide 6  Smart Phones (iPhone, Galaxy, etc.) have more features than making voice calls and sending text messages. They usually include digital cameras with the ability to record video, sound and images. Many run applications (apps) which are downloaded from online stores. Some provide the same functions as a GPS (Global Positioning System) providing maps and directions right on the phone. Some applications allow the creation of office documents. Internet access is standard on smart phones. If the phone uses higher speed 3G or 4G technology you may also watch streaming video on your phone.  Embedded computers  Special-purpose computer: Dedicated computers that perform specific tasks.  Controlling the temperature and humidity  Monitoring your heart rate  Monitoring your house security system  The program is etched on silicon so it cannot be altered. This is called firmware.

Basic Functions of a Computer  Receive input: Accept information from the outside world  Process information: Perform arithmetic or logical (decision- making) operations on information  Produce output: Communicate information to the outside world  Store information: Store and retrieve information from memory and storage devices Slide 7 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

Basic Components of a Computer  Memory and storage devices  Primary storage: RAM (Random Access Memory)  Secondary storage: Storage devices that serve as long-term repositories for data: – Hard disk drives – Recordable CD and DVD drives – Tape drives Slide 8 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

COMMON MISTAKE Slide 9 The word “memory” is typically used to refer to primary storage – RAM or ROM – not to secondary storage like hard disks. Thus it is usually incorrect to say “My files are using a log of memory” when you probably mean “My files are using a lot of storage space”. Similarly, you would not buy a new hard disk “with more memory” – you would buy a higher capacity hard disk. These may seem like minor points by they cost students marks in exams.

Information  Communication that has value because it informs  Anything that can be communicated, whether it has value or not Information comes in many forms  Words, numbers, pictures  Sound, movies In computer terminology the terms data and information are more or less interchangeable. Slide 10 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

Bit Basics  Bit, or binary digit  The smallest unit of information  Can have one of two values: 1 or 0  Can represent numbers, codes, or instructions  Byte: a collection of eight bits Slide 11 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

Using two symbols all numbers can be represented on a calculator as well as performing arithmetic. A calculator translates the touch on the numeric keypad into series of 0s and 1s.  Each number then is looked at as a component of its positional values (each a power of two).  = (128*0+64*0+32*0+6*1+8*0+4*0+2*1+1*1) = 19 Slide 12 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

Building with Bits  Bits As Numbers  Binary denotes all numbers with a combination of 0s and 1s.  Decimal numbers are automatically converted into binary numbers and vice versa.  Binary number processing is completely hidden from the user. Slide 13 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

Building with Bits (cont.)  Bits as Codes  ASCII The most widely used code An abbreviation of American Standard Code for Information Interchange  Unicode Uses 4 bytes, or 32 bits, to encode a character Slide 14 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

Building with Bits (cont.)  Bits as Instructions in Programs  Programs are stored as collections of bits.  Program instructions can tell a computer what to do, where to locate information, or where to store a result. Slide 15 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

Building with Bits (cont.)  Bits, Bytes, and Buzzwords  Bit-related terminology Slide 16 –Byte –Kilobyte (KB) –Megabytes (MB) –Gigabytes (GB) –Terabytes (TB) = 8 bits ≈ 1 Thousand Bytes ≈ 1 Million Bytes ≈ 1 Billion Bytes ≈ 1 Trillion Bytes Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

The CPU: The Real Computer  CPU (microprocessor)  Interprets and executes the instructions in each program  Supervises arithmetic and logical data manipulations  Communicates with all the other parts of the computer system indirectly through memory  An extraordinarily complex collection of electronic circuits  Housed along with other chips and electronic components on the motherboard Slide 17 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

The CPU: the real computer (cont.)  Compatibility  All software is not necessarily compatible with every CPU.  CPUs in the same family are generally designed to be backward compatible. » Newer versions of a processor can process all of the instructions handled by earlier models. Slide 18 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

The CPU: the real computer (cont.)  Performance  Overall performance determined by: » Its microprocessor’s internal clock speed » Measured in units called gigahertz (GHz) for billions of clock cycles per second  The architecture and word size of the processor » High-end workstations and servers use 64- bit processors. » Most PCs and Macintoshes use 32-bit processors. » Some embedded and special-purpose computers still use 8- and 16-bit processors. Slide 19 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

The CPU: the real computer (cont.)  Performance (cont.)  Heat increases as the CPU clock speed increases  Techniques for speeding up a computer’s performance: » Parallel processing » Server clusters Slide 20 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

COMMON MISTAKE Slide 21 A common mistake is to refer to the computer box that sits under your desk as the “CPU”. In fact the best term for this is the “system unit”. CPU refers only to the processor inside a computer. A processor cannot perform more than one instruction at a time. When you are using a word processor, listening to music, and running a web browser, your computer’s processor is switching between each of theses tasks very quickly – far quicker then you could notice. This type of system is known as multi-tasking. To truly perform multiple tasks at once, a multicore system can be used.

The computer’s memory  RAM (Random access memory)  Most common type of primary storage  Used to store program instructions and data temporarily  Unique addresses and data can be stored in any location  Can quickly retrieve information  Will not remain if power goes off (volatile) Slide 22 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

The computer’s memory (cont.)  ROM (read-only memory)  Information stored permanently on a chip  Contains start-up instructions and other permanent data  CMOS (complementary metal oxide semiconductor)  Special low-energy type of RAM  Flash memory  Used for phones, pagers, portable computers, handheld computers, and PDAs(Personal Digital Assistant) Slide 23 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

Buses, ports, and peripherals  Information travels between components on the motherboard through groups of wires called system buses, or just buses.  Comparable to roads  Buses  Typically have 32 or 64 wires  Connect to storage devices in bays  Connect to expansion slots  Connect to external buses and ports  Slots and ports  Make it easy to add external devices, called peripherals Slide 24 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

Buses, ports, and peripherals (cont.)  USB (Universal Serial Bus) ports  Keyboards, mice, printers, etc.  Video ports  One or more monitors  Firewire ports  Video cameras, external hard drives, etc.  Express or PC cards  Memory or additional ports for portable computers  Hot swappable Slide 25 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

COMMON MISTAKE Slide 26 It is common for people to use the term “USB” to refer to flash drives. However, USB strictly refers to the connection on the computer – a USB port can be used to connect flash drives, printers, mice, keyboards, digital cameras, and many other peripherals. Therefore it is better to refer to flash drives, USB memory sticks, or USB drives.