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CHAPER 3 COMPUTER HARDWARE. Learning Objectives. Identify the major hardware components of a computer Describe the design and functioning of the central processing unit Describe the main types of primary and secondary storage
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Learning Objectives • Identify the major hardware components of a computer • Describe the design and functioning of the central processing unit • Describe the main types of primary and secondary storage • Distinguish between primary and secondary storage along the dimensions of speed, cost, and capacity • Describe the hierarchy of a computer according to power and their respective roles • Differentiate the types of input and output technologies and their uses • Describe what multimedia systems are and what technologies they use
The Significance of Hardware Some basic understanding of computer hardware design and function is essential because firms (and individuals) frequently must assess their competitive advantage in terms of computing capability.
Computer Hardware • The physical equipment used for the input, processing, output, and storage activities of a computer system • Central processing unit (CPU) or processor • Memory (primary and secondary storage) • Input technologies • Output technologies • Communication techniques
The Central Processing Unit (CPU) a microprocessor is made up of thousands of transistors embedded in a circuit on a silicon wafer or “chip” • Control unit • Arithmetic-logic unit • Registers • stores very small amounts of data and instructions for short periods of time
Control Unit controls the flows of data according to instructions. Instructions are detailed descriptions of actions that should be done during data processing and transmission
Arithmetic/Logic Unit performs the arithmetic calculations and logical operations: • Arithmetic operations include addition, subtraction, multiplication, and division • Logical operation are: whether one item is greater than, less than, or equal to other item or 0
THE MICROPROCESSOR ARITHMETIC - LOGIC UNIT CONTROL UNIT Instruction Instruction Instruction REGISTERS Results Instruction PRIMARY STORAGE (MAIN MEMORY) How the CPU Works? DECODE EXECUTE FETCH STORE
Machine Cycle • Instructional cycle: • Fetch; • Decode; • Executive cycle: • Execute; • Store. MIPS – Machine Instruction cycle per second
Computer Speed is determined by : • The preset speed of the system clock • The word length • The bus width • The physical design of the chip • The line width • The amount of basic instructions programmed into the chip
Moore’s Law The transistor densities on a single chip will double every 18 months.
Advances in Microprocessor Design • increasing miniaturization of transistors • making the physical layout of the chip’s components as compact and efficient as possible • new materials for the chip that improve the conductivity (flow) of electricity • amount of basic instructions programmed into the chip • complex instruction set computing (CISC) • reduced instruction set computing (RISC)
System Unit • Contains a processor • In midrange and mainframe computers – a cabinet with circuit boards • In PCs - motherboard contains processor chip, memory chip, ports, add-in boards interconnecting all these components
Computer Memory Computer memory affects the type of program it can run and the work it can do, its speed, and both the cost of the machine and the cost of processing data. It is use to hold: • Operation system programs; • Application programs; • Data and instructions temporarily (in”virtual memory” ) • Other data and information needed in processing in the working storage area
Memory capacity • bits - ‘0’ or ‘1’ • byte - eight-bit string • kilobyte (KB) - 1,024 bytes (210 bytes) • megabyte (MB) - 1,048,576 bytes (210 x 210 bytes) • gigabyte (GB) - 1,073,741,824 bytes (210 x 210 x 210 bytes) • terabyte - 1,078,036,791,296 bytes
Memory characteristics • Volatile – means that stored data will be lost if there is no electricity in the circuits • Nonvolatile – means that stored data will not be lost if there is no electricity flowing though the medium
Registers • Part of the CPU that store very small amount of data and instruction for short periods of time • High-speed memory area for storing: • temporary results of ALU operations; • Certain control information
Primary storage • Stores for very brief periods of time three types of information • data to be processed by the CPU • instructions for the CPU how to process the data • operating system programs that manage various aspects of the computer’s operation • Tree types of primary storage • random access memory (RAM) • cache memory • read-only memory
Secondary storage • Stores very large amounts of data for extended periods of time • Non-volatile • Takes much more time to retrieve data • Can be much more cost effective than primary storage • Can take place on a variety of media, each with its own technology
Types of Second Storage • According to the media used for the storage device: • Magnetic • Optical; • According to type of data access: • Sequential; • Direct.
Magnetic media store data via magnetism • Sequential access method - Magnetic tape • Direct access method – Magnetic disks • Hard disk - permanently mounted in a unit that may be internal or external to the computer • Magnetic diskettes (floppy disks) - have much less capacity, ranging from 1.44 megabytes for a standard high-density disk to 200 megabytes for a disk formatted for a zip drive
Hard Drive A drive – a device, which contains a read/write unit for a second storage Stacks of hard disks are hermetically sealed in the hard drive Redundant Arrays of inexpensive disks (RAID) technology
Optical storage devices A pinpoint laser beam is used to burn tiny holes into the surface of a reflective plastic platter • Compact disk read-only memory (CD-ROM) - high-capacity, low cost, high durability, and read only but not written on • Write once, read many disk (WORM) • Rewritable CDs - allow the disk to be written upon and rewritten up to 1,000 times
Computer Hierarchy • Supercomputer • has the most processing power • especially valuable for large simulation models of real-world phenomena • Mainframe Computer • used in large corporations for centralized data processing and maintaining large databases • allowing for data and information to be shared throughout the organization
Computer Hierarchy (continued …) • Minicomputers (midrange computers) • perform the same functions as mainframe computers but to a limited extent • designed to accomplish specific tasks such as process control, scientific research, and engineering applications • Workstations • based on RISC (reduced instruction set computing) architecture • provide both very high-speed calculations and high-resolution graphic displays
Computer Hierarchy (continued …) • Microcomputers(micros or personal computers, PCs) • Desktop PCs - typical, familiar microcomputer system • Network computers (NCs) are efficient when: • Users work with limited set of programs: • Shared desktops; • Remote user who are difficult to support; • Security is critical. • Laptop and Notebook Computers - small, easily transportable, lightweight microcomputers
Desktop Personal Computer Portable Personal Computer Impractical for mobile computing Designed for mobile computing Lower cost Higher cost Easily expanded Difficult to expand Uncomfortable ergonomics (small keyboard, often with inconvenient placement of function keys) Comfortable ergonomics Easy-to-use mouse or other pointing device Awkward pointing devices (some allow traditional mouse to be connected) High resolution/brightness monitor Lower resolution, less bright High RAM and hard-drive capacity Somewhat less RAM and hard-drive capacity Easy serviceability More difficult to service/repair Can utilize all current PC chips Some models cannot use some chips, due to cooling problems Desktop or Portable PC : The Tradeoffs
Computer Hierarchy (continued …) • Palmtop Computer - hand-held microcomputers • configured for specific applications and limited in the number of ways they can accept user input and provide output • Computing Devices - ever-smaller computing/communication devices • Embedded computers • placed inside other products to add features and capabilities
Input Technologies • Human Data Entry Devices allow people to communicate with computers • Source Data Automation technology reduce or eliminate the human intervention for data entry.
Human Data Entry Devices • keyboard - designed like a typewriter but with many additional function keys • mice and trackballs - used to point a cursor at a desired place on the screen • touch screens - touch the desired area to trigger an action • joy stick - used primarily at workstations that can display dynamic graphics • microphone - used to dictate to the computer
Source Data Automation • Cash transaction devices • automated teller machines (ATMs) • point-of-sale (POS) terminals • Optical scanners • bar code scanners • optical data readers • optical mark readers; • optical character recognition devices • Magnetic ink character readers • Sensors • Cameras
Output Technologies • Monitors • Printers • Voice Output • Multimedia
Monitors the video screen used with most computers that displays input as well as output • Cathode tube technology • Beam of electrons illuminates points on the screen • Liquid Crystal Displays • Organic oil-like material is placed between two polarizers
Printers • impact printers • like typewriter, using some kind of striking action • non-impact printers • laser printer - uses laser beams to write information • Ink-jet printer – shoots tine dots of ink onto the paper • plotters • uses computer-directed pens for creating high-quality images
Output Technologies (continued …) • Voice Output • can be played through speakers • Multimedia • computer-based integration of text, sound, still images, animation, and digitized motion video • Multifunction Devices • combine a variety of technologies - fax, printer, scanner, copy machine, and answering machine
Strategic Hardware Issues • Productivity • businesses need to assess whether employees’ personal productivity is likely to increase after hardware replacement • Changing Work Styles • organizations must consider whether new work styles will benefit employees and the firm as a whole • New Products and Services • organizations should consider whether they are ready and able to take advantage of the advances, and new products and services that hardware may make possible for the business • Improved Communication • businesses need to judge whether they are ready to use multimedia