ICS 124

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ICS 124

• INTRODUCTION TO COMPUTER SYSTEMS

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Use of Computers

• Where are computers used in your company?
• Accounting and Payroll
• Marketing
• Finance
• POS (Point of Sale)
• Inventory and ordering
• security

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Networking The Global Village
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Global Village

• Seneca College
• http//www.senecac.on.ca
• Instructors
• http//ilearn.senecac.on.ca/homepage/Maureen.Randl
  es/ICS124S.html
• http//cs.senecac.on.ca/ics124/
• http//cs.senecac.on.ca/msaul/pp.html
• Computers
• http//www.prenhall.com/capron/

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Global Village

• Last Terms Texts
• UNIX SYSTEM V
• http//www.awl-he.com/titles/14834.html
• Computers (past terms text)
• http//www.prenhall.com/long/

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Global Village

• Other Sites
• http//www.askjeeves.com/ Ask ANYTHING
• http//tv.clicktv.com/ Customized TV Listing
• http//www.mapquest.com/ Maps
• http//www.math.toronto.edu/toronto/ Toronto
• http//home.netscape.com and http//www.yahoo.com
  Search engines

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Computer Hardware

• Internal workings
• Peripherals
• Buying or Upgrading Home Computer Systems.

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Computer Hardware

• Physical parts of the computer system that you
  can see or touch.
• Examples
• Monitor / Keyboard / Mouse
• CPU (Processor) / RAM / Main Board
• Diskettes / Hard Disk / CD-ROMs
• Modem / Printer / Scanner

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Computer Software

• Set of instructions (not easily seen or touched
  by humans) that control computer hardware and
  allow humans to interface and accomplish tasks
  with a computer system.
• Categories of Software
• System Software (Operating System)
• Application Software (Word, Excel, etc...)

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Why Study Computer Hardware?

• If you want to take advantage of ever-advancing
  PC technology, get the most for your PC dollar,
  and allow your PC to grow with your capabilities,
  you need to know whats inside your PC.
• Computers Brief Edition, Page 61

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Why Study Computer Hardware?

• Examples
• Purchasing best computer system based on your
  needs for least amount of dollars
• Upgrading your PC
• Adding Hardware components to your PC (Scanner)
• Newer software requires minimum computer hardware
  (e.g.. 64 Mb of RAM)

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Computer Hardware Elements

• CPU - Central Processing Unit -
• RAM - Random Access Memory
• Cache Size (Capacity, type of memory)
• Main Board - mother board
• Hard Disk - Hard drive - GiG - Giga Bytes
• CD-ROM (Read/Write Speed)
• Modem (Manufacturer, Speed, Type)
• Peripheral Devices (Types of Connectors)

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CPU(Central Processing Unit)

• Considered to be the brain or where data that
  is entered or accessed is processed
• CPU consists of two processors
• ALU (Arithmetic and Logic Unit) which performs
  mathematical and sorting/comparison operations
• Control Unit which directs data between ALU and
  temporary memory (RAM)

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The CPU

• The CPU interacts closely with memory (primary
  storage).

CPU
Memory, however, is not part of the CPU.
Memory
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Parts of the CPU

• The CPU consists of a variety of parts including

• Control unit

• Arithmetic/logic unit (ALU)

• Registers

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The Control Unit

• directs the other parts of the computer system to
  execute stored program instructions.

The control unit communicates with the ALU and
memory.
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The Arithmetic/Logic Unit (ALU)

• - performs mathematical operations
• addition, subtraction, multiplication and
  division
• - as well as logical operations
• Equal-to ()
• Less-than (lt)
• Greater-than (gt)

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Registers

• are temporary storage areas for data or
  instructions.

Data held temporarily in registers can be
accessed at greater speeds than data stored in
memory.
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Roles of Registers

• Special roles are assigned to registers
• Accumulator
• Address register
• Storage register
• General-purpose register

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The Accumulator

• temporarily collects and stores the results of
  on-going computations and logical operations.

Accumulator
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The Address Register

• keeps track of where a given instruction or piece
  of data is stored in memory, by means of an
  address.

Address Register
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The Storage Register

• temporarily holds data taken from or on its way
  to memory.

Storage Register
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The General-Purpose Register

• is used for several functions, such as the
  instructions for carrying out arithmetic
  operations.

General-purpose Register
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Memory (Primary Storage)

• Memory is the part of the computer that stores
  data and program instructions for processing.

CPU
Memory
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Memory

• is also referred to as RAM (random-access
  memory). Its size is referred as so many Mb -
  mega bytes. E.g. 64Mb of RAM

CPU
RAM is temporary, finite, and more expensive than
secondary storage.
Memory
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What is a Megabyte?

• 1 bit a binary digit - one or zero.
• 1 byte is 8 bits. (minimum space required to
  refer to one signed character - number, letter,
  special keyboard characters).
• 1000 bytes equivalent to one kilobyte (actually
  1024 bytes)
• 1million bytes equivalent to one megabyte
• 1 billion bytes equivalent one gigabyte
• Note these are rounded off to nearest even number

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Executing Program Instructions

• Before the CPU can execute a program, program
  instructions and data must be placed into memory
  from an input device or storage device.

Secondary Storage
Input
Processing
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Executing Program Instructions

• Once the necessary data and instructions are in
  memory, the CPU performs the following steps for
  each instruction

• Fetching
• Decoding
• Executing
• Storing

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Fetching Instructions

• The control unit fetches (gets) the instruction
  from memory.

Memory
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Decoding Instructions

• The control unit decodes the instruction and
  directs that the necessary data be moved from
  memory to the ALU.

Memory
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Executing Arithmetic/Logic Operations

• The ALU performs the arithmetic or logical
  operation on the data.

Memory
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Storing Results

• The ALU stores the result of its operation on the
  data in memory or in a register.

Memory
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Executing Program Instructions

• Eventually, the control unit sends the results in
  memory out to an output device or secondary
  storage.

Secondary Storage
Output
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Instruction Time

• The time it takes to fetch an instruction and
  decode it is called instruction time.

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Execution Time

• The time it takes to execute an ALU operation and
  then store the result is called execution time.

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Machine Cycle

• The combination of I-time and E-time is called
  the machine cycle.

E- time
I- time
Machine Cycle
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Measuring CPU Performance

• CPU Speed (Megahertz - MHz)
• The CPU executes instructions to the beat of a
  clock. Normally, several ticks of the clock
  (clock cycle) is used to fetch, decode and
  execute a single program instruction.
• One hertz is considered to be equal to one clock
  tick (cycle)

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Measuring CPU Performance

• Because the clock cycles are very fast, CPU speed
  is measured as Megahertz (million cycles per
  second) e.g. Pentium III 450MHz
• CPU clock speed runs at some multiple of the
  motherboard clock speed which currently run
  between 60MHz - 100 MHz. Anticipated to increase
  further with new technology to 133MHz and higher.
• The CPU speed in the above example runs 4.5 times
  a motherboard speed of 100MHz.

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Measuring CPU Performance

• Word Size
• Word Size of a CPU relates to the number of bits
  that are handled as a unit with the computer
  systems data bus or during internal processing
  (within CPU)
• The larger the word size, the better the
  performance. (32 bit , 64 bit sizes todays PCs)

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RAM(Random Access Memory)

• Temporary memory (memory chips used to store data
  prior to or directly after processing. Also known
  as internal, volatile or primary memory.
• Although RAM operates faster than hard disk, data
  stored in RAM is lost when computer is powered
  off. (i.e.. Volatile)
• CPU needs to use RAM to help in processing data.

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RAM(Random Access Memory)

• RAM generally comes in the form of mini-circuit
  boards called DIMMs or SIMMs
• DIMMs-Dual Inline Memory Module
• more expensive, but have a 64 bit data path
• SIMMs-Single Inline Memory Module
• less expensive, but have only a 32 bit data path

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RAM(Random Access Memory)

• RAM also comes in two major types of chips SRAM
  and DRAM
• SRAM (Static RAM)
• Faster speed memory, but more expensive!!
• DRAM (Dynamic RAM)
• Less expensive memory, but slower than SRAM

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Measuring RAM Performance

• Type of RAM Chip
• SRAM, DRAM, SDRAM (Synchronous DRAM-runs at the
  same speed as the main system), RDRAM (Rambus
  DRAM-highspeed dynamic - 1G/sec or faster
  transfer rate -Memory modules with RDRAM called
  RIMMs)
• RAM Capacity
• Megabytes, Upgradability options
• Data Path
• DIMM (64 bit data path)
• SIMM (32 bit data path)
• RIMM (different technology)

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Main Board

• A printed circuit board used to allow data to
  flow between the essential hardware components
  such as the CPU, RAM, hard disk, diskette, CD-ROM
  and all other components that are outside of the
  processor.
• Also is known as the Motherboard.

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Main Board

• Considered to be the most essential component of
  the computer since ALL computer hardware devices
  are somehow connected to this board.

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Main Board

• The main board (system board, mother board) is
  the physical foundation of the PC.
• The following components are connected to the
  main board
• CPU
• Memory Chips
• Expansion Slots
• Electronic Circuitry

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Main Board Performance

• Data Path
• 8 bit, 16 bit, 32 bit, 64 bit ,etc...
• Types of Bus Slots (Expansion Slots)
• ISA, PCI, USB, Other?
• Manufacturer of Motherboard
• Asus, Acer, Generic
• Type will dictate upgradability

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Data Bus

• The data bus is considered to be the electronic
  path (highway) on the main board through which
  the CPU communicates with memory components
  (except RAM) and peripheral devices (I/O buses -
  Input/Output)

1000001
1000001
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Data Bus

• Binary code (a series of bits or numbers
  consisting of either 0s or 1s) travel along an
  electrical path (printed circuit board).

1000001
1000001
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Data Bus

• The wider the path (highway) of the data bus, the
  more data (in the form of bits) can be
  transferred between the CPU and memory and
  peripheral devices thus improving processing
  performance
• Common Data Paths
• 8 bit, 16 bit (older PCs - 8088,80286,80386SX)
• 32 bit (80386DX, 80486)
• 64 bit (Pentium, Pentium II,Pentium III)

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Data Bus Slots(Expansion Slots)

• Data bus slots or expansion slots allow the
  user to expand the capabilities of their
  computer by adding peripheral devices
• Peripheral Devices include
• Advanced Graphics Card (Games, CAD)
• Sound Card
• Fax Modem
• Video Capture Card
• Printer / Scanner

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Types of Expansion Slots

• ISA- (Narrow data path - slower)
• PCI- (Wide data path - Faster)
• USB (Fast - Allows multiple connections - star
  topology)
• Serial Port (Transfer 1 bit at a time - used
• for devices such as a mouse)
• Parallel Port (Transfer multiple bits
• simultaneously used for devices
  such as a printer or scanner)
• SCSI Port (Small Computer System Interface -
  multiple connections - daisy-chain topology)

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Examples of Popular PC Ports - Smart
Computing,Vol.7 Issue 10, Pg.12
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Peripherals

• All devices that are considered to be physically
  outside of the processor box.
• Some peripherals such as the keyboard and mouse
  connect to the main board directly
• Other peripherals connect to the main board by
  expansion slots which are mini circuit boards
  which plug into the main board (usually at the
  back of the processor box)

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Communication Ports

• Peripheral devices can be linked to the processor
  by cables through a port
• These ports are considered to be receptacles that
  provide a direct link to the PCs common data
  transfer system (Data Bus)

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Web Links to Computer Hardware Resources

• M. Karbos Click and Learn page
• www.mkdata.dk/click/
• Toms Hardware Webpage
• www.tomshardware.com
• webopaedia (Computer Terms)
• www.webopaedia.com
• What Is It? (Computer Concepts)
• www.whatis.com

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For Next Week

• Buying or Upgrading Home Computer Systems - Jot
  down some points on
• What would you look for in a home computer
  system?
• How would you shop for a home computer system?
• How would you go about upgrading your computer
  system?

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Next Week

• Period 1 (Before break)
• Brief review of last weeks material.
• Introduction to Unix, UNIX commands
• logon, man, other commands
• Overview of network, lab locations and the Seneca
  computing environment.
• Assignment 1 - Handed out
• Period 2 (After break)
• Lab 1

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Next Week

• Read
• Photo Essay, Appendix A
• Chapters 1 to 4
• Parts 1 and 2 of the ICS124 NOTES
• Bring your ICS124 Seneca Notes to class next week.