[e-mail] E.mail

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• hosseini_at_ferdowsi.um.ac.ir E.mail
• Home Page hosseini.staffcms.um.ac.ir

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• Central Processing unit (CPU)
• Input / Output
• Storage
• Operating System
• ?????? ?? ??????? ?????? ?????
• ?????? ?? ???? ??? ????????? ? ???????
• ?????? ?? ??????? ?????????
• ?????? ?? ??????? ????????
• ?????? ?? ?? ? ?? ??????
• ?????? ?? LMS ? ????? ????? ????? ? ????? ?????
• ?????? ?? ????? ??????? ???? online
• ?????? ?? ????? ??? ?????? ?????
• ?????? ?? ??? ???????? ?? ???? ???
• ?????? ?? RSS (Really Simple Syndication )
  ????? ????? ??? ????? ????

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• ????? 1 ????? ???? ?? ???? ?? ????? 5 ????
• ????? 2 ????? ?? ???? ?? ???? ????? ?????
• ????? 3 ????? ?? ????? ?? ???? ??? OPAC(Online
  Public Access Catalog)
• ????? 4????? ?? ??? ????? ???? ????? ?????
• ????? 5 ??????? ?? ?????? ????? ?? ???? webinar

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7
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9
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• ???? ????? (Input Unit)
• ???? ????? (System Unit)
• ???? ????? (Output Unit)

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• ???? ????? (Memory Unit)
• ???? ????? (Control Unit)
• ???? ?????? ? ???? (Arithematic Logic Unit)

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The Little Man Computer
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• ????? ????
• - ????? ???? (Cache)
• - ???? ?? (Registers)
• - ????? ???? (Main Memory)
• ????? ?????

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RAM ?? ????? SAM

• RAM (Random Access Memory)
• ??? ??????? ?? ??? ??? ?? ????? ??  ?????? ??? .
  ??? ?? ???? ?? ?? ???? ????? ???????" ???????
  ???? ???
• SAM (Serial Access Memory)
• ????? ???SAM  ??????? ?? ?? ?????? ?? ?? ???? ???
  ????? ????? ? ????" ????? ??????? ?? ???? ?????
  ?????? ???? ????? ???? ???? ???? ????

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• RAM( Random Access Memory)
• ROM( Read Only Memory)
• PROM( Programmable ROM)
• EPROM( Erasable PROM)

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RAM

• 1- ?? ???????? (SRAM) ?? ??? ??? ????? ????? ??
  ??? ???? ???? ?? ???? ???? ????? ?? ??? ?? ??
  ????? ???? ?? ?? ????? ?? ???? ?????????? ?????
  ?? ???. ??? ??? ???? ????? ???? ????? ????
  ??????? ?????.2- ?? ???????? (DRAM) ????? ???
  ????? ???? ?? ???? ????? ?? ??? ?? ?? ??????????
  ???? ???? ???/??? ?? ???. ???? ???? ???? ??? ???
  ????????? ?? ??? ??? ????? ?? refresh ????. ???
  ??? ????? ?? ?????? ?? SRAM ????? ???? ???????
  ???? ( ???? ??????? ????? ) ??? ??????? ?? ????
  ?????.

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ROM

• Non-volatile memory to hold software that is not
  expected to change over the life of the system
• Magnetic core memory
• EEPROM
• Electrically Erasable Programmable ROM
• Slower and less flexible than Flash ROM
• Flash ROM
• Faster than disks but more expensive
• Uses
• BIOS initial boot instructions and diagnostics
• Digital cameras

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????? ?????

• ?? ?????? ???? ?????? ?????
• -1 ????? ??? ??? MAR
• LMC 100 (00 to 99)
• 2K where K width of the register in bits
• -2 ???? ???? ??????????
• 4 bits allows 16 locations
• 8 bits allows 256 locations
• 32 bits allows 4,294,967,296 or 4 GB
• ????? ????? ?? ??????
• Insufficient memory can cause a processor to work
  at 50 below performance

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Cache
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• Level 1 of Cache
• ???? ???????? ???? ?? ???? ????????? ?????? ?????
• Level 2 of Cache
• ????? ?? ???? ???????? ???? ? ????? ???? ? ????
  ????? ???
• Level 2 of Cache
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Fetch-Execute Cycle

• Two-cycle process because both instructions and
  data are in memory
• Fetch
• Decode or find instruction, load from memory into
  register and signal ALU
• Execute
• Performs operation that instruction requires
• Move/transform data

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????? ??? MAR ? MDR
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???? MAR-MDR
msb(memory storage buffer) lsb(latest significant
byte)
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Load Fetch/Execute Cycle
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Store Fetch/Execute Cycle
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ADD Fetch/Execute Cycle
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Instruction Elements

• OPCODE task
• Source OPERAND(s)
• Result OPERAND
• Location of data (register, memory)
• Explicit included in instruction
• Implicit default assumed

Addresses
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Instruction Types

• Data Transfer (load, store)
• Most common, greatest flexibility
• Involve memory and registers
• Whats a word ? 16? 32? 64 bits?
• Arithmetic
• Operators - /
• Integers and floating point
• Logical or Boolean
• Relational operators gt lt
• Boolean operators AND, OR, XOR, NOR, and NOT
• Single operand manipulation instructions
• Negating, decrementing, incrementing

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More Instruction Types

• Bit manipulation instructions
• Flags to test for conditions
• Shift and rotate
• Program control
• Stack instructions
• Multiple data instructions
• I/O and machine control

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Register Shifts and Rotates
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Stack Instructions

• Stack instructions
• LIFO method for organizing information
• Items removed in the reverse order from that in
  which they are added

Push
Pop
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Fixed Location Subroutine Return Address
Storage
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• Data Bus
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  ?????? ???? ??? ? ??? ??????? ???
• Address Bus
• ?????? ???? ?????? ????? ??? ?? ???????? ?? ????
  ?? ????? ??? ???? ???? ???? ?? ?? ?? ????? ????
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  ???? ?????? ???? ????? ???
• Control Bus
• ?????? ????? ??????? ??? ?? ????? ?????? ????
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Point-to-point vs. Multipoint
Plug-in device
Broadcast bus Example Ethernet
Shared among multiple devices
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• ???? ???? ?? CPU ? ????? ?????? ?? ????

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???????? ?? PC
AGP(Accelerated Graphics Port) PCI(Peripheral
Component Interconnect) ISA(Industry Standard
Architecture)
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Basic Model

• Processing speed or program execution
• determined primarily by ability of I/O operations
  to stay ahead of processor.

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I/O Considerations

• Speed Issues
• CPU operates at speeds much faster than the
  fastest I/O device
• Devices operate at different speeds
• Character device, there is not any addressing or
  searching, printer, network card
• Block devices (disk or tape drive)
• Coordination
• Several devices perform I/O simultaneously
• Unexpected input
• Various input formats
• Status information needed for each device

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I/O Device Interface Issues

• Different formats
• parallel interface
• serial interface
• Buffering of data
• Burst vs. stream
• Different control requirements
• electromechanical

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Examples of I/O Devices
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Simple I/O Configuration
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I/O Modules Functions

• Recognizes messages from device(s) addressed to
  it and accepts commands from the CPU
• Provides a buffer where the data from memory can
  be held until it can be transferred to the disk
• Provides the necessary registers and controls to
  perform a direct memory transfer
• Physically controls the device
• Copies data from its buffer to the device/from
  the CPU to its buffer
• Notifies with interrupts

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Input/Output Modules

• Programmed I/O
• CPU controlled I/O
• Interrupt Driven I/O
• External input controls
• Direct Memory Access Controllers
• Method for transferring data between main memory
  and a device that bypasses the CPU

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Programmed I/O
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Programmed I/O Example
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Programmed I/O Example
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Interrupts

• Signal that causes the CPU to alter its normal
  flow on instruction execution
• frees CPU from waiting for events
• provides control for external input
• Examples
• unexpected input
• abnormal situation
• illegal instructions
• multitasking, multiprocessing

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The CPU - The Interrupt Cycle

• Fetch / Execute cycle
• Interrupt cycle

START
Fetch Next Instruction
Execute Instruction
HALT
Interrupts Disabled
Check/Process Interrupt
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Interrupt Terminology

• Interrupt lines (hardware)
• Interrupt request
• Interrupt handlers
• Program that services the interrupt
• Also known as an interrupt routine
• Process Control Block (PCB)
• Located in a part of memory known as the stack
  area
• All registers of a program are saved here before
  control is transferred to the interrupt handler

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Interrupt Terminology

• Servicing the interrupt
• suspends program in progress
• saves pertinent information including last
  instruction executed and data values in registers
  in the PCB (process control block)
• branches to interrupt handler

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Servicing an Interrupt
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Use of Interrupts

• Notify that an external event has occurred
• real-time or time-sensitive
• Signal completion
• printer ready or buffer full
• Allocate CPU time
• time sharing
• Indicate abnormal event (CPU originates for
  notification and recovery)
• illegal operation, hardware error
• Software interrupts

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Multiple Interrupts Example
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Basic CPU-Memory-I/O Pathway
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External Interface Buses and Ports

• Parallel port
• Serial port
• RS-232C and RS-422 buses
• SCSI
• Small Computer System Interface
• USB, USB-2
• Universal Serial Bus

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• ???? FAT
• ???? DIR

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Storage Devices

• Primary memory
• Expanded storage
• Secondary storage
• Data and programs must be copied to primary
  memory for CPU access
• Permanence of data
• Direct access storage devices (DASDs)
• Online storage
• Offline storage loaded when needed

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Speed

• Measured by access time and data transfer rate
• Access time average time it takes a computer to
  locate data and read it
• millisecond one-thousandth of a second
• Data transfer rate amount of data that moves per
  second

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Hierarchy of Storage
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Secondary Storage Devices

• Hard drives, floppy drives
• CD-ROM and DVD-ROM drives
• CD-R, CD-RW, DVD-RAM, DVD-RW
• Tape drives
• Network drives
• Direct access vs. Sequential access
• Rotation vs. Linear

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Magnetic Disks

• Track circle
• Cylinder same track on all platters
• Block small arc of a track
• Sector pie-shaped part of a platter
• Head reads data off the disk
• Head crash
• Parked heads
• Number of bits on each track is the same! Denser
  towards the center.
• CAV constant angular velocity
• Spins the same speed for every track
• Hard drives 3600 rpm 7200 rpm
• Floppy drives 360 rpm

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A Hard Disk Layout
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Locating a Block of Data

• Average seek time time required to move from one
  track to another
• Latency time required for disk to rotate to
  beginning of correct sector
• Transfer time time required to transfer a block
  of data to the disk controller buffer

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Disk Access Times

• Avg. Seek time
• average time to move from one track to another
• Avg. Latency time
• average time to rotate to the beginning of the
  sector
• Avg. Latency time ½ 1/rotational speed
• Transfer time
• 1/( of sectors rotational speed)
• Total Time to access a disk block
• Avg. seek time avg. latency time avg.
  transfer time

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Magnetic Disks

• Data Block Format
• Interblock gap
• Header
• Data
• Formatting disk
• Disk Interleaving
• Disk Arrays
• RAID mirrored, striped
• Majority logic ? fault-tolerant computers

Disk Interleaving
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Disk Block Formats
Single Data Block
Header for Windows disk
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Alternate Disk Technologies

• Removable hard drives
• Disk pack disk platters are stored in a plastic
  case that is removable
• Another version includes the disk head and arm
  assembly in the case
• Fixed-head disk drives
• One head per track
• Eliminates the seek time
• Bernoulli Disk Drives
• Hybrid approach that incorporates both floppy and
  hard disk technology
• Zip drives

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Optical Storage

• Reflected light off a mirrored or pitted surface
• CD-ROM
• Spiral 3 miles long, containing 15 billion bits!
• CLV all blocks are same physical length
• Block 2352 bytes
• 2k of data (2048 bytes)
• 16 bytes for header (12 start, 4 id)
• 288 bytes for advanced error control
• DVD-ROM
• 4.7G per layer
• Max 2 layers per side, 2 sides 17G

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Optical Storage

• Laser strikes land light reflected into
  detector
• Laser strikes a pit light scattered

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Layout CD-ROM vs. Standard Disk
CD-ROM
Hard Disk
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CD-ROMs
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Types of Optical Storage

• WORM Disks
• Write-once-read-many times
• Medium can be altered by using a medium-powered
  laser to blister the surface
• Data stored in concentric tracks, sectored like a
  magnetic disk
• Medium-powered laser blister technology also used
  for
• CD-R, DVD-R, DVD-ROM
• CD-RW, DVD-RW, DVD-RAM, DVDRAM

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Displays

• Pixel picture element
• Size diagonal length of screen
• Resolution (pixels on screen)
• VGA 480 x 640
• SVGA 600 x 800
• 768 x 1024
• 1280 x 1024
• Picture size calculation
• Resolution bits required to represent number of
  colors in picture
• Example 16 color image, 100 pixels by 50 pixels
• 4 bits (16 colors) 100 50 20,000 bits

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Display Screen

• Screen size measured diagonally
• Resolution minimum identifiable pixel size

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Color and Displays

• Pixel color is determined by intensity of 3
  colors Red Green Blue or RGB
• 4 bits per color
• 16 x 16 x 16 4096 colors
• 24 bit color (True Color)
• 16.7 million colors
• Video memory requirements are significant!

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Text Monitors

• 24 lines x 80 chars
• A character is the smallest unit on a screen
• Very little memory required
• Fast for remote transmissions

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Printers

• Dots vs. pixels
• 300-2400 dpi vs. 70-100 pixels per inch
• Dots are on or off, pixels have intensities
• Types
• Typewriter / obsolete
• Dot matrix usually 24 pins, impact printing
• Inkjet squirts heated droplets of ink
• Laser jet

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Creating a Gray Scale
114
Laser Printer Operation

• Dots of laser light are beamed onto a drum
• Drum becomes electrically charged
• Drum passes through toner which then sticks to
  the electrically charged places
• Electrically charged paper is fed toward the drum
• Toner is transferred from the drum to the paper
• The fusing system heats and melts the toner onto
  the paper
• A corona wire resets the electrical charge on the
  drum

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Laser Printer Operation
116
Laser Printer Operation
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Other Computer Peripherals

• Scanners
• Flatbed, sheet-fed, hand-held
• Light is reflected off the sheet of paper
• User Input Devices
• Keyboard, mouse, light pens, graphics tablets
• Communication Devices
• Telephone modems
• Network devices

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  ????.
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  ?? ???? ?????.
• ???? ???? ?? 1024 ????(KB)
• ??? ???? ?? 1024 ???? ???? (MB)
• ???? ???? ?? 1024 ??? ???? (GB)
• ??? ???? ?? 1024 ???? ???? (TB)

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System Software
Programs that maintain operation of computer
Two types are operating systems and utility
programs
p. 398
121
Operating System

• A program that controls the execution of
  application programs
• An interface between applications and hardware

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Operating System

• Management
• Memory
• Process
• i/o
• file
• Virtual machine

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Layers of Computer System
124
Services Provided by the Operating System

• Program development
• Editors and debuggers
• Program execution
• Access to I/O devices
• Protected access to files

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Services Provided by the Operating System

• Error detection and response
• internal and external hardware errors
• memory error
• device failure
• software errors
• arithmetic overflow
• access forbidden memory locations
• error recovery

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Uniprogramming

• Processor must wait for I/O instruction to
  complete before preceding

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Multiprogramming

• When one job needs to wait for I/O, the processor
  can switch to the other job

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Multiprogramming
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Time Sharing

• Using multiprogramming to handle multiple
  interactive jobs
• Processors time is shared among multiple users
• Multiple users simultaneously access the system
  through terminals

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Main OS Concepts

• Processes
• Memory Management
• Information protection and security
• Scheduling and resource management
• System structure

132
Processes

• A program in execution
• An instance of a program running on a computer
• The entity that can be assigned to and executed
  on a processor
• A unit of activity characterized by a single
  sequential thread of execution, a current state,
  and an associated set of system resources

133
Process

• Consists of three components
• An executable program
• Associated data needed by the program
• Execution context of the program
• All information the operating system needs to
  manage the process

134
Process
135
Memory Management

• Process isolation
• Automatic allocation and management
• Support for modular programming
• Protection and access control
• Long-term storage

136
Virtual Memory

• Allows programmers to address memory from a
  logical point of view

137
File System

• Implements long-term store
• Information stored in named objects called files

138
Paging

• Allows process to be comprised of a number of
  fixed-size blocks, called pages
• Virtual address is a page number and an offset
  within the page
• Each page may be located any where in main memory
• Real address or physical address in main memory

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Virtual Memory Addressing
141
Types of Operating Systems
Stand-alone complete operating system working on
PC, laptop, mobile computing device. like DOS,
Windows, Mac OS X, Unix, Linux Network OS
designed specially to support a network, like
netware, windows server 2003,Unix, Linux and
Solaris Embedded OS on most PDA and small
devices Like, windows CE, windows mobile 2003,
Palm OS and Symbian OS

142
Stand-Alone Operating Systems

• DOS (Disk Operating System)

• Developed in early 1980s for personal computers
• Hardly used today because it does not offer GUI
• Used command-line interface when first
  developed, later included menus

143
Stand-Alone Operating Systems

• Microsoft Windows

144
Stand-Alone Operating Systems

• Mac OS X

• Available only for computers manufactured by
  Apple
• Macintosh operating system has been model for
  most GUIs

145
Stand-Alone Operating Systems

• OS/2 Warp Client

• IBMs GUI multitasking operating system
• Supports networking, Java, the Internet, and
  speech recognition

146
Stand-Alone Operating Systems

• UNIX

• Used by power users because of its flexibility
  and power
• Most versions offer GUI
• Both a stand-alone and a
• network operating system

147
Stand-Alone Operating Systems

• Linux

• Popular, free, multitasking UNIX-type operating
  system
• Open-source softwareecode is available to
  public
• Both a stand-alone and a network operating
  system

Red Hat provides a version of Linux called Red
Hat Linux. The GNOME graphical user interface is
shown in this example.
148
Network Operating Systems

• Allows users to share printer, Internet access,
• files, and programs on a network
• Administers security by establishing
• user name and password for each user

OS/2 Warp Server for e-business IBMs network
operating system for businesses
Windows Server 2003 Upgrade to Windows 2000
Server
149
Embedded Operating Systems

• Found on most mobile computers, PDAs, and other
  small devices
• Windows CE is scaled-down version of Windows

150
Embedded Operating Systems

• operating systems for PDAs

• Pocket PC 2002 for Pocket PC
• Newer versioins Windows Mobile 5 6
• Palm OS for Palm, Visor, and CLIE
• Embeded Linux

151
Embedded Operating Systems

• Mobile Operating systems
• Windows Mobile Smartphone
• A scaled down version of PDAs
• Symbian
• Open-source, multitasking operating system
  designed for smart phones
• Make telephone calls, save appointments, browse
  Web, send and receive e-mail and faxes, and more

152
Utility Programs

• disk scanner

• Detects and corrects problems on hard disk or
  floppy disk
• Searches for and removes unnecessary files

• backup utility

• Copies selected files or entire hard disk onto
  another disk or tape
• compress files during backup to require less
  storage space

153
Utility Programs

• disk defragmenter

• Reorganizes files and unused space on hard disk
  so programs run faster

154
Utility Programs

• screen saver

• Causes monitors screen to display moving image
  or blank screen if there is no activity for a
  specified time

• To secure computer, user configures screen saver
  to require password to deactivate

155
Utility Programs

• diagnostic utility

• Compiles technical information about hardware and
  some software
• Prepares report outlining problems

156
Stand-Alone Utility Programs

• What is a virus?

• Potentially damaging computer program
• Affects computer without users knowledge

157
Stand-Alone Utility Programs

• antivirus program

• Identifies and removes viruses in memory, storage
  media, and incoming files
• Must be updated frequently

158
Stand-Alone Utility Programs

• file compression utility

• Shrinks size of files to free up room and improve
  performance
• Compressed files are sometimes called zipped
  files, or rared files
• Two popular utilities WinRAR and WinZip

159
Stand-Alone Utility Programs

• personal firewall

• Protects personal computer from unauthorized
  intrusions
• Monitors all transmissions to and from computer