System Software

1
System Software
2
BIOS

• Basic Input Output System
• A kind of ROM
• Execute routines Checking RAM, detecting hard
  disk, floppy disk, CDROM, etc

3
Cold Boot

• Restart the system
• Press the reset button, power on the system
• Run the routines in BIOS
• Load the Operating System (OS) to RAM
• Pass the control to OS if found
• An error message Non-system disk will be
  displayed if OS cannot be found in hard disk,
  floppy or CDROM.

4
Warm Boot

• Another way to restart the system
• Press the Ctrl-Alt-Del keys, no need to power on
  or reset the system
• Do not need to run the BIOS routines
• Some start up processes have to be reloaded
• Reset the system resources such as RAM
• Usually needed when running out of memory, system
  is unstable or after installation of new
  application software

5
Operating System

• Act as the interface between Users(Application
  software) and hardware
• Provide an environment for the user to develop
  and execute program without knowing the details
  of hardware
• User do not need to control the hardware
  directly, just call the routines in OS
• Such as displaying text on screen, reading
  characters from keyboard, getting the position of
  mouse.

6
Functions of OS

• Execution of program (Process management)
• Memory management
• File management (File read/write)
• Input and Output Devices Control
• Error handling
• Scheduling of jobs
• Allocate the system resources

7
Examples of OS

• DOS Disk Operating System
• Windows family such as XP, 2000, NT, CE
• Linux
• Unix
• Mac OS
• IBM OS/2

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DOS (1)

• A command line interpreter
• All the commands recognized are stored in the
  file COMMAND.COM
• Can execute files with file extension .com, .exe
  and .bat
• Can access 1MB memory by default

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DOS (2) memory management

• In order to run memory above 1MB, need extended
  memory or expanded memory
• To use extended memory (XMS), need to install
  HIMEM.SYS in the CONFIG.SYS file
• To use expanded memory (EMS), need to install
  EMM386.EXE in the CONFIG.SYS file

10
DOS (3) - Interrupt

• Interrupt a signal to tell the CPU to stop the
  current process, handle the outside request
  first, resume the process after fulfilling the
  request. E.g. saving a file to disk, printing a
  file, usually I/O request
• Interrupt Vector Table located in memory, use
  to store the addresses of the Interrupt Handlers.
• Interrupt Handler programs to handle the
  interrupts.

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DOS (4) File Management

• File Allocation Table (FAT)
• Similar to a content page of a book
• Store the physical location(addresses) of files
  and directories in disk
• The disk become useless if FAT is corrupted,
  files stored cannot be retrieved
• The disk need to format again but all the files
  will be erased

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DOS (4) - continue

• DOS format disk to tracks and sectors
• Sectors are grouped to a logical unit, clusters
• The size of cluster varies with the size of hard
  disk
• File names are in 8.3 format. 8 for file name, 3
  for file extension (see p.29).
• e.g. abcdefgh.xyz

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DOS (5) adding new hardware

• Device driver programs are needed whenever a new
  hardware is installed e.g. a printer driver, a
  scanner driver, a VGA driver
• The OS does not support the installation of new
  driver
• The new hardware have to configure manually

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Windows (1)

• Members include, windows 3.0, 3.1, 3.11, 95, 98,
  NT, Me, 2000, XP
• Windows 98, Me, XP home edition are for personal
  use
• Windows NT workstation, Windows 2000
  professional, XP professional are for business
  purpose
• Windows NT server, 2000 server and XP server are
  for server purpose

15
Windows (2)

• Graphical User Interface (GUI)
• Multitasking can execute many programs at the
  same time. It divides the CPU time into small
  units called time-slices and allocates to
  different programs.
• Multi-user - server versions such as NT and 2000
  can support multi-user processing. The time-slice
  technology is used to share the CPU time between
  different users. It is called Time-Sharing
  operating mode.

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Windows (3) memory management

• It use virtual memory concept.
• Apart from the on-board memory RAM, it can use
  the free space on hard disk as the virtual
  memory, therefore applications that need a lot of
  system memory can be run at the same time.

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Windows (4) File system

• It can use FAT32, FAT16 and NTFS filing system
• FAT16 is used for backward compatibility with DOS
• FAT32 is used for windows 95 and 98
• NTFS is used for windows NT, 2000 and XP, which
  is more secure and efficient than FAT filing
  system.

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Windows (5) Adding new hardware

• Support plug-n-play installation
• When adding new hardware, common devices can be
  detected, drivers are loaded automatically
• No need to configure the hardware manually

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Linux

• Derived from UNIX
• Command line interface
• Can install X-windows for GUI interface, two
  common shells are KDE and Gnome
• Commonly used in Servers, because of built-in
  network support, security, stability and minimal
  hardware requirement

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Operation with file system-in windows

• Using Window Explorer a hierarchical file
  system
• Creating and moving directories (folders)
• Copying, moving, renaming and deleting files
• Allow long filenames up to 255 characters
• Support file extensions, which can associate the
  corresponding application

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File Attributes

• Read Only file cannot be modified
• Hidden file name does not display
• Archive for backup purpose
• System system file, vital for the system,
  usually hidden
• To change the file attributes go to Options,
  View menu

22
Batch file

• A text file with .bat extension
• Consists of a sequence of commands or programs to
  be executed one by one when the batch file is
  executed.
• Usually run in DOS mode
• Refer to p.29 and p.58 for details

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DOS commands (1)

• dir listing files in current directory
• dir/w listing files in wide format
• dir/p listing files by page
• md x make directory x
• rd x remove directory x
• cd x change to the directory x
• cd .. change to the parent directory
• copy f1 f2 copy f1 to f2
• del f1 delete file f1
• cls clear the screen

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DOS Commands (2)

• echo lttextgt display the text on screen
• echo on display the command it executes on
  screen
• echo off do not display the commands it
  executes
• _at_echo off suppress the display of first command
  echo off

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DOS commands (3)

• chkdsk C - check error for drive C
• format A - format the disk in drive A
• xcopy s d copy all files in source directory to
  destination directory
• deltree x remove all contents under the
  directory x

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System Utility Programs

• Backup utility for backup and restore files
• Notepad for editing text
• WordPad for editing text with some formatting
  features
• Calculator
• Paint for drawing bitmap graphics
• Disk defragmenter to rearrange the files in
  hard disk, to reduce the access time
• ScanDisk to scan the hard disk for errors,
  repair for bad sectors

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Installation of System Software

• Check the hardware requirement
• Create a boot disk with CDROM driver if the
  system software is stored in CD
• Phases in installation
• Format the hard disk
• Copy files from CD-ROM, to speed up the process
• Decompress the files in correct folders
• Detection of hardware and installation of drivers
• Registration of software and connection to
  Internet for more support (e.g. on-line user
  manual)