Transcript System Software

System Software
BIOS
Basic Input Output System
A kind of ROM
Execute routines Checking RAM,
detecting hard disk, floppy disk,
CDROM, …etc
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.
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
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.
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
Examples of OS
DOS – Disk Operating System
Windows family such as XP, 2000, NT,
CE
Linux
Unix
Mac OS
IBM OS/2
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
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
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.
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
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
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
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
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.
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.
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.
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
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
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
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
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
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
DOS Commands (2)
echo <text> – display the text on screen
echo on – display the command it
executes on screen
echo off – do not display the commands
it executes
@echo off – suppress the display of first
command ‘echo off’
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
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
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
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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)