System Software BIOS Basic Input Output System A

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 1 MB memory by default

DOS (2) – memory management In order to run memory above 1 MB, 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 EMM 386. EXE in the CONFIG. SYS file

DOS (3) - 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. 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 FAT 32, FAT 16 and NTFS filing system FAT 16 is used for backward compatibility with DOS FAT 32 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 f 1 f 2 – copy f 1 to f 2 del f 1 – delete file f 1 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 Word. Pad – 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 Scan. Disk – 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 n n 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)