UNIT 1.1 Introduction to Computer System

UNIT 1.1 Introduction to Computer System

Number System

 Computer Concepts  Operating System – DOS  Operating System – WINDOWS COM E 211: Basic Computer Programming

Computer Concepts


 Is an electronic device that can perform prescribed operation given to it.

Computer System


 Is the computer’s physical components such as the keyboard, screen and printer 


 Is the computer programs containing a set of instructions that tell the hardware what to do.

COM E 211: Basic Computer Programming

Categories of Software

Application software

 Includes programs written to accomplish as specific task (or application) such as word processor, spreadsheet or database program.

System software

 Includes programs that are necessary for your computer to run. These are programs that direct hardware related tasks. For instance, operating systems.

COM E 211: Basic Computer Programming

Basic Parts of a Computer

 Input Unit  Computer accept coded information by means of input units, which is consists of devices capable of reading such data.  Example: keyboard, mouse, scanner  Memory Unit  Sole function is to store programs and data.

Classes of Memory devices:

 Primary Storage (main memory)   Is a fast memory capable of operating at electronic speed, where programs & data are stores during execution.

Examples:  RAM (random access memory) • Used to store volatile programs & data  ROM (read-only memory) • Is non-volatile memory  Secondary Storage  Used when a large amount of information have to be stores particularly if some of these data need not be accessed frequently.

 Example: disk  ALU (Arithmetic Logic Unit)  Execution of most operation with in the computer.

COM E 211: Basic Computer Programming

 CU (Control Unit)  Sends control signals to other units of the computer system.

 Coordinates the operation of the computer system to maintain its proper operation.

 Output Unit  Is to return the processed result to the outside world.

 Examples: monitor, printer COM E 211: Basic Computer Programming

UNIT 1.1 Introduction to Computer System

Number System

Computer Concepts

 Operating System – DOS  Operating System – WINDOWS COM E 211: Basic Computer Programming

Operating System

 A collection of programs that supervises all the activities that take place within a computer.

COM E 211: Basic Computer Programming

Disk Operating System (DOS)

 Four parts of DOS:  System files    Internal Commands / Programs External Commends / Programs DOS Utility Programs  System Files  command.com

 IBMBIO.com (IO.sys)  IBMDOS.com (MSDOS.sys)  Internal DOS Commands  Reside in the memory as part of command.com

 Two parts of command.com

 Resident part  Transient part  External Commands  Commands which need an external files to be loaded to memory for its execution.

 DOS must locate the command on disk and then loaded into computer memory.

 Precede the command name with directory path to the program file.

 DOS Utility Programs  Programs used for specialized purpose.

COM E 211: Basic Computer Programming


  Booting, starting the computer Perform to program that reside the ROM   POST (Power On Self Test)  Check the existence of necessary peripheral devices of the computer Bootstrap Loader  Short routine that loads necessary programs to boot DOS.

 DOS is the first program your computer run each time it starts.

 Bootable disk  Is a system disk capable of starting DOS  Ways computer can be reset/restart:  Turn OFF the power switch then turn it ON again  Press reset button  Press Ctrl+Alt+Del keys at the same time COM E 211: Basic Computer Programming

DOS Common Internal Commands

 Clearing the screen  Syntax: CLS  Changing drive  Syntax: target_drive:  Display the version of DOS  Syntax: VER  Display the current date  Syntax: DATE or DATE mm-dd-yy  Display current time  Syntax: TIME or TIME hh:mm:ss  Modifies the DOS prompt  Syntax: A:> PROMPT desired_prompt  Displays files inside the disk  Syntax: DIR or DIR/option COM E 211: Basic Computer Programming

DOS Common Internal Commands

 Change the filename of the existing file  Syntax: REN old_name new_name  Copies file’s content to another file / disk  Syntax: COPY source_file target_file  Syntax: A:> COPY C: filename B:  Creating a file  Syntax: COPYCON target_file  Display content of a text file  Syntax: TYPE target_file  Delete file(s) from the disk  Syntax: DEL target_file  Help on DOS command options, syntax format  Synatax: DOS_command/?

 Example: DIR/?, COPY/?

COM E 211: Basic Computer Programming

 Working with group of files  WILDCARD characters (* and ?), help select a group of files  Replaces the character with the name of all matching files  The Asterisk Wildcard (*)  Perform file operation s on a group of files by specifying “don’t care” character positions within the filename or extension  The Question Mark Wildcard (?)  Directs DOS to ignore the character in the position containing the wildcard.

 Represent only one character position.

 Redirection (>)  To redirect the output from the terminal screen to a file or to a printer.

  Example: A:> DIR > files.dat

A:> TYPE files.dat > prn  Creating Batch Files  Batch File  Is a file that contains the name of one or more DOS commands.

 Uses BAT extension  Autoexec.bat

 Most useful batch file  Unique from all other batch files because each time the computer starts, DOS automatically locates and executes the command in this special file.

COM E 211: Basic Computer Programming

DOS Common External Commands

 Prepares a disk for use by DOS  Creates File Allocation Table (FAT)  Contains info to keep track of the used, unused and bad sector  External file: format.com

 Syntax: FORMAT disk_drive:  Recover the data of the newly formatted disk  External file: unformat.com

 Syntax: UNFORMAT disk_drive:  Used to make copies of a disk  External file: diskcopy.com

 Syntax: DISKCOPY source_drive: target_drive:  Copies files, advance form of COPY command  External file: xcopy.com

 Syntax: XCOPY source_drive: target_drive: /option COM E 211: Basic Computer Programming

DOS Common External Commands

 Copies system ile from one disk to another  External file: sys.com

 Syntax: SYS target_drive:  Creates or change the volume label of disk  External file: label.exe

 Syntax: LABEL target_drive: volume_name  Modifies the attribute of a file  External file: attribute.exe

 Syntax: ATTRIB option target_file  Collects a previous DOS commands  External file: doskey.com

 Syntax: DOSKEY  Displays all directories present on your disk  External file: tree.com

 Syntax: TREE COM E 211: Basic Computer Programming

DOS Directories

 Root directory (\)  Internal commands in working with directories:  MD – make directory  CD – change directory  CD\ – returns to root directory  CD.. – returns the user to parent  RD – remove directory  Before using RD command: • • Erase all content of the directory (files & subdirectories) Remove all directory & its parent or at a much higher directory COM E 211: Basic Computer Programming

UNIT 1.1 Introduction to Computer System

Number System

Computer Concepts

Operating System – DOS

 Operating System – WINDOWS COM E 211: Basic Computer Programming



is a graphical operating system. Users communicate with the computer by choosing items or menu options & small graphical images instead of typing hard-to recall text commands such as were found in older operating system such as DOS. It is greatly made easy for users to use different software without having to learn new commands in a new environment or application.

COM E 211: Basic Computer Programming


    an input device which is cable connected to the PC through a serial port or special “ mouse port ” it has a mouse ball that senses the movement of the mouse it is implemented in Windows through:  select menu commands     move icons size windows start programs choose options a pointer on the screen that represents the mouse is called MOUSE POINTER 

COMMON MOUSE TERM Point Click Double-click Drag Drag & Drop

moves the pointer on the screen until it is over the desired location or object.

quickly press & release the left mouse button quick press the left mouse button twice hold down the left mouse button while moving the mouse hold down the left mouse button while moving the mouse; release the mouse button when the pointer is over the desired location COM E 211: Basic Computer Programming

 Icon  a picture representing a program, disk, drive, file, folder or other items 

COMMON Desktop Setup Desktop START button Taskbar

the entire background area of your screen; represents your working environment when you are operating your PC as a starting point for day-to-day activities such as running programs, opening & editing document & finding files helps you monitor & switch between the various activities you’ll perform

Sound Volume Control

for multimedia computing, provides a quick way of changing the sound volume

Time Box

you’ll see the current time displayed at the right end of the Taskbar; double-clicking, easily reset time when wrong

My Computer

allows you to browse the disk drives on your PC

Recycle Bin

represents a temporary storage are on your hard disk for files you no longer need; retrieve file that is in the Recycle Bin; once emptied, file is irretrievable

Microsoft Exchange Inbox

provides access to Microsoft exchange, a feature that allows you to send & receive e-mail messages and fax message & to view & organize all your message in one place

Network Neighborhood

provides a gateway to any other computers connected to your PC as part of a network COM E 211: Basic Computer Programming


Control Icon

menu of commands for moving, resizing & closing the window contains the window’s name

Title Bar Menu Bar

causes a drop-down menu to appear

Minimize Button

shrinks the window so that it appear only as a button on the Taskbar

Maximize/ Restore Button

switches the window between its maximum size & the smaller size to which it was previously set

Close Button

closes the window

Status Bar

contains information or messages relevant to the contents or activity in the window

Window Borders

dragging, resizing the window COM E 211: Basic Computer Programming

Shutdown & Reset

 to use Shut Down menu, which prepares the computer to be turned off or restarted 


 Using the Programs Menu  programs groups on the Programs menu depend on what software has been installed on the PC  Launching from the Folder window  by finding a program’s icon in the folder where it’s located & double-clicking on icon  Using the RUN command  from the Start menu COM E 211: Basic Computer Programming

Control Panel

 provides you with a number of utilities that allow you to set up Windows & your computer hardware in a way that suits you 

Help System

 consists of step by step instructions on hundreds of Windows tasks; there is specific Help System for each Windows accessory COM E 211: Basic Computer Programming


 a group of programs consists of various utilities that can help you get the most out of your PC.

System Tools Scandisk CD Player Media player contain tools for managing & maintaining your hard & floppy disk check your disk surface, files & folders for errors & to repair damaged area Disk Defragmenter rearranges files & folders on your hard disk so that program can run faster Multimedia to use these accessories in this program group one must have a sound card installed; any combination of text, pictures, sound & video play audio CD in your CD-ROM drive play audio, video or animation files & to control settings for multimedia hardware devices Sound Recorder to record, play & edit sound files; microphone for live recording Games Word Pad Calculator mini word processing program helps perform calculations HyperTerminal Connections exchange files with a remote computer via modem or connect to computer bulletin boards Phone Dialer automatically dial a telephone number from any PC w/ modem attached Character Map Note Pad to insert special characters into documents very basic word processing program COM E 211: Basic Computer Programming

Organizing Files & Folders

 to create some new folders, move existing files into those folders & perhaps rename & delete some files 

Windows Explorer

 a feature you can use to view the contents of your computer & network drives in a hierarchical structure 

Find, Shortcuts & Timesavers, Running MS-DOS

 find from the Start menu  creating / removing shortcut onto desktop;


that links to a file or folder is an icon  running MS-DOS (opening; using & customize the prompt window; properties) COM E 211: Basic Computer Programming