1. PC Components,
Features,
System Design

2. Hardware Outside the Case Inside the Case
Input/Output devices: connected through Ports
Peripherals: monitor, keyboard, mouse, printer
Inside the Case
Systemboard or Motherboard
Memory, such as SIMMs and DIMMs
Interface Cards for monitors, scanners ...
Power Supply
Hard, floppy, and CD-ROM Drives

3. Software Operating Systems, which consist of:
Program files controlling Input/Output
A means of Booting the system
Interfaces
Command-driven, such as DOS
Menu-driven, such as the DOS Shell
Icon-driven, such Windows and Macintosh
May be Multitasking
Examples of Operating environments are
DOS, Windows, OS/2, Mac OS, UNIX

4. Applications Software
Types:
Word processors such as Word and WordPerfect
Spreadsheets such as Excel and Lotus 123
Database management such as Access
Graphics
Communications
Games
Installed from Disk or CD-ROM

5. Directories
Root or main directory, created when a hard drive is first formatted
Subdirectories or folders for program applications and data files
Paths point to the location of a file folder and a particular file

6. Hardware - Outside the Case
Input/output devices or peripherals
Monitor
Primary output device
Displays images with pixels
Keyboard
Primary input device
Mouse
Pointing device
Printer
Produces paper output called hard copy

7. Hardware - Outside the Case
Cables connected to ports

8. Hardware - Inside the Case
Inside the computer case

9. Hardware - Systemboard
The most important circuit board, it holds microchips and interface cards:
CPU or microprocessor
Does most of the computer’s “thinking”
Coprocessor
Speeds up performance of older CPUs
ROM
Read-Only Memory, unchanging
Holds programs or instructions that tell the CPU how to perform many tasks

10. Hardware - Systemboard
RAM
Random-Access Memory, volatile
Individual chips or banks of chips such as SIMMs, DIMMs or RIMMS
System clock
Times the activities of the chips on the systemboard
CMOS configuration chip
System chip that contains setup information such as time and date, and drive size and type

11. Hardware - Systemboard
Bus
Paths along which data is passed
Expansion Slots
Interface cards are plugged into these slots to enhance the computer’s hardware, such as:
16-bit ISA slots
32-bit VLB slots
32-bit and 64-bit PCI slots

12. Hardware - Systemboard
Components on a systemboard

13. Divisions of Memory Under DOS
Hardware - Memory
Conventional memory - used by older XT computers
Upper memory - used to load drivers
Extended memory - used by Windows
Divisions of Memory Under DOS

14. Hardware - Circuit board
Plugs into expansion slots
Some types of circuit boards:
Video card
Hard drive controller card
Multi-input/output controller card
Internal modems
Scanner card
Network Interface Card (NIC)

15. Hardware - Circuit board
Circuit boards mounted in expansion slots

16. Hardware - Expansion Card
Expansion card and port

17. Hardware - Power Supply
Converts electricity, reducing it to a voltage the computer can use - either 5, 12, or 3.3 volts DC
Runs a cooling fan when the computer is on
Provides connectors to power the main Systemboard and Floppy, CD, Tape, and Hard drives

18. Hardware - Power Supply
Power supply with connections

19. Hardware - Secondary Storage
Hard drive
Sealed case containing rotating disks and read/write heads
Floppy disk drives
5 1/4” disks
3 1/2” double-density or high density disks
CD-ROM drives, DVD drives
Tape drives
Removable drives

20. A floppy drive subsystem

21. Software Programs that instruct the computer to perform specific tasks
Operating system software
DOS, Windows, OS/2, Mac OS, UNIX
Applications software
Word processor, spreadsheet, database, graphics, communications, games

22. Software - Operating Systems
The operating system is stored in files on the hard drive but is executed from memory

23. Software - Operating Systems
DOS
First Operating System used by IBM PCs
The most common OS of the 1980’s and early 1990’s
Command-driven from DOS prompt
Example: C:\> DIR A:

24. Software - Operating Systems
C:\>time
Current time is 6:12:09.41a
Enter new time:
C:\>ver
MS-DOS Version 6.22
C:\>copy config.sys config.bak
Overwrite CONFIG.BAK (Yes/No/All)?y
1 file(s) copied
C:\>
C prompt
An operating system command-driven interface: the C prompt

25. Software - Operating Systems
Windows 3.1
Menu-driven File Manager
Choose from a list of options on screen to perform various operations
Icon-driven Program Manager
Graphical-User Interface
Choose operations by selecting or clicking on pictures on screen

26. A menu-driven interface: File Manager in Windows 3.1
Software - Interfaces
A menu-driven interface: File Manager in Windows 3.1

27. An icon-driven interface: Program Manager in Windows 3.1
Software - Interfaces
An icon-driven interface: Program Manager in Windows 3.1

28. An icon-driven interface: Windows Explorer in Windows 95
Software - Interfaces
An icon-driven interface: Windows Explorer in Windows 95

29. Software - Multitasking
Ability of the computer to perform more than one function at a time
Example: Use a Modem, a Word Processor, and a Spreadsheet at the same time
Requires newer CPUs, such as a 486 or Pentium
Requires a special OS, such as Windows 95 or Windows NT

30. Software - Multitasking
A multitasking environment allows two or more applications to run simultaneously

31. Software - Operating Environment
Operating environment refers to the overall support that software provides to applications software
DOS manages its single-tasking environment and relates to hardware in single-task fashion
Windows 3.x performs some functions of an OS and provides an environment in which applications software works

32. Software - Operating Systems
Advantages and Disadvantages of DOS

33. Applications Software
Applications software falls into six main categories:
Word processing
Spreadsheet
Database management
Graphics
Communications
Games

34. Applications Software
Designed to work on top of a particular OS
An application written for one OS may not work with another
Comes on floppy disks or CD-ROMs
Usually installed on the hard drive

35. How Software Works
In the final stages of startup, the computer passes control to the OS
When OS completes its startup procedures, control passes to the user
For DOS users, the C prompt will appear
Example: C:\>
Files with extensions of .COM, .EXE, and .BAT can be run from the DOS prompt

36. Software - The Boot Process
C:\>C:\WINDOWS\SMARTDRIVE.EXE
MICROSOFT SMARTDrive Disk Cache version 4.0
Copyright 1991, 1992 Microsoft Corp.
Cache size: 761,856 bytes
Cache size while running Windows: 0 bytes
Disk Caching Status
Drive read cache write cache buffering
A: yes no no
B: yes no no
C: yes yes no
For help, type "Smartdrv /?"
C:\>
DOS prompt after booting

37. How DOS Searches for Executable Programs
Path - tells DOS where to look for files
If no path is given, DOS looks in the current directory
If a path is given in front of the file name, DOS looks in the PATH provided
Ex: C:\DOS\CHKDSK
If the file is not found in the current directory, DOS looks in the path given by the last PATH command
Ex: Path= C:\;C:\DOS\;C:\WINDOWS

38. Copying Programs into Memory
DOS cannot execute a program directly from the hard drive or floppy disks
DOS copies the program into RAM
It goes to the first address occupied by the program to receive its first instruction
DOS manages requested read/write tasks to and from memory
It performs other requested tasks and returns to the application when done

39. Applications software is stored in files but executed from memory

40. Software - Errors When an error occurs, either
The applications program detects the error and displays its own error message
The operating environment software detects the error and displays an error message

41. Software - Errors
Disk error in Windows 95

42. Windows error while using Paintbrush
Software - Errors
Windows error while using Paintbrush

43. Software Interactions with Hardware
The user interacts with the applications program
The applications program interacts with the OS
The OS interacts with the hardware, possibly through device drivers

44. Software Interactions with Hardware
Layers of software when printing