1. Computer Systems
I’m ONLY a
machine!

2. Hardware
Hardware refers to all the parts of the Computer System that we can touch.
An item of hardware is called a device.
Microprocessor
Main memory
Input / Output
Backing Storage

3. Central Processing Unit
CPU
Input
Output
RAM
ROM
Backing Storage

4. The Processor Carries out the actual process
Follows a set of instructions called a program
Like a brain but can’t think or act for itself
INPUT
PROCESS
OUTPUT

5. Representing Graphics & Text
Bit-Mapped Graphics
Dots called pixels
Each pixels is either
On (1 – black) or Off (0 – white)
Text – ASCII standard file format
= MUJTABA BE QUIET

6. Units of Storage Binary Unit Value Bit 1 or 0 Byte 8 bits
Kilobyte (KB)
1024 bytes
Megabyte (MB)
1024 Kilobytes
Gigabyte (GB)
1024 Megabytes
Terabyte (TB)
1024 Gigabytes

7. Main Memory
CPU
Input
Output
RAM
ROM
Backing Storage

8. Main Memory Where the computer stores programs & data Types: RAM ROM
Random Access Memory
ROM
Read Only Memory

9. Main Memory ROM Chip Permanent storage
Data is safe when computer is switched off
Data can not be added to ROM
Some OS are stored on ROM Chips
RAM Chip
Temporary storage
Data is lost when computer switched off
Data can be written to RAM
Upgrading is easy with RAM Chips

10. Input
CPU
RAM
Backing Storage
Input
Output
ROM

11. Input Devices (Navigational)
Mouse
Trackball
Track pad
Touch Screen
Joystick
SmartBoard

12. Input Devices (Data Input)
Keyboard
Graphics Tablet
Scanner
Digital Still camera
Digital Video Camera
Webcam
Microphone

13. Backing Storage
CPU
RAM
Backing Storage
Input
Output
ROM

14. Backing Storage Method used to physically store data.
Constantly increasing in capacity to meet demands.
Magnetic Storage
Floppy disc, Hard Disc, Magnetic Tape
Optical Storage
CD, DVD
Solid State
USB Flash Drive

15. Drive or Media
Drive
Media

16. Magnetic Storage Hard Disk Drive Floppy Disk Magnetic Tape
Usually main type of backing store
Non-removable media
Floppy Disk
Plastic disk with rectangular cover
Removable media
Magnetic Tape
Sequential Access
Think VHS tape
Easy to damage – put next to magnet it will be wiped

17. Optical Storage

18. Optical Storage CD-ROM DVD-ROM CD-Recordable (CD-R) / DVD-R
Read by a laser beam that reflects of surface “pits” and “lands”
DVD-ROM
Similar to CD but with larger capacity because of multiple layers
CD-Recordable (CD-R) / DVD-R
Write Once, Read Many
CD-Rewritable (CD-RW) / DVD-RW
Still uses a laser but contents can be changed
Advantages – high storage capacities
Disadvantages – Harder than mag but still easy to damage

19. USB Flash Drive Universal Serial Bus: Solid State Memory Advantages
Computer interface used by different devices.
Solid State Memory
No moving parts
Advantages
Portable
Can have large memory (currently 8GB)
Goes through the wash

20. Flash Memory Cards Solid State Memory Advantages No moving parts
Used in cameras and mobile phones
Advantages
Portable
Can have large memory (currently 8GB)
Can be read by a card reader
Goes through the wash

21. Output
CPU
RAM
Backing Storage
Input
Output
ROM

22. Comparison of Printers
Output Devices
Printer
Laser
Inkjet
Comparison of Printers
Resolution
Dots Per Inch (DPI)
Speed
Pages Per Minute (PPM)
Cost
Capital Cost
Running Costs

23. Output Devices Plotter Monitor (VDU) LCD TFT Multimedia Projector
Liquid Crystal Display
TFT
Thin Film Transistor
Multimedia Projector
Speakers

24. Types of Computer Desktop Laptop/Notebook Palmtop
Think about the different I/O

25. Types of Computer
Mainframe
Think about the different I/O