its best define about computer memories and its function and computer operating system.

1. Presented By
Abdul Majid

3. Index What is RAM and ROM
 Type of RAM and ROM
 What is Cache memory
 Bus interconnection
 What is operaing system
 Major function of operating system
 Type of operating system

4. MEMORY
RAM
• RAM(Random Access Memory) is a
form of data storage that can be
accessed randomly at any time, in
any order or form any physical
location, allowing quick access and
manipulation.
• RAM allow the computer to read data
quickly to run application. It allows
reading and writing.
• RAM is volatile memory.
• It expressed in kilobyte (KB) and
megabyte (MB)
ROM
• ROM (Read Only Memory) is also
form of data storage that can be
easily altered or reprogrammed.
Stores instructions that are not
necessary for re-booting up to make
the computer operate when it is
switched off.
• ROM stores the program to required
initially boot the computer.it only
allows reading.
• ROM is non- volatile.

5. Type of RAM
DRAM (DYNAMIC RAM)
 Stores each bit of data in a separate
Capacitor in the form of electric charge.
 Chip is refreshed frequently.
 Accessible data in the form of 0s and 1s.
 It used old microcomputers.
 Its slow speed than SRAM.
 Less expensive.

6. Type of RAM
SRAM (STATIC RAM)
 Memory cell are made
from digital gate.
 Gates store data.
 It is not refreshed frequently.
 About 10 time Faster than DRAM.
 Used modern computer.
 More expensive than DRAM.

7. Type of ROM
Programmable ROM
 Consists of blanks chip in which data and program stored.
 Burning process.

8. Type of ROM
Erasable programmable ROM (EPROM)
 It can be erased and reprogrammed repeatedly.
 The EPROM chip has a small window on top allowing it to be
erased by shining ultra-violet light on it.
 Much more useful than a regular PROM.
 It required erasing light.
 Access time is around 45 – 90 nanoseconds.

9. Type of ROM
Electrically erasable programmable
ROM(EEPROM)
 it much easier to erase and reprogram.
 It can be erase under the software controlled.
 Access times between 45 and 200 nanoseconds.

10. What is cache memory
Cache memory is fast memory that serves as a buffer between
the processor and main memory. The cache hold data that
recently used by the processor and saves a trip all the way back
to slower main memory.
Without cache memory, every time the CPU requests for data, it
would send the request to the main memory which would then be
sent back across the system bus to the CPU. This is a slow
process.

11. Levels of Cache
• Level 1(L1) Cache: This cache is inbuilt in the processor and is made of
SRAM(Static RAM). primary cache ranges in size from 8 to 64 KB. This
type of Cache Memory is very fast because it runs at the speed of the
processor.
• Level 2(L2) Cache: The L2 cache is larger but slower in speed than L1
cache. It is used to see recent accesses that is not picked by L1 cache and is
usually 64 to 2 MB in size. A L2 cache is also found on the CPU or
separate chip.
• Level 3(L3) Cache: L3 Cache memory is an enhanced form of memory
present on the motherboard of the computer. It is an extra cache built into
the motherboard between the processor and main
memory to speed up the processing operations and
having more than 3 MB of storage in it.

12. Bus interconnection
• For exchange of data between the computer system and other
devices through internal communication channel.
What is bus:
 The collection of wires that are used to carry data from one
part of the computer to another.
 Wires consist of parallel metal lines and flexible ribbon cable.
 Each line in the bus can carry one bit of data at a time.
 A group of line is used to simultaneously carry multiple bits of
data.
 The number of lines used simultaneously to carry data called
bus width.

13. Type of busses
1. System bus connects the processor with the main
memory and other devices.
2. Expansion bus allows the processor to
communicates with the peripheral devices
connected to the computer.

14. Component busses in the bus
interconnection
1.Data bus
• The line that are used to carry data between the microprocessor
and the main memory.
• Data bus is bi-direction bus.
• write and read operation.
2. Address bus
• A group of line to specify the source or destination of the data on
the data bus.
• Address bus is a unidirectional bus.
3.Control bus
• A separate group of line is used to select which component will use
the data and address busses at a particular time.
• Control signal
• Control signal consist of timing information and command signal.

15. Operating System and its
Functions

16. What is Operating System
• operating system is the set of programs that
controls a computer.
• It provide a pleasant and effective interface
between the user and the hardware.
• Without it, computer can not run.
• when the computer is on, OS will first load
into the main memory

17. Contd……..

18. Functions of Operating system
• Process Management
• Managing hardware resource
• Memory management
• Allocation and assignment
• Scheduling
• Providing user interface

19. 1.Process management
• By process management OS manages
many kinds of activities :-
All process from start to shut down
Creation and deletion of user and system
processes.

20. 2.Managing hardware resources
• OS manages the activities of the computer
system.
• It keeps information about various system
resources and devices.
• It allows the authorized user to log on the
system

21. 3. Memory Management
• The major activities of an operating
regard to memory-management are:-
Decide which process are loaded into memory
when memory space becomes available.
Allocate and deallocate memory space as needed.

22. 4.Allocation and assignment
• OS allocates computer resources to the
programs.
• It assigns location in memory for data and
instruction.
• It monitors the contents of the main memory
and clear item from memory when they are
no longer required by the CPU.

23. 5.Scheduling
• A computer can run several programs
simultaneously. The OS schedules these
programs in various areas of the computer so
that different parts of different programs can
be worked on at same time.

24. 6.Providing user interface
• A Providing user interface is an interface
between system and the user. There are
two types of user interface:-
Command line
Graphical user interface

25. Contd……
• With a command line user interface the user
interact with the OS by typing command to
perform specific tasks
• With a graphical user interface the user
interacts with the OS by using a mouse to
access windows icons and menus

26. Different Types of Operating Systems
• iOS
• Linux
• OS X
• QNX
• Microsoft Windows
• IBM z/OS
• RedHat