This document discusses computer memory units and storage capacity. It defines the basic units of storage like a bit, byte, kilobyte, megabyte, etc. and explains how they relate to each other. It then provides a block diagram of the main components of a computer system including the input, CPU and output units. The CPU contains the control unit, ALU and memory unit. It describes the functions of each of these components and how they work together to process data in the computer.

1. BLOCK DIAGRAM OF COMPUTER &
STORAGE UNIT OF MEMORY
Designed by Rita Gokani

2. MEASURING STORAGE CAPACITY
 As you know that all items that we purchase are
measured in some measuring units, In the same
way, we have units to measure Storage Capacity of
various computer Devices.
 Smallest Storage unit of Memory is a BIT(Binary
Digit i.e. 0 & 1).
 Computer understands only binary language i.e it
recognizes only 2 digits 0 & 1.

3. STORAGE UNIT OF MEMORY
 1 Bit = 0 & 1
 1 Nibble = 4 Bits
 1 Byte = 8 Bits
 1 KiloByte(KB) = 1024 Bytes
 1 MegaByte(MB) = 1024 KB
 1 GigaByte(GB) = 1024 MB
 1 TeraByte(TB) = 1024 GB
 1 PetaByte(PB) = 1024 TB
 1 ExaByte(EB) = 1024 PB
 1 ZettaByte(ZB) = 1024 EB
 1 YottaByte(YB) = 1024 ZB

4. COMPUTER SYSTEM
 A computer system is made up of 3 main
Parts:
 Input Unit
 CPU( Central Processing System)
 Output Unit

5. BLOCK DIAGRAM OF COMPUTER

6. INPUT
 This is the process of entering data and
programs into the computer system.
 As you know that computer is an electronic
machine which takes as inputs raw data and
performs some processing giving out
processed data.
 The devices that give data & instructions to
computer are called Input Devices
 Example: Keyboard, Mouse, Light Pen,
Scanner etc.

7. CPU(CENTRAL PROCESSING UNIT)
 CPU is the heart of the computer.
 CPU performs all types of data processing
operations.
 It stores data, intermediate results, and instructions
(program).
 It controls the operation of all parts of the computer.
 The CPU has 3 parts. They are :
 Control Unit
 ALU (Arithmetic and Logic Unit)
 Memory Unit

8. CONTROL UNIT
 It controls all other units in the computer.
 The control unit instructs the input unit, where
to store the data after receiving it from the user.
 It controls the flow of data and instructions from
the storage unit to ALU.
 It also controls the flow of results from the ALU
to the storage unit.
 The control unit is generally referred as the
central nervous system of the computer that
control and synchronizes its working.

9. ARITHMETIC AND LOGICAL UNIT(ALU)
 All calculations are performed in the Arithmetic
Logic Unit (ALU) of the computer.
 It also does comparison and takes decision.
 The ALU can perform basic operations such as
addition, subtraction, multiplication, division, etc
and does logic operations like, >, <, =, ‘etc.
 Whenever calculations are required, the control unit
transfers the data from storage unit to ALU once the
computations are done, the results are transferred
to the storage unit by the controls unit and then it is
sent to the output unit for displaying results.

10. MEMORY UNIT
 It stores data, instructions & results of processing.
 The process of saving data and instructions
permanently is known as storage.
 Data has to be stored into the system before the
actual processing starts.
 It is because the processing speed of Central
Processing Unit (CPU) is so fast that the data has
to be provided to CPU with the same speed.
 The result of calculation is also stored in Memory.

11. OUTPUT UNIT
 The output unit of a computer provides the
information and results of a calculation.
 The devices that displays or give the result
after processing of the data are called
Output Devices.
 Example: Monitor, Printer, Speaker, Plotter,
Visual Display Unit (VDU), floppy disk drive,
hard disk drive, magnetic tape drive etc.