# Summary 1 13=D 1 1 1 0 14=E 1

Summary of
Chapter#1: Data Storage

Bits and Their Storage: Information
in form of 0’s & 1’s is called “bits” (short form of
Binary Digits). The bit ‘0’ stands for False Value/Off state and the
other one represents True Value/On state.

We Will Write a Custom Essay Specifically
For You For Only \$13.90/page!

order now

The operations that utilize these
values are known as “Boolean Operations”. Some basic operations of theme
are OR, AND, NOT & XOR.

AND
(Act as a multiplicative operator)

OR

NOT
(Act as an inverse operator)

XOR
(Functions like OR except the outputs are same)

Inputs

Output

Inputs

Output

Input

Output

Inputs

Output

0     0

0

0     0

0

0

1

0     0

0

0     1

0

0     1

1

0     1

1

1     0

0

1     0

1

1

0

1     0

1

1     1

1

1     1

1

1     1

0

AND

OR

NOT

NAND

NOR

XNOR

XOR

Gate: A device which gives the output
of any Boolean Operations when the inputs are given, called Gate.

Flip-Flops: Bistable gates/flip-flops, are
the types of circuits which is interconnected with logic gates in Integrated
Chips(IC’s). They have two states On & Off or 1 & 0; they are often
used for retrieving information. The outputs can change their states according
to rules & remains in the state until a signal is received. It’s normally
used in Electronics, Computers & Communication Technologies.

Hexa-Decimal Equivalents

23       22       21       20
(8Zeros   (4Zeros
(2Zeros   (1Zero
&
8Ones) & 4Ones) & 2Ones) & 1One)

Hexa-Decimal Equivalent

0       0
0       0

0

0       0
0       1

1

0       0
1       0

2

0       0
1       1

3

0       1
0       0

4

0       1
0       1

5

0       1
1       0

6

0       1
1       1

7

1       0
0       0

8

1       0
0       1

9

1       0
1       0

10=A

1       0
1       1

11=B

1       1
0       0

12=C

1       1
0       1

13=D

1       1
1       0

14=E

1       1
1       1

15=F

Bit Patterns: In computers, we must deal with
0’s & 1’s; sometimes they have patterns called Bit Patterns.

The 8-bit pattern 11100110 can be
written as E6, obtained by dividing into groups of four & changing it with
their Hexa-Decimal values.

16-bits pattern= (1111111001110011)2=
(FE73)16.

Ø
A
long string of bits is quite often known as “Stream”.

Main Memory: A computer device contains large number of
flip-flops; each of them has a memory of single bit. This stocker refers to
machine’s main memory. A computer’s memory is in the form of cells, each
holds eight-bit (i.e. 1Byte). A typical memory cell contains only one Byte.

Most Significant Bit (MSB)          0110110001        Least Significant Bit (LSB)

A
computer’s main memory is quite often refers to Random Access Memory (RAM).
Every individual cell has a unique name,

DRAM (Dynamic RAM) or SDRAM
(Synchronous DRAM) is used in illusion to DRAM that is decreases the time
elapsed to retrieve things from memory chips.

Measuring Memory Capacity: 210=1024, it is
closed to 1000, so that’s why it is neglected as Kilo.

1KB                                         1KiloByte                                            1024Bytes

1MB                                        1MegaByte                                          1024KiloBytes

1GB                                         1GigaByte                                            1024MegaBytes

1TB                                         1TeraBytes                                          1024GigaBytes

Mass Storage: Secondary/Mass Storage devices are additional memory
devices, their different classes are:

Magnetic System:
Normally called Hard
Disk-Drive/HDD (Magnetic Disk), has a spinning disk coated with magnet is
used to store data. It is a fixed disk & having non-volatile memory
that can store & retrieve data on computer.

Optical System: It is the storage method in
which data can be hold by a reflective disk by creating marks on it. Usually a
Laser Beam is used to detect/read data by checking variations on the
spinning disk. Some examples are:

CD-
(Compact Disk)                                        600-700MB

CD-DA
(Compact Disk-Digital Audio)                        approx.
74 minute audio or beyond (decreased pitch)

DVD
(Digital Versatile Disk)                           approx.
4.7 GB

BD
(Blu-Ray Disk)                                          Over
five times Capacity of DVD’s

Flash Drives: It is a kind of storage, unlike
the HDD or Optical Devices, it has no moving parts. Normally used to transfer
or save data from Computers, Digital Cameras etc. Some examples are:

SD                   Secure Digital

SDHC              SD- High Capacity

SDXC              SD-Extended Capacity

Representing Information in Bit Patterns: As all we know that computer
only can understand binary language in contrast to Human Language, that is why
it retrieve information/data in term of bits & our “Program” converts it
the human readable form. (Things they represent)