For M.C.Qs
Chapter No. 01:
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Chapter No. 02:
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Chapter 01
Bit: Binary Digit (0 or 1)
Numbers
Text characters
Images
Sound
And others"
Boolean Operation:
"An operation that manipulates one or more true/false values."
Specific operations
AND
OR
XOR (exclusive or)
NOT
Gate:
"A device that computes a Boolean operation."
- Often implemented as (small) electronic circuits
- Provide the building blocks from which computers are constructed
- VLSI (Very Large Scale Integration)
Flip-flop:
"A circuit built from gates that can store one bit."
One input line is used to set its stored value to 1
One input line is used to set its stored value to 0
While both input lines are 0, the most recently
stored value is preserved
Hexadecimal notation:
"A shorthand notation for long bit patterns."
Divides a pattern into groups of four bits each
Represents each group with a single symbol
Example: 10100011 becomes A3
Cell:
"A unit of main memory (typically 8 bits which is one byte)."
Most significant bit: is the bit at the left
(high-order) end of the conceptual row of bits
in a memory cell
Least significant bit: is the bit at the right
(low-order) end of the conceptual row of bits in
a memory cell
Address:
A “name” that uniquely identifies one cell in the computer’s main memory
The names are actually numbers.
These numbers are assigned consecutively
starting at zero.
Numbering the cells in this manner associates
an order with the memory cells.
Memory Terminology
Random Access Memory (RAM):
"Memory in which individual cells can be easily accessed in any order."
Dynamic Memory (DRAM):
"RAM composed of volatile memory"
Measuring Memory Capacity
Kilobyte: 210 bytes = 1024 bytes
Example: 3 KB = 3 times1024 bytes
Megabyte: 220 bytes = 1,048,576 bytes
Example: 3 MB = 3 times 1,048,576 bytes
Gigabyte: 230 bytes = 1,073,741,824 bytes
Example: 3 GB = 3 times 1,073,741,824 bytes
Mass Storage
Additional devices:
- Magnetic disk
- CDs
- DVDs
Advantages over main memory
- Less volatility
- Larger storage capacities
- Low cost
- In many cases can be removed
- Magnetic tape
- Flash drives
- Solid-state disks
Flash Drives
Flash Memory
– circuits that trap electrons in tiny silicon dioxide chambers
- Repeated erasing slowly damages the media
- Mass storage of choice for:
- Digital cameras Smartphones
- SD Cards provide GBs of storage
Representing Text
Each character (letter, punctuation, etc.)
is assigned a unique bit pattern.
ASCII: Uses patterns of 7-bits to represent most symbols used in written English text
ISO developed a number of 8-bit extensions
to ASCII, each designed to accommodate a major language group
Unicode: Uses patterns up to 21-bits to represent the symbols used in languages
worldwide, 16-bits for the world’s commonly
used languages
Representing Numeric Values
- Binary notation: Uses bits to represent a number in base two.
- Limitations of computer representations of numeric values.
- Overflow: occurs when a value is too big to be represented.
- Truncation: occurs when a value cannot be represented accurately.
Representing Images
Bit map techniques
Pixel: short for “picture element”
RGB
Luminance and chrominance
Vector techniques
Scalable
TrueType and PostScript
Representing Sound
Sampling techniques
Used for high-quality recordings
Records actual audio
MIDI
Used in music synthesizers
Records “musical score”
The Binary System
The traditional decimal system is based on powers of ten.
The Binary system is based on the powers of two.
Storing Integers
Two’s complement notation: The most popular means of representing integer
values.
Excess notation: Another means of representing integer values
Both can suffer from overflow errors
Storing Fractions
Floating-point Notation: Consists of a sign bit, a mantissa field, and an exponent
field.
Related topics include:
Normalized form
Truncation errors
Data and Programming
A programming language is a computer system created to allow humans to precisely express algorithms using a higher level of abstraction.
Getting Started with Python
Python: a popular programming
language for applications, scientific computation,
and an introductory language for students
Python is an interpreted language
Typing:
print('Hello, World!')
Results in:
Hello, World!
Variables
Variables: name values for later use Analogous to mathematic variables in
algebra.
Examples:
s = 'Hello, World!'
print(s)
my_integer = 5
my_floating_point = 26.2
my_Boolean = True
my_string = 'characters'
my_integer = 0xFF
Operators and Expressions
print(3 + 4)
# Prints 7
print(5 – 6) # Prints -1
print(7 * 8) # Prints 56
print(45 / 4)
# Prints 11.25
print(2 ** 10)
# Prints 1024
s = 'hello' + 'world'
s = s * 4
print(s)
Currency Conversion
# A converter for currency exchange.
USD_to_GBP = 0.66 # Today's exchange rate
GBP_sign = '\u00A3' # Unicode value for £
dollars = 1000 # Number dollars to convert
# Conversion calculations
pounds = dollars * USD_to_GBP
# Printing the results
print('Today, $' + str(dollars))
print('converts to ' + GBP_sign + str(pounds))
Debugging
Syntax errors:
print(5 +)
SyntaxError: invalid syntax
pront(5)
NameError: name 'pront' is not defined
Semantic errors
Incorrect expressions like:
total_pay = 40 + extra_hours * pay_rate
Runtime errors
Unintentional divide by zero
Data Compression
- Lossy versus lossless
- Run-length encoding
- Frequency-dependent encoding (Huffman codes)
- Relative encoding
- Dictionary encoding (Includes adaptive dictionary encoding such as LZW encoding.)
Compressing Images
- GIF: Good for cartoons
- JPEG: Good for photographs
- TIFF: Good for image archiving
Compressing Audio and Video
- MPEG
- High-definition television broadcast
- Video conferencing
- MP3
- Temporal masking
- Frequency masking
Communication Errors
- Parity bits (even versus odd)
- Check bytes
- Error-correcting codes.
1 Comments
good work keep it up✔.
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