Computer Science 1.2

What is the primary number system used in modern computers?

Binary (base-2)

Which number system did Charles Babbage use for his inventions?

Decimal (base-10)

What is the ternary system?

A number system based on three digits (base-3).

What was the Setun computer known for?

It used a ternary system and was developed in the Soviet Union in 1958.

Why did binary logic replace other number systems?

Due to practical challenges and widespread adoption of binary logic.

What does binary represent in terms of electrical states?

On (1) and Off (0).

What is a bit?

A binary digit; a single digit, either 1 or 0.

How many bits are in a byte?

8 bits.

What is noise in computing?

Unwanted electrical disturbances that can affect signal integrity.

What is Boolean algebra used for?

It is the mathematical framework for logical circuit design and operation.

What is hexadecimal?

A base-16 number system that uses 16 distinct symbols.

What symbols are used in hexadecimal?

Digits 0 to 9 and letters A to F.

Why is hexadecimal used in computing?

It provides a compact way to represent binary values and simplifies conversion.

What is ASCII?

American Standard Code for Information Interchange, a character encoding standard.

How many characters can standard ASCII represent?

128 characters.

What is extended ASCII?

An 8-bit extension of ASCII that can represent 256 characters.

What is Unicode?

A character encoding standard that provides a unique number for every character.

How many characters does the current Unicode Standard encode?

149,186 different characters.

What is the Basic Multilingual Plane (BMP) in Unicode?

It contains the most commonly used characters and symbols for modern languages.

What is a shift cipher?

A type of substitution cipher where each letter is shifted a certain number of positions.

What is brute force in the context of cipher breaking?

A method of systematically trying every possible key until the correct one is found.

What was significant about Russel Kirch's work in 1957?

He created the first digital image by scanning an analogue photo.

What is the main advantage of using binary in computer systems?

It reduces hardware complexity and enhances reliability.

What is the relationship between binary and digital electronics?

Digital electronics, such as transistors, operate naturally in binary mode.

What are debugging tools?

Software applications used to identify, analyze, and fix bugs in programs.

What is a memory dump?

A process of capturing and saving the contents of a computer's memory for diagnosis.

What are the benefits of using standardized binary encoding schemes?

They enable consistent storage, retrieval, and processing across different systems.

What enabled the transition from film to digital in various industries?

The development of early digital cameras and scanners.

What are bitmap images also known as?

Raster images.

How do bitmap images reproduce images?

Using a grid of pixels, each assigned a specific color and intensity.

What is the resolution of a bitmap image?

The number of pixels contained within the image, expressed as width x height.

What does bit depth refer to in digital images?

The number of bits used to represent the color of each pixel.

What is the formula to calculate the size of a bitmap image?

Image size = width (pixels) x height (pixels) x color depth (bits per pixel).

What is metadata in the context of digital images?

Information that describes other data, such as dimensions and color depth.

What happens when you increase the resolution of a bitmap image?

It increases the image quality, allowing for greater detail and clarity.

What is the trade-off for a higher resolution image?

Larger file size, impacting storage and transfer efficiency.

What is the impact of increasing color depth in an image?

It allows for a wider range of colors, resulting in more vibrant images.

What is banding in digital images?

When gradients appear as distinct steps rather than smooth transitions due to low color depth.

What does analogue-to-digital conversion (ADC) do?

It converts continuous analogue signals into discrete digital values.

What is the significance of the sampling rate in audio?

It determines how often the amplitude of sound is measured, affecting audio quality.

What is the sampling rate for CD-quality audio?

44.1 kHz.

What does stereo sound reproduction use?

Two or more audio channels to create the perception of sound from different directions.

What is amplitude in sound waves?

The magnitude of change in a sound wave, representing loudness or intensity.

What is the purpose of video container formats like MP4 or MKV?

To encapsulate various components of a video, including frames, audio tracks, and metadata.

How are video frames stored?

As a sequence of still images encoded in binary format.

What is the typical frame rate for video playback?

Usually between 24 to 60 frames per second.

What is spatial compression in video?

A technique that reduces file size by eliminating redundant information within each frame.

What is temporal compression in video?

A technique that reduces file size by eliminating redundant information between frames.

What color model is often used for video compression?

YUV, which emphasizes luminance for better compression.

What is the primary benefit of increasing pixel density (PPI)?

It improves the clarity of images displayed on screens.

What is the bit depth of professional audio?

24 bit, allowing for 16,777,216 possible values.

What is the effect of a low color depth in images?

It can lead to banding and less vibrant colors.

What does increasing the number of pixels in an image do?

It enhances the image quality and detail.

Why is temporal compression important?

It is particularly effective for videos with significant detail changes, such as animations and live broadcasts.

What does unsigned binary represent?

It represents only positive integers using binary digits (0s and 1s).

What is two's complement?

A method for representing signed integers in binary, where the most significant bit indicates the sign.

How do you convert a positive binary number to its negative in two's complement?

Invert all bits and add 1 to the least significant bit.

What is a limitation of two's complement?

In an 8-bit system, it reduces the range of representable numbers from 0 to 255 to -128 to +127.

What is one's complement?

A binary representation method for signed integers where the most significant bit indicates the sign, and positive numbers are inverted to get negative counterparts.

What is a limitation of one's complement?

It has two representations for zero (positive and negative), which can cause confusion in arithmetic operations.

What is sign-magnitude representation?

A method where the most significant bit indicates the sign, and the remaining bits represent the magnitude of the number.

What is the range of values for one's complement and sign-magnitude?

Both represent numbers from -127 to +127.

What is binary-coded decimal (BCD)?

A method of representing decimal numbers where each digit is encoded separately into its own binary form.

Why is BCD useful?

It avoids rounding errors in applications requiring exact decimal representation, like financial applications.

What is Gray code?

A binary system where two successive values differ by only one bit, useful for minimizing transition errors.

What is Excess-N representation?

A system where a fixed bias (N) is added to the actual value to form an encoded value for easier comparisons.

How does Excess-3 encoding work for the decimal number 2?

It is encoded as 2 + 3 = 5, which is 0101 in binary.

What is fixed-point representation?

A method to store real numbers in binary by fixing the position of the binary point.

What are the trade-offs of fixed-point representation?

It allows straightforward representation of fractional numbers but limits range and precision.

How is the number 5.25 represented in a fixed-point system with 4 bits for integer and 4 bits for fractional parts?

As 0101.0100.

What is floating-point representation?

A method to represent real numbers that can have a large range or fractional parts, using a sign, exponent, and mantissa.

What are the advantages of floating-point representation?

It efficiently handles very large, very small numbers, and numbers with fractional parts with reasonable precision.

What is the purpose of the sign bit in IEEE 754 single-precision floating-point numbers?

The sign bit determines whether the number is positive or negative.

How many bits are used for the exponent in IEEE 754 single-precision representation?

Eight bits.

What is the Excess-127 system in the context of IEEE 754?

It is a method where 127 is added to the actual exponent value for storage.

What does the mantissa represent in IEEE 754 single-precision?

The mantissa represents the significant digits of the number.

How is the number -5.75 represented in IEEE 754 format?

1 (sign) 10000001 (exponent) 01110000000000000000000 (mantissa).

What is a key limitation of the IEEE 754 standard?

It is not precise enough to represent all decimal numbers, which can lead to rounding errors.

What are logic gates?

Logic gates are fundamental components in digital electronics that perform specific logical functions.

What are the basic types of logic gates?

AND, OR, and NOT gates.

What is the function of an AND gate?

An AND gate outputs high (1) only when both inputs are high (1).

How does an OR gate operate?

An OR gate outputs high (1) when at least one of its inputs is high (1).

What is the output of a NOT gate when the input is high (1)?

The output will be low (0).

What is a NAND gate?

A NAND gate is an AND gate followed by a NOT gate, outputting low (0) only when both inputs are high (1).

What does a NOR gate do?

A NOR gate outputs high (1) only when both inputs are low (0).

What is the difference between an XOR gate and an OR gate?

An XOR gate outputs true only when the inputs are different, while an OR gate outputs true when at least one input is true.

What is an XNOR gate?

An XNOR gate is an XOR gate followed by a NOT gate, outputting high (1) when both inputs are the same.

What is Boolean algebra used for in logic circuits?

Boolean algebra is used to represent logic circuits and simplify logical expressions.

What is a Karnaugh map (K-map)?

A K-map is a tool that helps simplify Boolean expressions visually, making it easier to create efficient digital circuits.

What should the groups in a K-map contain?

Groups must contain powers of 2: one, two, four, eight, or sixteen 1s.

What is the rule for grouping 1s in a K-map?

Groups must be rectangular or square, cannot be diagonal, and should be as large as possible.

Can groups in a K-map overlap?

Yes, groups can overlap to form larger groups.

What is the goal when minimizing groups in a K-map?

To use the smallest number of groups to cover all the 1s.

What happens to a variable in a K-map if its value changes across a group?

The variable is discarded from the simplified expression.

What is the significance of the control wire in a transistor?

The control wire regulates the current between the source and drain, allowing the transistor to switch states.

What is the output of a NAND gate when both inputs are low (0)?

The output will be high (1).

What is the output of an XOR gate when both inputs are high (1)?

The output will be low (0).

What does the term 'biased form' refer to in the context of the exponent in IEEE 754?

It refers to storing the exponent value after adding a bias (127) to it.

How many bits are used for the mantissa in IEEE 754 single-precision?

Twenty-three bits.

What is the purpose of truth tables in relation to logic gates?

Truth tables systematically list all possible input combinations and their corresponding outputs.