Computer Science Mocks Flashcards by Abigail Elcome

What is a bit?

A binary digit that is a 0 or 1

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What is a nibble?

A group of 4 bits or 1/2 a byte

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What is a byte?

A group of 8 bits that can store 1 of 256 numbers

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How many bytes in a kilobyte?

1000

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Order of bytes?

Bit - Nibble - Byte - Kilobyte - Megabyte - Gigabyte - Terabyte - Petabyte

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How many kilobytes in a megabyte?

1000

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How many megabytes in a gigabyte?

1000

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How many gigabytes in a terabyte?

1000

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How many terabytes in a petabyte?

1000

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How do overflow errors occur?

When binary addition results in a 9 digit number

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What is a binary shift?

A way of multiplying or dividing binary by powers of 2

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Is a right binary shift multiplying or dividing?

Dividing

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Is a left binary shift multiplying or dividing?

Multiplying

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Why might the size of a file need to be reduced?

Less storage space required
Faster download times for better online experience
Faster streaming of video/audio files

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Two types of compression?

Lossy

- Lossless

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What is lossy compression?

When unrequired data is removed from a file

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An example of lossy compression?

MP3s where sound quality may reduce but not enough to notice.

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What is lossless compression?

When data is temporarily removed from a file but added back (rebuilt) when the file is used again

An example of lossless compression?

Zip files, they need to be extracted before they can be used

How do MP3s use lossy compression?

Certain frequencies that are not noticeable are removed which reduces data but no noticeable loss of quality

How do online chatting and mobile phone networks use lossy compression?

Used to ensure only a small amount of bandwidth is used which reduces sound quality but is still understandable by the other person

How do images use lossy compression?

Details of the image may be lost but not impairing overall quality

Why is lossy compression important on websites?

Page load speeds can be affected by images that are especially large in size

Two types of lossless compression?

Run Length Encoding

- Dictionary Coding

What is the largest number that a byte can hold?

255

How do you convert hexadecimal to binary?

Find the binary value of the first digit, find the binary value of the second digit and put them together

How do you convert binary to hexidecimal?

1. Split it into nibbles or add 0's if you can't 2. Draw tables with 8, 4, 2, 1 3. Fill in the table with the binary numbers 4. Convert each value into hexadecimal

How do you convert hexadecimal to denary?

1. Draw a table with 16 then 1 2. Put the hexadecimal values into the table 3. Multiply the first value by 16 and the second value by 1 4. Add these values together, this is your denary number

How do you convert denary to hexadecimal?

1. Draw table with 16 then 1 2. Divide the denary number by 16 3. Divide the remainder by 1 4. Put the first and second value together to get the hexadecimal number

Does lossy or lossless compression give a smaller file?

Lossy

What is machine code?

A very low level language that a CPU can understand

Examples of machine code?

Binary and hexadecimal

What is assembly language?

Low level language

Features of machine code?

Hard for humans to write and read

Features of assembly language?

Easier for humans to write but still difficult`

Purpose of high level langauge?

Easy to understand and write and can be translated into a language that can be understood by the CPU

What are translators?

Programs that convert high level language commands into something that the CPU can understand and process

What are the three types of translators?

- Compiler - Interpreter - Assembler

What does a compiler do?

Converts the whole code into one file which can be run on any computer without a translator, can take a long tim

What does an interpreter do?

Converts source code into machine code 1 line at a time so is very slow but good for programs in development for programmers to highlight issues

What does an assembler do?

Converts assembly level language into machine code

What is an IDE?

Integrated development environment

What are the parts of an IDE?

- Source Code Editor - Interpreter - Automation Tools - Debugger - Compiler - Auto-Documentation