Data Representation 3 Flashcards
(17 cards)
What is Binary?
A base-2 number system that’s made up of only two numbers or digits: 0 and 1. It’s the language that computers understand.
What is a Character set?
A complete set of characters and their number codes that can be recognised by a computer system.
What is the ASCII Table?
A character set that can represent up to 128 different characters.
What is Unicode?
A character set that can represent up to 65,536 different characters.
What does File size refer to?
How big the file is, in terms of data storage units.
How do you calculate file size?
Formula to calculate file size: (Width x Height) x Bit depth.
E.g. Width of image = 8, Height of image = 8, Bits (bit depth) = 2, (8 x 8) x 2 = 128 bits.
What is Pixel?
One of the small squares that make up an image on a computer screen. The more pixels there are, the more the image looks real or accurate.
What is Bit depth?
The number of bits per pixel. The more bits we use to represent each pixel, the more colours we can use.
E.g. A bit depth of 1 gives a choice of using up to 2 colours (0 for white, 1 for black).
What is Resolution?
The number of pixels per inch. The more pixels an image has per inch, the greater the resolution.
What is Metadata?
Data that gives information about other data.
E.g. When you take photos and look at the info, you can see extra info such as when it was taken, where, the size of the photo etc.
What are Data storage units?
Bit (one bit of data, 0 or 1), Nibble (4 bits of data), Byte (8 bits of data), Kilobyte (1000 bytes of data), Megabyte (1000 Kilobytes), Gigabyte (1000 Megabytes), Terabyte (1000 Gigabytes), Petabyte (1000 Terabytes).
What is Sample rate?
The number of samples taken per second. The more samples taken per second, the better the quality of the recording.
What is Bit depth in audio?
The number of bits used per sample of sound. A higher bit depth means a better quality of sound because more amplitudes can be represented.
What is Data Compression?
Reducing the amount of data needed to store or transmit a file.
What is Decompression?
Restoring a file to its original form.
What is Lossy compression?
When the file is compressed by removing data and loses some of its quality.
What is Lossless compression?
The file is compressed by changing the way the data is represented, without losing any quality.
