Chapter 1 - Digital Data Flashcards
What is data?
Raw facts and figures, without meaning
Give an example of data
14
What is information?
Data that has been processed and has meaning
Give an example of information
14 years old
What is input?
When data is entered into a computer
What is Processing?
When a computer runs a program to change data into information
What is output?
When a computer sends information back to the user
What is a bit (b)?
A binary Digit. A single 1 or 0.
What is a byte (B)?
8 bits
What is a Nibble (Nybble)?
4 bits
What is a character?
A letter, digit, punctuation mark or control code stored in digital format as a byte
What is a KiloByte (KB)?
1024 Bytes
What is a MegaByte (MB)?
1024 KB or 1024 KiloBytes
What is a GigaByte (GB)?
1024 MB or 1024 MegaBytes
What is a TeraByte (TB)
1024 GB or 1024 GigaBytes
What is ASCII?
American Standard Code for Information Interchange
ASCII is a way of representing letters and symbols using binary codes.
ASCII uses 7 bits to represent each character.
ASCII can represent 128 different characters.
What is Extended ASCII?
Uses 8 bits to represent each character.
245 characters can be represented.
What is a data type?
Data can be allocated a data type.
Data types include: Number; Text (or String); Date/Time
What is a NUMBER data type?
A number type can represent:
- integers (whole numbers);
- Real numbers (with a decimal point)
Give an example of an integer
4
Give an example of a real number
4.4
What is a STRING data type?
String data types can represent:
- Characters (single letters)
- Text (a word or sentence)
Give an example of a character
A
Give an example of a text string
The brown fox jumped over the lazy dog
Give an example of a short date
01/01/2000
Give an example of a long date
1st April 2024
What is a pixel?
- The smallest unit of an image that can be edited/displayed
- Each pixel can have its own colour
- A Bitmap image is made up of pixels
- Each pixel is stored as a series of binary digits
What is resolution?
Resolution is a measure of the quality of the image.
It is measured in pixels per inch / number of pixels
How does resolution affect image quality?
More pixels = better quality = larger file size = more storage space
Fewer pixels = lower quality = smaller file size = less storage space
What is a bitmap graphic?
A bitmap image is made up of pixels
What is a vector graphic?
Stores information about the components (shapes) that make up an image
The components are mathematical objects such as lines, curves and shapes
A vector graphic can be resized without losing quality
What is file compression?
Compression removes unnecessary data from a file to make it smaller (so it takes up less storage space)
There are 2 types of compression:
- lossy compression
- lossless compression
What types of image file format are uncompressed?
.bmp files
What types of image file format are compressed?
.gif (Graphics Interchange Format) - Also allow animated images
.png (Portable Network Graphics) - Developed for use on webpages
.jpg (Joint Photographic Expert Group) - Allows different levels of compression so files can be kept better quality or reduced in size as required
What is lossy compression?
The data that is removed is lost and cannot be recovered
What is lossless compression?
The data that is removed can be recovered so the quality is maintained
What is pixelation?
When a bitmap image is enlarged so that the individual pixels become visible
What is streaming?
A process that allows sound or video to be played on a website straight away without waiting for the full video to download
What is a buffer? (In the context of audio or video streaming)
Computer memory used to store part of a video file before it is seen
What is sample rate?
The number of audio samples captured each second when recording sound digitally
Measured in Hertz (Hz)
Higher sample rate = better quality = larger file size = more storage required
What is bit depth?
The number of bits used to record each sound sample
Higher bit depth = better quality = larger file size = more storage required
What is bit rate?
The number of bits processed in a given amount of time
Usually measured in Kilobits per second (kbps)
What is an analogue signal?
A continuously varying signal that represents a physical quantity
What is digital format?
Data stored as 1’s and 0’s
What is an ADC?
Analogue to Digital Converter
Converts an analogue signal (like light, sound, temperature) into digital format for computer input
What is a DAC?
Digital to Analogue Converter
Converts a digital signal into analogue format for output from a computer
Name 3 sound file formats
.wav (Windows Audio Waveform)
.mp3 (Moving Picture Experts Group)
.wma (Windows Media Audio)
Name 4 portable text file formats
.txt (text)
.csv (Comma Separated Variable)
.rtf (Rich Text Format)
.pdf (Portable Document Format)
What is a MIDI file?
Musical Instrument Digital Interface
A file format…
…that allows musical instruments to be connected to a computer for input/output
Name 2 portable video file formats
.mp4 (Moving Picture Experts Group)
.avi (Audio Video Interleaved)
