Ict Flashcards
Data
Data is raw facts and figures with no context or meaning
E.g. 12
Information
Information is data which has been processed or given meaning
E.g. the boy is 7 years old
Data types
Charcter/text/string
Boolean eg yes/no l/0 true/false
Integer-can be positive or negative whole numbers
Real numbers/float. E.g. 1.34
Date/time e.g. 03/09/24
30khz
30000 hertz
Vectors
Logos
Lines, curves and shapes
Mathematical objects
Edit individual objects
Are stored as coordinates of shapes
Bitmaps
Photograph
High quality
Made up of a grid of pixels
Stored using binary
Meta data is used for individual information E.g colour
Colour depth
The number of bits per pixel
The more colours required the more pixels needed
3 bits=2x2x2=8
File size
The size of the grid (width and depth)
E.g. an image which is 1000x800 with a 16 bit colour depth
(1000x800)x16= 12,800,000 bits
Written as 12MB
Data storage in order
Bit
Nibble (4 bits)
Byte (8 bits)
Kilobyte (1024 bytes)
Megabyte (1024 KB)
Gigabyte (1024 MB)
Terabyte (1024 GB)
Pixelation
Pixelation is when you enlarge or zoom into a bitmap image
(Pixels are getting larger and appearing like a number of small blocks pit together)
Low resolution images
Grainy course dots and grainy appearance with jagged diagonal lines and curves
High resolution images
Many small dots closer together and produce clearer images
Streaming a video
Allows video to be viewed on a website or app straight away without waiting for the full video to be downloaded
(Allows video to be streamed in real-time)
Buffer
Allocated part of memory used to store downloaded part of video before watched
Used to download the next part when user is watching a video
Helps to prevent disruptions in streaming a video before played
Advantages of buffering
Video unlikely to be replicated as the user doesn’t save a full copy
User doesn’t have to wait for entire file to download to their computer
Users computer doesn’t need to be capable of storing the entire file
Sound
Sample rate
Bit depth
Bit rate
Sample rate
Number of audio sound samples captured every second to represent the sound digitally
Measured in Hertz
More samples taken per second, the more accurate the digital representation of the original sound
Bit depth
Number of bits used to store each sound sample
Higher quality sound requires a higher bit depth
Bit depth CD
16 bits has a resolution of 65536 possible values
Bit rate
Quantity of data measured in bits that is processed in a given amount of time
Kilobytes per seconds
Analogue
Continuous varying signal that represents a physical quantity such as sound
ADC
Analogue to digital conversion
Digital
Represented in binary format
Digital to analogue conversion
- Sound is recorded on a microphone in analogue format
2.converted into digital format before before stored into the computer
3.analogue to digital converter is required to do this
4.if needed to play back again
Analogue to digital converter
Sample a sound wave at regular time intervals
If number of samples per second is low will have loss of audio quality because samples don’t show what the sound wave is doing in-between each sound sample
Ensure original sound is maintained, sampling per second should be increased
Data compression definition
Reducing the storage requirements of a file by following one or more compression algorithms
Lossless compression definition
Makes its original file to be fully restored to its original state
Lossy compression definition
Discarding some of the data for the compression process so data can’t be reinstated
Compression used to reduce volume
Volume of storage required on devices, making larger quantities of data to fit into the same amount of storage space
Compression used to reduce bandwidth
Bandwidth required to transfer multimedia files across communication links (locally, nationally and globally)
Without compression volume
Very high volumes of storage required, occupying more space and slow down intervals/save times
Without compression bandwidth
Available bandwidth most local and global networks wouldn’t cope with volumes of data being sent and disrupting communication services (lagging and video streaming)
Benefits of compression
Will have a price
System software
Interface between computer hardware and user application programs
Enables the computer to operate its hardware and application software
Application software
Enables the computer to do a particular task (word processing)
Types of software
Operating system
Utility programs
Utility programs
Disc defragmentation
Task scheduling
Data backup and restore
Antivirus
Operating system
Manages all other programs being used on the computer (ms windows)
Operating system what it does
Manages memory given to programs and files being processed
Locates free memory space in RAM and allocate this to the program or file data
Allocates processing time to the programs using techniques like time slicing
Manage the storage of data on external storage devices (backups)
Real time processing
Data processed immediately after its input
Output generated is processed quickly which influences the next input received
Real time processing examples
Airline/concert booking, online stock control systems, air traffic control systems
Advantages of real time processing
System can cope with a of changes or processes in a short period of time
Safe running of systems (air traffic control)
Disadvantages real time processing
Limit to the number of users or tasks who can access the system so some users must wait
Batch processing definition
Collecting groups of batches of similar data over a period of time and inputting data at an agreed time
Processed without human
What is batch processing used for
Large volumes of data E.g. payroll, billing systems and banking
Utility software definition
A program which carries out a specific task to assist the operating system
Batch processing advantages
Processor can be used to execute multiple programs with the appearance of simultaneous usage
File fragmentation
A single file may be broken up and stored in different parts of the disc
Disc defragmentation
Before a file is stored on a disc is broken down into a number of data blocks by the operating system
Each block is stored in a free block of space on the disc
Not always possible to locate enough adjacent free block spaces for the blocks to be stored together
Purpose of disc defragmentation
rearranges the data on the disc so that
Files are stored in blocks that are all together
All the free blocks are together in the same part of the disc
Speeds up the time needed to access files
Task scheduling
Method which the processor time is divided amongst a number of tasks
Make maximum use of the processor time making system more efficient
Task scheduling steps
Multi user system robinhood method
Processed deals with a task from the first computer then moves it to the next sequence
When it reaches the last computer it automatically starts over again with the first computer
Attempts to process as many tasks as possible in a given time frame
Data backup definition
A copy of the original data or file incase it gets damaged or lost
Backup
Businesses should have more than one copy
Hard disc fails
Virus destroyed the data stored
User accidentally deletes a file
Fire destroys the building where files are stored
Backups where should be stored
Secure location
Used to restore the original data to its previous state by uploading the latest backup file into the system
Examples of backups where should be stored
If I was to store data/backup put it out of site
Virus
Program attach itself to a file once opened, it can spread itself to other files and computers linked to the internet
Anti virus
Scan files stored on the computer and data entering the computer system and compare to known database of viruses
It’s important to for antivirus
To update so the antivirus software can detect all know viruses or been created
