Storage of data Flashcards
What is MIDI?
Musical Instrument Digital Interface is a communication protocol that allows electronic musical instruments to interact with each other.
What is MPEG-3?
It is a software that uses audio compression algorithms to convert music into MP3 file format.
How are file sizes reduced by up to 90%?
Through use of Perceptual Music Shaping, which removes sounds that the human ear cannot perceive.
What is MPEG-4?
File format that permits storage of multimedia, more than just music.
What is JPEG?
Format for compressing image files.
How is text compressed?
It is stored in an ASCII format.
What is lossy compression?
Type of file compression in which the compression algorithm eliminates the bits of data that are unnecessary. It is not possible to get the original file back.
What is lossless compression?
Type of file compression in which no bits of data are eliminated, and all data from the original file is reconstructed after the file is uncompressed.
What are some examples of lossy compression?
MP3, MP4, JPEG
What are some examples of lossless compression?
Compression of text and number files (ASCII format), ZIP file format
What is primary storage/memory?
Primary storage is the location where data is stored for immediate access by the computer’s processor, generally in the RAM.
What is secondary storage/memory?
It is the location where data is stored for long term use, and it stores data until it is deleted or overwritten.
What is offline storage/memory?
Storage medium that cannot be accessed by the computer once removed.
What is RAM and what are its features?
Random Access Memory is the primary storage for a computer.
- it is volatile/temporary memory - when the power is turned off, its contents are lost
- the contents of the memory can be changes, written to and read from
What is ROM and what are its features?
Read Only Memory is another form of primary storage for a computer.
- it is non-volatile/permanent memory - the contents are retained even if the power is switched off
- its contents cannot be changed, only read
What are the applications of ROM and RAM?
ROM:
- stores start up routines
- stores company settings
- stores library routines
RAM:
- stores data that is being executed by the processor currently
- sub-routines/library routines
- other data received by the control unit
How can the size of a file be estimated?
Each character of text occupies 1 byte of memory. Each pixel occupies around 3 bytes of memory.
What are HDDs?
HDDs are forms of secondary storage in a computer.
How do HDDs work?
Data is stored on the magnetic platters.
Each platter has 2 sides.
Each platter is divided into a billions of sections, each one representing either a 1 or a 0.
There are two read-write heads for each platter - one to read the top one and other to read the bottom one.
How do SSDs work?
Data is stored by controlling the movement of electrons within NAND chips.
0s and 1s are stored in the millions of transistors in the chip.
This produces a non-volatile, rewritable memory.
What are the advantages of SSDs over HDDs? What are its drawbacks?
- more reliable
- lighter
- lower power consumption
- cooler than HDD
- faster
Durability of SDD is an issue.
How do CD/DVDs work?
Laser light is used for reading and writing data on the surface of the disk.
Light sensitive organic dye or a thin layer of metal alloy is used for storing data.
Red laser is used for reading the data.
DVDs make use of dual-layering technology, which increases storage capacity.
How do DVD-RAMs work?
Concentric layers of tracks are used, which allows for faster operation since several read-write operations can be performed simultaneously.
How do Blu-Rays work?
Have a single light sensitive layer that stores information. Blue laser reads the data.
