1.2 Memory and Storage Keywords

Question 1

Primary Storage

Answer 1

“At GCSE level you can think of primary storage comprising of Random Access Memory (RAM) and Read Only Memory (ROM). It holds data and instructions which the CPU can much more easily and quickly access than from secondary storage devices.”

Question 2

RAM

Answer 2

• Random Access Memory
• “Volatile (data lost when power is off) Read and write.
  Purpose: temporary store of currently executing instructions and their data.
  E.g. applications and the operating system in use.”

Question 3

ROM

Answer 3

• Read Only Memory
• “Non-volatile (data retained when power is off) Read only.
  Purpose: stores instructions for starting the computer called the bootstrap.”

Question 4

Virtual Memory

Answer 4

“Using part of the hard disk as if it were random access memory.
Allows more applications to be open than physical memory could hold.”

Question 5

Secondary Storage

Answer 5

“Permanent storage of instructions and data not in use by the processor. Stores the operating system, applications and data not in use. Read/write and non-volatile.”

Question 6

Optical Storage

Answer 6

“CD/R, CD/RW, DVD/R, DVD/RW Use: music, films and archive files. Low capacity. Slow access speed. High portability. Prone to scratches. Low cost.”

Question 7

Magnetic Storage

Answer 7

“Hard disk drive. Use: operating system and applications. High capacity. Medium data access speed. Low portability (except for portable drives). Reliable but not durable. Medium cost.”

Question 8

Solid State Storage

Answer 8

“Memory cards & solid state hard drive (SSD). Use: digital cameras and smartphones. Medium capacity. High portability. Reliable and durable. No moving parts. Fast data access speed. High cost.”

Question 9

Storage Capacity

Answer 9

“The amount of data a storage device is able to store. ”

Question 10

Storage Speed

Answer 10

“The read/write access speed of a storage device.”

Question 11

Storage portability

Answer 11

“How easy it is to transport a given storage medium. E.g. Solid state and optical storage and designed to be highly portable, whereas more traditional magnetic storage is designed to stay in place.”

Question 12

Storage Durability

Answer 12

“How resistant to damage and wear a tear a storage device is. Devices with low durability will wear out easily over time.”

Question 13

Storage Reliability

Answer 13

“A relative measure of how confidant you can be that a given storage device will correctly allow you to write, read, delete and modify data.”

Question 14

Storage Cost

Answer 14

“The relative price of a storage device e.g. per Megabyte of data”

Question 15

Bit

Answer 15

“The smallest unit of storage in a computer system, represented by either a binary 1 or 0.”

Question 16

Nibble

Answer 16

“Half a byte / 4 bits.”

Question 17

Byte

Answer 17

“A collection of eight bits.”

Question 18

Kilobyte

Answer 18

“1 Kilobyte (KB) is 1024 Bytes. For the purpose of calculations in an exam you can assume 1000.”

Question 19

Megabyte

Answer 19

“1 Megabyte (MB) is 1024 Kilobytes (KB). For the purpose of calculations in an exam you can assume 1000.”

Question 20

Gigabyte

Answer 20

“1 Gigabyte (GB) is 1024 Megabytes (MB). For the purpose of calculations in an exam you can assume 1000.”

Question 21

Terabyte

Answer 21

“1 Terabyte (TB) is 1024 Gigabytes (GB). For the purpose of calculations in an exam you can assume 1000.”

Question 22

Petabyte

Answer 22

“1 Petabyte (PB) is 1024 Terabytes (TB). For the purpose of calculations in an exam you can assume 1000.”

Question 23

Denary Numbers

Answer 23

“A numerical system of notation which uses 10 as its base. The 10 Decimal base digits are 0-9.”

Question 24

Binary Numbers

Answer 24

“Binary describes a numbering scheme in which there are only two possible values for each digit: 0 and 1. The term in computing refers to any digital encoding system in which there are exactly two possible states. E.g. in memory, storage, processing and communications, the 0 and 1 values are sometimes called “low” and “high”, respectively.”

Question 25

Binary Arithmetic

Answer 25

“The process of adding together two of more positive 8-bit binary numbers (0-255).”

Question 26

Overflow

Answer 26

“The generation of a number that is too large to be represented in the device meant to store it.”

Question 27

Hexadecimal

Answer 27

“A numerical system of notation which uses 16 rather than 10 as its base. The 16 Hex base digits are 0-9 and the letters A-F.”

Question 28

Binary Shifts

Answer 28

“Allows you to easily multiple and divide base-2 binary numbers. A left shift multiplies by 2 and a right shift divides by 2.

Question 29

Character Set

Answer 29

“The set of symbols that may be represented in a computer at a particular time. These symbols, called characters, can be letters, digits, spaces or punctuations marks, the set includes control characters.”

Question 30

ASCII

Answer 30

“America Standard Code for Information Interchange: “A character set devised for early telecommunication systems but proved to be ideal for computer systems. ASCII codes use 7-bits giving 32 control codes and 96 displayable characters (the 8th bit is often used for error checking).”

Question 31

Unicode

Answer 31

“Standard character set that replaces the need for all the different character sets. It incorporates characters from almost all the world’s languages. It is a 16-bit extension of ASCII.”

Question 32

Pixels

Answer 32

“A pixel is the smallest unit of a digital image or graphic that can be displayed and represented on a digital display device. A pixel is represented by a dot or square on a computer monitor display screen.”

Question 33

Metadata

Answer 33

“A set of data that describes and gives information about other data.”

Question 34

Colour Depth

Answer 34

“Also known as bit depth, is either the number of bits used to indicate the colour of a single pixel, in a bitmapped image or video frame buffer, or the number of bits used for each colour component of a single pixel.”

Question 35

Resolution

Answer 35

“The number of pixels (individual points of colour) contained on a display monitor, expressed in terms of the number of pixels on the horizontal axis and the number on the vertical axis.”

Question 36

Image Quality

Answer 36

“The overall detail of an image, this is affected by the colour depth and resolution.”

Question 37

Image File Size

Answer 37

“The file size of an image is increased when either its resolution (width & height in pixels) or its colour depth (number of bits needed to store a single pixel) increases.”

File size of an image = colour depth x image height (px) x image width (px)

Question 38

Sample Rate

Answer 38

“The number of samples taken per second, measured in Hertz (Hz).”

Question 39

Sample duration

Answer 39

“How many seconds of audio the sound file contains.”

Question 40

Sample bit depth

Answer 40

“The number of bits available to store each sample e.g. 16-bit”

Question 41

Playback Quality

Answer 41

“The number of bits available to store each sample e.g. 16-bit”

Question 42

Sound File Size

Answer 42

“The overall size of a sound file is found by the following formula:

Sample rate x duration (s) x bit depth”

Question 43

Compression

Answer 43

“The process of reducing the size of a file in terms of its storage size.”

Question 44

Lossy compression

Answer 44

“A compression scheme where their generally involves a loss of resolution in parts of the image where experiences shows that it will be least noticed.”

Question 45

Lossless Compression

Answer 45

“A compression scheme that allows the original images to be recreated.”