Data Representation and Types Flashcards
Absolute Value
also known as the magnitude, can be found by taking a negative binary number and switching all the 1s to 0s and all the 0s to 1s
ASCII
American Standard Code for Information Interchange
the type of code that tells your keys what is being typed, offering 128 characters, with one bit per character
Extended ASCII
the same as standard ASCII, but with 96 additional characters
Standard ASCII
contains 128 characters, only large enough for Americans, not English people
Analogue
contains infinite states
Analytical Engine
a computer designed by Charles Babbage and Ada Lovelace to compose music that never got made because Lovelace developed a gambling addiction
Backward Compatibility
the phenomenon under which the first 128 characters of ASCII and Unicode use the same codes
BITs
Binary Digits
either a 1 or a 0
Nybble
4 bits
B
Byte
8 bits
KB
Kilobyte
1024 bytes
MB
Megabyte
1024KB
GB
Gigabyte
1024MB
TB
Terabyte
1024GB
PB
Petabyte
1024TB
EB
Exabyte
1024PB
ZB
Zettabyte
1024EB
YB
Yottabyte
1024ZB
Bucket
used to store more than one piece of data across a hash table
Character Set
all the characters recognised by the computer
Collisions
occur when the hash function generates the same index for more than one key. In this case, both entries are stored in the same bucket
Data Structure
holds multiple values, e.g. array
Difference Engine
an early calculator designed by Charles Babbage in the 1820s
Digital
involves two states
Graphics
the use of computers linked to display screens to generate and manipulate visual images
Bitmap Graphics
a type of raster image and is composed of many tiny parts, called pixels, which are often many different colours. It is possible to edit each individual pixel
Raster Graphics
dot matrix data structures representing a grid of pixels and cannot scale up without loss of apparent quality. They tend to be large in terms of the memory required to store them
Vector Graphics
allow the graphic to resize without losing quality, unlike the other two. This is because they use geometrically primitive objects such as points, lines, curves and shapes or polygons which are based on mathematical expression to represent images
Hash Function
distributes entries across a group of buckets
Hash Table
dynamic data structure that maps keys to index values in an array
Least Significant Bit
the bit right at the end of the binary number, that has the least effect
Linked List
dynamic data structure where data is not necessarily stored in order or in contiguous memory locations, a multi-dimensional list where each entry has a link to the next
Load Factor
the ratio of a number of entries in the table divided by the total number of buckets. As the load factor increases, access rates slow. Ideally, the load factor should always be less than one
Logarithms
a quantity representing the power to which a fixed number (the base) must be raised to produce a given number
Magnitude
also known as the absolute value, can be found by taking a negative binary number and switching all the 1s to 0s and all the 0s to 1s
Most Significant Bit
the bit right at the beginning of the binary number, that has the most effect, because it shows whether a number is positive or negative
Non-Principle Characters
characters such as umlauts
Pixels
picture elements
small coloured dots that make up graphics
Primitive Data Type
holds only one value, eg and integer
Principle Characters
important characters such as letters and numbers
Separating Chaining
this overcomes the data collision issue where the same location is generated for more than one piece of data. The original table is used to store a dynamic data structure like a linked list.
Signed
where is is said whether or not a number is positive or negative by the most significant bit, with 1 as negative and 0 as positive
Signedness
whether it is said whether a number is positive or negative by the most significant bit, with 1 as negative and 0 as positive
Two’s Complement
the law that states that the most significant bit should show whether a number is positive or negative, with 1 as negative and 0 as positive
Unicode
similar to ASCII, but has 65536 characters, so is big enough to deal with languages such as Chinese, Japanese and Thai
Unsigned
where it is not said whether a number is positive or negative, meaning it is most likely positive
Word
amount of data processed in one CPU cycle
