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Chapter 2 - Coggle Diagram
Chapter 2
2.4 File management
Computers store data for a number of reasons.
is loaded into memory, RAM, that the computer is currently using in its applications
contains the instructions that a computer uses to function and run applications
storage allows users to keep information that they would like to access on the computer (be it
short-term or long-term).
WINDOWS REGISTRY (HIERARCHICAL DATABASE)
Registry is a hierarchical database that stores low-level settings for the operating system and for
applications.
file type has its own unique data structure
that records all the information in a format only the software can understand.
Registry is used to store much of the information and settings for software programs,
hardware devices, user preferences, operating system configurations, and much more.
Databases are
structured to facilitate the storage, retrieval, modification, and deletion of data
FILES
A document stored on your
computer is an example of a file.
The operating
system can save data on all of the available storage devices called drives
COMPUTER FILE MANAGEMENT
Files are stored on a computing device in folders or directories
. These folders are
used to help organize the computer’s files so that they can be easy to search and
locate.
FILE SPECIFICATIONS
A file is saved in is recorded in the file path for that file.
file path tells you on which storage device the file is saved
Each file has a unique file path that starts with the storage device’s drive letter
(C: or D: drive)
HIERARCHICAL STRUCTURE: REASONS FOR A FILE STRUCTURE
A Windows operating system organises its drives, folders, and files in a
hierarchical tree structure
Files are stored on a drive within directories; also
known as folders in Microsoft Windows
REASONS FOR HAVING A FILE STRUCTURE
guarantees high levels of productivity
helps user to organise data
increases efficiency when retrieving files and data
helps user to easily identify files
ensures that related data are organised and grouped together.
2.1 The link between data, information and knowledge
DATA REPRESENTATION
Data representation refers to the form in which data is stored, processed and
transmitted
. Digital devices store data using the binary number system
BITS AND BYTES
8 bits together form 1 byte
byte can represent any number between 0 (represented in bits
as 00000000) and 255 (represented in bits as 11111111).
Bytes tell the computer
specific colour every pixel on the screen should be for every frame
order in which to show the frames
frequency and the time each different sound is played.
Bits and bytes also store information about the types of data stored
2.2 Number systems
DECIMAL NUMBERING SYSTEM (BASE 10
The prefix
‘deci’ means 10
there are 10 numbers in the decimal system:
0, 1, 2, 3, 4,
5, 6, 7, 8 and 9.
In the decimal system, each time the value of a number increases by 1
CONVERTING FROM BINARY TO DECIMAL
In the decimal numbering system, each digit can hold ten unique values
each new digit has a place value that is ten times as large as the previous digit.
Each digit can only hold
two unique values,
CONVERTING FROM DECIMAL TO BINARY
Step 1
: Find the largest power of 2 that is smaller than or equal to the decimal number.
Step 4:
Rewrite the decimal number in terms of the division and its remainder.
Step 5
: Repeat this process with the remainder until there is no remainder left.
Step 3
: Write down the answer of the division (1) underneath the power.
Step 6
: Write down 0 under all the powers that were not used.
Step 2
: Divide the decimal number by this power
HEXADECIMAL NUMBERING SYSTEM
suffIx -decimal means ten while the prefiix hexa- means 6 (as in hexagon)
hexadecimal numbering system thus has 16 unique numbers.
Hexadecimal system uses the first six letters of the alphabet in its numbering system, with
A equal to 10
B equal to 11
C equal to 12
D equal to 13
E equal to 14
F equal to 15
CONVERTING FROM DECIMAL TO HEXADECIMAL
Step 3: Write down the answer of the division underneath the power
Step 6: Write down 0 under all the powers that were not used.
Step 1: Find the largest power of 16 that is smaller than or equal to the decimal
number
Step 4: Rewrite the decimal number in terms of the division and its remainder.
Step 2: Divide the decimal number by this power
Step 5: Repeat this process with the remainder until there is no remainder left.
BINARY NUMBERING SYSTEM (BASE 2
prefix bi- means two (as in bicycle)
There are only two unique values: 0 and 1.
2.3 Digital character and primitive data type
PRIMITIVE DATA TYPES AND THEIR STORAGE
The primitive data types used when programming
Boolean
DESCRIPTION
data type that can only be
TRUE or FALSE
REPRESENTATION
Integer
REPRESENTATION
Float
REPRESENTATION
Char