Unit 1 Flashcards
What was the effective communication method between ships before radio communication, what was the downfall of this
Morse code, data could not be successfully stored unless written down and it was mechanically operated which is very slow
What are numbers represented in the decimal number system
Probably because we have ten fingers and basic calculations could be done using our fingers before calculators were invented
What is the decimal number system
Base 10
What Is the octal number system
Base 8
What is the binary number system
Base 2
What is the hexadecimal number system
Base 16
What is bit an abbreviation for
BInary digit
What is the smallest unit of storage
A bit
What does a bit contain give examples
One value, either a:
0 or 1
Which can represent a:
False or true
Off or on
What is a byte
A group of 8 bits
How much is one kilobyte worth
1024 bytes
How much is one megabyte worth
1024 kilobytes
How much is one gigabyte worth
1024 megabytes
How much is one terabyte worth
1024 gigabytes
How much is 1 petabyte worth
1024 terabytes
What is the order of prefixes
Kilo, mega, giga, tera, peta
What is a word size
The number of bits that a computer’s CPU can process at once. Older computers use 32 bits and newer ones 64 bits
How do we calculate the largest number a certain amount of unsigned bits can represent
2^n -1 where n is the number of bits
What is a the smaller number a certain amount of unsigned bits can represent
0
How do we represent sign and size of a number
- Convert to decimal to binary
- Add extra bits to make up to 8 bits
- Add a 1 to the first to show the number is negative OR 0 to the first to show the number is positive
How do you represent 2s compliment of a number
- Convert decimal to binary
- Add extra bits to make up 8 bits
- If positive leave answer as is, but if negative change every 1 to 0 and 0 to 1.
- Add 1 to the number
How do you calculate the largest number a certain number of signed bits can represent
2^(n-1) -1
How do you calculate the smallest number a certain number of signed can represent
-2^(n-1)
How do you calculate overflow in unsigned bits
- calculate the largest number the amount of bits can represent
- Subtract that number from the number you want to represent in overflow.
- Represent the difference as binary in those bits
How is an IPv4 address written
32-bit numeric address: 4 decimal numbers (8 bit each) separated by fullstops
How is an IPv6 address written
128 bit address: 6 hexadecimal numbers separated by colons
How do we calculate the number of combinations possible form n bits
2^n
What does MAC stand for
Media access control
What is a MAC
A media access control of a device provides a unique identifier assigned to its network interface card. It is like an ID number and is guaranteed to be unique within the network it is used. Typically it consists of six groups of two hexadecimal digits separated by hyphens, colons, or no separator.
Where is the MAC address stored
I’m firmware or a ROM on the device
How many combinations of MAC addresses are there
16^12
What is a pixel
A picture element that is the smallest programmable colour unit on a computer display.
How many buts in each pixel
8,10 or 16 bits of colour per pixel in old computers and 24 bits of colour for each pixel in modern computers
What primary colours are represented in a pixel
RGB: red green blue
What is the number of possible colours for each pixel
2^8 x 2^8 x 2^8 = 2^24 = 16.7 million colours
