Computer science
Change the binary number 00110011 to denary
(128×0)+(64×0)+(32×1)+(16×1)+(8×0)+(40)+(2×1)+(1×1) 0+0+32+16+0+0+2+1 =51
Change the hexadecimal number 40AA into binary
0100/0000/1010/1010 =0100000010101010
What should you consider when transmitting data?
1. Direction of data transmission 2. Method of data transmission 3. Method of synchronisation
State the type of data transmission and the direction
1. Simple data transmission--one direction only 2. Half duplex--both directions but not at the same time 3. Full duplex--both directions and at the same time
Change the binary number 0111010011100 into hexadecimal
0000/1110/1001/1100 0 E 9 C =0E9C
What happens when a device is plugged into a computer?
°Computer detects that device is present °Device is automatically recognized and appropriate device driver is loaded
What are the uses of hexadecimal
°Memory dumps or tracing errors in a program °Hyper text mark up language(HTML) °Media access control(MAC) °Web addresses °Assembling code and machine code
Name some advantages of hexadecimal
°Shorter and easier to recognize °Less errors when typing °Easier to recognize or remember or to read and write
Change the denary number 127 into binary
128 64 32 16 8 4 2 1 0. 1. 1. 1. 1. 1. 1. 1 =01111111
How many bits does a nibble consist of?
4
How many bits does a byte consist of?
8
What is MAC
A number which uniquely identifies a device on the internet. It refers to the network interphase card(NIC). MAC is usually made of 48 bits, which are shown as 6 hexadecimal digits. First half of the digits identify the manufacturer of the device and the second part identify serial number of device
Serial data transmission+ advantages+disadvantages
Data is sent down a single wire one but at a time, works well over long distances 1. Works well over long distance 2. Saves on cost since single wire is used 3. No problem of skewing Used for USB connections 1. Data is transmitted at a slower rate since only one Chanel is used
Web addresses
Each website is assigned a unique series of characters known as an URL (uniform resource locator). Components are protocol, domain name, & the page name.
What does a Universal serial bus use?
It uses serial data transmission
Parallel data transmission+advantages and disadvantages
Several bits of data are sent down several wires at the same time and each wire is used to transmit 1 bit 1. Works well over short distance, if sued over long distance bits become skewed 2. Fast method of transmission Can be used for external connection within the computer 1. Expensive cause so many wires required
How do you change hexadecimal to denary/decimal
Take each hexadecimal digit and multiply it by its place value, add the totals together to get the denary value
How do you change denary/decimal to hexadecimal
Using powers of 16 find the largest number on the numberline which can get into the given number. Find out how many times the number from the numberline gets into the given number. Put answer on the appropriate column on the numberline and find the remainder
What are memory dumps?
When memory contents are output to a computer or monitor
What is HTML
When writing and developing work pages, often used to represent colours of text on computer screen. Values change to represent different colours
