Summary Grade 11 Information Technology (IT) Theory Notes | Full Year

11/7/22, 2:52 PM IT THEORY NOTES - FULL YEAR




IT THEORY NOTES - FULL YEAR
UNIT 1: DATA REPRESENTATION AND BOOLEAN LOGIC


Word Size: the number of bits a CPU can process at once


Buses: Either built with 32 bit (4 bytes) or 64bit (8 bytes)


Binary
0 represents off
1 represents on
usually grouped together in multiples of 8 in registers of buses


Eg) 2 x 2 x 2 = 2^3 = 8


Binary addition
0 0 1
+ 0 + 1 + 0
-----------------------
= 0 1 1




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,11/7/22, 2:52 PM IT THEORY NOTES - FULL YEAR




NOTE: if you see something where it is 1 + 1 + 1, it is equal to 1.


Unsigned bits:
smallest number - 0
largest number - 2^n-1

In positive numbers, we ad 0's to the front of the binary to complete the multiple of 8
Eg) 9 = 10012
therefore, 9 = 000010012

In negative numbers, we use the first most left binary value to indicate negative
Eg) 9 = 10012
= 000010012
therefore, = 100010012 = -9

Two's complement
Represent -47 in 8 bits with two's complement
you need:




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, 11/7/22, 2:52 PM IT THEORY NOTES - FULL YEAR




the number itself
number of bits
representation code (sign and size or two's complement)

-47 = -101111
= - 00101111 (multiple of 8)
= -00101111
= 11010000 (drop the minus and swap the 0s and 1s, this is ones complement)


11010000
+ 1
= 11010001 (two's complement)




Replacing binary with hexadecimal




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