# A.1.2. Notes and resources

:::info
This is a note for notes of the IB Syllabus starting M27. If you want to see more, you should check the note of the teaching material index here:

https://hackmd.io/@dprieto/David-Index#Computer-Science-New-syllabus-first-examination-2027
:::

:::warning
This is not ordered whatsoever yet
:::

## A1.2.1 Binary-hexadecimal

### Bits

{%youtube USCBCmwMCDA %}
https://www.youtube.com/watch?v=USCBCmwMCDA

Shifting bits tool:

{%preview https://www.advanced-ict.info/interactive/binary.html %}

### Hexadecimal

{%preview https://www.advanced-ict.info/interactive/hexadecimal.html %}

### Binary-decimal-hexadecimal conversion references

{%youtube 8T4F7WboWPQ %}

{%youtube pg-HEGBpCQk %}

https://www.wikihow.com/Convert-from-Decimal-to-Binary

https://www.cuemath.com/numbers/decimal-to-binary/

### Exam questions

#### Pass from a to be type

##### State the the binary equivalent to the hexadecimal number 5B

5 -> 0101 B -> 1011 so 01011011

#### Trick questions: Registers

Registers (see 1.1) have a specific size. So we need to stay into that register. If it's bigger, we write 0s

##### State the the binary equivalent to the hexadecimal number 5B in a 7 bit register

1011011

#### State the binary equivalent to the hexadecimal number 5B in an 16 bit register

00000000 01011011
(first byte and second byte)

### Tell how many elements can we have given a certain size of register (or element in binary)

#### Tell how many possible colours can we have using 3 Bytes.

(This is actually the RGB colours)

$2^{24} = 2^{8^3}$

We can consider that we have 8·3 = 24 bits so that is $2^{24}$ possibilities. So the possible colours that we can have is $2^{24}$

#### How many numbers can we have unsigned in a int

## A1.2.2 How binary is used to store data

### Numbers


### Characters (and Strings)



https://www.utf8-chartable.de/unicode-utf8-table.pl

### Images


This is the main thing but I also mentioned the difference between raster and vector and also we mentioned YMCK and RGB.

### Audio


https://www.youtube.com/watch?v=nTo4mwd_aKg

Phone calls, that have a worse quality they have a sampling of 8 KHz https://dsp.stackexchange.com/questions/22107/why-is-telephone-audio-sampled-at-8-khz

### Video

https://www.youtube.com/watch?v=J9RemuYxA4s


## Exam like questions

1) Outline what is meant by sampling while representing audio using binary. [2]
2) Outline what is meant by quantization while representing audio using binary. [2]
3) Explain how colours can be represented using binary [4]
4) Explain how sounds can be represented using binary [6]
5) Explain how video can be represented using binary [6]