Programming Lesson One Notes

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	Hardware
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hardware - all physical devices of a computer.
component - one of these devices

- The Central Processing Unit (CPU)
	CPU
- Main Memory (RAM = Random Access Memory)
	Short term memory
- Secondary Storage (Hard Disk/Solid State Drive)
	Long term memory
- Input Devices:
	mouse, keyboard, microphone, touchpad, touchscreen
- Output Devices:
	monitor, printer, fax machine, game controller vibrates

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	Software
============================

Software is the nonphysical parts of a computer. Another word for software is computer programs.

System Software
---------------
-Operating Systems:
	The most fundemental program that runs all other hardware and software.
-Utility Programs:
	Specialized task programs. (antivirus programs, cleaner programs, compression programs, data backup programs)
-Software Development Tools:
	Programs to make and modify other programs. IDE - Integrated Development Enviornment

Application Software
--------------------
Programs that make computers useful to humans.
(microsoft word, excel, OBS, google chrome, team fortress 2)

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Data Storage - How a computer stores information
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1s and 0s
on and off switches
ups or downs

1 switch = 1 bit
8 bits = 1 byte
nanosized mb, kb, gb, tb

1 byte is enough information to store one number or character(symbol)


00000001 = 1
00000010 = 2
00000011 = 3

How numbers are stored:
1st bit = 2^7 = 128
2nd bit = 2^6 = 64
3rd bit = 2^5 = 32
4th bit = 2^4 = 16
5th bit = 2^3 = 8
6th bit = 2^2 = 4
7th bit = 2^1 = 2
8th bit = 2^0 = 1

00000101 = 5
00100001 = 33

How letters/symbols are stored:
ASCII - American Standard Code for Information Interchange
00100001 = 33 = !
01000100 = 34 = "

ASCII has only 128 characters. There are extended sets like Unicode with several thousand.

Special number cases
What if I want a number that is bigger than 1 + 2 + 4 + 8 + 16 + 32 + 64 + 128 (255)
Then, you add another byte

The order of the bytes varies.
There is little endian (the smallest values come first),
and big endian (the largest come first).

For little endian:


first byte
1st bit = 2^7 = 128
2nd bit = 2^6 = 64
3rd bit = 2^5 = 32
4th bit = 2^4 = 16
5th bit = 2^3 = 8
6th bit = 2^2 = 4
7th bit = 2^1 = 2
8th bit = 2^0 = 1

second byte
9th bit = 2^17 = 131072
10th bit = 2^16 = 65536
11th bit = 2^15 = 32768
12th bit = 2^14 = 16384
13th bit = 2^13 = 8192
14th bit = 2^12 = 4096'
15th bit = 2^11 = 2048
16th bit = 2^10 = 1024
17th bit = 2^9 = 512
18th bit = 2^8 = 256

This gives 262,143 possibilities! Characters that use two bytes are called DBCS or the Double Byte Character Set
But this isn't enough, even during the early days of computing
So, people invented triple byte numbers, which go even higher. Then there are quadruple, and even pentuple byte numbers!


Another special case:
What if I want to store decimals?
floating point notation - numbers that use this are called floats

What if I want to store negative numbers?
Two's Compliment Notation - Usually done automatically

What if I want to store an image in memory?
different formats:
png, jpeg, dds, vtf, etc etc
convert pixel information into bytes
1 unit of info = 1 pixel

What if I want to store sound data in memory?
frequency and pitch are stored in binary.
1 unit of a sound file = 1 sample


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The Fetch Decode Execute Cycle
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BEFORE fde, info about proccesses is moved to RAM, or main memory.

Fetch - The CPU fetches the information it needs from the ram.
Decode - The CPU decodes what the information means.
Execute - The CPU sends out commands to other components to execute the data.


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Programming Languages
=====================

- SINCE Machine Language is impossible to read by human standards, programming languages were developed.

- The first programming languages were known as Assembly Languages. Assembly languages are made up of
nmenoics, small words short for commonly used commands

- Assembly languages are converted into Machine Language in a process known as Assembling.

- Eventually, Languages evolved and became Higher-Level Languages, which are used today and covered in these videos.

- These languages include:
	Python
	BASIC
	Visiual Basic
	C
	C#
	C++
	Java
	Ruby
	JavaScript

- Higher leveled languages all have Key Words/Reserved Words
		-Key Words: words that are reserved for a certain function, and cannot be used for ANYTHING else.

- Higher leveled languages all have operators
		-Examples in Python
		+ (addition)
		- (subtraction)
		/ (division)
		* (multiplication)
		% (modulus/remainder of division)

		ALSO INCLUDE:
		++, --, -=, +=, *=, /=, %=, etc