All about computers!


What makes a computer computer?

All computers share the same four things:input,storage,prossesing and output.

Input is what you do with the computer,storage is like memory,prossesing is taking-
info and aplying algorithoms to help the computer understand the info,
output is what happens!


As again...

1.Input:key bords, touchscreens
2.Storage:files
3.procssing:CPU
4.Output:screen,robots,sound


There are many electrical bits, a few of those bits make a circut,NOT CIRCUT:a not circut gives you the opossit,
a and circut gives you a 0 at least one of the two"inputs"is a 0,it wil only give you a
1 if both of the "inputs"are 1's!


AN 8 BIT ADDER:A 8 bit adder has 16 inputs!It can do up to an eqation wich equals 11111111,or255!
back in the day,8 bit adders were the size of a room!.smaller computers and circuts are faster cause the electricity has less way to travel



CSS

CSS stands for cascading style sheets,CSS saves you a lot of work.
An internal style sheet you place in the head sectoion,it allters the whole page,
Inline style only aplys to your line,External styling is to your whole webpage!


OPERATING SYSTOM(OS)+hardware and soft ware

Hard ware is phisical stuff like circuts,wires and other stuff,soft ware is stuff you dont see or touch
The CPU controls the hard ware and soft ware, the CPU has many small circuts in it
but the magic how it knows when to use the programs.
OS..........is the master program that manages how the soft ware uses the hard ware of a computer
OS examples are windows,android,ios,linux.the OP lets you install programs,
and dicides if a program can interact with the CPU, and acsses the input and output sistom.
IN EVEREY COMPUTER THERE IS AN OS

yay for........................................................................COMPUTERS!!!!!!


IP ADRESSES AND DNS


Ip stands for Internet proticall so an IP adress stands for Internet Proticall adress.
An IP adress has numbers insted of letters,the numbers are represented in bits,
with 32 bits and 8 per part(8 p.p.),its like this,country/network,region/more network,subnetwork,and divice
Thats IPV 4,but it only provides network for 4 billion divices,we are now in the middle of transfering......
......to IPV 6,with 128 bits 16 bits per part,it can provide sirvice for 340 undicilion divices,thats more than enough...
for every grain of sand on earth to have its own divice!DNS stands for Domain Name Systom, and turns every thing into numbers

J.S.


External scripts are practical when the same code is used in many different web pages. JavaScript files have the file extension .js. To use an external script, put the name of the script file in the src (source) attribute of a script tag


Packets routers and reliability

Info travels in things called packets,images and things are sent in many packets
routers controll the flow of packets and moniter conjunctions.its fault tolerent and reliable
TCP(trnsmission controll protocall) tells you if all your data has come,TCP and routers are scale-able.


High level language V.S. Low level language


H level


Is easy for programers to understand


Contains engish words

L level


The computers own language


binary numbers in ones and zeros


Compiled V.S. Scripted
code with these langauges are converted to
binary or machine language beforebthey can be run
code is written in these languages that are not compiled first.
code is interpreted and exicuted in therun time enviroment

java script works together with HTML/CSS to create web applications.

HTML provides the content
CSS provides the presentation
Java script programs the beheivior

UI = user interface
UX = user experiance

java script is a client side program that runs inside
the browser of your client, and for security purpuses JS:

cannot read files from the clients machine can only connect to another server cannot close window that does not open

Let and Var control variables

DOM = Document object model
HTML parser
CSS parser
JS engine

An array is a variable that can hold Two+ variables at a time

Came case

example

Camel Non camel
myVeryLongName myverylongname

true or false operators are using things with boolian conditions

HTML ASCII

A FOR loop runs through a statement a sertain number of times ... Needs a counter

The first statement in a For loop is executed once before the execution of the block o' code

The second statement is executed onetime before the execution of the code block

The third statement is execuded everywhere after the code block has been executed.

MORE STUFF ON FOR LOOPS, ABOUT THE STATEMENTS 1-3

Normally you will use statement 1 to initialize the variable used in the loop (i = 0).
This is not always the case, JavaScript doesn't care. Statement 1 is optional.
You can initiate many values in statement 1 (separated by comma)


Often statement 2 is used to evaluate the condition of the initial variable.
This is not always the case, JavaScript doesn't care. Statement 2 is also optional.
If statement 2 returns true, the loop will start over again, if it returns false, the loop will end.


Often statement 3 increments the value of the initial variable.
This is not always the case, JavaScript doesn't care, and statement 3 is optional.
Statement 3 can do anything like negative increment (i--), positive increment (i = i + 15), or anything else.
Statement 3 can also be omitted (like when you increment your values inside the loop):


DATA TYPES

STRING:is a line of charicters

NULL:is for unknown values

UNDEFINED:is where the computer doesent know what what type it is

OBJECT:is for more complex stuff

SYMBOL:is for unique identifiers

OBJECT

An object has properties and functions

classes are blueprints for objects

Database Notes