GRADE 2 SESSION 3

Grade 2 Session 3
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Windows Memory Management
-------------------------
Memory - Storage : where we can store anything, any kind of data
			Data - It can be anything - Text, Document, Pic, Music, Video
Management - Allocating memory -  Which process will comsume what amount of memory, at what time what sort of memory will be used.

Memory Management - How to allocate the memory to the process, how to allocate memory to the application. How to store the data in the hard disk drive.

How to optimize your hard disk?
-------------------------------
	temp ---> delete
	Background processes
	disk cleanup --> Defragmentation
	%temp%
	prefetch --> boot temporary files

When i start my OS, what are the things which runs in the sequence
	BIOS --> Basic Input/Output System
	GRUB
	Windows Fetch
	OS Loader

There are two types of memory
=============================
1. Primary Memory
2. Secondary Memory

1. Primary Memory
=================
	In which data wipes out, when ever you start the OS. It is also known as temporary memory.
	Ex ---> RAM --> Random Access Memory

2. Secondary Memory
===================
	In which we can permanently store the data, When ever we store data in this type of memory, it will remain there, until the user deletes it manually.
	Ex --> Hard Disk Drive, Pen drive, CD, DVD

CD  --> compact Disk --> 712 MB
DVD --> Digital Versatile Disk --> 4.7 GB

Virtualization
==============
	Sharing the resources of one device for better and more processes.
	VMWare, Virtual Machine, Virtual Box

1. Type 0 --> Bare Bone --> In the hard disk, you directly install the virtualization software and then you install virtual OS.


2. Type 1 --> In the Hard Disk, you install the OS and in that OS, you install the Virtualization software and on that you install virtual OS.

Virtual Memory
==============
	It is the space which is not actual the physical space but a virtual space. when the space in the RAM get low, then It borrows some memory form the HDD, for continuing the processes.

Virtual Table
=============
	They are like my content page, index page in the book. They tell me at which location my process is located and will help the RAM to access the process.

Virtual Page
============
	Contains the collection of virtual table, in which all the processes are mapped.

Dymanic Memory Allocation
=========================
	Malloc()
	calloc()
	realloc()
	free()

Malloc --> Memory allocation
			To allocate the memory in any manner, it is not continuous memory allocation. It used pointer.
calloc --> Contigious Memory Allocation
			It allocated the continuous block of the memory.
			It uses the pointer for allocating the memory.

realloc --> If, while performing the process, the memory runs out, then I am here to assist you with more memory by again allocating it to the process.

Free ---> to make the memory vacant which is consumed by the background processes.

https://www.tutorialspoint.com/cprogramming/c_memory_management.htm

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How Data is stored in CD|DVD
	CD is divided into tracks and sectors.

How Does Cyber Forensic Works
=============================
	1. They never operate on the original source.
	2. I will make atleast 15 copies|clones of the reterived source.
	3. I will maintain a journal, for each and everything we collected, with location and the time.
	4. I will always take the source to the isolated place, for forensics.

Data Recovery
=============
=	Recuva --> Recovery Application software
		https://recuva.en.softonic.com/download --> download link
=	Active Undelete


Data Forensics
==============
	We can recover almost any sort of data from the digital media.
		CD
		DVD
		Pen drive
		HDD
		Computer

Number System In Computers
==========================
1. Binary
2. Decimal
3. Octal
4. Hexa Decimal

Decimal 		Binary 			Octal			HexaDecimal
-----------------------------------------------------------
0-9 			0 and 1 		0-7 			0-9|A-F
10 Digits 		2 digits 		8 digits 		16 digits
Base 10 		base 2 			base 8 			base 16
------------------------------------------------------------
0 				0 				0 				0
1 				1 				1 				1
2 				10 				2 				2
3 				11 				3 				3
4 				100 			4 				4
5 				101 			5 				5
6 				110 			6 				6
7 				111 			7 				7
8 				1000 			10 				8
9 				1001 			11 				9
10				1010 			12 				A --> 10
11 				1011 			13 				B --> 11
12 				1100 			14 				C --> 12
13 				1101 			15 				D --> 13
14				1110 			16 				E --> 14
15 				1111 			17 				F --> 15





Computer Programming Language
=============================
1. High Level Language
2. Low Level Language
3. Mid Level Language

1. High Level Language
======================
	Are written and understood by the humans. These type of Programming Language uses english and mathematical expression. That's why it is understandable to humans.
	c, c++, java, python, ruby

2. Low Level Language
=====================
	It is a language which is only and only understandabel to machine or computers. It contains 0 and 1 --> Binary Language
	222 ---> 101010

3. Mid Level Language
=====================
	Are the languages which converts high level language to a low level Language.
	They use registers, hex values as the location.
	We can retriev mid level language from low level language.
	Ex --> Assembly Language

High ----> Mid Level Language ---> Low Level Language
C programming example
.c 		--> .o 				--> exe

Assembely Language
==================
	It uses registers and the memory location in hexa decimal for storing the content of other programming language.

8085 processor

Registers
=========
1. General Purpose Registers
2. Special Purpose Registers
3. Segment Registers

1. General Purpose Registers
============================
	Are used to store any transient data. ---> Temporary data.
	Registers which are required by the program
		AX
		BX
		CX
		DX
	They are the combination of two 8 bit registers
		Low Byte
		High Byte
		AX --->    AL 		AH
		16 bit --> 8 bit 	8 bit
		AX = 1234
			AL --> 34
			AH --> 12
	Low Byte | High Byte
	====================
	AL 			AH
	BL 			BH
	CL 			CH
	DL 			DH


Extended form of the Register
-----------------------------
 EAX
 EBX
 ECX
 EDX

 	EAX ---> 32 bit register
 			---> EAL ---> 16
 			---> EAH ---> 16

2. Special Purpose Register
===========================
	Data Structure
		Array
		Union
		Structure
		Heap
		Stack

	They store the data in the form of a stack.
		1. SP --> Stack Pointer ---> It points at the top of the stack.
		2. BP --> Base Pointer ---> It points at the base of the stack.
		3. IP --> Instruction Pointer --> It points at the next instruction.
		4. SI --> Source Index Pointer
		5. DI --> Destination Index Pointer

3. Segment Registers
====================
	CS --> Code Segment
	DS --> Data Segment
	ES --> Extra Segment
	SS --> Stack Segment

General Registers for 8085 Processor
====================================
1. Accumulator --> A
2. Base Register --> B
3. Couter Register --> C
4. Data Register --> D
5. Extended Register --> E
6. High ---> H
7. Low ----> L