# OS Fundamentals

- Process Management
- Process Sync
- Memory Management
- CPU Scheduling
- File Management
- Security

### What is OS Kernel ? The core program of the OS

### Types Operating Systems
- Mobile OS = > iOS, Android, Windows Phone
- Desktop OS => Windows 10, Mac, Ubuntu
- Server OS /Network OS => Windows 2022, Windows Server 2016, Windows Server 2019, Red Hat Enterprise Linux
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WINDOWS OS
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What is Task Bar
System Tray ?
Context Menu => Right Click menu

C: , D: etc are called "Drive Letters" in windows
In Linux, Unix (Mac) there are no drive letters. They have volumes.

Drives use a format Called "File System" . Windows mostly uses NTFS File System to store its files.
File System => NTFS, FAT32, CDFS

32 Bit OS . 2^32 memory availablity, 2^64 memory availability. Bit OS
Task Bar
System Tray => Bottom Right section of the Windows Task bar
Task Mananager - > To view currently running apps, processes etc.

Pinning an app to task bar

Folder Structure
Critical Folder

C:\Windows
C:\Windows\System32
C:\Windows\System

C:\ProgramFiles
C:\Program Files(x86) => For 32 bit programs.

A few popular file format examples:

.CSV   - Comma Seperated Values (used for data exchange)
.TXT   - Plain text file
.HTML  - HTML File
.EXE   - Executable (Programs in windows )
.XLSX  - Excel file format
.DOCX  - Documetn format. Microsoft Word file format
.PPTX  - Power Point
.XML   - eXtended Markup Language. Used for data exchange
.JPG - Pictures.
.JPEG -Both are mthematics
.MPEG -Motion Pictures Experts Group
.PNG - Portable Network Graphics
.GIF - Graphical Interchange Format. (Moving)
.BMP - Bitmap Format  (Uncompressed/Large).If you create a file in microsoft paint and save it , it will have.bmp extension by default.

.py - Python code
.c - C program file
.CPP - C++ code File
.cs - C# code
.java - java
.js - Java SCript file 
.TS - Type Script File
.vb - VB File

Command Prompt
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Basic Commands

dir   => To list contentes of a directory 
cls   => To clear screen
del   => To delete a file
exit  => To exit out of the command shell
cd    => To change directory 
cd .. => To change one level up
cd \  => To change directory all the way up to the root. 
/? => Suffixed with any command to get additional help.
date => Current Date
time => Current time
echo => To Echo something on the console.
copy => To create a copy of a file
copy con => To create a text file