Introduction to LINUX SYSTEM ADMINISTRATION.

What is Linux?
Linux is neither an operating system nor a programing language but it is a KERNEL.

Linux us highly secure, it’s the base which is available in GUI i.e., Graphical User Interface and CLI i.e., Command Line Interface.

KERNEL: The one who work between the translation of hardware and software (vice versa). Kernel are mainly classified in two types-

·       Monolithic KERNEL: In this you are not allowed to make any changes in the source code.

·       Modular KERNEL: In this you have the permission to make changes in source code.

Linux is a Modular KERNEL.

CLOSED SOURCES

1.       Closed source refers to the computer software which source code is closed means public is not given access to the source code.

2.       It can’t be modified.

3.       You’ve to purchase the software i.e., get the subscription.

4.       You can’t distribute applications i.e., it can’t be shared with anyone without providing the license to them.

Example:

•          Windows
•          MAC
•          CISCO
•          JUNIPER

OPEN SOURCES

1.       Open source refers to the computer software which source code is open means public can access the source code.

2.       It can be modified.

3.       Software can be availed free in Open Source.

4.       No such boundations. It can easily be shared without providing license.

Example:

•          Linux
•          Android

 

KERNEL in the both Closed Sources and Open Sources is same there are only cosmetic changes.

WINDOWS	LINUX
Microsoft embedding extra drivers with KERNEL.	Basic set of drivers are part of KERNEL.
It comprises of DRIVERS.	It contains MODULES.
.exe is the naming extension.	.rpm is the naming extension.  ( Redhat Package Manager)
C: Drive is main.	/root is main.
Users in Windows: example for a company Administrator, employees and the boss at same place.	Users in Linux: example in company /(user) and root home directory. Users and The Admin in different sections.
Windows store configuration file in form of REGISTRY.	Linux store configuration file in the form of /etc.
It comprises of Program File.	It contains /user (User System Resource)
Temp (for cache files) is a part of C: drive.	/tmp is automatically a part of root but can be changed.
KERNEL goes in the C: drive. If the KERNEL crashes everything is lost.	KERNEL is in /boot . If KERNEL crash we can recover it from /boot .
Windows store everything in C: drive	You can store accordingly to your requirement.
It consists of Page File.	It has Swap Memory.

 

 HARD DISK NAMING CONVENTION:

·       SDA- Sata Drive or Disk A stands for 1

·       SDB- Sata Drive or Disk B stands for 2

·       HDA- Pata Drive or disk A stands for 1 (very old)

·       SSD- M Sata, M.2 Sata
 

PARTITION

If we provide 1 TB Hard Drive and set automatic separation than linux would keep the important files like /root, /boot, /tmp at one place so if the /root crashes as a result the every data will be lost so companies follow CUSTOM PARTITION scheme as per their requirement.

TYPES OF PARTITION

      

•               Extended Partition can be divided as per our need and desire. The extended partition comprises of all logical partitions.
•              Maximum 4 Primary Partitions can be created no matter what’s the size of hard disk.
•               Maximum 1 Extended Partition can be created.
•               If there is MS-DOS then the partition will be in the form of primary and extended.
•               If you give 1 part to primary and rest to extended, you can make maximum 15 logical partitions further as MS-DOS follows MBR Partition Scheme.
•             GPT Partition Scheme says you can have maximum 128 partitions. No as such part like primary of extended.

There are two partition schemes MS-DOS and GPT. Both have different schemes as listed above.

TOPIC OF Gib and Mib:

In simple words Gb and Mb are the terms calculated in multiples of 1000 where as Gib and Mib are calculated in multiples of 1024.

1Gb = 1,000³ and 1Gi = 1024³

1Mb = 1,000² and 1Mi = 1024²