Kali Linux Training | Hacking sessions | Learn Linux in Faisalabad

The NDG Linux Essentials course objectives cover the following subject areas:

• Linux as an operating system

• Considerations for choosing an operating system

• The basics of open source software and licensing

• Basic knowledge of working with Linux

• Basic Linux command line skills

• How to use help commands and navigate help systems when using Linux

• How to work with Linux files and directories

• Search and extract data from Linux files

• Basic understanding of the concept of scripting

• The components of desktop and server computers

• Where data is stored on a Linux system

• Query vital network settings for a Linux computer on a Local Area Network

• Various types of users on a Linux system

• Creating users and groups on a Linux system

• Managing Linux file permissions and ownership

• Special Linux directories and files

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Storing Switch Configuration Files

When you configure a switch, it needs to use the configuration. It also needs to be able to retain the configuration in case the switch loses power. Cisco switches contain randomaccess memory (RAM) to store data while Cisco IOS is using it, but RAM loses its contents when the switch loses power or is reloaded. To store information that must be retained when the switch loses power or is reloaded, Cisco switches use several types of more permanent memory, none of which has any moving parts. By avoiding components with moving parts (such as traditional disk drives), switches can maintain better uptime and availability. The following list details the four main types of memory found in Cisco switches, as well as the most common use of each type: 

■ RAM: Sometimes called DRAM, for dynamic random-access memory, RAM is used by the switch just as it is used by any other computer: for working storage. The running (active) configuration file is stored here.

■ Flash memory: Either a chip inside the switch or a removable memory card, flash memory stores fully functional Cisco IOS images and is the default location where the switch gets its Cisco IOS at boot time. Flash memory also can be used to store any other files, including backup copies of configuration files. 

■ ROM: Read-only memory (ROM) stores a bootstrap (or boothelper) program that is loaded when the switch first powers on. This bootstrap program then finds the full Cisco IOS image and manages the process of loading Cisco IOS into RAM, at which point Cisco IOS takes over operation of the switch. 

■ NVRAM: Nonvolatile RAM (NVRAM) stores the initial or startup configuration file that is used when the switch is first powered on and when the switch is reloaded.