Why should we care about the OSI Reference Model ?
What is the main purpose for creating this osi model?
why it is a layered model?

message’s can transfer from one place to other .and the message not demaged for other . so this model can be create . they have 7 layers r there
1. physical level
2.data level
3.tranport level
4.session level
5.application level
6.network level
7.presentation level

when osi model is nt created no to system of different manufracture can communicate because they all are having different protocols. and osi model give them standard protacols which are universal. hence system manufracture by different companies can easily communicate.

1. When planning your backup strategy you need to consider how often you will perform a backup, how much time the backup takes and what media you will use. What other factor must you consider when planning your backup strategy? _________
2. Many factors are taken into account when planning a backup strategy. The one most important one is how often does the file ____________.

1. You attempt to use shadow passwords but are unsuccessful. What characteristic of the /etc/passwd file may cause this? Choose one: a. The login command is missing. b. The username is too long. c. The password field is blank. d. The password field is prefaced by an asterick.
2. You create a new user account by adding the following line to your /etc/passwd file. bobm:baddog:501:501:Bob Morris:/home/bobm:/bin/bash Bob calls you and tells you that he cannot logon. You verify that he is using the correct username and password. What is the problem? Choose one: a. The UID and GID cannot be identical. b. You cannot have spaces in the line unless they are surrounded with double quotes. c. You cannot directly enter the password; rather you have to use the passwd command to assign a password to the user. d. The username is too short, it must be at least six characters long.

Item Title Hits What is the minimum number of partitions you need to install Linux?
What command can you use to review boot messages?
What command you execute to display the last five commands you have entered?
Which partitions might you create on mail server HDDs other than the root, swap and boot partitions?
Which partitioning tool is available in all distributions?
Which two commands can you use to delete directories?
Which file defines all users on your system?