Linux system admin interview questions

Unix/Linux system admin interview questions
Q: How would you make the following SQL statement run faster? SELECT * FROM TABLEA WHERE COL1=’A’ AND COL2=’B’;
A: Make sure that COL1 and COL2 have indexes.
Find out which condition will return less values and use that as the first conditonal.

Q: What is Data Mining

A: Data Minig is the process of sifting through extremeley large amounts of Data to find trends or relevent information.

Q: Name the Seven layers in the OSI Model.

A: Appication, Presentation, Session, Transport, Network, Data Link, Phyiscal

Q: What is one way to view a unix network share on a Windows computer, within explorer
A: NFS, The Unix computer can be running a NFS Server Daemon.

Q: How would you find all the processes running on your computer.

A: Unix, is ps -ef or ps -aux depending on version.

Q: What is DHCP
A: DHCP is a way to dynamically assign IP address to computers. Dyanmic Host Configuration Protocol

Q: What is HTTP Tunneling
A: HTTP Tunneling is a security method that encryptes packets traveling throught the internet. Only the intended reciepent should be able to decrypt the packets. Can be used to Create Virtual Private Networks. (VPN)

Q: Scenario: You have 9 identical looking balls, however one ball is heavier than the others. You have two chances to use a balance. How do you find out which ball is the heaviest?
A: Split into groups of three, randomly choose two groups and use balance on them. If one group is heavier, then discard the other 6 balls. If the two groups are the same weight. The heavier ball must be in the group that was not on the scale. Now randomly choose two balls and test on balance. If they are the same weight, the heaviest ball is on one that was not tested. Else the heaviest ball is already known from the balance.

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