Jose Alberto Salazar
OECS-205-D02
Homework 2

Answer Exercises 1 and 3 on page 499 (End of chapter 10)

1.- How does single-user mode differ from multiuser mode?
When a system is in single-user mode, you can log in only at the console. Not all of the file systems are mounted,and many daemons are not running. With the system in multiuser mode you can login at any terminal or workstation that is set up for login, most or all of the filesystems are mounted, and all of the daemons that your system is set up to run arerunning.

3.-What do the letters of the su command stand for? (Hint: It is not Superuser.) What canyou do with su besides give yourself root privileges? How would you log in as Zach ifyou did not know his password but knew the root password? How would you establishthe same environment that Zach has when he first logs in?
The letters su stand forsubstitute user. With su you can use the su utility can spawn a shell or execute aprogram with th identity and privileges of a specified user, including root.Byfollowing the su on the command line with Zach’s name as long as you are working with root privileges will allow you to log on as Zach.By using the su commandutility and the root password will alow you to log on as Zach with the sameenvironment

Answer Exercises 1,3,5,6,7 on page 530 (End of chapter 11)

1.- What is the function of the /etc/hosts file? Which services can you use in place of or to supplement the hosts file?

This file holds the hostname and IP address of the local system. It also holds a special entry for localhost. This entry supports the loopback service, which allows the local system to talk to itself. The IP address of the loopback serviceis always 127.0.0.1, while 127.0.1.1 names the local system.

3.- What is an inode? What happens to the inode when you move a file within a filesystem?

An inode is a data structure, stored on disk, that defines a file’s existence and is identified by an inode number. An inode contains critical information about a file, such as the UID of the owner, where it is physically located on the disk, and how many hard links point to it. In addition, SELinux stores extended information about files in inodes. An inode that describes a directory file maps each of the filenames in the directory to the inode that describes that file. This setup allows an inode to be associated with more than one filename and to be pointed to from more than one directory.
6. What is a FIFO? What does FIFO stand for? What is another name for a FIFO? How does a FIFO work? A FIFO is a special file, also called a named pipe. You read from and write to the file to read from and write to the pipe. The term FIFO stands for “first in, first out.” The first information that you put in one end is the first information that comes out the other end.