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Personal System Administration Guide


Chapter 1
Overview of System Administration

Underlying the applications and tools you use on your IRIS is the IRIX (TM) operating system (a version of the UNIX operating system). IRIX is much more flexible and powerful than traditional personal computer operating systems in these ways:

Along with the advanced capabilities of the IRIX operating system come certain responsibilities for setting up, maintaining, and troubleshooting it. This set of responsibilities is known as system administration. Click a topic below for more information.


Choosing an Administrator and Privileged Users

You need to decide which people will be responsible for keeping the system in good running order and, if the system is connected to a network, who will work in conjunction with the network administrator to access network services.

About User Privileges and the Primary User

Because many people may use the same system, the system provides a built-in security scheme where you can grant different people different capabilities for changing the system. There are three levels of capability:

User:

Any person who has a login account on the system. When a User logs in, he can change only his personal work area. A User can run the graphical administration tools from the System toolchest, but the features of the tools that change system information are not available.

Privileged User:


A person whose login account includes administrative privileges. When a Privileged User logs in, he can change his personal work area, and can use the graphical administration tools to change or customize the entire system (for example, set up a disk or create a login account). There can be more than one Privileged User on the same system.

Administrator:

The person who can use the most privileged account, the root account. This person should have his own personal login account for daily use, but, when there are serious system problems to correct, the person logs in to the root account to change system information using the graphical tools or using the IRIX shell.


The Administrator has all the capabilities of a Privileged User, plus the capability to change information in the root account (such as the password) and to log in to an IRIX shell as root. Because there is only one root account, there is only one Administrator per system. The System Manager window for a particular system includes the name of the system's Administrator so other users know who to contact for help.

In a large, secure, networked environment run by an experienced network administrator, the scheme could work in this manner:

In a smaller, less secure environment where each person has one system, the scheme could work in this manner:

For environments in which one person uses a particular system much more frequently than anyone else (where the person is essentially the system's owner), you can designate that person as the Primary User. The Primary User does not necessarily have any special access privileges; the person's name appears along with the Administrator's name in the system's System Manager window so other users know who uses the system regularly. There is only one Primary User per system.

Note: The System Setup tool supports the model where one person has one system which he must maintain. When you create a login account for a person using this tool, it designates that person as the Primary User, and also makes the person a Privileged User. If necessary, you can later use the User Manager to remove administrative privileges or assign the title of Primary User to someone else.

The Responsibilities of Privileged Users

A Privileged User can use administration tools to perform these tasks:

If your system will be part of a network, the Privileged User is also responsible for:

The Network Administrator's Role

The responsibilities of a network administrator vary greatly from site to site. If you will be using the network, it's important to contact the network administrator to understand all the services that are available to you. In general, the network administrator is responsible for:

For more information on network administration, see Chapter 15, "Understanding Silicon Graphics Networking Products,"Chapter 16, "Planning a Network," and Chapter 17, "Setting Up a Network" in the IRIX Advanced Site and Server Administration Guide.


Using System Administration Tools

As the Administrator or Privileged User you can use two different types of tools:

This online information describes how to use the graphical tools in the System toolchest to perform as many administration tasks as possible; in cases where no graphical tools support a task, you must use IRIX commands or edit system files. If you prefer to perform all administrative tasks without using the System toolchest, see the IRIX Advanced Site and Server Administration Guide (choose "Online Books" from the System toolchest, and look in the SGI_Admin bookshelf). Regardless of whether you edit system files manually or let the graphical tools do it for you, you are changing the same system files.

The System Toolchest

The administrative tools that you'll use most frequently are in the System toolchest menu; you run a tool by choosing it from the menu. The first tool in the menu is the System Manager. Tools that you use less frequently appear when you choose "System Admin Tools" from the Tools menu in the System Manager window.

The System toolchest includes these tools:

System Manager


Lets a User view which of the system's resources are available for use by other systems on the network, check the hardware and software inventory of the system, and get business card information about the system's Primary User and Administrator.

Lets a Privileged User run all the system administration tools and designate the Primary User. See also XXX (ch7, chosts stuff)

Disk Manager

Shows how much disk space you are using and how much is still available. Privileged Users can specify when the system should warn that the disk is nearly full. When you install a new disk, a Privileged User also uses this tool to specify a dirctory (mount point) from which to access the disk.

User Manager

Lets Users view information about their own and other people's login account, and lets them change business card information about their own account. Privileged Users can use the tool to create, change, and delete user login accounts.

NFS Mount Manager


Available only on systems that have the optional NFS software installed. Lets Privileged Users access (mount) directories on other systems so that Users can access the directories as if they resided on the local system.

Printer Manager


Lets Users view the list of available printers and drag printer icons onto their desktop for use. Lets Privileged Users set up the software for local or remote printers so the system can access the printers.

Software Manager


Lets Users view a list of installed software. Lets the Administrator install and remove software from the system's manufacturer.

Backup & Restore


Lets any User back up files and directories that are owned by the User. Lets the Administrator create full system backups from which you can restore the entire system in the event of a serious system software failure.

View System Log


Displays a log of all the system messages, and lets a Privileged User customize when and how the System Log Viewer should notify Users of system problems.

Run Confidence Tests


Displays a window that lets Users test various peripherals and system components, such as the mouse, keyboard, and monitor.

Logging In as root Through a Shell Window

Only the Administrator can perform administrative tasks that are not supported by the graphical tools since he must use the root account in a shell window. The home directory for the root account is the root (/) directory of the filesystem. The user logged in to the root account can move, change, and delete every file and directory on the system, regardless of who owns them and what type of permissions they have set. Be sure to create a password for this account that only the Administrator knows. (See "Designating the Administrator with the User Manager".)

Note: Some UNIX and IRIX documents refer to the user of the root account as the superuser rather than the Administrator.

When you're already logged in as a regular user, you can start a shell window and log in as root by following these steps:

    Choose "Unix Shell" from the Desktop toolchest.

    Position your cursor within the new window and type:

    login root

    Then press <Enter>.

    If a prompt for a password appears, type the password then press <Enter>. If a prompt appears but the root account has no password, just press <Enter>. (See "Customizing System Account Information" to create, change, or remove a password.)

You are now logged in to the root account and are located in the root (/) directory. When you are logged in as root, the IRIX prompt is a pound sign (#) rather than a percent sign (%).

To log out of the root account, type:

logout

Then press <Enter>. The shell window disappears.


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