Chapter 1. Overview of System Administration
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## Chapter 1. Overview of System Administration

Underlying the applications and tools you use on your workstation is the IRIX™ 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:

- IRIX is a multiuser operating system, which means several users can work on the system simultaneously and maintain private files.

- IRIX makes the workstation a multi-tasking system, which means the workstation can run several applications, print files, and update files simultaneously.

- IRIX lets you connect the workstation to a network where you can transparently transfer files to and from another system or peripheral device.

- IRIX lets you add a broad range of hardware peripherals such as printers, terminals, disk drives, and modems without additional software.

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” describes the responsibilities and permission levels of different users.

- “Performing System Administration Tasks” describes how to administer a system using the System Manager's interactive guides and the IRIX shell.

## Choosing an Administrator

You need to decide who 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

Because many people may use the same system, it 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 users log in, they can change only their personal workareas. Users can run the interactive guides from the System Manager window, but guides that change system information are not available unless a user knows the password for the root account or has been assigned specific administrative privileges.
Privileged User |  | A person whose login account includes administrative privileges. The Administrator (see below) of the system can assign privileges to users on an individual basis. Depending on what privileges a user has been assigned, that user can use the interactive guides to make changes to the system. For information about using the Privilege Manager to assign privileges, see “Setting System Administration Privileges.”
Administrator |  | The person who can use the most privileged account, the root account. This person should have a 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 interactive guides or using the IRIX shell. The Administrator can change information in the root account (such as the password) and log in to an IRIX shell as root. Because there is only one root account, there is only one Administrator per system. This guide assumes that you are the Administrator of your own system and as such, have access to the root account and password.

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

- The network administrator is the Administrator for every system; this means that the network administrator is the only person who can use the root account and who knows the root password.

- The Administrator creates a standard personal login account for each person who uses a particular system; the average is three users per system.

- Out of all the users, the Administrator selects one person to be responsible for maintaining the system daily; the Administrator adds administrative privileges to this person's account using the Privilege Manager. See “Setting System Administration Privileges” for more information.

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

- Each user is completely responsible for maintaining his or her own system. Users typically perform administrative tasks while logged in to their personal accounts. But when a user must use the IRIX shell with administrative privileges, the user logs into the root account.

- The Administrator adds login accounts for other people who occasionally need to use the system. If one of these users ever needs to perform administrative tasks, the Administrator assigns the appropriate privileges to the user's account. See “Setting System Administration Privileges” for more information.

### The System Administrator's Responsibilities

As the Administrator for a system, you are responsible for performing these tasks:

- Setting up the system initially as a standalone system or as a member of an existing network. (See “Setting Up Your System.”)

- Creating login accounts so all users of the system can access it. (See “Creating a User Login Account.”) If the system will be connected to a network, the Administrator may work in conjunction with the network administrator.

- Connecting any peripheral devices and configuring software so that the devices work properly. (See “Setting Up Peripheral Connections” and “Setting Up Printer Connections.”)

- Setting up a connection over a phone line using ISDN or a modem. (See the ISDN User's Guide for information about configuring ISDN; the guide also provides information about setting up PPP (point-to-point protocol) connections. See “Setting Up Network Connections” for information about setting up a modem.)

- Installing application software and updating system software. (See Chapter 4, “Installing and Removing Software.”)

- Performing regular backups of the entire filesystem and, in some cases, of individual users' data, and restoring data when it is lost. (See “Backing Up and Restoring.”)

- Monitoring and troubleshooting the system to keep it working efficiently and properly. (See Chapter 6, “Managing Disks and Filesystems,” and Chapter 7, “Maintaining the System,” and Chapter 8, “Troubleshooting.”)

If your system is part of a network, you are also responsible for these tasks:

- Contacting the network administrator before connecting your system to the network. The network administrator provides information that you need to uniquely identify your system on the network and to ensure that the regular users of your system can have accounts on other systems on the network. (See “Setting Up Network Connections.”)

- Making all, some, or none of your system's directories available to all, some, or none of the other systems and users on the network. (See “Making Your Disk Space Available to Other Users.”)

- Providing access to printers on other systems so the users working on your system can send files to them. (See “Accessing a Printer Connected to a Remote Workstation.”)

- Providing access to removable media on other systems so the users working on your system can use them. (See “Accessing Removable Media Devices Across the Network.”

- Providing access to disk space that's available on other systems on the network. (See “Using Disk Space on Other Systems.”)

### 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 these tasks:

- Setting up and maintaining the network so connections are reliable and data is transferred as quickly as possible.

- Creating, maintaining, and periodically distributing a list of all systems and users so that each has a unique identity on the network.

- Setting up and maintaining network services such as electronic mail and the Network Information Services (NIS).

For more information on network administration, see Chapter 1, “Understanding Silicon Graphics' Networking Products,” Chapter 2, “Planning a Network,” and Chapter 3, “Setting Up a Network” in IRIX Admin: Networking and Mail.

## Performing System Administration Tasks

You have the following options for performing system administration tasks.

- The System Manager window provides access to the System Administration guides. These interactive guides lead you step-by-step through the various system administration tasks, such as adding a user account. Each guide consists of pages in which you enter information. After you finish filling out the pages, you simply click the OK button and your system completes the task. For more information, see “Using the System Manager's Interactive Guides.”

- The IRIX shell accepts IRIX commands that you use for more advanced administrative tasks.

This online information describes how to use the interactive System Administration guides to perform most of the administration tasks; in cases where an interactive guide does not exist for a particular task, you must use IRIX commands or edit system files. If you prefer to perform all administrative tasks without using the interactive guides, see the IRIX Admin set of guides (choose “Online Books” from the Help toolchest, and look in the SGI_Admin bookshelf). Regardless of whether you edit system files manually or use the interactive guides, you are changing the same system files.

### Using the System Manager's Interactive Guides

To use the interactive system administration guides, follow these steps:

1. Choose System Manager from the System toolchest.

   The righthand column of the System Manager window displays an overview of the System Manager and each of its categories. The lefthand column displays a table of contents, organized by the various categories of guides.

2. To view the various guides, select categories in the lefthand column.

   When you click a category, a list of the guides (and managers) in that category appears in the righthand column.

3. To open an interactive guide, click the title of the guide in the righthand column.

   After a couple of seconds, the first page of the guide appears. This first page describes the guide and tells you how many pages you'll need to fill out to complete it. (Most guides consist of four to ten pages.)

4. Read the information on the first page to learn about the guide and then click the Next button to continue.

5. Enter information in the pages as requested, clicking the Next button to go to each subsequent page.

   If you want to go back to an earlier page, click the Prev button. You can also go back to the first page of the guide using the Prev button.

   The last page of the guide, usually titled “Confirm your settings,” gives you the opportunity to view all of the settings you made in the previous pages.

6. If you agree with the settings on the last page, click the OK button to have the system implement them.

   If necessary, you can click Prev to go back and change any of the settings. You also have the opportunity to quit without performing the task by clicking the Cancel button.

#### Overview of the Categories

The System Manager window provides the following categories of guides. You can find descriptions of each category in the System Manager Overview window.

Software |  | Includes the Software Manager, which you can use to install software; and the License Manager, which you use to add, remove, and update software licenses on your system.
Hardware and Devices |  | Provides guides that let you manage printers, modems, serial devices, hard disk drives, and removable media devices like CD-ROM, floppy, and tape drives.
Security and Access Control |  | Provides guides to help you improve system security, manage user accounts, control access to files, share files and directories, share printers and removable media devices, and change users' privileges on the system.
Network and Connectivity |  | Includes guides that let you set up network connections on your local network and over phone lines (including ISDN), turn on NIS (Network Information Services), turn on NFS® (Network File System), mount remote filesystems, and modify network settings.
Files and Data |  | Contains guides that allow you to mount and unmount local filesystems, and perform backups of important files and directories on your workstation.
System Performance |  | Provides guides to help you improve performance by creating logical and virtual swap space. Also gives you access to information about your system, including the System Log and the System Administration Log.

The window also includes “Overview,” discussed earlier, and “About This System,” which lets you view basic information about your system, including the version of operating system running, the amount of main memory available, and so on.

#### About the Managers

Many of the categories listed above also include Managers. You can use Managers to view information about particular areas of your system, such as printers, serial devices, filesystem, shared resources, and so on. You can also access various guides from within a Manager window. For example, when you open the Serial Device Manager in the Hardware and Devices category, a window appears and provides information about all the serial devices currently connected to your system. The window also includes Add and Delete buttons, which, when clicked, open the “Add a Serial Device” and “Delete a Serial Device” guides, respectively.

### Using the Shell Window

To perform administrative tasks that are not supported by the interactive guides, 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 the root account that only you, as the Administrator, know. (See “Improving System Security.”)

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

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:

1. Choose “Open Unix Shell” from the Desktop toolchest.

2. 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 “Creating, Changing, and Deleting Passwords” 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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Personal System Administration Guide |  | Chapter 2. Getting Started