Sams Teach Yourself Mac OS X Digital Media All In One - page 293

Summary

With the drawing tools in Elements, it's easy to create simple images such as logos and clip art, or to edit an existing graphic so that it suits your needs more exactly. The options for each tool give you control, while allowing you the freedom to experiment as you wish. And, through the use of gradients, layer styles, effects, blending and distortions, you can create complex images without the use or photographs.

Part IV: Advanced System Management

Chapter

27 Sharing (and Securing) Your Computer

28 Managing Your System

29 Recovering from Crashes and Other Problems

Chapter 27. Sharing (and Securing) Your Computer

Now that you've learned how to use multimedia applications, including the iLife suite and Photoshop Elements, it's time to return focus to your operating system and some topics dealing with advanced system management. The chapters in this section are more challenging than in the previous ones, but with powerful tools such as your Macintosh often come complex features and their related upsides and downsides.

In this chapter, our attention will be on sharing your system and files with others and the flip side of that, protection from unwelcome visitors . First, we'll delve into how to set up your computer so other users can have their own space. We'll then look at the ways that you can share files from your Mac. (You'll also learn how to connect to other computers that are sharing their files.) Our last topic will be security, both local and online, where you will learn some ways to protect your computer from unauthorized users.

Sharing Your Computer with Multiple Users

As you've heard in previous chapters, Mac OS X is a true multiuser operating system because everyone who works on the computer has a separate, private area in which to store personal files. While you don't have to make use of the multiuser capabilities of your Mac, they affect the system's structure which may require special attention, in terms of both their benefits and problems.

Understanding User Accounts

In a multiuser system, everyone who works on the computer can have a separate account. In practice, that means when one user saves a document to the desktop, it does not appear on the desktop that the other users see when they sit down to use the same computer. Also, each person can set system preferences that show up only when he or she is logged in. Users can customize the Dock and the desktop appearance and expect them to remain that way.

An interesting feature of multiuser operating systems has to do with remote access. Because the operating system assigns a separate desktop to each account, multiple people can use files on a single computer at the same time. Although this requires connecting to the machine from another computer and enabling remote login, the OS is designed to cope with different simultaneous processes so that users can work as though they were alone on the system. We'll take a look at remote login later in this chapter.

The home folders for user accounts are located in the Users folder of the Mac OS X hard drive, as shown in Figure 27.1. A house icon is used in the Finder window toolbar to represent the current user's home folder. Inside the home folder are several different folders, which were discussed briefly in our look at the Finder's file system during Chapter 2, "Exploring the Desktop."

Figure 27.1. Every user has a home folder in which to store his or her files.

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Although individual users can see the contents of most files on the hard drive, they might not be able to see each other's files. That's because users in a multiuser system can set permissions on their files that restrict access to keep their work private. They can specify whether a file can be read or altered by everyone, by a limited number of other people, or only from within the account in which the files were created.

For example, Figure 27.2 shows what the home folder of the user robyn looks like to another user. Most of the folders have an icon with a red circle containing a minus sign. That means these folders are not accessible from user accounts which did not create, or own, them.

Figure 27.2. By default, other users are restricted from accessing all but the Public and Sites folders.

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You can change the permissions on a file or folder that you own under the Users and Permissions section of the Get Info panel (Commmand-I). We discuss how later in this chapter.

Adding and Removing Users

When you first installed Mac OS X, an account was created using the name you supplied. The system uses the short name you gave as your account name, but you can use either your full or short name to log in to the system at the console. Because this account can access system settings and install new software, it's referred to as an administrator account .

When logged in with an administrator account, you're granted the privilege of adding other users and you can choose to give them administrative privileges as well. Remember, that means other people can add new accounts and modify the system, so you should be cautious about creating other administrative accounts. Be sure that you trust your users not to delete important files or disrupt the system in other ways before you give them administrator privileges.

New user accounts are added from the Users pane of the Accounts Preferences panel, shown in Figure 27.3.

Figure 27.3. The Users pane of the Accounts Preferences panel lists current users and enables you to edit them or add new ones.

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To create a new user account, follow these steps:

Click the New User button to open the sheet shown in Figure 27.4.

Figure 27.4. Enter a username and password and select an image for the new user.
Type the name of the person using the account as well as a short name to be displayed for logging in.
Type the password once, and then type it again to verify it. The Password Hint box is for a short description or question to remind the user of his password when he forgets it.
Choose the picture that shows up next to the user's name in the login screen.
If you want your new user to have administrative powers, as discussed previously, check the box labeled Allow User to Administer This Computer.
If you want Windows users to be able to connect to the new user's home folder, check the box for Allow User to Log In from Windows.
When you're done, click OK.

The Users Preferences panel now lists your new user, who has a folder in the Users folder.

If you want to further control the access of users who aren't allowed to administer the computer, you can click the Capabilities button to choose which applications are visible to them, whether they can access System Preferences, and burn CDs or DVDs. You can also enable a setting called Simple Finder, which simplifies system navigation by opening all Finder elements in a single window.

Through a similar process, you can edit an existing user account, including changing the password. Simply select the user account to be edited and click the Edit User button. Note that although you can change many things about a user account, you can't alter the short name used to log in. Choose wisely the first time.

To alter the settings for the currently active administrative account, you must enter your current password to provide authorization.

Now that you know how to add a user, you should learn how to remove a user. This again requires you to open the Users tab of the Accounts Preferences panel. To delete a user account, simply select the account to be deleted and click the Delete User button. In this way, you can delete any user account except the original administrator account. A sheet appears to confirm your choice and to inform you that the deleted user's files are stored as a disk image ( .dmg file) in the Deleted Users folders. If you don't want the contents of the deleted account, you can open that folder and delete the .dmg file.

When an account is deleted for the first time, the Deleted Users folder is created. Even though you can delete the .dmg files inside it, there is no way to delete the folder itself from within the Mac OS X interface. If you attempt this, you will be denied permission.