Other Installation Commands

Many versions of Linux have bundled their own package management system. These can be either character-based, like installpkg and RPM, or graphical. A good example of such a tool is LISA (Linux Installation and System Administration), a tool bundled with Caldera OpenLinux (a Slackware release) and some other versions of Linux. LISA can be run from the character terminal or from X terminals. LISA offers a menu-driven interface that prevents you having to worry about all the command-line options that bog down RPM and installpkg.

When you start LISA, the opening menu lets you select either system administration tasks or package management (see Figure 5.1). Keyboard arrow keys move between the selections.

Figure 5.1.  LISA’s menu-driven interface is much more friendly than a command line.

From the main menu, choose the Software Package Administration option, and a new menu appears that lets you examine packages already installed or add new packages, as shown in Figure 5.2.

Figure 5.2.  LISA lets you examine packages already installed or add new packages.

If you choose to examine available packages, LISA shows a list of the default packages Linux knows about. Figure 5.3 shows the main list of available packages. Further information about the files in each package can be obtained from each package choice. You can add other packages by inserting media (such as a CD-ROM or providing a pathname) and having LISA examine the new package options. From there, you can choose which packages to install, and LISA takes care of the rest, just as RPM and installpkg did.

Figure 5.3.  The primary distribution packages accompanying this version of Linux.

Multiple CD-ROM Devices

In theory, there is no real limit to the number of CD-ROM devices your Linux system can handle. As long as there are device numbers (major and minor device numbers are discussed in Chapter 33, “Devices”), then the device is legal. So why would anyone want more than one CD-ROM device on his system? There are a number of reasons: CD-ROM changers, CD-ROM writers, and CD-ROM libraries are all common. We can look at each of these in turn.

CD Changers

One of the most common reasons for multiple CD-ROM devices is that a CD-ROM changer is being used. A CD-ROM changer allows you to have three, six, or some other number of CDs inside the changer body, but only one CD-ROM is actually used by the read mechanism at a time. A good example of a popular CD-ROM changer is the NEC Multispin series, both internal and external devices allowing multiple CD-ROMs to be inserted into the changer and individually accessed with either front-panel buttons or software commands.

When configured on a Windows system, CD-ROM changers usually set up a different drive letter for each of the CD-ROMs possible in the changer. For example, when a six-disk NEC Multispin is installed under Windows 95, the devices are numbered from the last hard drive up; so if you have a single hard drive C:, the CD-ROMs would be D: through I:. You can’t read two of the CD-ROM drives at the same time, but changing drive letters in Windows changes the loaded CD-ROM in the changer.

Linux works with changers in one of two ways: You can configure the changer as a single CD-ROM drive and use the front-panel buttons to manually change disks, or you can set up different devices for each CD-ROM. The choice is yours, not Linux’s. Of the two, the former is easier but the latter gives you more flexibility. Because Linux doesn’t like you changing CD-ROMs after they have been mounted, you really should unmount the CD-ROM before changing CDs whichever option you choose. To configure a changer for more than one CD-ROM device, follow the same procedure as a single CD-ROM but increment the device number (/dev/cd0, /dev/cd1, /dev/cd2, and so on). Only one of these devices can be linked to /dev/cdrom at a time.

CD Writers

CD writers are another reason to install multiple CD-ROM drives on your Linux system. CD write devices enable you to burn your own CD-ROMs, usually in a one-shot method, although CD rewritable devices are slowly becoming more reasonably priced. Although the manufacturers of the CD writers (such as Hewlett-Packard’s SureStore series) do not directly support Linux, there are some drivers available for Linux, mostly developed by other users.

A CD writer can be used as a read-only standard CD-ROM device under Linux with no special configuration. Since most CD writer devices are SCSI based, the configuration as a SCSI CD-ROM is simple. If you do want to configure it as a writable device, you need one of the previously mentioned drivers, usually available at FTP sites. Because copying CD-ROMs is one of the most prevalent uses of a CD writer, you will often configure the CD writer as a second device (/dev/cd1) after the first, normal CD-ROM (/dev/cd0). You can have both IDE and SCSI CD-ROM devices active at the same time.

CD Libraries

Finally, a common use for multiple CD-ROM devices is to act as a library subsystem. Suppose you have a large amount of data that must be accessed over a network, or you’ve got reference material you want to offer through the Internet. Whatever the reason, there are many arguments for using multiple CD-ROM drives instead of high-capacity hard drives to offer material (not the least of which is cost).

Configuring multiple CD-ROMs in this case is simple: Set up the devices in order (/dev/cd0, /dev/cd1, and so on) and mount each CD-ROM in the proper location on the Linux file system. Users accessing the server are steered to the proper CD-ROM drive because of the mounting.