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Whether you are using X or a text-based installation, a screen appears that lists all the packages on the Linux CD-ROM. You can select which packages are to be installed during the setup process. You can install as many or as few of these packages as you want. You can delay the installation of many of them until later if you want.
After selecting the packages to be installed, you can see a message asking whether you want to have individual package contents displayed for selection. This lets you select only portions of the more generic packages for installation. If you select this option, you must wait by your screen and provide input at regular intervals. If you want Linux to install all the components in a package, answer No to this prompt, and you can leave the system to install by itself.
After you have selected the packages to be installed, Red Hat’s installation routine starts installing the software. You can see status messages on the screen as the process goes along.
After the installation process has formatted the drive partitions and copied all the software packages you selected to the data partition, you are asked whether you want to run LILO to set up the boot system for this drive. If you have a disk drive devoted only to Linux or it is a split DOS/Linux drive, you can run LILO and set the drive to boot into either operating system.
If you are running another operating system, such as UNIX or OS/2, you may elect not to use LILO and create a boot floppy instead. LILO is covered in much more detail in Chapter 4, “Using LILO.”
Hard disks are divided into partitions, or areas dedicated to an operating system. A hard disk can have up to four primary partitions, with some partitions being further divided into more logical drives by the operating system software. A more complete discussion of partitions is in Chapter 4.
If you are running Linux from a DOS partition using the UMSDOS root image, you don’t have to worry about repartitioning your drives. Your existing drive’s partitions are used. However, since UMSDOS is a poor filesystem compared to Linux, you probably want to create your own Linux partitions. Check the later section “Using UMSDOS,” for information on setting up UMSDOS.
Linux really requires two partitions: one for the Linux swap space, and one for the Linux software filesystem itself. The swap space is used as an extension of your machine’s physical RAM and can be quite small. The Linux filesystem partitions tend to be quite large because they must hold all the Linux software. You can have several Linux file-system partitions, although one must be designated as the boot partition (where the kernel and primary utilities are located).
If you are using an existing hard disk that has an operating system already installed on it, you must repartition your hard disk to make room for Linux. This tends to be a destructive process, meaning that anything on your hard disk will be destroyed. Make backups of your existing data if you want to keep it!
Partitioning of a hard disk is done with the fdisk utility. If you have used fdisk in DOS, the Linux version does the same task, although the menus are completely different (and much more complicated). Many PC-based UNIX systems also use fdisk to partition hard drives.
Tip:
A DOS utility called FIPS sometimes allows nondestructive changes to your partitions, assuming no data is on the areas that are to be repartitioned. FIPS is available from many sources, including most of the Linux FTP sites and on some Linux CD-ROMs. However, you should make backups, just in case.
You must decide how much space to allocate to the different partitions before you start because changing your mind later means destroying all the data you have saved to disk. The Linux swap space partition size depends on the amount of RAM in your system, the number of users you expect, and the type of development you will do.
If you are going to maintain a DOS partition on the same disk, you must balance the disk space requirements of both operating systems against your total disk capacity. A minimum Linux filesystem partition will be about 20MB, although closer to 100MB is needed for a full X-based installation.
How big should the swap space partition be? There’s no single size that works for all installations, unfortunately. Generally, since the swap space is used as an extension of physical RAM, the more RAM you have, the less swap space is required. You can add the amount of swap space and the amount of RAM together to get the amount of RAM Linux will use. For example, if you have 8MB of RAM on your machine’s motherboard and a 16MB swap space partition, Linux will behave as though you had 24MB RAM total.
Linux uses the swap space by moving pages of physical RAM to the swap space when it doesn’t need that page at the moment, and vice versa when it needs the memory page. So why not make a very large swap space and let Linux think it’s in heaven? Because the swap space is much slower in access time than RAM, and there is a point where the size of the swap space acts against your Linux system’s efficiency, instead of for it.
Swap space may not even be needed if you have lots of RAM. For example, if you have 16MB of physical RAM and don’t intend to do any application development or run X, you won’t make much use of the swap space because Linux can fit everything it needs in the 16MB. (You still should have a small swap space, just in case.)
If you are running X, developing applications, or running memory-hog applications, such as databases, swap space is crucial even if you have lots of physical RAM. Even 16MB RAM is not enough for X, so you need swap space.
A good rule is to create a swap space with the maximum size limit of 16MB. Unless you have a very small-capacity hard disk, this won’t be a major drain on your resources, and it gives Linux plenty to work with. If you don’t want to allocate this much space, a good rule is to have a total of 16MB RAM (swap space plus physical RAM). Don’t eliminate the swap space completely, though, unless you have a lot of RAM. At a minimum, set up a 4MB swap space. Running out of RAM can cause Linux to lock up or crash, which isn’t a pretty sight!
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