Having Linux and Windows on the Same PC

1.Partitions

There is no need to get rid of Windows to run Linux. In fact, there are many ways to run both of them on the same PC. Each operating system has its own strengths and weaknesses, so often having both on the same PC can be an advantage.
Before the actual installation, we need to go over some basics of Linux and Windows such as partitions and filesystems.

A partition is a way of sectioning off space on a hard drive. Most PCs have their hard drive partitioned into one large drive. It doesn't have to be this way. Drives can be divided into several partitions. This is often done to separate the programs from the data and also for storing multiple operating systems on the same drive.

The first section of a hard drive contains information on the partitions, including where the start and end of each partition is located. It also contains the location of the boot loader, which starts loading the operating system. Each operating system has its own boot loader. Windows 3x, 95, and 98 use IO.SYS and DOS.SYS, Windows NT uses NTLOADER, and Linux uses LILO. There are also commercial and shareware boot
loaders, such as Norton System Commander, that are designed to make it easier to boot with multiple configurations and multiple operating systems.

2. Filesystems

There are also several different filesystems used by Linux and Windows. A filesystem is simply a way of organizing files on a partition. Windows uses FAT, FAT16, FAT32 (VFAT), and NTFS (NT Filesystem). The native filesystem for Linux is ext2, although it supports many other filesystems. FAT is the original filesystem used by DOS. It is an eight-bit filesystem and will support partitions of up to 32 MB. This was no problem in the early 1980s, when most PCs didn't even have hard drives. FAT supports the following file attributes:
• Read-only— When set, the file can't be deleted or changed.
• Archive— Determines whether a file has been changed. This is used by many backup programs.
• Hidden— The file doesn't show up in the directory contents.
• System— Used for system files. System files are treated differently by the operating system.
Later, as hard drives came into use, the 32 MB limitation of FAT became a burden and an improved FAT16 replaced it. FAT16 increased the available size of the filesystem to 2 GB. Other than the filesystem size, FAT16 is essentially the same as the original FAT filesystem. FAT16 is supported by DOS 4.0 and greater, all versions of Windows, and all current versions of Linux.
With Windows 95 release 2, Microsoft introduced FAT32. This increased the size of the filesystem to 2 terabytes, which is larger than any hard drives currently available for PCs. It is also faster and more robust than FAT16.
NTFS is the native filesystem for Windows NT and 2000. Like FAT32, it also supports 2- terabyte filesystem sizes, but the boot partition is currently limited to 7.8 GB. For some files such as database files, NTFS can support up to 16 exabytes. NTFS offers better reliability and security than any FAT-based filesystem.

The reliability factors are beyond the scope of this book, but NTFS security considerations need to be covered. First of all, everything in the filesystem has an owner. By default, the user who creates an object (anything in the filesystem is an object) is the owner. The owner has full rights to the object unless the rights are taken away.
There are also groups, which contain users. Three special group accounts are: administrator, everyone, and guest.
• The administrator account has all rights to the filesystem. This account can change, create, and delete all objects as well as change the rights of other accounts.
• Everyone is a group that includes all the user accounts on the system. This account is used to change the rights for every user on the system.
• The guest account is a default account with minimal rights. It is often used for accounts such as FTP access accounts, which only need access to a few specific files.
Files in NTFS have the same attributes as files in the FAT filesystem: read-only, hidden, system, and archive. Each user and group can also be assigned rights to objects in the NTFS filesystem. The rights that can be assigned are:
• List folder contents— Shows up in a directory listing.
• Read— Can read the contents of the object.
• Read and execute— Can read and execute the object.
• Write— Can change or delete the object.
• Modify— Can change the rights on the file.
• Full control— Has all of the above rights.
There are three settings for the rights: allow, deny, and inherited.
• Allow— Allows rights on the object.
• Deny— Takes away rights on the object.