Wednesday, May 28, 2008

Windows Vista File System Formats, Partitions, and Volumes

Managing the file systems, partitions, and volumes are key in the setup of Windows Vista. Without an understanding of these concepts, you can’t even install an operating system from scratch. In this section, we will cover the file systems supported by Windows Vista, the types of partitions available, and volumes. Continuing on with our previous example, we must decide on what file system to choose, what type of partition(s) will be created, and the type of volume used so we will can into practice what we learn. Before doing so, we must define a file system, a partition, and a volume. We must also be familiar with the choices we have in each. For example, when we create a partition with the new drive, should we create a primary partition or create an extended one? Or should we do a combination of both? As you can see, there is a lot to think about. Before moving on, we should first define some important terms and concepts.

Disk Management Terms

File System. A system for storing and organizing folders and files on a storage medium making it easy to find and access them—for example, FAT32, NTFS, and so on.

Format. Prepares a disk for storage using a particular file system. Partition Used to segment hard drives into isolated sections. Each partition is treated by the operating system as a separate drive.

Volume. Can be a disk or a subdivision of a disk that is formatted and available for storage.

Partitions and Volumes

The terms partitions and volumes are used interchangeably. After you install a new disk, you must create at least one partition on the new disk. Windows Vista supports two types of volumes:

■ Basic volumes

■ Dynamic volumes

Basic volumes are partitions on a basic disk. The storage for a basic volume must reside on a single physical disk. Basic volumes can only be simple volumes. So a basic volume is made up of:

■ Primary partitions (Master Boot Record [MBR] and Globally Unique Identifier Partition Table [GPT types])

■ Logical drives within extended partitions (only available with MBR partition styles)

Dynamic volumes reside on dynamic disks and include simple and spanned volumes. Simple volume types under dynamic volumes are the equivalent of primary partitions. Some rules to be aware of with simple volumes on dynamic disks:

■ If only one dynamic disk exists, you can only create simple volumes.

■ Simple volumes can be increased in size to include any unallocated space on a physical dynamic disk or even on a separate disk.

Spanned volumes are able to combine areas of unallocated space from two or more disks into one logical volume. The areas of unallocated space do not have to be the same size. In other words, you can have one drive that is 100GB and another that is 50GB created as a spanned volume and appearing as one logical volume. When implementing spanned volumes, keep these points in mind:

■ NTFS or unformatted volumes can only be extended.

■ After the creation of a spanned volume, you cannot delete any portion of it without

deleting the entire volume.

■ You cannot stripe spanned volumes.

■ Spanned volumes do not provide fault tolerance.

What we need to do now is explore the different types of partitions available to us in Windows Vista so we make the best decision possible for our own scenarios.We know that a basic disk that can only contain basic volumes can have up to four partitions, but if we go further, we see that this limitation actually applies to those disks that use a Master Boot Record (MBR). Basic disks using GUID Partition Tables (GPT) can have as many as 128 partitions, but more about partition styles later. The following are descriptions of the partition types available in Windows Vista.

Primary Partition. The partition on a drive that holds and starts the operating system. Multiple primary partitions can reside on a disk, but not all have to hold an operating system.

Extended Partition. A partition that does not hold a drive letter in itself but can be divided into logical drives. An extended partition is not formatted; the logical drives that reside on it are instead.

Active Partition. The partition from which x86-based systems start up. The active partition must be on the first physical drive (Disk 0).

Boot Partition. The partition where the Windows system files are located.

System Partition. The partition that contains the bootstrap files that Windows uses to start the system. The system partition displays the boot menu.

Now that we’ve reviewed volumes and partitions and the types available, we must define what partition styles are and discuss the two varieties available.

Partition Style

Most administrators who have not installed Windows 2003 Server with Service Pack 1 or the 64-bit version of Windows XP Professional will find the concept of partition styles a bit foreign. A partition style is the method that Windows Vista uses to organize partitions on a disk. Windows XP Professional only supported MBR partition styles on x86 computers while also supporting GPT on its 64-bit version. Windows Vista supports both on the x86 architecture.

Master Boot Record

The Master Boot Record (MBR) is the traditional partition style. The MBR contains a partition table that describes where the partitions are located on the disk. Before Windows 2003 SP1 and XP Professional 64-bit, administrators never had to worry about choosing the MBR, it was the only style supported. MBR disks can support up to four primary partitions or three primaries and one extended. Within the extended partition you can create unlimited logical drives.

Globally Unique Identifier Partition Table

The Globally Unique Identifier Partition Table (GPT) provides a more flexible way of partitioning disks than the older MBR scheme. It was introduced as part of Intel’s Extensible Firmware Interface (EFI).This specification defines a new model for the interface between operating systems and platform firmware. You can find more information about EFI at www.intel.com/technology/efi. Although it may seem a bit more confusing with the use of GPT, this partition style can reside on either basic disks or dynamic disks. GPT in Windows Vista supports up to 18 exabytes and 128 partitions per disk. Since GPT does not limit administrators to four primary partitions, extended partitions and logical drives are not available with it.

File Systems

A file system by definition is the structure in which files are named and where they are placed logically for storage and retrieval. File systems specify conventions for naming files. This includes the maximum number of characters in a filename and which characters are allowed. For a file system to be placed on a volume, the operating system must format it.

An allocation unit (or cluster) is the smallest amount of disk space that can be allocated to hold a file. All file systems under Windows Vista organize their drives based on allocation units. This is determined by the number of sectors the allocation unit contains. An example would be a disk that uses 512 byte sectors: a 512-byte allocation unit contains one sector, whereas a 4KB allocation unit contains eight sectors. Each file system under Windows Vista uses different allocation unit sizes depending on the size of the volume, plus each file system has a maximum number of allocation units it can support. The smaller the allocation unit size the more efficient a disk stores information.

This is because the unused space within an allocation unit cannot be used by another file. So the smaller the cluster size (or allocation unit) the more efficient the file system.

Let’s examine the different file systems supported by Windows Vista:

■ File Allocation Table (FAT)

■ File Allocation Table 32 (FAT32)

■ New Technology File System (NTFS)

■ Universal Disk Format (UDF)

■ CD-ROM File System (CDFS)

Selecting which file system is best depends on the type of media you are formatting. With hard disks, you have the option of choosing FAT, FAT32, or NTFS. Optical media such as DVDs or CDs can be formatted using UDF or CDFS. Windows Vista provides you with choices that should fit any file system needs. We will now go over each of the file systems Windows Vista supports.

FAT

File Allocation Table (FAT), sometimes referred to as FAT16, has its origins back in the days of DOS, so it’s been around a long time. FAT is a 16-bit file system. It can support volume sizes of up to 4GBs, although in today’s world that wouldn’t even be ideal for holding the operating system, much less the pagefile that accompanies it. It does not provide any file system security. FAT is appropriate for floppy disks or very small hard drive partitions. It supports the old 8.3 filename format. FAT’s allocation unit size can grow to 64KB, which on drives up to 4GB in size wastes a lot of space.

FAT32

Introduced with Windows 95 OSR2, FAT32 provides better support for users. FAT32 supports long filenames (LFN) of up to 255 characters. In theory, FAT32 supports volumes up to 8TB (8 terabytes), but under Windows Vista, you are forced to use NTFS for volumes larger than 32GB. Just like its predecessor, FAT32 does not include any file system security. The size of a FAT32 allocation unit is determined by the system, and can range in size from 1 sector (512 bytes) to 128 sectors (64KB). FAT32 is ideal for USB flash drives.

NTFS

One could actually write an entire book on NTFS—in fact, some have. What you need to know about NTFS is it is the preferred file system of Windows Vista. NTFS is a true 64-bit file system. It always has been ever since NT 3.1. NTFS can support drives up to 16TBs (minus 64KBs) in size. It uses a Master File Table (MFT), which is the first file located on an NTFS drive. The MFT keeps records of each file and directory on the drive. NTFS is also a recoverable file system guaranteeing the consistency of a volume by using transaction logging and recovery techniques. More detailed information about NTFS and its architecture is available on the Internet, but is beyond the scope of this book. If you convert either a FAT or FAT32 drive to NTFS, you cannot convert it back. If you need to change the drive back to the previous file system, you would need to reformat the drive.

NTFS Features

Indexing Service. Provides the ability to perform searches on directories located on the system.

File and Folder Permissions. Provides the ability to set permissions on files and folders. Can specify which users or groups have access.

Encryption. Provided by the BitLocker Drive Encryption or the Encrypted File System (EFS). BitLocker encrypts entire hard drives while EFS can encrypt individual files and directories.

Disk Quotas. Controls disk space usage on NTFS volumes.

File Compression. Provides the ability to compress individual files, files in a directory, and even entire NTFS volumes.

Mounted Drives. Volumes attached to an empty folder on an NTFS drive. Functionality is similar to other volumes except that mounted drives are assigned labels and not drive letters.

Distributed Link Tracking. Ensures that OLE (Object Linking and Embedding) links shell shortcuts continue to work even after the target file is moved or renamed.

Sparse Files. Used by the Indexing Service, sparse files provide a method of saving disk space for files containing meaningful data.

POSIX Compliance. Available in Vista only after the Subsystem for Unix-based Applications feature is enabled.

NTFS Change Journal. Provides a persistent log of changes made to files on an NTFS volume. Is used to track information about files that are added, deleted, and/or modified.

Compact Disc File System

Compact Disc File System (CDFS) is the file system used on compact discs. Windows Vista is able to read from, and write to, compact discs that are formatted in the ISO 9660 standard. CDFS is considered an old format and has been all but replaced by UDF.

Universal Disk Format

Universal Disk Format (UDF) is a file system defined by the Optical Storage Technology Association. UDF is based on ISO 13346 and is the successor to the ISO 9660 (CDFS) format. UDF is used for removable media like DVDs and CDs. Windows Vista is able to read and write to versions 1.02, 1.50, 2.0x, and 2.50. It can read, but not write to, 2.60.

*.* Source of Information : Syngress How to Cheat at Microsoft Vista Administration



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