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Windows File Systems CGS2564. Who Cares? C:\Documents\Taxes\Tax04.DOC.

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Presentation on theme: "Windows File Systems CGS2564. Who Cares? C:\Documents\Taxes\Tax04.DOC."— Presentation transcript:

1 Windows File Systems CGS2564

2 Who Cares? C:\Documents\Taxes\Tax04.DOC

3 Formatting a Disk Organizes tracks and sectors Sets up data structures on first track Boot sector Root directory File allocation table (2) Performs surface scan Checks for bad sectors

4 Disk Data Structures

5 Boot Sector Information about the disk itself OS name and version number. Bytes per sector. Sectors per cluster in the data area. Number of reserved sectors. Max. number of entries in the root directory. Total number of sectors. Media description (is this a hard disk?). Number of sectors per FAT Number of sectors per track. Number of disk read heads. Number of hidden sectors. BOOT-strap program routine, which starts the operating system.

6 Disk Directory A database of what is on the disk

7 File Allocation Table A table of where files are located

8 Units on a Disk Sector – the smallest unit of data storage 512 bytes (½ K) Allocation Unit or Cluster The actual minimum space allotted to a file One or more sectors

9 Operating SystemFile System(s) DOSFAT16 Windows 95/98FAT16, FAT32 Windows NTFAT16, NTFS Windows 2000/XPFAT16, FAT32, NTFS File Systems

10 FAT 16 Inefficient storage on large disks Size of FAT is fixed (2 16 entries) As disk capacity increases cluster size increases Maximum disk size = 2 GB

11 FAT 32 More efficient storage on large disks Increased FAT size (2 32 entries) So cluster size can be decreased Maximum disk size = 32 GB

12 NTFS Uses Master File Table system (MFT) Even more efficient use of disk space Support for larger disk sizes Windows File Protection feature (WFP) Prevents alteration or deletion of critical system files Extended file attributes File permissions But Not accessible by other file systems

13 NTFS Cluster Size

14 Volume SizeFAT16 Cluster SizeFAT32 Cluster SizeNTFS Cluster Size 33MB – 64MB1KB512 bytes 65MB – 128MB2KB1KB512 bytes 129MB – 256MB4KB2KB512 bytes 257MB – 512MB8KB4KB512 bytes 513MB – 1GB16KB4KB1KB 1GB – 2GB32KB4KB2KB 2GB – 4GB64KB4KB 4GB – 8GBNot supported4KB 8GB – 16GBNot supported8KB4KB 16GB – 32GBNot supported16KB4KB File Systems and Cluster Size

15 Slack Space Wasted space not used by a file

16 Comparison of Cluster Usage

17 File Attributes Archive Indicates if file has changed Used by backup programs Read-only Protect file from being overwritten Hidden Hide file from view Additional NTFS Attributes Compress Encrypt Index

18 Filenames Pre Windows 95 8 characters max No spaces VFAT - Windows 95/98 MFT – Windows 2000 Support for long filenames and spaces Stores two different filenames for each file For backward compatibility

19 Long Filenames

20 Aliases MS-DOS filenames for long filenames

21 File Path Drive:\Directory\Subdirectory\Filename.ext C: Program Files My Documents Assignments Assign03.doc Projects WINNT C:\My Documents\Assignments\Assign03.doc

22 Types of Files User Data Files Created by user in application

23 Types of Files Program Files Make up application itself

24 Types of Files Executable files Actually run the program

25 File Association Or Registered File type Association between A file extension and A file type Then between That file type and A programs executable file


27 Types of Files Binary files Contain program instructions, document information, formatting codes, etc. User data and program files Pure text or ASCII files Contain only standard text characters User data and program files How to tell? View in Notepad

28 Pure Text File

29 Binary File

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