Disk Management

Disk Management is a system utility for managing hard disks and the volumes, or partitions, that they contain.

Disk Management enables you to perform most disk-related tasks without shutting down the system or interrupting users; most configuration changes take effect immediately.

Simplified tasks and intuitive user interface. Disk Management is easy to use. Menus that are accessible from the right mouse button display the tasks you can perform on the selected object, and wizards guide you through creating partitions or volumes and initializing or converting disks.

1. DISK MANAGEMENT SUBMITTED BY : ANJALI NEGI & YANGSHAIN LAGZOMJI

2. CONTENTS Overview of disk management Difference between a disc & a disk Disk terminology Disk Structure Disk Scheduling Disk Operations Disk management tools

3. Overview of Disk Management Disk Management is a system utility for managing hard disks and the volumes, or partitions, that they contain. Disk Management enables you to perform most disk-related tasks without shutting down the system or interrupting users; most configuration changes take effect immediately . Simplified tasks and intuitive user interface. Disk Management is easy to use. Menus that are accessible from the right mouse button display the tasks you can perform on the selected object, and wizards guide you through creating partitions or volumes and initializing or converting disks.

4. Introduction to Disk What's the difference between a "disc" and a "disk?“ Discs A disc refers to optical media, such as an audio CD, CD-ROM, DVD-ROM, DVD-RAM, or DVD-Video disc. Some discs are read-only (ROM), others allow you to  burn content  (write files) to the disc once (such as a CD-R or DVD-R, unless you do a  multisession  burn), and some can be erased and rewritten over many times (such as CD-RW, DVD-RW, and DVD-RAM discs). All discs are removable, meaning when you unmount or eject the disc from your desktop or Finder, it physically comes out of your computer.

5. Introduction to Disk(contd..) Disks A disk refers to magnetic media, such as a floppy disk, the disk in your computer's hard drive, an external hard drive. Disks are always rewritable unless intentionally locked or write-protected. You can easily  partition  a disk into several smaller volumes, too. Disks are usually sealed inside a metal or plastic casing (often, a disk and its enclosing mechanism are collectively known as a "hard drive").

6. Disk Terminology

7. Disk Terminology Cylinder It is the sum set of tracks that have the same track value of all discs. A cylinder is a group of tracks with same radius Track It is a circular path on the surface of disk or diskette on which information is magnetically recorded and from which recorded information is read.

8. Disk Terminology(contd..) Sector It is a subdivision of a track on a magnetic disk or optical disk. Each sector stores a fixed amount of user accessible data.

9. Disk Structure

10. Disk Structure The above figure is the internal structure of a typical disk drive. The disk doesn't contain a single disk but a bulk of them which look like CD's and are called Platters. The surface of each platter is logically divided into tracks which are in turn divided into sectors. The both sides of platter are covered with magnetic material. The information is magnetically stored on these materials. There will also be read-write heads used for reading or writing data. These are attached to a disk arm, that moves all the heads as a unit. All the tracks at one arm position form a cylinder. .

11. Transfer time is the time needed for transferring of data between the hard drive and computer. It has two parts 1. The time needed to move the disk arm to the desired cylinder called seek time and 2. The time needed for the desired sector to rotate under the read-write head called rotational latency

12. Disk Performance Parameters Seek Time The time it takes to move the disk arm to the required cylinder Rotational Latency The time it takes for the disk to rotate so that the required sector is above the hard disk Access Time The time it takes to get in position to read or write. Seek time + Rotational Latency Time to get the data Access Time + Transfer time

13. Disk Scheduling A disk operation request specifies several pieces of information: Is this input or output? Disk address for the transfer . Memory address for the transfer Number of bytes to be transfered When a request is initiated by a process, if the disk is available, the request is serviced immediately If the disk is busy, a request queue can form. Upon completion of a disk request, the operating system can choose which pending request to service next We discuss several disk scheduling algorithms that determine how to choose the next request to service

14. First Come First Served In FCFS, we process the requests in the order they arrive, without regard to the current position of the heads . Shortest Seek Time The SSTF disk scheduling algorithm moves the heads the minimum amount it can to satisfy any pending requests

15. Scan Disk Scheduling The read/write heads are move in toward the spindle, then out toward the platter edge, then back toward the spindle and so forth.

16. HAVE YOU EVER HEARD OF A HEAD CRASH???

17. A  head crash is a hard-disk failure that occurs when a  read–write head of a hard disk drive comes in contact with its rotating  platter, resulting in permanent and usually irreparable damage to the magnetic media on the platter surface. It is most commonly caused by a sudden severe motion of the disk

18. Disk Management What is Disk Management? Microsoft   Windows  utility that was introduced with  Windows  XP as a replacement to the fdisk command that enables users to view and manage the disk drives installed in their computer and the partitions associated with those drives. As can be seen in the picture below, each drive is displayed followed by the layout, type, file system, status, capacity, free space, % free, and fault tolerance.

19. OPERATIONS PERFORMED ON DISK

20. How to partition hard disk

21. Extend Volume You can add more space to existing primary partitions and logical drives by extending them into adjacent unallocated space on the same disk. To extend a basic volume, it must be raw or formatted with the NTFS file system. You can extend a logical drive within contiguous free space in the extended partition that contains it. If you extend a logical drive beyond the free space available in the extended partition, the extended partition grows to contain the logical drive.

22. Shrink value You can decrease the space used by primary partitions and logical drives by shrinking them into adjacent, contiguous space on the same disk. For example, if you discover that you need an additional partition but do not have additional disks, you can shrink the existing partition from the end of the volume to create new unallocated space that can then be used for a new partition .

23. Change driver letter and path You can use Disk Management to assign a mount-point folder path (rather than a drive letter) to the drive. Mount-point folder paths are available only on empty folders on basic or dynamic NTFS volumes.

24. Reactivate Volume A dynamic disk may become Offline if it is corrupted or intermittently unavailable. A dynamic disk may also become Offline if you attempt to import a foreign (dynamic) disk and the import fails. An error icon appears on the Offline disk. Only dynamic disks display the Missing or Offline status.  Only dynamic disks can be reactivated.

25. Install disks in the new computer If the disks are external, plug them into the computer. If the disks are internal, make sure the computer is turned off and then physically install the disks in that computer. Start the computer that contains the disks you moved and follow the instructions on the Found New Hardware dialog box.

26. Initialize Disk New disks appear as Not Initialized. Before you can use a disk, you must first initialize it. If you start Disk Management after adding a disk, the Initialize Disk Wizard appears so you can initialize the disk. The disk is initialized as a basic disk .

27. Disk Management Tools Here are some of the free tools for partitioning, cloning, diagnostics, repair, recovery, encryption, wiping or drive information

28. TestDisk TestDisk allows you to repair boot sectors, recover deleted partitions, fix damaged partition tables, and recover deleted data, as well as copy files from deleted/inaccessible partitions. The choice of actions you can perform on each partition include: (1)    analysing the partition for the correct structure (and repairing it accordingly if a problem is found) (2)    changing the disk geometry (3)    deleting all data in the partition table (4)    recovering the boot sector (5)    listing and copying files (6)    recovering deleted files (7)    creating an image of the partition

29. WinDirStat It is a disk usage and clean-up utility that allows you to visualize how data is distributed across a disk and what types of data or which locations are hogging up most space.

30. Defraggler Defraggler is a lightweight yet powerful defragmentation tool that allows you to defrag whole drives or selected files/folders. It has an intuitive interface that helps you to quickly visualize how much of the drive is fragmented and which files are causing most fragmentation.

31. HD Tune It can measure the read/write performance of your HDD/SSD, scan for errors, check the health status and display drive information.

32. Recuva In a few simple clicks, Recuva allows you to recover files from your computer that were accidentally deleted or that have become damaged or corrupt. The Quick-Start Wizard walks you through the recovery process by asking a couple of simple questions about what you want to recover and where you want to recover it from and then initiating a quick scan. You can skip the wizard and go straight to the application if you wish.

33. References

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