Disk scheduling & Disk management

disk scheduling and disk management

1. Disk scheduling & D isk management By k.Sivapriya Msc (IT) Nadar Saraswathi College Of Aarts and Science Theni

2. concept Disk scheduling Important of disk scheduling Seek time Rotational Latency Transfer time Disk Access Time Disk Response Time Purpose of disk scheduling Disk management Disk management availability How to use disk management More information on disk management

3. Disk Scheduling Disk scheduling   is done by operating systems to schedule I/O requests arriving for the disk. Disk scheduling is also known as I/O scheduling.

4. Important of disk scheduling Multiple I/O requests may arrive by different processes and only one I/O request can be served at a time by the disk controller. Thus other I/O requests need to wait in the waiting queue and need to be scheduled. Two or more request may be far from each other so can result in greater disk arm movement. Hard drives are one of the slowest parts of the computer system and thus need to be accessed in an efficient manner.

5. Seek Time Seek time is the time taken to locate the disk arm to a specified track where the data is to be read or write. So the disk scheduling algorithm that gives minimum average seek time is better.

6. Rotational Latency Rotational Latency is the time taken by the desired sector of disk to rotate into a position so that it can access the read/write heads. So the disk scheduling algorithm that gives minimum rotational latency is better .

7. Transfer Time Transfer time is the time to transfer the data. It depends on the rotating speed of the disk and number of bytes to be transferred.

8. Disk Access Time  Disk Access Time is : Disk Access Time = Seek Time + Rotational Latency + Transfer Time

9. Disk Response Time Response Time is the average of time spent by a request waiting to perform its I/O operation.  Average Response time  is the response time of the all requests.  Variance Response Time  is measure of how individual request are serviced with respect to average response time. So the disk scheduling algorithm that gives minimum variance response time is better.

10. Purpose of Disk Scheduling The main purpose of disk scheduling algorithm is to select a disk request from the queue of IO requests and decide the schedule when this request will be processed .

11. Disk management Disk Management is an extension of the Microsoft Management Console that allows full management of the disk-based hardware  recognized by Windows.  Disk Management is used to manage the drives installed in a computer like hard disk drives  (internal and  external),   optical disk drives, and flash drives   . It can be used to partition   drives, format  drives, assign drive letters, and much more.

12. Disk Management Availability Disk Management is available in most versions of Microsoft Windows including  Windows 10, Windows 8, Windows 7, Windows Vista, Windows XP and Windows 2000.

13. How to Use Disk Management Disk Management has two main sections a top and a bottom: The top section of Disk Management contains a list of all the partitions, formatted or not, that Windows recognizes. The bottom section of Disk Management contains a graphical representation of the physical drives installed in the computer.

14. More Information on Disk Management The Disk Management tool has a graphical interface like a regular program and is similar in function to the command line utility  diskpart , which was a replacement  of an earlier utility called  fdisk .

15. Cont… You can also use Disk Management to check free hard device space. Look under the Capacity and Free Space   columns (in the  Disk List  or  Volume List  view) to see the total storage capacity of all the disks as well as how much free space is remaining, which is expressed in units (i.e. MB and GB) as well as a percentage.

16. Cont… Disk Management is where you can create and attach virtual hard disk files in Windows 10 and Windows 8. These are single files that act as hard drives, which means you can store them on your main hard drive or in other places like external hard drives.