L-6.2: Disk Access Time with Example | Seek Time, Rotational Time and Transfer Time
Gate Smashers・2 minutes read
Seek time is crucial in disk architecture as it determines the time taken to access data tracks, while rotational time and transfer time are also essential factors affecting overall disk performance. Queue time plays a role in delaying data access as requests wait in a buffer, highlighting the importance of minimizing seek, rotational, and transfer times for optimal disk performance.
Insights
- Seek time, the duration for the read-write head to locate the desired track on a disk, significantly impacts overall performance by affecting how quickly data can be accessed.
- Disk access time is a composite of seek time, rotational time, and transfer time, with each component playing a crucial role in determining the efficiency of data retrieval processes, highlighting the intricate interplay of hardware components in storage systems.
Get key ideas from YouTube videos. It’s free
Recent questions
What is seek time in disk architecture?
Seek time is the time taken by the read-write head to reach the desired track on a disk. It is crucial as it determines the time taken to access data, impacting overall performance.
How is rotational latency calculated?
Rotational latency is half of the rotation time of the disk. It represents the time taken for the desired sector to be reached, essential for efficient data access.
What factors determine transfer rate on a disk?
Transfer rate on a disk is determined by the number of heads, track capacity, and rotations per second. These factors influence the speed at which data can be transferred.
What is the total disk access time composed of?
The total disk access time is the sum of seek time, rotational time, transfer time, and optionally, controller time. These components collectively determine how quickly data can be accessed.
What does queue time refer to in disk operations?
Queue time in disk operations refers to the time requests wait in a buffer before being fulfilled by a slower disk compared to the CPU. It involves key time components such as seek time, rotational time, and transfer time.
Related videos
Gate Smashers
L-6.3: Disk Scheduling Algorithm | Operating System
Abelardo Pardo
Hard Disk Drives
Gate Smashers
L-6.1: Hard Disk Architecture in Operating System in Hindi
Gate Smashers
Lec-94: Numerical Example on I/O Cost in Indexing | Part-1 | DBMS
Gate Smashers
Lec-93: Why Indexing is used | Indexing Beginning | DBMS
Summary
00:00
Understanding Disk Access Time Components
- Seek time is the time taken by the read-write head to reach the desired track on a disk.
- Disk architecture involves multiple platters connected by a spindle that rotates clockwise or anticlockwise.
- Platters have upper and lower surfaces with circular tracks where data is stored.
- The read-write head moves track by track, either forward or backward, to access data.
- Seek time is crucial as it determines the time taken to reach the desired track, affecting performance.
- Rotation time is the time taken for one full rotation of the disk, essential for accessing data sectors.
- Rotational latency is half of the rotation time, representing the time taken to reach the desired sector.
- Transfer time is calculated by dividing the data to be transferred by the transfer rate, usually given per second.
- Transfer rate is determined by the number of heads, track capacity, and rotations per second.
- The total disk access time is the sum of seek time, rotational time, transfer time, and optionally, controller time.
14:19
Understanding Queue Time in Computer Systems
- Queue time refers to the time requests wait in a buffer before being fulfilled by a slower disk compared to the CPU, with the key time components being seek time, rotational time, and transfer time.
