Disk Scheduling Algorithms and Technologies in Operating Systems

Magnetic disk is a storage device commonly known as a hard disk.

Read-write head is responsible for reading and writing data on the magnetic disk.

There are two types of heads in a hard disk: fixed head and moving head.

🔑 Harddisk with moving head is slower than harddisk with fix head because the moving head needs to change its position to read and write data.

🔑 Shock Protection System (SPS) technology reduces the risk of damage to harddisks caused by unintentional shocks.

🔑 Smart technology allows harddisks to communicate with computers, perform self-checks, and provide reports on their condition.

🔑 Solid State Disks (SSD) offer faster data reading and writing speeds compared to harddisks with magnetic disks.

🔑 Magnetoresistive head technology replaces the older inductive head technology in harddisks, allowing for simultaneous read and write processes.

✨ The video discusses various technologies and algorithms related to disk scheduling.

💡 One of the technologies mentioned is Maximum Likelihood, which converts analog data to digital data, resulting in higher data density and increased data storage capacity.

🔌 Hotswap and plug n play are popular features that allow users to add hardware to a computer without turning it off and easily configure and use the new hardware.

🌱 Environment Protection Agency (EPA) is a technology that helps save energy by enabling power-saving features in hard disks.

🔧 Error Correction Code (ECC) is a technology that can correct reading errors in magnetic disks without having to reread the entire track and sector.

⚡️ Auto transfer is a method that accelerates data transfer from a hard disk to the main memory by using parallel read and write commands.

📝 Data transfer can be accelerated by utilizing third-party servers with advanced features.

💽 The last topic discussed is disk access, which includes algorithms for service order and backup during reading.

➡️ The first algorithm discussed is the First-Come-First-Served (FCFS) algorithm, which serves the first request in the queue.

🔑 The video discusses disk scheduling algorithms, specifically focusing on the SCAN algorithm.

⏭️ The SCAN algorithm prioritizes accessing the nearest and furthest tracks from the initial position of the read head.

💡 Another disk scheduling algorithm mentioned is the LRU algorithm, which moves the read head up to the largest track and then down to the smallest track.

📝 The video discusses different disk scheduling algorithms, including FCFS, SSTF, SCAN, C-SCAN, LOOK, and C-LOOK.

🔄 The algorithms FCFS and SSTF access tracks in the order they appear, while SCAN and C-SCAN scan from one end to the other and then retreat.

↕️ LOOK and C-LOOK move towards the closest track and skip tracks that have already been accessed.

🔑 Disk scheduling algorithms determine the order in which disk requests are processed.

⏩ The circular scan algorithm is similar to the scan algorithm, where the head moves from the starting position to the largest track, accessing all the tracks in between.

🔄 Once the head reaches the largest track, it moves directly to the smallest track without accessing any tracks in between.