PPT-Disks and I/O Scheduling

Don Porter Portions courtesy Emmett Witchel 1 Quick Recap CPU Scheduling Balance competing concerns with heuristics What were some goals No perfect solution Today Block device scheduling. Chapter 5: CPU Scheduling. Basic Concepts. Scheduling Criteria . Scheduling Algorithms. Thread Scheduling. Multiple-Processor Scheduling. Operating Systems Examples. Algorithm Evaluation. Objectives. RAID (Redundant Arrays of Independent Disks). Disk . organization technique that manages a large number of disks, providing a view of a single disk of. High capacity and high speed up using multiple disk in parallel. I/O Management and Disk Scheduling. Patricia Roy. Manatee Community College, Venice, FL. ©2008, Prentice Hall. Operating Systems:. Internals and Design Principles, 6/E. William Stallings. Given Credit Where It is Due. Phil Armitage. Colorado. Processes in Protoplanetary Disks. Disk structure. Disk evolution. Turbulence. Episodic accretion. Single particle evolution. Ice lines and persistent radial structure. Transient structures in disks. Group Report. Ken Ayoob Dean, College of Arts, Humanities & Social Sciences . . (CAHSS). Richard Bruce CAHSS . Office Manager. , Former Psych Department . . Coordinator & University Senator. and RAID. Outline. Disks. Disk scheduling algorithms. Redundancy in storage . systems, RAID. 2. Disk Geometry. Disks have multiple platters. Each platter has . an arm and a head for accessing data. The arms for the different platters move together. Pawel. . Artymowicz. U of Toronto. MRI turbulence. Some non-MRI turbulence. Roles and the dangers of turbulence. UCSC Santa Cruz 2010. I borrowed some . figures & slides from. X. Wu (2004). R. Nelson (2008). BYU CS 345. Disc Scheduling. 2. CS 345. Stalling’s Chapter. #. Project. 1: Computer System Overview. 2: Operating System Overview. 4. P1:. Shell. 3: Process Description and Control. 4: Threads. 4. OPERATING SYSTEMS. SCHEDULING. 5: CPU-Scheduling. 2. What Is In This Chapter?. This chapter is about how to get a process attached to a processor.. It centers around efficient algorithms that perform well.. Reads and writes are equally fast.. Arrays of these disks are used to provide highly reliable storage.. Increasingly popular as they are fast and do not contain moving parts.. Magnetic Disks.. . What is a magnetic disk and how it works. Two main types: Magnetic and Optical. Random access to memory. The hardware must be controlled by driver software called the “controller” in order to be used. Hard Disks, RAID, and Error Handling. Chapter 6: CPU Scheduling. Basic Concepts. Scheduling Criteria . Scheduling Algorithms. Thread Scheduling. Multiple-Processor Scheduling. Real-Time CPU Scheduling . (Skip). Operating Systems Examples. Use multiple smaller disks (c.f. one large disk). Parallelism improves performance. Plus extra disk(s) for redundant data storage. Provides fault tolerant storage system. Especially if failed disks can be “hot swapped”. CSE 2431: Introduction to Operating Systems. Instructor: Adam C. Champion, Ph.D.. Reading: Chap. 11. , §§13.5, 14.5.6 . [OSC]. Outline. Disk Organization. Disk Performance. Disk Scheduling Algorithms.