PPT-Disks Disks.. Most common (magnetic hard disks)

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. 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. Prince Sultan College For Woman. Dept. of Computer & Information Sciences. CS 251. Introduction to Computer Organization . & Assembly Language. Lecture 8. (Computer System Organization). Secondary Memory. 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. ASHIMA KALRA . . Hard disks.. . Floppy disks.. . CD ROMs.. . DVDs.. . INDEX. ….. Floppy Disks. The first floppy disks were 8 Inches in diameter.They hold upto 256 KB.. The next generation were 5.25 inches in diameter.It Could hold up to 1.44 MB.It is a standard one.. 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. 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. 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). ?. Holds. data, instructions, and information for future use.. A . storage medium . is the physical. material on which data is stored.. Examples. : DVD, CD, flash-drive, and floppy disk.. Storage. Capacity. 2. Understanding and Selecting Storage. Save files to a variety of media types, including:. Floppy disks.. Flash random access memory (RAM) devices.. CDs and . DVDs.. Hard disks. . 3. Disk Drives. Hard disk drive. 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. 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”. Chapter 8 Adding Disks Loops Run instructions again, and again, and again…. Check some condition If true, repeat 2 types of loops for loop while loop First, the variable used in loop condition must be initialized, then execution of the loop begins. 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. 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.