CSE380 - Operating Systems. Communicating with Devices
|
|
- Megan Spencer
- 6 years ago
- Views:
Transcription
1 CSE380 - Operating Systems Notes for Lecture 15-11/4/04 Matt Blaze (some examples by Insup Lee) Communicating with Devices Modern architectures support convenient communication with devices memory mapped I/O ports via special I/O instructions Hardware can hide details and support efficient use of devices interrupts device controllers DMA Main problems for OS: protocol for communicating with device controllers linking processes with the devices they are using
2 Kinds of devices Some devices are naturally associated with the OS itself clock interrupt, etc, OS problem: protocol for communicating w/ device this is what we ve looked at so far Others naturally associated with some user process serial ports, terminal lab instruments, etc. additional OS problems: associating process with device; relaying data between device and process Still others shared with many processes simultaneously disks, network interfaces, etc. additional OS problems: demultiplexing (e.g., file system abstraction); relaying data between device and appropriate process Devices and user processes Naming problem: how does a user process reference a given device? Communication problem: how does a user process send & received data to & from a given device? Also, blocking and unblocking process when I/O not ready Control problem: how can user process issue privileged commands to a device Contention and multiplexing problems: how does OS manage multiple processes access to a given device
3 Naming Devices Even with memory mapped I/O, it isn t usually reasonable to require processes to hard-code the addresses used for communicating with the various devices installed on a system Instead, many operating systems have a notion of a device namespace that processes can use to refer to devices System calls can operate on devices in this namespace, similar to system calls operating on files e.g., open them, etc. On Unix systems, this is integrated with the file system e.g., the first printer might be named /dev/printer1 User Process Communication with Devices Once a process tells the OS the name of a device it wants to use, how does it communicate with it? If the device uses memory-mapped I/O, the OS could map the device s addresses to a page in the process virtual address space e.g., a system call that takes the name of the device and returns a pointer to the mapped memory advantage: no direct O/S involvement on each I/O disadvantage: no chance for O/S involvement in I/O Or the process could treat the device like a file syscall returns file descriptor, process does read, write, etc assumes device can use file-style I/O Or the OS could have special system calls for communicating with a particular device
4 User Process Control of Devices Not all operations on devices can/should be available to user processes e.g., installing interrupt handlers But some functions need to be made available e.g., setting the bit rate on a serial interface device interface to such operations is often esoteric Usual solution is to perform these functions through standardized system calls device driver provides interface between control system call and device Unix systems use the ioctl system call for this Multiplexing, contention, scheduling devices Some devices might be used by more than one process at a time e.g., disks (via file accesses) Some sequences of operations must be done atomically, others must be translated first e.g., move disk head and write sector Solutions: Have all access go through a subsystem that translates requests, schedules I/O and enforces order might be in OS kernel or in a user process e.g., file system manages access to disks
5 Device drivers Device drivers are the interface between the OS and a device OS usually provides a standard set of hooks for installing new device drivers driver includes device-specific interrupt handlers and device-specific I/O routines and device-specific control routines (ioctl) Device drivers may be hard-coded part of OS kernel, dynamically loaded, or even part of a user process depends on OS and kind of device Example device: serial interface ( tty ) Asynchronous serial port (RS-232) is a standard communication interface to many kinds of peripheral equipment modems, terminals, printers, lab equipment, etc Can send and receive bits at low-moderate speed (e.g., 28Kbps) typical transfer unit is one byte (8 bits) devices usually issue an interrupt when input comes in or output queue ready Many options and configurations speed, parity bit, start/stop bits, flow control, etc.
6 Serial interface device drivers Read and write syscalls would be a natural interface for sending and receiving data Need input and output buffers: interface is much slower than CPU might still be sending last byte when process tries to send next one data might arrive at any time even though process hasn t done read yet buffering avoids need for busy waiting and helps prevent lost data Also need some way to set options e.g., speed, parity, etc Serial interface in Unix Namespace in file system e.g., /dev/tty04 open of a tty returns a file descriptor can do read & write with it, just like a file Device driver includes interrupt handler device sends interrupt when new data arrives and when output queue available Options set by an ioctl arguments include file descriptor and options ioctl options determined by driver man 4 tty, man 2 ioctl for details
7 Pseudo-terminals in Unix The serial interface is so useful that it s even used when there s no physical serial device two process can be hooked together via a pseudo terminal; a write to one is available as a read to the other as far as the processes are concerned they re talking to a serial port A virtual device driver relays bytes between pseudo terminals No actual hardware involved, but still uses device drivers Next example: Disk Drives We ve already talked about how a disk works Soon we ll talk about how file systems use disks file system acts as the interface between most user processes and the disk devices processes don t communicate directly with the disk driver file system does disk scheduling and implements the system s file structure But right now, we ll talk about how the OS communicates with disks
8 Disk Access Disk interface: move head to location, read/write sector addresses are complex (cylinder number, head number, sector number) sectors can be given logical numbers that get decoded by controller Driver provides simpler interface to processes open, seek to byte #, read, write provides view of disk as one big linear array of bytes standard open, seek, read and write system calls work Design considerations for driver what is the interface provided by the controller? how to optimize performance Disk Scheduling Time to read or write a sector is influenced by: seek time (usually longest) rotational delay (usually in the middle) transfer time (usually smaller) Controller and device driver can each exploit knowledge of disk structure to improve performance in general, there will be a queue of pending requests for reads and write in what order should they be sent to the disk?
9 Disk-Arm Scheduling: FCFS Basic strategy for moving disk arm across cylinders: First-come-first-served queue disk queue: 98, 183, 37, 122, 14, 124, 65, 67 initial r/w head position: cylinder ! ! " total head movement = = we move across 640 tracks In practice: OK for small load, low variance of waiting time Disk-Arm Scheduling:SSF Shortest Seek-Time First (SSF): Pick the closest one next Consider example from last slide: ordering will be 65, 67, 37, 14, 98, 122, 124, 183 total head movement (starting at 53) = = 236 tracks In practice: Better performance, but high variance (starvation possible)
10 Disk-Arm Scheduling: Scan Maintain a direction bit Pick the request with shortest seek time in current direction first, and change direction only at edges. Previous example: Assume head was moving toward 0. Ordering: 37, 14, 0, 65, 67, 98, 122, 124, 183 total head movement = = 236 In practice: Almost as good as SSF in mean wait time, but lower variance. Disk-Arm Scheduling Algorithms Elevator (Look): Variation of Scan algorithm Change direction if no more requests farther down in current direction Preferable to Scan (gives total head movement 208 in previous example) Another variant: circular elevator Always scan in the same direction servicing cylinders in a circular manner (i.e. go to lowest numbered pending request if no requests are higher than current position)
11 Fault Tolerance for Disks Underlying disk mechanical disk technology is unreliable and failure prone Corrupted bits and sectors Manufacturing defects Disk crashes Many countermeasures implemented directly by disk and controller hardware Error correction within sectors Extra sectors within a disk usually not visible to OS Other measures can be implemented by OS Backups at intervals Automatic mirroring RAID (provides redundancy and parallelism) Bad Sectors Sectors become defective for a various reasons disk hardware often can detect this via ECC Every track has extra (spare) sectors that are not part of logical address space Disk controller keeps track of bad sectors and does remapping of sector numbers Two choices for renumbering Substitute a spare sector for defective Renumber all by shifting Obvious tradeoff Efficiency of reading consecutive sectors Initial effort of rewriting preambles in each sector
12 Read Errors After reading a sector, what if reduantcy code indicates an error? ECC may allow error correction Read again, and error may go away If read error seems to happen repeatedly, then the sector can be marked as bad, and replaced by a spare sector OS may need to keep track of bad sectors, or it may be transparently handled by controller hardware Backup process may have to manage bad sectors Reliability by Redundancy Mirroring (or Shadowing): duplicate disks Write writes every block to both of the disks Read can be performed from either disk this can be exploited to allow parallelism and speeding up of reads mainly for error correction: if first read fails, try the other Crash recovery: If one disk crashes, then the other one can be used to restore data If failures are independent, this dramatically increases meantime to failure Mirroring can be managed by device controller hardware (if it can handle multiple disks) or by the OS software Disadvantage: duplicate disks are expensive (twice the cost) and can be slow if not mirrored in hardware
13 RAID: Redundant Array of Independent Disks Basic idea: spread work over several physical disks RAID controller talks to OS just like a device driver and manages a suite of disks to improve reliability and performance Striping: Organize logically consecutive chunks of data across different disks to improve performance Striping can be at bit-level, byte-level, or sector-level Incoming request is split into all relevant disks by RAID controller, and their outputs are put together Redundancy through duplication: Multiple requests can be load-balanced Error recovery on faults RAID Level 0 Array of disks with block-level striping Stripe = k sectors (for suitably chosen k) First k sectors are on first stripe of first disk, next k sectors are on first strip of second disk, and so on Advantages: A large request spanning multiple stripes can be parallelized easily Not much overhead Used in high-performance applications Disadvantages No redundancy Mean-time to failure is, in fact, less than standard disks (why?) No parallelism for small requests
14 RAID Level RAID Level 1 Like mirroring, but with striping of level 0 Use same number of backup disks with same striping Same benefits/issues as in mirroring
15 RAID Level 2 Called memory-style error correcting code organization Uses bit-level striping Some of the bits used for parity or other error correction Sample: 4-bits of data encoded by additional 3-bits of ECC, and resulting 7 bits stored on 7 different disks CM-2 machine: 32-bits of data with 7-bits of ECC spanning over array of 39 disks Advantages Great parallelism for read as well as write Even if one disk crashes, all data can be recovered (due to ECC) Disadvantages Drives have to synchronized Overhead in putting together reads from different disks Crash recovery much slower (compared to RAID-1) RAID Levels 3-5 Raid levels 3 through 5 Backup and parity drives are shaded
CSE 380 Computer Operating Systems
CSE 380 Computer Operating Systems Instructor: Insup Lee University of Pennsylvania Fall 2003 Lecture Note on Disk I/O 1 I/O Devices Storage devices Floppy, Magnetic disk, Magnetic tape, CD-ROM, DVD User
More informationCSE380 - Operating Systems
CSE380 - Operating Systems Notes for Lecture 17-11/10/05 Matt Blaze, Micah Sherr (some examples by Insup Lee) Implementing File Systems We ve looked at the user view of file systems names, directory structure,
More informationLecture 9. I/O Management and Disk Scheduling Algorithms
Lecture 9 I/O Management and Disk Scheduling Algorithms 1 Lecture Contents 1. I/O Devices 2. Operating System Design Issues 3. Disk Scheduling Algorithms 4. RAID (Redundant Array of Independent Disks)
More informationI/O Hardwares. Some typical device, network, and data base rates
Input/Output 1 I/O Hardwares Some typical device, network, and data base rates 2 Device Controllers I/O devices have components: mechanical component electronic component The electronic component is the
More informationOperating Systems 2010/2011
Operating Systems 2010/2011 Input/Output Systems part 2 (ch13, ch12) Shudong Chen 1 Recap Discuss the principles of I/O hardware and its complexity Explore the structure of an operating system s I/O subsystem
More informationDisk Scheduling. Based on the slides supporting the text
Disk Scheduling Based on the slides supporting the text 1 User-Space I/O Software Layers of the I/O system and the main functions of each layer 2 Disk Structure Disk drives are addressed as large 1-dimensional
More informationMass-Storage. ICS332 - Fall 2017 Operating Systems. Henri Casanova
Mass-Storage ICS332 - Fall 2017 Operating Systems Henri Casanova (henric@hawaii.edu) Magnetic Disks! Magnetic disks (a.k.a. hard drives ) are (still) the most common secondary storage devices today! They
More informationI/O, Disks, and RAID Yi Shi Fall Xi an Jiaotong University
I/O, Disks, and RAID Yi Shi Fall 2017 Xi an Jiaotong University Goals for Today Disks How does a computer system permanently store data? RAID How to make storage both efficient and reliable? 2 What does
More informationCSE 120. Overview. July 27, Day 8 Input/Output. Instructor: Neil Rhodes. Hardware. Hardware. Hardware
CSE 120 July 27, 2006 Day 8 Input/Output Instructor: Neil Rhodes How hardware works Operating Systems Layer What the kernel does API What the programmer does Overview 2 Kinds Block devices: read/write
More informationCS510 Operating System Foundations. Jonathan Walpole
CS510 Operating System Foundations Jonathan Walpole Disk Technology & Secondary Storage Management Disk Geometry Disk head, surfaces, tracks, sectors Example Disk Characteristics Disk Surface Geometry
More informationInput/Output. Chapter 5: I/O Systems. How fast is I/O hardware? Device controllers. Memory-mapped I/O. How is memory-mapped I/O done?
Input/Output : I/O Systems Principles of I/O hardware Principles of I/O software I/O software layers Disks Clocks Character-oriented terminals Graphical user interfaces Network terminals Power management
More informationV. Mass Storage Systems
TDIU25: Operating Systems V. Mass Storage Systems SGG9: chapter 12 o Mass storage: Hard disks, structure, scheduling, RAID Copyright Notice: The lecture notes are mainly based on modifications of the slides
More informationCSE325 Principles of Operating Systems. Mass-Storage Systems. David P. Duggan. April 19, 2011
CSE325 Principles of Operating Systems Mass-Storage Systems David P. Duggan dduggan@sandia.gov April 19, 2011 Outline Storage Devices Disk Scheduling FCFS SSTF SCAN, C-SCAN LOOK, C-LOOK Redundant Arrays
More informationI/O Management and Disk Scheduling. Chapter 11
I/O Management and Disk Scheduling Chapter 11 Categories of I/O Devices Human readable used to communicate with the user video display terminals keyboard mouse printer Categories of I/O Devices Machine
More informationIntroduction Disks RAID Tertiary storage. Mass Storage. CMSC 420, York College. November 21, 2006
November 21, 2006 The memory hierarchy Red = Level Access time Capacity Features Registers nanoseconds 100s of bytes fixed Cache nanoseconds 1-2 MB fixed RAM nanoseconds MBs to GBs expandable Disk milliseconds
More informationInput/Output. Today. Next. Principles of I/O hardware & software I/O software layers Disks. Protection & Security
Input/Output Today Principles of I/O hardware & software I/O software layers Disks Next Protection & Security Operating Systems and I/O Two key operating system goals Control I/O devices Provide a simple,
More informationCISC 7310X. C11: Mass Storage. Hui Chen Department of Computer & Information Science CUNY Brooklyn College. 4/19/2018 CUNY Brooklyn College
CISC 7310X C11: Mass Storage Hui Chen Department of Computer & Information Science CUNY Brooklyn College 4/19/2018 CUNY Brooklyn College 1 Outline Review of memory hierarchy Mass storage devices Reliability
More informationChe-Wei Chang Department of Computer Science and Information Engineering, Chang Gung University
Che-Wei Chang chewei@mail.cgu.edu.tw Department of Computer Science and Information Engineering, Chang Gung University l Chapter 10: File System l Chapter 11: Implementing File-Systems l Chapter 12: Mass-Storage
More informationCS370: Operating Systems [Fall 2018] Dept. Of Computer Science, Colorado State University
CS 370: OPERATING SYSTEMS [DISK SCHEDULING ALGORITHMS] Shrideep Pallickara Computer Science Colorado State University L30.1 Frequently asked questions from the previous class survey ECCs: How does it impact
More informationModule 13: Secondary-Storage Structure
Module 13: Secondary-Storage Structure Disk Structure Disk Scheduling Disk Management Swap-Space Management Disk Reliability Stable-Storage Implementation Operating System Concepts 13.1 Silberschatz and
More informationCS370: Operating Systems [Fall 2018] Dept. Of Computer Science, Colorado State University
Frequently asked questions from the previous class survey CS 370: OPERATING SYSTEMS [DISK SCHEDULING ALGORITHMS] Shrideep Pallickara Computer Science Colorado State University ECCs: How does it impact
More informationChapter 10: Mass-Storage Systems
Chapter 10: Mass-Storage Systems Silberschatz, Galvin and Gagne Overview of Mass Storage Structure Magnetic disks provide bulk of secondary storage of modern computers Drives rotate at 60 to 200 times
More informationUC Santa Barbara. Operating Systems. Christopher Kruegel Department of Computer Science UC Santa Barbara
Operating Systems Christopher Kruegel Department of Computer Science http://www.cs.ucsb.edu/~chris/ Input and Output Input/Output Devices The OS is responsible for managing I/O devices Issue requests Manage
More informationMass-Storage. ICS332 Operating Systems
Mass-Storage ICS332 Operating Systems Magnetic Disks Magnetic disks are (still) the most common secondary storage devices today They are messy Errors, bad blocks, missed seeks, moving parts And yet, the
More informationDisk Scheduling. Chapter 14 Based on the slides supporting the text and B.Ramamurthy s slides from Spring 2001
Disk Scheduling Chapter 14 Based on the slides supporting the text and B.Ramamurthy s slides from Spring 2001 1 User-Space I/O Software Layers of the I/O system and the main functions of each layer 2 Disks
More informationCS370: System Architecture & Software [Fall 2014] Dept. Of Computer Science, Colorado State University
CS 370: SYSTEM ARCHITECTURE & SOFTWARE [MASS STORAGE] Frequently asked questions from the previous class survey Shrideep Pallickara Computer Science Colorado State University L29.1 L29.2 Topics covered
More informationI/O Systems and Storage Devices
CSC 256/456: Operating Systems I/O Systems and Storage Devices John Criswell! University of Rochester 1 I/O Device Controllers I/O devices have both mechanical component & electronic component! The electronic
More informationLecture 23: Storage Systems. Topics: disk access, bus design, evaluation metrics, RAID (Sections )
Lecture 23: Storage Systems Topics: disk access, bus design, evaluation metrics, RAID (Sections 7.1-7.9) 1 Role of I/O Activities external to the CPU are typically orders of magnitude slower Example: while
More informationDisc Allocation and Disc Arm Scheduling?
CSE 2431: Introduction to Operating Systems Disc Allocation and Disc Arm Scheduling? Study: 9 th (12.4, 12.5, 10.4) 10 th (14.4, 14.5, 11.2) 11-29-2018 Presentation K Gojko Babić Moving-Head Disk Mechanism
More informationChapter 11 I/O Management and Disk Scheduling
Operating Systems: Internals and Design Principles, 6/E William Stallings Chapter 11 I/O Management and Disk Scheduling Patricia Roy Manatee Community College, Venice, FL 2008, Prentice Hall 1 2 Differences
More informationChapter 10: Mass-Storage Systems
Chapter 10: Mass-Storage Systems Silberschatz, Galvin and Gagne 2013 Chapter 10: Mass-Storage Systems Overview of Mass Storage Structure Disk Structure Disk Attachment Disk Scheduling Disk Management Swap-Space
More informationCS370: Operating Systems [Spring 2017] Dept. Of Computer Science, Colorado State University
CS 370: OPERATING SYSTEMS [DISK SCHEDULING ALGORITHMS] Shrideep Pallickara Computer Science Colorado State University Frequently asked questions from the previous class survey Can a UNIX file span over
More informationChapter 10: Mass-Storage Systems. Operating System Concepts 9 th Edition
Chapter 10: Mass-Storage Systems Silberschatz, Galvin and Gagne 2013 Chapter 10: Mass-Storage Systems Overview of Mass Storage Structure Disk Structure Disk Attachment Disk Scheduling Disk Management Swap-Space
More informationI/O CANNOT BE IGNORED
LECTURE 13 I/O I/O CANNOT BE IGNORED Assume a program requires 100 seconds, 90 seconds for main memory, 10 seconds for I/O. Assume main memory access improves by ~10% per year and I/O remains the same.
More informationLecture 21 Disk Devices and Timers
CS 423 Operating Systems Design Lecture 21 Disk Devices and Timers Klara Nahrstedt Fall 2011 Based on slides by YY Zhou and Andrew S. Tanenbaum CS 423 - Fall 2011 Overview Administrative announcements
More informationMass-Storage Structure
CS 4410 Operating Systems Mass-Storage Structure Summer 2011 Cornell University 1 Today How is data saved in the hard disk? Magnetic disk Disk speed parameters Disk Scheduling RAID Structure 2 Secondary
More informationCS3600 SYSTEMS AND NETWORKS
CS3600 SYSTEMS AND NETWORKS NORTHEASTERN UNIVERSITY Lecture 9: Mass Storage Structure Prof. Alan Mislove (amislove@ccs.neu.edu) Moving-head Disk Mechanism 2 Overview of Mass Storage Structure Magnetic
More informationCS370 Operating Systems
CS370 Operating Systems Colorado State University Yashwant K Malaiya Spring 2018 Lecture 24 Mass Storage, HDFS/Hadoop Slides based on Text by Silberschatz, Galvin, Gagne Various sources 1 1 FAQ What 2
More informationChapter 11. I/O Management and Disk Scheduling
Operating System Chapter 11. I/O Management and Disk Scheduling Lynn Choi School of Electrical Engineering Categories of I/O Devices I/O devices can be grouped into 3 categories Human readable devices
More informationFile. File System Implementation. Operations. Permissions and Data Layout. Storing and Accessing File Data. Opening a File
File File System Implementation Operating Systems Hebrew University Spring 2007 Sequence of bytes, with no structure as far as the operating system is concerned. The only operations are to read and write
More informationIntroduction. Operating Systems. Outline. Hardware. I/O Device Types. Device Controllers. One OS function is to control devices
Introduction Operating Systems Input/Output Devices (Ch12.1-12.3, 12.7; 13.1-13.3, 13.7) One OS function is to control devices significant fraction of code (80-90% of Linux) Want all devices to be simple
More informationIntroduction. Operating Systems. Outline. Hardware. I/O Device Types. Device Controllers. (done)
Introduction Operating Systems Input/Output Devices (Ch 13.3, 13.5; 14.1-14.3) One OS function is to control devices significant fraction of code (80-90% of Linux) Want all devices to be simple to use
More informationI/O CANNOT BE IGNORED
LECTURE 13 I/O I/O CANNOT BE IGNORED Assume a program requires 100 seconds, 90 seconds for main memory, 10 seconds for I/O. Assume main memory access improves by ~10% per year and I/O remains the same.
More informationSilberschatz, et al. Topics based on Chapter 13
Silberschatz, et al. Topics based on Chapter 13 Mass Storage Structure CPSC 410--Richard Furuta 3/23/00 1 Mass Storage Topics Secondary storage structure Disk Structure Disk Scheduling Disk Management
More informationChapter 14: Mass-Storage Systems. Disk Structure
1 Chapter 14: Mass-Storage Systems Disk Structure Disk Scheduling Disk Management Swap-Space Management RAID Structure Disk Attachment Stable-Storage Implementation Tertiary Storage Devices Operating System
More informationI/O Device Controllers. I/O Systems. I/O Ports & Memory-Mapped I/O. Direct Memory Access (DMA) Operating Systems 10/20/2010. CSC 256/456 Fall
I/O Device Controllers I/O Systems CS 256/456 Dept. of Computer Science, University of Rochester 10/20/2010 CSC 2/456 1 I/O devices have both mechanical component & electronic component The electronic
More informationChapter 13: Mass-Storage Systems. Disk Scheduling. Disk Scheduling (Cont.) Disk Structure FCFS. Moving-Head Disk Mechanism
Chapter 13: Mass-Storage Systems Disk Scheduling Disk Structure Disk Scheduling Disk Management Swap-Space Management RAID Structure Disk Attachment Stable-Storage Implementation Tertiary Storage Devices
More informationChapter 13: Mass-Storage Systems. Disk Structure
Chapter 13: Mass-Storage Systems Disk Structure Disk Scheduling Disk Management Swap-Space Management RAID Structure Disk Attachment Stable-Storage Implementation Tertiary Storage Devices Operating System
More informationInput Output (IO) Management
Input Output (IO) Management Prof. P.C.P. Bhatt P.C.P Bhatt OS/M5/V1/2004 1 Introduction Humans interact with machines by providing information through IO devices. Manyon-line services are availed through
More informationUNIT 4 Device Management
UNIT 4 Device Management (A) Device Function. (B) Device Characteristic. (C) Disk space Management. (D) Allocation and Disk scheduling Methods. [4.1] Device Management Functions The management of I/O devices
More informationPart IV I/O System. Chapter 12: Mass Storage Structure
Part IV I/O System Chapter 12: Mass Storage Structure Disk Structure Three elements: cylinder, track and sector/block. Three types of latency (i.e., delay) Positional or seek delay mechanical and slowest
More informationVirtual Memory. Reading. Sections 5.4, 5.5, 5.6, 5.8, 5.10 (2) Lecture notes from MKP and S. Yalamanchili
Virtual Memory Lecture notes from MKP and S. Yalamanchili Sections 5.4, 5.5, 5.6, 5.8, 5.10 Reading (2) 1 The Memory Hierarchy ALU registers Cache Memory Memory Memory Managed by the compiler Memory Managed
More informationPhysical Representation of Files
Physical Representation of Files A disk drive consists of a disk pack containing one or more platters stacked like phonograph records. Information is stored on both sides of the platter. Each platter is
More informationChap. 3. Input/Output
Chap. 3. Input/Output 17 janvier 07 3.1 Principles of I/O hardware 3.2 Principles of I/O software 3.3 Deadlocks [3.4 Overview of IO in Minix 3] [3.5 Block Devices in Minix 3] [3.6 RAM Disks] 3.7 Disks
More informationChapter-6. SUBJECT:- Operating System TOPICS:- I/O Management. Created by : - Sanjay Patel
Chapter-6 SUBJECT:- Operating System TOPICS:- I/O Management Created by : - Sanjay Patel Disk Scheduling Algorithm 1) First-In-First-Out (FIFO) 2) Shortest Service Time First (SSTF) 3) SCAN 4) Circular-SCAN
More informationRef: Chap 12. Secondary Storage and I/O Systems. Applied Operating System Concepts 12.1
Ref: Chap 12 Secondary Storage and I/O Systems Applied Operating System Concepts 12.1 Part 1 - Secondary Storage Secondary storage typically: is anything that is outside of primary memory does not permit
More informationFile. File System Implementation. File Metadata. File System Implementation. Direct Memory Access Cont. Hardware background: Direct Memory Access
File File System Implementation Operating Systems Hebrew University Spring 2009 Sequence of bytes, with no structure as far as the operating system is concerned. The only operations are to read and write
More informationCSCI-GA Operating Systems. I/O : Disk Scheduling and RAID. Hubertus Franke
CSCI-GA.2250-001 Operating Systems I/O : Disk Scheduling and RAID Hubertus Franke frankeh@cs.nyu.edu Disks Scheduling Abstracted by OS as files A Conventional Hard Disk (Magnetic) Structure Hard Disk
More informationAdministrivia. CMSC 411 Computer Systems Architecture Lecture 19 Storage Systems, cont. Disks (cont.) Disks - review
Administrivia CMSC 411 Computer Systems Architecture Lecture 19 Storage Systems, cont. Homework #4 due Thursday answers posted soon after Exam #2 on Thursday, April 24 on memory hierarchy (Unit 4) and
More informationOperating Systems, Fall
Input / Output & Real-time Scheduling Chapter 5.1 5.4, Chapter 7.5 1 I/O Software Device controllers Memory-mapped mapped I/O DMA & interrupts briefly I/O Content I/O software layers and drivers Disks
More informationI/O Handling. ECE 650 Systems Programming & Engineering Duke University, Spring Based on Operating Systems Concepts, Silberschatz Chapter 13
I/O Handling ECE 650 Systems Programming & Engineering Duke University, Spring 2018 Based on Operating Systems Concepts, Silberschatz Chapter 13 Input/Output (I/O) Typical application flow consists of
More informationSecondary storage. CS 537 Lecture 11 Secondary Storage. Disk trends. Another trip down memory lane
Secondary storage CS 537 Lecture 11 Secondary Storage Michael Swift Secondary storage typically: is anything that is outside of primary memory does not permit direct execution of instructions or data retrieval
More information2. Which of the following resources is not one which can result in deadlocking processes? a. a disk file b. a semaphore c. the central processor (CPU)
CSCI 4500 / 8506 Sample Questions for Quiz 4 Covers Modules 7 and 8 1. Deadlock occurs when each process in a set of processes a. is taking a very long time to complete. b. is waiting for an event (or
More informationBlock Device Scheduling. Don Porter CSE 506
Block Device Scheduling Don Porter CSE 506 Logical Diagram Binary Formats Memory Allocators System Calls Threads User Kernel RCU File System Networking Sync Memory Management Device Drivers CPU Scheduler
More informationBlock Device Scheduling
Logical Diagram Block Device Scheduling Don Porter CSE 506 Binary Formats RCU Memory Management File System Memory Allocators System Calls Device Drivers Interrupts Net Networking Threads Sync User Kernel
More informationCS370: System Architecture & Software [Fall 2014] Dept. Of Computer Science, Colorado State University
CS 370: SYSTEM ARCHITECTURE & SOFTWARE [DISK SCHEDULING ALGORITHMS] Frequently asked questions from the previous class survey Shrideep Pallickara Computer Science Colorado State University L30.1 L30.2
More informationChapter 12: Mass-Storage
hapter 12: Mass-Storage Systems hapter 12: Mass-Storage Systems To explain the performance characteristics of mass-storage devices To evaluate disk scheduling algorithms To discuss operating-system services
More informationCSE506: Operating Systems CSE 506: Operating Systems
CSE 506: Operating Systems Disk Scheduling Key to Disk Performance Don t access the disk Whenever possible Cache contents in memory Most accesses hit in the block cache Prefetch blocks into block cache
More informationChapter 12: Mass-Storage
hapter 12: Mass-Storage Systems hapter 12: Mass-Storage Systems Overview of Mass Storage Structure Disk Structure Disk Attachment Disk Scheduling Disk Management RAID Structure Objectives Moving-head Disk
More informationDisk scheduling Disk reliability Tertiary storage Swap space management Linux swap space management
Lecture Overview Mass storage devices Disk scheduling Disk reliability Tertiary storage Swap space management Linux swap space management Operating Systems - June 28, 2001 Disk Structure Disk drives are
More informationPart IV I/O System Chapter 1 2: 12: Mass S torage Storage Structur Structur Fall 2010
Part IV I/O System Chapter 12: Mass Storage Structure Fall 2010 1 Disk Structure Three elements: cylinder, track and sector/block. Three types of latency (i.e., delay) Positional or seek delay mechanical
More informationLecture 21: Reliable, High Performance Storage. CSC 469H1F Fall 2006 Angela Demke Brown
Lecture 21: Reliable, High Performance Storage CSC 469H1F Fall 2006 Angela Demke Brown 1 Review We ve looked at fault tolerance via server replication Continue operating with up to f failures Recovery
More informationOPERATING SYSTEMS CS3502 Spring Input/Output System Chapter 9
OPERATING SYSTEMS CS3502 Spring 2018 Input/Output System Chapter 9 Input/Output System Major objectives: An application s I/O requests are sent to the I/O device. Take whatever response comes back from
More informationStorage. Hwansoo Han
Storage Hwansoo Han I/O Devices I/O devices can be characterized by Behavior: input, out, storage Partner: human or machine Data rate: bytes/sec, transfers/sec I/O bus connections 2 I/O System Characteristics
More informationIntroduction. Operating Systems. Outline. Hardware. I/O Device Types. Device Controllers. One OS function is to control devices
Introduction Operating Systems Input/Output Devices (Ch12.1-12.3, 12.7; 13.1-13.3, 13.7) One OS function is to control devices significant fraction of code (80-90% of Linux) Want all devices to be simple
More informationComputer Organization and Structure. Bing-Yu Chen National Taiwan University
Computer Organization and Structure Bing-Yu Chen National Taiwan University Storage and Other I/O Topics I/O Performance Measures Types and Characteristics of I/O Devices Buses Interfacing I/O Devices
More informationMass-Storage Structure
Operating Systems (Fall/Winter 2018) Mass-Storage Structure Yajin Zhou (http://yajin.org) Zhejiang University Acknowledgement: some pages are based on the slides from Zhi Wang(fsu). Review On-disk structure
More informationToday: Secondary Storage! Typical Disk Parameters!
Today: Secondary Storage! To read or write a disk block: Seek: (latency) position head over a track/cylinder. The seek time depends on how fast the hardware moves the arm. Rotational delay: (latency) time
More informationChapter 5 Input/Output
Chapter 5 Input/Output 5.1 Principles of I/O hardware 5.2 Principles of I/O software 5.3 I/O software layers 5.4 Disks 5.5 Clocks 5.6 Character-oriented terminals 5.7 Graphical user interfaces 5.8 Network
More informationThe term "physical drive" refers to a single hard disk module. Figure 1. Physical Drive
HP NetRAID Tutorial RAID Overview HP NetRAID Series adapters let you link multiple hard disk drives together and write data across them as if they were one large drive. With the HP NetRAID Series adapter,
More informationESE 333 Real-Time Operating Systems 163 Review Deadlocks (Cont.) ffl Methods for handling deadlocks 3. Deadlock prevention Negating one of four condit
Review Deadlocks ffl Non-sharable resources ffl Necessary conditions for a deadlock to occur 1. Mutual exclusion 2. Hold and wait 3. No preemption 4. Circular wait ffl Resource graph ffl Use resource graph
More informationBlock Device Scheduling. Don Porter CSE 506
Block Device Scheduling Don Porter CSE 506 Quick Recap CPU Scheduling Balance competing concerns with heuristics What were some goals? No perfect solution Today: Block device scheduling How different from
More informationCS 537 Fall 2017 Review Session
CS 537 Fall 2017 Review Session Deadlock Conditions for deadlock: Hold and wait No preemption Circular wait Mutual exclusion QUESTION: Fix code List_insert(struct list * head, struc node * node List_move(struct
More informationCS 471 Operating Systems. Yue Cheng. George Mason University Fall 2017
CS 471 Operating Systems Yue Cheng George Mason University Fall 2017 Review: Disks 2 Device I/O Protocol Variants o Status checks Polling Interrupts o Data PIO DMA 3 Disks o Doing an disk I/O requires:
More informationOperating Systems. Operating Systems Professor Sina Meraji U of T
Operating Systems Operating Systems Professor Sina Meraji U of T How are file systems implemented? File system implementation Files and directories live on secondary storage Anything outside of primary
More informationChapter 12: Secondary-Storage Structure. Operating System Concepts 8 th Edition,
Chapter 12: Secondary-Storage Structure, Silberschatz, Galvin and Gagne 2009 Chapter 12: Secondary-Storage Structure Overview of Mass Storage Structure Disk Structure Disk Attachment Disk Scheduling Disk
More informationChapter 11: File System Implementation. Objectives
Chapter 11: File System Implementation Objectives To describe the details of implementing local file systems and directory structures To describe the implementation of remote file systems To discuss block
More informationCHAPTER 12 AND 13 - MASS-STORAGE STRUCTURE & I/O- SYSTEMS
CHAPTER 12 AND 13 - MASS-STORAGE STRUCTURE & I/O- SYSTEMS OBJECTIVES Describe physical structure of secondary storage devices and its effects on the uses of the devices Explain the performance char. of
More informationChapter 10: Mass-Storage Systems. Operating System Concepts 9 th Edition
Chapter 10: Mass-Storage Systems Silberschatz, Galvin and Gagne 2013 Objectives To describe the physical structure of secondary storage devices and its effects on the uses of the devices To explain the
More informationI/O Devices. Chapter 5 Input/Output. Memory-Mapped I/O (2) Memory-Mapped I/O (1) Interrupts Revisited. Direct Memory Access (DMA) 11/26/2013
MODERN OPERATING SYSTEMS I/O Devices Third Edition ANDREW S. TANENBAUM Chapter 5 Input/Output Figure 5-1. Some typical device, network, and bus data rates. Memory-Mapped I/O (1) Memory-Mapped I/O (2) Figure
More informationRAID (Redundant Array of Inexpensive Disks)
Magnetic Disk Characteristics I/O Connection Structure Types of Buses Cache & I/O I/O Performance Metrics I/O System Modeling Using Queuing Theory Designing an I/O System RAID (Redundant Array of Inexpensive
More informationTape pictures. CSE 30341: Operating Systems Principles
Tape pictures 4/11/07 CSE 30341: Operating Systems Principles page 1 Tape Drives The basic operations for a tape drive differ from those of a disk drive. locate positions the tape to a specific logical
More informationOPERATING SYSTEMS CS3502 Spring Input/Output System Chapter 9
OPERATING SYSTEMS CS3502 Spring 2017 Input/Output System Chapter 9 Input/Output System Major objectives: An application s I/O requests are sent to the I/O device. Take whatever response comes back from
More informationChapter 12: Mass-Storage
Chapter 12: Mass-Storage Systems Chapter 12: Mass-Storage Systems Revised 2010. Tao Yang Overview of Mass Storage Structure Disk Structure Disk Attachment Disk Scheduling Disk Management Swap-Space Management
More informationCSE 153 Design of Operating Systems Fall 2018
CSE 153 Design of Operating Systems Fall 2018 Lecture 12: File Systems (1) Disk drives OS Abstractions Applications Process File system Virtual memory Operating System CPU Hardware Disk RAM CSE 153 Lecture
More informationLecture 16: Storage Devices
CS 422/522 Design & Implementation of Operating Systems Lecture 16: Storage Devices Zhong Shao Dept. of Computer Science Yale University Acknowledgement: some slides are taken from previous versions of
More informationFree Space Management
CSC 4103 - Operating Systems Spring 2007 Lecture - XVI File Systems - II Tevfik Koşar Louisiana State University March 22 nd, 2007 1 Free Space Management Disk space limited Need to re-use the space from
More informationDatabase Systems. November 2, 2011 Lecture #7. topobo (mit)
Database Systems November 2, 2011 Lecture #7 1 topobo (mit) 1 Announcement Assignment #2 due today Assignment #3 out today & due on 11/16. Midterm exam in class next week. Cover Chapters 1, 2,
More informationPrinciples of Operating Systems CS 446/646
Principles of Operating Systems CS 446/646 5. Input/Output a. Overview of the O/S Role in I/O b. Principles of I/O Hardware c. I/O Software Layers d. Disk Management Physical disk characteristics Disk
More informationCSE 120. Operating Systems. March 27, 2014 Lecture 17. Mass Storage. Instructor: Neil Rhodes. Wednesday, March 26, 14
CSE 120 Operating Systems March 27, 2014 Lecture 17 Mass Storage Instructor: Neil Rhodes Paging and Translation Lookaside Buffer frame dirty? no yes CPU checks TLB PTE in TLB? Free page frame? no yes OS
More information