The choice of file system is often important in maximizing the performance of the device. But for any scheme, we can imagine a large enough disaster that all copies are destroyed. Disks may be attached to a computer system in one of two ways. Chapter 12 mass storage structure operating system. Magnetic disks provide bulk of secondary storage of modern computers. Usb mass storage devices, including diskettes, support both pcfs and ufs file systems.
Overview of mass storage structure magnetic disks provide bulk of secondary storage of modern computers drives rotate at 60 to 200 times per second transfer rate is rate at which data flow between drive and computer positioning time randomaccess time is time to move disk arm to desired cylinder seek time and time for desired sector to rotate under the disk head. The earliest storage devices were punched paper cards, which were used as early as 1804 to control silkweaving looms. A computers hard drive is a massstorage device, as are flash, cd, and dvd drives. In this section we present a general overview of the physical structure of secondary and tertiary storage devices. In chapter 11, we described the internal data structures and algorithms used by the operating system to implement this interface. Magnetic disks provide the bulk of secondary storage for modern computer systems. Removable volumes, such as an sd card, appear in the file system as part of external storage. Secondary storage structure and disk scheduling algorithms. Surface of platter divided into circular tracks over 50k100k tracks per platter on typical hard disks each track is divided into sectors a sector is the smallest unit of data that can be read or. It is recognized that each structure is different, and some variation may be required depending upon the project. Overview of mass storage structure magnetic disks provide bulk of secondary storage of modern computers drives rotate at 60 to 250 times per second transfer rate is rate at which data. Describe the physical structure of secondary and tertiary storage devices and the resulting effects on the uses of the devices explain the performance characteristics of massstorage devices discuss operatingsystem services provided for mass storage, including raid and hsm 4.
Secondary storage refers to fixeddisk storage systems hard drives. On most devices, internal storage is smaller than external storage. Massstorage systems zhi wang florida state university. Data is stored on disk in units called disk blocks, which is the unit of reading or writing. This tutorial covers magnetic disk structure and disk scheduling algorithms first come first serve, shortest seek time first and scan algorithm. Usb mass storage devices, as all others used by the solaris operating system, must be formatted and contain a file system before they can be used. Ondisk structure about fs, how fs maps the calls to the structure. Overview of mass storage structure surendar chandra. Usb disk drive does not show up under file explorer. In chapter 11, we examine the user and programmer interface to the file system.
Hierarchical storage involves extending file systems out onto tertiary storage, swapping files from hard drives to tapes in much the same manner as data. Overview of mass storage structure disk structure disk attachment disk scheduling disk management swapspace management raid structure disk attachment stables slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. This wiki shows how to enable mass storage gadget in the sdk using a sd card. In this chapter, we begin a discussion of file systems at the lowest level. In chapter 12, we describe the internal data structures and algorithms used by the operating system to implement this interface. It is a comprehensive computer storage system that. Hard disk speed is the speed at which content can be read and written on a hard disk. How to format a usb mass storage device without vold running. For example, the number of floors, basements, and other levels will vary from. How to use mass storage gadget ridgerun developer connection. However, internal storage is always available on all devices, making it a more reliable place to put data on which your app depends.
The file structure is to be adhered to in the creation, compilation, and delivery of files for bim projects. Traditional magnetic disks have the following basic structure. Cmos silicon structure and high speed, low power consumption. Overview of mass storage structure magnetic disks provide bulk of secondary storage of modern computers drives rotate at 60 to 250 times per second transfer rate is rate at which data flow between drive and computer positioning time randomaccess time is time to move disk arm to desired cylinder seek time and time for desired sector to rotate under the disk head rotational latency head. Most secondary storage devices are either magnetic disks or magnetic tapes. Modern disk drives are structured as a large onedimensional array of logical disk blocks which is usually 512 bytes. Modern mass storage devices include all types of disk drives and tape drives mass storage is distinct from memory, which refers to temporary storage areas within the computer. And tertiary storage refers to removable media, such as tape drives, cds, dvds, and to a lesser extend floppies, thumb drives, and other detachable devices. In this chapter, we discuss the lowest level of the file system.
The file system uses a portion of the drive for partition information, superblocks, free list info, and file metadata i. The sd card used for the mass storage space is the same where the boot and rootfs partitions are. Overview of mass storage structure magnetic disks provide bulk of secondary storage of modern computers zdrives rotate at 60 to 200 times per second ztransfer rate is rate at which data flow between drive and computer zpositioning time randomaccess time is time to move disk arm to desired. Content overview of mass storage structure disk structure. But the largest part of the discrepancy is typically file system overhead. These practice exercises are different from the exercises provided in the text. Each modern disk contains concentric tracks and each track is divided into multiple sectors. Using powers of 2 vs powers of 10 to calculate size prefixes, counting space lost to overhead for errorcorrecting codes, etc. From windows explorer, users can copy, move, and delete files in the devices. Operating systemmass storage structure powerpoint slides. Every time you load an application or save a file on a pc, youre using a massstorage device.
The file system can be viewed logically as consisting of three parts. They provide the bulk of secondary storage in operating systems today. Storage and file structure overview of physical storage media magnetic disks raid tertiary storage storage access file organization organization of records in files datadictionary storage. In windows computers, massstorage devices appear as drives in my computer. Operating systems introduces operating system concepts and designs, including operating system structures, process and thread, cpu scheduling, process synchronization and deadlocks, main memory, virtual memory, file system interface and implementation, mass storage structure, io systems, protection and security, unix system basics and shell programming, etc. Lets discuss about auxillary storage also known as secondary storage in operating system.
Multiple blocks can be read in at a time to improve io performance for sequential processing. Abraham silberschatz, greg gagne, and peter baer galvin, operating system concepts, eighth edition, chapter 12 12. Mass storage refers to various techniques and devices for storing large amounts of data. Mass storage devices used in desktop and most server computers typically have their data organized in a file system. Database physial storage and file structure 1 physical storage media file. Overview of mass storage structure disks can be removable drive attached to computer via io bus ubusses vary, including eide, ata, sata, usb, fibre channel, scsi, sas, firewire uhost controller in computer uses bus to talk to disk controller built into drive or storage array platters of magneticdisks range from.
Summary disk drives are the major secondarystorage io devices on most computers. Partition the disk into one or more groups of cylinders. We first describe the physical structure of magenetic disks and magnetic tapes. This method is best from the point of view of the individual sequential file. The second part can be omitted without loss of continuity for later chapters. A disk can be used in its entirety for a file system. How to format a usb mass storage device without vold.
Several types of data storage exist in most computer systems. Pdf mass storage structure shivashekharayya viraktamath. Overview of mass storage structure magnetic disks provide bulk of secondary storage drives rotate at 70 to 250 times per second ipod disks. Whenever windows accesses one file, i get a callback and encrypt the data on the fly. It can store anywhere from 160 gigabytes to 2 terabytes. Io systems 6 disk attachment hostattached storage accessed through io ports talking to io busses scsi itself is a bus, up to 16 devices on one cable, scsi initiator requests operation and scsi targets perform tasks each target can have up to 8 logical units disks attached to device controller. We provide solutions to the practice exercises of the ninth edition of operating system concepts, by silberschatz, galvin and gagne. I create a filesystem in userspace with fuse, and offer it to windows via massstorage. Usb mass storage controller free download and software. Mass storage systems n disk structure n disk scheduling n disk management n swapspace management n raid structure n disk attachment n stablestorage implementation n tertiary storage devices n operating system issues n performance issues. The fundamental technique for stable storage is to maintain multiple copies of the data, so that if one copy is destroyed, some other copy is still available for use. One or more platters in the form of disks covered with magnetic media.
Yodot file recovery is a right application for you to recover lost or deleted data from usb mass storage devices on windows computer. If reading more than one sector on the same track, sort the sector numbers first. Program code can access files using filesystem apis or. When to use a storage device implementing a massstorage function is a solution for systems that need to. Storage and file structure this chapter presents basic. Storage devices secondary storage hard disk the hard disk drive is the main, and usually largest, data storage device in a computer. Magnetic disks provide bulk of secondary storage of computer system. Usb disk drive does not show up under file explorer device can be viewed in device and printers in the control panel but when i got to file explorer it will not show up. Alternatively a physical disk can be broken up into multiple partitions, slices, or minidisks, each of which becomes a virtual disk and can have its own filesystem.
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