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C OMPUTER H ARDWARE(4)

C OMPUTER H ARDWARE(4). What are the basic components of a data storage system?. A data storage system has two main components: A storage medium is the disk, tape, CD, DVD, paper, or other substance that contains data.

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C OMPUTER H ARDWARE(4)

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  1. COMPUTER HARDWARE(4)

  2. What are the basic components of a data storage system? • A data storage system has two main components: • A storage medium is the disk, tape, CD, DVD, paper, or other substance that contains data. • A storage device is the mechanical equipment that records and retrieves data from a storage medium. • Storage devices include hard disk drives, floppy disk drives, tape drives, CD drives, DVD drives. • The term storage system refers to • storage device and • the media it uses.

  3. How does a storage device interact with other computer components? Data gets copied from a storage device into RAM, where it waits to be processed. After data is processed it is held temporarily in RAM

  4. How does a storage device interact with other computer components? • When data is stored, the 1s and 0s representation; suitable for processing, must be converted into signal or mark in the surface of a storage medium. • Exactly how this transformation happens depends on the storage technology. • Three types of storage technologies are commonly used for personal computers: • magnetic(hard disk), • optical (CD,DVD), • solid state(flash memory).

  5. Which storage technology is best? • Each storage technology has its advantages and disadvantages. • To compare storage devices, it is useful to apply the criteria of: • Versatility • Durability • Speed • Capacity

  6. 1.Versatility

  7. How can one storage technology be more versatile (many sided) than another? • Versatility: same drive can read from more than one media. • Hard disk drive preserved inside a system unit is not very versatile; it can access data only from its fixed disk platters. • A DVD drive is versatile because it can access computer DVDs, DVD movies, audio CDs, and CD-Rs.

  8. 2. Durability

  9. What makes a storage technology durable? • Most storage technologies are sensitive to damage from mishandling or environmental factors. • Some technologies are more sensitive than others to damage that could cause data loss. • CDs and DVDs tend to be more durable than hard disks.

  10. 3. speed

  11. What factors affect storage speed? • Quick access to data is important, so fast storage devices are preferred over slower devices. • Access time is the average time it takes a computer to locate data on the storage medium and readit. • Access time for a personal computer storage device, such as a disk drive, is measured in milliseconds. • Lower numbers indicate faster access times.

  12. What factors affect storage speed? Access time is best for random-access devices than sequential access devices. • Random access is the ability of a device to “jump” directly to the requested data. • Hard disk, CD, DVD, and solid state drives are random access devices. • Sequential access devices, as tape drive, must use slower by reading through the data from the beginning of the tape. • Hard disk capacity = sector size* number of sectors per track * number of track per platter*number of platters.

  13. What factors affect storage speed? • Data transfer rate (DTR) is the amount of digital data that is moved from one device (HD) to another(RAM or processor) in a given time. • For example: • a hard drive may have a maximum data transfer rate of 480 Mbps • while your ISP may offer an Internet connection with a maximum data transfer rate of only 1.5 Mbps.

  14. 3. Capacity

  15. What’simportantabout storage capacity? • Storage capacity is directly related to storage density. • Storage density is the amount of data that can be stored in a given area of a storage medium, as the surface of a disk. • The higher the storage density, the more data is stored. • Storage density can be increased by making the particlesrepresentingbitssmaller, by packing them closer together.

  16. Which storage technology is best? • Versatility • Durability • Speed • Capacity

  17. What is magnetic disk and tape technology? Hard disk, floppy disk, and tape storage technologies can be classified as magnetic storage. • Magnetic storage stores data by magnetizing microscopic particles on a disk or tape surface. • Particlesholdtheirmagneticorientationuntilchanged,making disks and tapes permanent but modifiable storage media. • A read-write head mechanism in disk drive can magnetize particlestowritedata,andsensetheirpolaritiestoreaddata.

  18. What is magnetic disk and tape technology? • Data stored on magnetic media can be accidentally altered by : • magnetic fields, • dust, • smoke particles, • heat, • mechanical problems with a storage device Some experts estimate that the reliable life span of data stored on magnetic media is about three years.

  19. What is magnetic disk and tape technology? Before data is stored, particles on the surface of the disk are scattered in random patterns. Disk drive’s read-write head magnetizes particles, and orients them in • a positive (north) direction (0) • negative (south) direction (1)

  20. Why are hard disk drives so popular? • Hard disk technology is the preferred type of main storage for most computer systems for three reasons: • First, it provides lots of storage capacity. • Second, it provides fast access to files. • Third, a hard disk is economical.

  21. How does hard disk technology work? • A hard disk drive contains one or more platters and their associated read-write heads. • A hard disk platter is a flat, rigid disk made of aluminum or glass and coated with magnetic iron oxide particles. • More platters mean more data storage capacity. • Platters rotate as a unit on a spindle, making thousands of rotations per minute. • Each platter has a read-write head that flies over the surface to read data.

  22. How does hard disk technology work? • Storage capacities of personal computer hard disk are ranging from 40 GB to 2 TB. • Hard disk drive speed is sometimes measured in revolutions per minute (rpm).

  23. How does hard disk technology work?

  24. What’s the downside of hard disk storage? • Harddisksarenotasdurableasotherstoragetechnologies. • Read-write heads in a hard disk fly a microscopic distance above the disk surface. • Ifaread-writeheadfaces adustparticleondisk,itmight cause a head crash, which damages some data on the disk. • To help prevent dustsfrom contacting the platters and causing head crashes, a hard disk is preserved in its case.

  25. What’s the downside of hard disk storage? • You should also make backup copies of the data stored on your hard disk in case of a head crash.

  26. Can I use a second hard disk drive to increase storage space? • Hard disk drives are available as internal or external units. • Internal drives are inexpensive and can be easily installed in a desktop computer’s system unit. • External drives are slightly more expensive and connect to a desktop or notebook computer using a cable.

  27. What is floppy disk technology? • A floppy disk is a round piece of flexible plastic covered with a thin layer of magnetic oxide and sealed inside a protective casing. • They are classified as magnetic storage. • They are also referred to as floppies or diskettes. • A floppy disk drive are designed for high-density (HD) double-sided (DS) disks.

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