The document discusses different types of storage devices and media. It explains that storage devices write and read data from storage media, which is the physical material that holds data, like the surface of a floppy disk. The two main storage technologies are magnetic, which uses iron particles on disks and tapes to store data magnetically, and optical, which uses pits and lands on disks to store data through reflected light. Formatting prepares magnetic disks for use by dividing them into tracks and sectors to organize how data is stored.

1. Lecture # 5
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2.  Storage devices hold data, even when the computer
is turned off.
 The physical material that actually holds data is
called a storage medium. The surface of a floppy
disk is a storage medium.
 The hardware that writes data to or reads data from
a storage medium is called a storage device. A
floppy disk drive is a storage device.
 The two primary storage technologies are magnetic
and optical.
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4.  Surface of magnetic Disks and tapes are
coated with millions of tiny iron particles so
that data can be stored on them
 Read/Write heads of a magnetic disk or tape
drive contains electromagnets that generate
magnetic fields in the iron on the storage
medium as the head passes over the disk
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5.  A storage device is the computer hardware
that records and/or retrieves items to and
from storage media
Reading is the process
of transferring items
from a storage medium
into memory
Writing is the process of
transferring items from
memory to a storage
medium
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6.  Access time measures:
 The amount of time it
takes a storage device
to locate an item on a
storage medium
 The time required to
deliver an item from
memory to the
processor
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7.  Formatting is the process of dividing the disk into tracks
and sectors so that the operating system can store and
locate data and information on the disk
 Before a magnetic disk can be used, it must be formatted—
a process that maps the disk's surface and determines how
data will be stored.
 During formatting, the drive creates circular tracks around
the disk's surface, then divides each track into sectors.
 The OS organizes sectors into groups, called clusters, then
tracks each file's location according to the clusters it
occupies.
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8.  Boot sector
 File allocation Table (FAT)
 Root folder
 Data Area
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9.  Tracks-
 circular areas of the disk
 Length of a track one circumference of disk
 Over 1000 on a hard disk
 Data first written to outer most track
 Sectors-
 Divides tracks sections
 On a floppy 9 sectors exits
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10.  Cylinders-
 Logical groupings of the the same track on
each disk surface in a disk unit
 Clusters-
 Groups of sectors used by operating system
 64 sectors in one cluster
 Partitioning: divide hard disk into separate areas
called partitions; each partition functions as if it
were a separate hard disk drive.
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11.  File Allocation Table(FAT)
 FAT32
 New Technology file system (NTFS)
 NTFS 5
 High performance File System (HPFS)
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12.  Uses magnetic storage technology
 Has read / write heads
 Includes a motor that rotates the disk on a
spindle and read/ write head that can move to
any spot on the disk’s surface as the disk spins
 Disk Density- the amount of data that a disk can
hold
 To determine disk density multiply its total
number of sectors by the number of bytes each
sector can hold
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13.  Hard disks can store data
using longitudinal recording
or perpendicular recording
 Includes one or more platters
mounted on a central spindle
 Each platter is covered with a
magnetic coating
 It includes motor to spin
platters and read/write heads
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15.  An external hard disk is a separate free-
standing hard disk that connects to your
computer with a cable or wirelessly
 A removable hard disk is a hard disk that you
insert and remove from a drive
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16.  Tape is a magnetically coated ribbon of
plastic capable of storing large amounts of
data and information
 A tape drive reads and writes data and
information on a tape
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17.  An optical disc consists of a flat, round, portable disc
made of metal, plastic, and lacquer that is written and
read by a laser
 An optical disk is a high-capacity storage medium. An
optical drive uses reflected light to read data.
 To store data, the disk's metal surface is covered with
tiny dents (pits) and flat spots (lands), which cause
light to be reflected differently.
 When an optical drive shines light into a pit, the light
cannot be reflected back. This represents a bit value of
0 (off). A land reflects light back to its source,
representing a bit value of 1 (on).
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18.  A magnetic stripe card contains a magnetic
stripe that stores information
 A smart card stores data on a thin
microprocessor embedded in the card
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19.  A CD-Recordable (CD-R) drive lets you record
your own CDs, but data cannot be overwritten
once it is recorded to the disk.
 A CD-Rewritable (CD-RW) drive lets you
record a CD, then write new data over the
already recorded data.
 PhotoCD technology is used to store digital
photographs.
 DVD recordable
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20.  Flash memory
 Smart Cards
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