Storage, Multimedia andFile Organization

CIS 105

List the benefits of secondary storage Identify and describe storage media that are

available for personal computers Differentiate among the principal types of secondary

storage Describe how data is stored on a disk Discuss the benefits of multimedia Explain how data is organized, accessed, and

processed

Storage and Multimedia: The Facts and More

Secondary Storage

Separate from the computer itself Software and data stored on a semipermanent

basis (Unlike memory, not lost when power is lost)

Benefits Space Reliability Convenience Economy

Memory vs. Storage (Volatile) (Non-volatile)

Temporarily holds instructions to be completed and data to be used with those instructions

Holds data, instructions, and information for future use.

Access time = nanoseconds

(billionths of a second)

Access time = milliseconds

(thousandths of a second)

Cost and Speed

Formatting

Formatting is the process of preparing a disk, hard disk, or CD for reading or writing.

Formatting organizes the disk into storage locations called tracks ( a band that forms a circle on the disk).

Formatting breaks the tracks into sectors which are small pie-shaped areas.

Data stored in sectors must be retrieved for use and placed in memory. The time required to access and retrieve data is called access time.

Tracks

Sectors

(Cluster: 2-8 sectors)

Care of Floppy Disks

Hard Disk Characteristics

Platter Low (vendor) and High Level (operating system

defines), Format Partitions Removable available IDE (Integrated Drive Electronics) SCSI (Small Computer System Interface) – daisy

chaining RAID (Redundant Array of Independent Disks) –

level 1 (mirroring) and Striping

RAID (Redundant Array of Independent Disks)

(RAID LEVEL 0)

Compact Disks

CD-ROM - drive can only read data from CDs CD-ROM stores up to 700 MB per disk Primary medium for software distribution

CD-R - drive can write to disk once Disk can be read by CD-ROM or CD-R

drive

CD-RW - drive can erase and record over data multiple times Some compatibility problems trying to read

CD-RW disks on CD-ROM drives

Digital Versatile Disk (DVD)

Short wavelength laser can read densely packed spots DVD drive can read CD-ROMs Capacity up to 17GB Allows for full-length movies Sound is better than on audio CDs

Several versions of writable and rewritable DVDs exist

CDs and DVDs

CD-ROM (compact disk) 700 MB Single track

DVD-ROM (digital video disk) 4.7-17 GB Denser; 2

layers

Disk Terms

Floppy disk/diskette Portable, inexpensive, 3.5”

Formatting Process of preparing disk by organizing into locations (tracks/sectors)

Track Narrow recording band; forms circle on disk surface

Sector Pie-shaped arcs making up track. 512 bytes;

Cluster 2-8 sectors; smallest unit of space to store data

Density # sides (2) x tracks (80) x sectors/track (18) x 512 (bytes/sector) = 1.44MB

FAT (File Allocation Table) Table of info used to locate files on a disk

Write protect notch Small opening in floppy disk with tab to slide to cover/expose notch; indicates whether info can be written to disk

High Capacity Portable Disks/Drives Superdisk, Zip, USB Flash

Storage Strategies

Enterprise Storage Systems (ESS) Focuses on availability,

protection, organization, and back up of storage in a company.

Goal: Consolidate storage so that

operations run as efficiently as possible.

Examples: RAID, tape libraries, Storage

Area Networks (SAN)

Data Warehouses Centralizes the computing

environment, in which large megaservers store data, information, and programs, and less powerful client devices connect to the megaservers to access these items

Storage vs Memory?

3 Types of RAID?

Storage Strategies?

Temporary vs future;

SpeedEnterprise Storage

SystemsData Warehouse

MirroredStriped

Combination

Multimedia

Presents information with text, illustrations, photos, narration, music, animation, and film clips

Not practical until the advent of the optical disk

Organizing and Accessing Data

Database File Record Field Character

Key Field

File Organization

Three major methods of organizing data files in secondary storage Sequential Direct Indexed

the benefits of secondary storage The types of storage media that are available

for personal computers the principal types of secondary storage how data is stored on a disk the benefits of multimedia how data is organized, accessed, and processed

If asked, can you explain…

Questions?

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Terms to Know: Storage, Multimedia & File Management

Access time Backup Bad sectors Character Cluster CD-ROM Database Digital Versatile disk (DVD) FAT (File Allocation Table) Field Formatting Fragmented Key field

Preformatted RAID Record Secondary Storage Sectors Server

Striping Tracks USB Flash Drive Zip drive

Sources

Capron; Computers: Tools for An Information Age, 8th Ed. 2003

Pfaffenberger; Computers in Your Future 2003

Microsoft Clipart