Chapter 3: Storage

storage media

hardware where data is stored

DVD disc, flash memory card

2 examples of storage media

storage device

medium is inserted into device to be used

DVD drive, flash memory card reader

2 examples of storage device

letter

Storage devices are typically identified by _____.

nonvolatile

Storage media are _____.

random access

allows data to be retrieved from any location on the storage medium

direct access

Random access is also called as _____.

random access

Virtually all storage devices use _____.

sequential access

retrieval of data can occur only in the order in which it was physically stored on the storage medium

magnetic tape drive

example of sequential access

File

Anything stored on a storage medium, such as a program, document, digital image, or song

File name

Name given to a file by the user

Folder

Named place on a storage medium into which files can be stored

Logical file representation

Individuals view a document stored as one complete unit in a particular folder on a particular drive

Physical file representation

Computers access a particular document stored on a storage medium using its physical location or location

magnetic, optical, electrons

3 types of storage technology used

magnetic

conventional hard drives

optical

optical discs

electrons

flash memory media

Hard Drive

Used to store most programs and data

Hard Drive

Can be internal or external

Hard Drive

Can be encrypted

Magnetic Hard Drives

One or more permanently sealed metal magnetic disks with an access mechanism and read/write heads

tracks, sectors, clusters, cylinders

4 divisions of hard disks

Tracks

Concentric path on disk where data is recorded

Sectors

A small piece of the track

Clusters

One or more sectors; smallest addressable area of a disk

Cylinders

Collection of tracks located in the same location on a set of hard disk surfaces

64GB

Media tablets often have _____ of storage

Solid State Drives (SSDs)

Use flash memory technology

Solid State Drives (SSDs)

Use less power and have no moving parts

Solid State Drives (SSDs)

Particularly appropriate for portable computers and mobile devices

Data Recovery Experts

Can recover data from damaged storage devices

Data Recovery Experts

Can be used when devices are physically damaged or just stop working

Data Recovery Experts

Back up to prevent data loss

Internal hard drives

Permanent storage devices located inside the system unit

Internal hard drives

Removed only if a problem develops

External hard drives

Commonly used to transport large amounts of data from one computer to another

External hard drives

Portable _____ are smaller and easier to transport

External hard drives

Most connect with a USB connection although some may be wireless

full-sized external hard drives

• are about the size of a 5 by 7-inch picture frame, but thicker

• this drive contains two magnetic hard drives, which hold 6 TB total

portable hard drives (magnetic)

• are about the size of a 3 by 5 inch index card, but thicker

• this drive holds 2 TB

portable hard drives (ssd)

• are about the size of a credit card, but thicker

• this drive holds 256 GB

Disk access time

Total time that it takes for a hard drive to read or write data

seek time, rotational delay, data movement time

3 components of disk access time

SSDs

_____ don’t require seek time or rotational delays

Disk cache

• Memory used in conjunction with a magnetic hard drive to improve system performance

• Typically consist of memory chips on a circuit board inside the hard drive case

memory chips on a circuit board

Disk cache typically consist of _____ inside the hard drive case

Hybrid Hard Drive

Combination of flash memory and magnetic hard drive

Hybrid Hard Drive

Allows encryption to be built into the drive

flash memory

Hybrid Hard Drive uses _____ for cache

Magnetic Hard Drive

This 2TB drive contains 2 hard disks and 4 read/write heads that operate in a manner similar to a conventional hard drive.

Flash Memory Disk Cache

This drive contains 8 GB of flash memory to duplicate data as it is stored on the hard disks so the data can be accessed when the hard disks are not spinning.

Partitioning

Divides the physical capacity of a single drive logically into separate areas, called partitions.

efficiency (smaller drives use smaller clusters)

Partitioning increases _____

independent hard drives

Partitions function as _____.

logical drives

Partitioning is referred to as _____.

recovery partition, new logical drive for data, dual boot system

Partitions used to create (3):

File system

Determines the partition size, cluster size, maximum drive size, and maximum file size

FAT, FAT32, NTFS

3 examples of file systems

hard drive interface standards

Determine how a drive connects to the computer

Parallel ATA (PATA), Serial ATA (SATA), eSATA, SCSI and the newer serial attached SCSI (SAS), Fibre Channel, Fibre Channel over Ethernet (FCoE), Internet SCSI (iSCSI)

8 common hard drive interface standards

Optical Disc

A type of storage read from and written to using laser beams

Optical Disc

Today’s standard for software delivery

single spiral track (groove)

Optical disc is divided into sectors like magnetic discs but use a _____.

Optical Disc

Have a relatively large capacity and are durable

backup purposes and for storing and transporting music, photos, video, etc.

Optical Disc are used for _____.

Read-only optical disc

Surface of disc is molded or stamped

Recordable or rewritable disc

Optical drive is used and the reflectivity of the disc is changed using a laser to represent the data

Pits and lands

_____ are used to represent 1s and 0s.

transition between a pit and a land

represents a 1

no transition between a pit and a land

represents a 0

writing data

when data is written to a the disk, a laser beam creates pits, represented by dark, nonreflective area on the disc.

pits

when data is written to a the disk, a laser beam creates _____, represented by dark, nonreflective area on the disc.

reading data

• A low intensity laser beam reads the disc

• A transition between a pit and a land is interpreted as a 1; a set period of time between transition is interpreted as a 0.

CD, DVD, Blu-Ray Disc (BD)

3 categories of disks

Optical Drives

Can be read-only, recordable, or rewritable

downward compatible

Optical Drives are almost always

single, dual layer discs

Optical Drives can support _____ or _____.

burning

Recording data onto disc

120-mm (about 4.7 inches)

Standard size of optical discs

80-mm

size of mini discs

hearts, triangles, irregular shapes, a hockey-rink shape

Optical discs theoretically can be made into 4 various shapes but none of these different shapes are currently available

Patent battle

exists about changing optical disc shapes

large capacity

major advantage of optical discs and drives

single layer, 650 or 700 MB

CD discs are normally _____ and hold_____.

4.7 GB (single-layer), 8.5 GB (dual-layer)

DVD discs hold _____ or _____.

25 GB (single-layer), 50 GB (dual-layer)

BD discs hold _____ or _____.

double-sided

Discs can also be _____.

CD ROM, DVD ROM, BD-ROM

Can be read from, but not written to, by the user

pre-recorded

CD ROM, DVD ROM, BD-ROM normally come _____.

compact disc read-only memory

CD ROM

digital versatile disc read-only memory

DVD ROM

Blu-Ray Disc read-only memory

BD-ROM

CD-R, DVD-R, DVD+R, BD-R Discs

• Can be written to, but cannot be erased and reused

physically molded pits

CD-R, DVD-R, DVD+R, BD-R Discs have no _____.

backing up files, sending large files to others, creating custom music CDs

CD-R, DVD-R, DVD+R, BD-R Discs are used for _____, _____, and _____.

recording layer

CD-R, DVD-R, DVD+R most have a _____ containing organic light-sensitive dye between disc’s plastic and reflective layers

inorganic material

BD-R disc has _____.