Chapter 3-IT Flashcards

Storage

1
Q

Storage system

A

Storage medium-is the hardware where the data is stored (flash memory etc. DVD disc)
Storage device-is the hardware into which the storage medium is inserted (DVD drive)

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2
Q

Volatility and Random vs Sequential Access

A

Volatility-storage media are nonvolatile, and therefore is used for data to be saved for later use
Random-Direct access, allows data to be retrieved from any location on the storage medium
Sequential access-That retrieval of data can occur only in the order in which it was physically stored o the storage medium etc magnetic tape

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3
Q

Logical vs Physical Representation

A

Logical-How we view how data is stored
Physical-How computers view how data is stored

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4
Q

Types of storage technology

A

Magnetic(conventional hard drives)
Optical(optical discs)use light rays
Electrons(flash memory media)

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5
Q

Hard drives

A

Stores most programs and data for personal computer
Available with built-in encryption that limits access to only authorized users

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6
Q

Magnetic Hard drive

A

HDD contains particles on the metal disks inside the drive that are magnetized to represent the data’s 0s and 1s

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7
Q

Hard disk organization

A

Tracks-concentric paths on the disk where data is recorded
Sectors-Are small pieces of a track
Clusters-Consist of one or more sectors(smallest addressable area of a disk)
Cylinders-are a collection of tracks located in the same location on a set of hard disk surfaces

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8
Q

Magnetic hard drive technologies

A

Traditional-longitudinal magnetic recording aligns magnetic particles on a hard disk horizontally, parallel to the hard disk’s surface
Newer-Perpendicular magnetic recording (PMR) places bits upright and closer together to increase capacity and reliability

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9
Q

Data recovery experts

A

Recover data from damaged storage devices
Used when devices are physically damaged or just stop working
It is important to backup data to prevent data loss

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10
Q

Solid state drives

A

Uses flash memory technology to store data
Uses less power and has no moving parts
Generate less heat and no noise
Much faster than magnetic hard drives, but more expensive
The norm for netbooks, other portable devices

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11
Q

Solid state hybrid drives

A

Uses a combination of magnetic disks and flash memory chips
The data that is most directly associated with performance is stored in the flash memory
Nearly as fast as solid-state drivers(SSDs)
Slightly more expensive than magnetic hard disk drives
Reduces the number of times the magnetic disks need to be read/written to

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12
Q

Internal hard drives

A

Permanent storage devices located inside the system unit

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13
Q

External hard drives

A

Transport large amounts of data from one computer to another, for backup, and for additional storage, typically powered by the computer throughout the USB port

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14
Q

Disk access time

A

Is the total time that it takes for a hard drive to read or write data
Consists of seek time, rotational delay, data movement time

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15
Q

Disk cache

A

Consists of memory used in conjunction with a magnetic hard drive to improve system performance
Consists of RAM-based disk cache located inside the hard drive case
Can speed up performance ad save battery life and reduces wear and tear. Stores copies of data and programs that are on the HD and that might be needed soon in memory to avoid having to re-read it

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16
Q

Hard drive partitioning

A

Partitioning divides the physical capacity of a single drive logically into separate areas, called partitions
Each partition functions as an independent hard drive ,referred to as logical drives
Increases efficiency(small drives use smaller clusters)

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17
Q

Partition are used to create

A

A recovery partition(to restore the computer to its earlier state)
A new logical drive for data(Easier to locate ad back up or to upgrade an OS)
A dual boot system(using two different OS on the same drive)

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18
Q

File system vs interface standards

A

File system is the method the OS uses to store and organize file’s .It determines the partition size, cluster size, max drive size, max file size
Interface standards determine how a drive connects to the computer

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19
Q

Optical discs

A

Are thin circular plastic discs
are read from and written to using laser beams
Are commonly used for software delivery
Divided into sectors like magnetic discs but use a single spiral track
Have a relatively large capacity and are durable
Used for backup purposes and for storing and transporting music, photos

20
Q

Representing data on an optical disc

A

Pits and lands are used to represent 1s and 0s
The transition between a pit and a land represents a 1 , no transition represents a 0

21
Q

Read-only optical disc

A

Surface of disc is molded/stamped to represent data

22
Q

Recordable/rewritable disc

A

The reflectivity of the disc is changed using a laser beam to represent the data
Different types of optical discs use different types of laser beams

23
Q

Optical drivers

A

Read optical discs
The optical drive must support the type of optical disc being used
Almost always backward-compatible
Recording data onto a optical disc is called burning

24
Q

Advantages of optical discs

A

Large capacity(can also be double-sized)
Read on one side at a time ;must be turned over to access the 2nd side

25
Q

Read-only optical discs

A

CD-ROM, DVD-ROM, BD-ROM discs can be written to, but not erased and reused
Pits are permanent

26
Q

Recordable optical discs

A

CD-R, DVD-R, DVD+R, AND BD-R discs can be written to, but cannot be erased and reused
Pits are created in the disc when the disc is recorded
Most discs have a recording layer containing organic light-sensitive dye between disc’s plastic and reflective layers to create permanent pits
Used for backing up files, sending large files to others, and storing multimedia files

27
Q

Rewritable Optical discs

A

CD-RW, DVD-RW, DVD+RW and BD-RE discs can be written to, erased, and overwritten just like magnetic hard disks
Uses phase change technology
Heating and cooling is used to change the reflectivity of the disc
Appropriate for transferring large files from one computer to another/otherwise temporarily storing data(disc can be reused)

28
Q

Flash memory

A

Is a chip-based storage medium that represents data using electrons
Used in a variety of storage systems

29
Q

Embedded flash memory

A

Refers to flash memory chips embedded into products
Smartphones, tablets and even sunglasses
Usually the primary storage for mobile devices

30
Q

Flash memory cards

A

General-purpose flash memory card-Appropriate for most applications
Specialized flash memory cards-Professional flash memory cards(photographer)
Gaming flash memory cards
Encrypted flash memory cards(to secure data)
Project vault is essentially a computer on a flash memory card

31
Q

USB Flash drives

A

Consist of flash memory media integrated into a self-contained unit that plugs into and is powered by a USB port

32
Q

Network storage

A

Using a storage device via a local network.(to back up/share data)

33
Q

Network attached storage

A

Devices are high performance storage systems connected individually to a network

34
Q

A storage area network

A

Consists of separate network of hard drives or other storage devices that are attached to the main network
NAS and SAN are scalable(add more capacity as demand increases)

35
Q

Cloud storage (online storage)

A

Is accessed via the internet
Cloud apps
Online storage sites
Files can be synched between PC and cloud storage
Increasingly used for backup purposes

36
Q

Smart cards

A

Can be used for payment/identification purposes
Processor in a smart card can do calculations ,encrypt data

37
Q

Storage server

A

Contains multiple high-speed hard drives, larger than typical NASs, scalable so that hard drives can be added as needed
Can use magnetic and/or SSD drives

38
Q

RAID(Redundant arrays of independent discs)

A

Is a method of storing data on two/more hard drives that work together to record redundant(duplicate) copies
Protects critical data on large storage systems, helps to increases fault tolerance(ability to recover from failure)

39
Q

Different levels of RAID

A

RAID 0=Disk striping(spread files over two or more hard drives)
To increase speed(does not provide fault tolerance)
RAID 1=Disk mirroring(duplicate copy) to increase fault tolerance

40
Q

Striping vs Mirroring

A

Striping when a file is written to a RAID system using stripping, it is split among two or more drivers
Mirroring when a file is written to a RAID system using mirroring, an identical copy of the file is sent to another drive in the system

41
Q

Newer RAID systems

A

Connects to a computer/network via a USB cable
Contains drive bays into which hard drives can be inserted
Has capacity and status indicators-drives can be inserted and removed as needed

42
Q

Data archiving

A

Is the process of identifying and moving data that is no longer actively being used from regular storage systems to a separate long-term archival storage system
Large hard drives such as helium

43
Q

Magnetic tape

A

Sequential storage
Typically cartridge tapes; can be libraries(internal/external)
Higher capacity, archival Blu-ray discs that are becoming available so are optical jukeboxes
cloud storage

44
Q

Product characteristics to consider

A

Speed, compatibility, storage capacity, convenience and portability

External drives are usually slower than internal ones

45
Q

Seek time vs rotational delay vs data movement time

A

Seek time-Time taken to move the heads to the correct cylinder
Rotational delay-Time taken to rotate the plotters so that the heads are over the correct part of cylinder
Data movement time-Time taken to read/write the data