Levi Krein Associate Professor CIS CIS 101: Introduction to
Computers Chapter 7 Storage
Slide 2
Levi Krein Associate Professor CIS What is storage? p. 7.02
Fig. 7-1 Holds data, instructions, and information for future use
Storage medium is physical material used for storage Also called
secondary storage
Slide 3
Levi Krein Associate Professor CIS What is capacity? Number of
bytes (characters) a storage medium can hold Largest single
database is 500 Terabytes at an east coast university (nuclear
accelerator data) Kilobyte (KB)1 thousand Gigabyte (GB) 1 billion
Megabyte (MB)1 million Petabyte (PB)1 quadrillion Terabyte (TB)1
trillion Exabyte (EB)1 quintillion Zettabyte (ZB)1 sextillion
Yottabyte (YB)1 septillion
Slide 4
Levi Krein Associate Professor CIS How does volatility compare?
Storage medium is nonvolatilecontents retained when power is off
Memory is volatileholds data and instructions temporarily
Slide 5
Levi Krein Associate Professor CIS Writing Process of
transferring items from memory to storage media Writing What is a
storage device? Reading Process of transferring items from storage
media to memory Reading MemorySDRAM Functions as source of Input
Records Output Hardware = I/O or Read/Write Devices
Slide 6
Levi Krein Associate Professor CIS Access time is the
combination of two tasks: Time it takes storage device to locate
item on storage medium Time required to deliver item from memory to
processor faster transfer rates slower transfer rates Data Transfer
Rate Secondary Storage Primary Storage Hard Disk Flash Memory Cards
and USB Flash Drives CDs and DVDs Tape Items waiting to be
interpreted and executed by the processor Operating system,
application software, user data and information Digital pictures or
files to be transported Software, backups, movies, music Backups
Memory (most RAM) Stores Remember, the access time of RAM is
200,000 times faster than a hard drive
Slide 7
Levi Krein Associate Professor CIS What is a hard disk? hard
disk installed in system unit High-capacity storage Consists of
several inflexible, circular platters that store items magnetically
Components enclosed in airtight, sealed case for protection
High-speed platters spin at 5400-7200 rpm Link to How Hard Disks
Work Hard Drive = 7200 rpm 120 rpSecond
Slide 8
Magnetic Disks Formatting prepares disk for use Track is narrow
recording band that forms full circle on disk Sector stores up to
512 bytes of data
Slide 9
Levi Krein Associate Professor CIS How does disk storage work?
Disks are Magnetic = data is stored by aligning positive &
negative particles
Slide 10
Levi Krein Associate Professor CIS Magnetic Disks What are
characteristics of a hard disk? p. 361 Fig. 7-11 Sample Hard Disk
Characteristics Advertised capacity120 GB Platters3 Read/write
heads6 Cylinders16,383 Bytes per second512 Sectors per track63
Sectors per drive234,441,648 Revolutions per minute7,200 Transfer
rate133 MB per second Access time8.9 ms actual disk capacity 750 GB
Fall 2006 Check the capacity of our lab computers
Slide 11
Levi Krein Associate Professor CIS How does a hard drive look?
Platters are made of metal (aluminum), glass, or ceramic & has
a metal surface that can be magnetized.
Slide 12
Levi Krein Associate Professor CIS Video: Install a New Hard
Drive Speed up your computer with a new hard drive Obsolete $65
Sale $90 Sept. 2009 Hard Drive Video $60 New 1 Terabyte $60
Slide 13
Levi Krein Associate Professor CIS What is a cylinder? Vertical
section of track through all platters Same track number on multiple
surfaces Single movement of read/write head arms accesses all
platters in cylinder; reduce access time platter read/write head
platter sides cylinder track sector
Slide 14
Levi Krein Associate Professor CIS Maintaining Hard Disk Data A
little Preventive maintenance! Defragment = reorganize files to
make better used of space; programs will run faster Two ways: 1
Start, Accessories, System Tools 2 My Computer, Properties, Disk
Cleanup & Tools
Slide 15
Levi Krein Associate Professor CIS What is a head crash?
clearance read/write head platter hair dust smoke Spinning creates
cushion of air that floats read/write head above platter Occurs
when read/write head touches platter surface A smoke particle, dust
particle, or human hair could render drive unusable Clearance
between head and platter is approximately two-millionths of an
inch
Slide 16
Levi Krein Associate Professor CIS hard disk What is a disk
cache? Portion of memory that processor uses to store frequently
accessed items second request for datato hard disk disk cache first
request for datato disk cache processor
Slide 17
Levi Krein Associate Professor CIS What are external hard disks
and removable hard disks? External hard disk freestanding hard disk
that connects to system unit Removable hard disk hard disk that you
insert and remove from hard disk drive Used to back up or transfer
files Hard drive is designated as drive C
Slide 18
Levi Krein Associate Professor CIS What is a miniature hard
disk? Provide greater storage capacities than flash memory Smaller
than notebook computer hard disks A pocket hard drive is a
self-contained unit
Slide 19
SAS controller supports many connected devices at once,
including hard disks, CD and DVD drives, printers, scanners,
digital cameras, and more EIDEEnhancedIntegratedDrive Electronics)
controller supports four hard disks, provides connections for CD
and DVD drives EIDE (Enhanced Integrated Drive Electronics)
controller supports four hard disks, provides connections for CD
and DVD drives Magnetic Disks What is a disk controller? SCSI
controller supports up to fifteen devices including hard disks, CD
and DVD drives, tape drives, printers, scanners, network cards
Serial Advanced Technology Attachment) controller uses serial
signals to transfer data, instructions, and information SATA
(Serial Advanced Technology Attachment) controller uses serial
signals to transfer data, instructions, and information Chip and
circuits that control transfer of data from disk
Slide 20
Levi Krein Associate Professor CIS What is online storage?
Others can be authorized to access your data Offsite backup of data
Service on Web that provides storage for minimal monthly fee Files
can be accessed from any computer with Web access Large files can
be downloaded instantaneously Video
Slide 21
Magnetic Disks What is a floppy disk? Portable, inexpensive
storage medium (also called diskette) Thin, circular, flexible film
enclosed in 3.5 wide plastic shell Obsolete?
Slide 22
Levi Krein Associate Professor CIS Push the same button to
close the tray. Optical Discs = CDs and DVDs Most PCs include an
optical disc drive Flat, round, portable metal discs with
protective plastic coating Can be read only or read/write Insert
the disc, label side up. Push the button to slide out the tray.
Disc: Alternative spelling of disk. Disc is often used for optical
discs, while disk generally refers to magnetic discs, but there is
no real rule.diskoptical
Slide 23
Levi Krein Associate Professor CIS How does a laser read data
on a CD or DVD? laser diode prism light- sensing diode 01 lens
pitland disc label Step 1. Laser diode shines a light beam toward
disc. Step 2. If light strikes a pit, it scatters. If light strikes
a land, it is reflected back toward diode. Step 3. Reflected light
is deflected to a light-sensing diode, which sends digital signals
of 1 to computer. Absence of reflected light is read as digital
signal of 0. Link to How CDs Work
Slide 24
Levi Krein Associate Professor CIS How is data stored on a CD
or DVD? Typically stored in single track Track divided into evenly
sized sectors that store items single track spirals to edge of disc
disc sectors
Slide 25
Levi Krein Associate Professor CIS What is a CD-ROM? Compact
disc read-only memory Cannot erase or modify contents
Single-session Typically holds 650 MB to 1 GB Commonly used to
distribute multimedia (music) and complex software
Slide 26
Levi Krein Associate Professor CIS What is the data transfer
rate of a CD-ROM drive? Original CDs Transferred at 150 KBps (kilo
bytes per second) 1X 10X = 150 x 10 or 1,500 KBps 48X: 48 150 KBps
= 7,200 KBps or 7.2 MBps 1X 10X 48X 75X ? 75 150 KBps = 11,250 KBps
or 12.25 MBps
Slide 27
Levi Krein Associate Professor CIS What is a Picture CD? p.
7.19 Fig. 7-25 Film developers offer Picture CD service Can be
modified using photo editing software Stores digital versions of
roll of film Step 3. At home, print images from Picture CD on your
ink-jet photo printer. At a store, print images to Picture CD at
kiosk. Step 1. Drop off film to be developed. Mark the Picture CD
box on the film-processing envelope. Step 2. When you pick up
prints and negatives, a Picture CD contains digital images of each
photograph. A CD-ROM drive can read a Picture CD & other CDs
(but CAN NOT read DVDs) Kodak
Slide 28
Levi Krein Associate Professor CIS What are CD-Rs and CD-RWs?
Must have CD recorder or CD-R drive Cannot erase discs contents
CD-R (compact disc-recordable) c disc you can write on once CD-RW
(compact disc-rewritable) ce erasable disc you can write on
multiple times Must have CD-RW software and CD-RW drive
Multi-session?
Slide 29
Levi Krein Associate Professor CIS digital versatile disc -ROM
or digital video disc -ROM? DVD DVD drive High capacity disc
capable of storing 4.7 GB to 17 GB Must have DVD-ROM drive or DVD
player to read DVD-ROM Stores databases, music, complex software,
and movies What is a DVD-ROM ?
Slide 30
Levi Krein Associate Professor CIS DVDs Blu-ray discs storage
capacity = 100 GB Blu-ray has won the high definition storage
medium for movies HD-DVD discs lost out to Blue-ray HD-VMDs have
storage capacity of up to 40 GB or more Competitor to Blu-ray 20
layers UMD can store up to 1.8 GB Mini-DVD; PlayStation
Portable
Slide 31
Levi Krein Associate Professor CIS How does a DVD-ROM store
data? DVD-ROM Storage Capacities SidesLayersStorage Capacity 1147
GB 118.5 GB 219.4 GB 2217 GB Two layers of pits are used, lower
layer is semitransparent so laser can read through Some are
double-sided Data is packed (pits are closer together) more densely
DVD-RW is a rewritable DVD It can write on CD-R, CD-RW, DVD-R &
DVD-RW
Slide 32
Levi Krein Associate Professor CIS What is tape? p. 7.24 Fig.
7-29 Magnetically coated plastic ribbon capable of storing large
amounts of data at low cost Sequential access, like music Primarily
used for backup Sequential access is the opposite of Direct access
used on hard disks, CDs, and DVDs which can locate particular item
immediately
Slide 33
Levi Krein Associate Professor CIS What is a PC Card? Adds
capabilities to computer Credit-card-sized device commonly used in
notebook computers
Slide 34
Levi Krein Associate Professor CIS What is miniature mobile
storage media? Storage for small mobile devices Miniature mobile
storage media CompactFlashSecure Digital xD Picture Card Memory
Stick
Slide 35
Levi Krein Associate Professor CIS What is a card reader? Reads
information stored on miniature mobile storage media Type of card
determines type of card reader needed
Slide 36
Levi Krein Associate Professor CIS What is a USB Flash Drive?
Plugs in a USB port on a computer or mobile device Storage
capacities up to 64 GB How flash drives are made. Check out the
robotics. 8 minutes
Slide 37
Levi Krein Associate Professor CIS What is a smart card? Stores
data on microprocessor embedded in small card Input, process,
output, and storage capabilities Sometimes called intelligent smart
card Prepaid telephone cards
Slide 38
Levi Krein Associate Professor CIS What are microfilm and
microfiche? Store microscopic images of documents on roll or sheet
of film Microfilm 100- to 215-foot roll of film Microfiche small
sheet of film, usually 4 6
Slide 39
Levi Krein Associate Professor CIS How do life expectancies of
various media compare? Microfilm and microfiche have longest life
of any storage media
Slide 40
Drive Letter Designations Floppy Disks Drive Letter A & B
Hard Disks Drive Letter C More Hard Disks = D, E, etc. Optical
Drives Next available letter after hard disks Flash Drives Next
available letter after optical drives Levi Krein Associate
Professor CIS
Slide 41
Levi Krein Associate Professor CIS Other Storage Devices
Dogtags View Video
Slide 42
Levi Krein Associate Professor CIS Other Storage Devices
Storage Cube View Video Notice Floppy Disks and Magnetic Tape
Slide 43
Levi Krein Associate Professor CIS Summary of Storage Chapter 7
Completed