Transcript Judul - Binus Repository

Matakuliah
Tahun
Versi
: T0604-Pengantar Teknologi Informasi
: 2008
: 2.0/0.0
Pertemuan 10
Hardware: Secondary Storage
Sumber:
Chapter 4. Hardware: The CPU &
Storage, p.189
Williams, B.K, Stacy C. Sawyer (2007).
Using Information Technology: A
Practical Introduction to Computers &
Communications. Seventh Edition,
McGraw-Hill, New York. ISBN-13: 978-007-110768-6
1
Learning Outcomes
Pada akhir pertemuan ini, diharapkan mahasiswa
akan mampu:
• menjelaskan berbagai jenis secondary
storage yg ada pada masa kini, dan
perkembangannya ke depan (C2)
2
Outline Materi
• Secondary Storage
• Future Developments in Processing &
Storage
3
Secondary Storage
Storage Types
Descriptions
1. Floppy and Zip disks
1. Removable disks.
2. Hard disks
2.
3. Optical disks
4. Magnetic tape
3.
4.
5. Smart Cards
6. Flash memory
7. Online secondary
storage
5.
6.
7.
a. Floppies store 1.44 MB
b. Zip disks store 100, 250, or 750 MB
Made from thin rigid metal covered with
magnetizable substrate. Most disks have 2 or
more platters
Removable CDs and DVDs
Thin plastic tape coated with magnetizable
substance
Like a credit card, but contains a
microprocessor and memory chips
Nonvolatile memory – no moving parts
Lets you store data on an online vendor’s server
4-4
Secondary Storage
Floppies and Zip Disks
• Floppies
• Zip Disks
– Flat piece of mylar plastic
inside a 3.5” plastic case
– Store about 1.44 MB
– Have a write-protect notch
– Data is recorded in tracks:
concentric recording bands
– Formatting breaks the
tracks into small wedgeshaped sectors
– Read/Write head transfers
data between the computer
and disk
– Floppies DO wear out!
– Disks with a high-quality
magnetic coating
– Store 100, 250, or 750 MB
– Require a Zip drive; won’t
work on floppy drives
– Used to store larger files
than floppies can hold
– Zip disks wear out too!
4-5
Secondary Storage
Hard Disks
• Thin, rigid metal, glass, or ceramic platters covered
with a substance that allows data to be held in the
form of magnetized spots
– The more platters there are, the higher the drive capacity
– Store data in tracks, sectors, and clusters
– Formatting creates a file allocation table that maps files to
clusters or inodes
• Typical file systems are VFAT & NTFS for Windows, HFS and ext2
for Unix
– Drive heads ride on .000001” cushion of air, and can
crash!
– Important data should always be backed up!
4-6
Secondary Storage
Hard Disks
• Hard Disk Types:
– External Hard Disks – a freestanding disk drive
– Removable Hard Disk – inserted into a cartridge drive
on the PC
• Hard Disk Controllers
– EIDE – Enhanced Integrated Drive Electronics
• Supports up to 4 disks at 137 GB per disk
• Marketed as SATA, Fast ATA, Ultra ATA, ATA-2, ATA/100
– SCSI – Faster than EIDE controllers
– Fibre Channel – used in large servers – faster and
costlier than SCSI
4-7
Secondary Storage
Optical Disks
• CDs and DVDs are Optical disks
• Data is written and read using lasers, not a disk
head
– CD-ROM is Compact Disk Read-Only Memory
• CD-R is used for recording only once
• CD-RW is an erasable optical disk that can both record and
erase data over and over again
– DVD is a CD-style disk with extremely high capacity
• Stores 4.7 or more GB
• DVD-R is used for recording only once
• DVD-RW, DVD-RAM, DVD+RW are reusable DVDs
4-8
Secondary Storage
Magnetic Tape
• Thin plastic tape coated with a substance
that can be magnetized
– Store 200 GB and higher
– Used in the form of tape cartridges
– Still popular for large backups because of
their large data capacity
– But don’t get it near a magnet as that will
erase it!
4-9
Secondary Storage
Smart Cards
• Resembles a credit card, but contains a microprocessor
and memory chips
– Holds more information than standard magnetic-strip
credit cards; 8 – 40 MB of data
– UltraCard
• Uses a magnetic shim that draws out of the card to be read,
then retracts into the drive
• Provides 2 GB of storage
– Contact smart cards
• Must be swiped through card readers
• Can wear out from use
– Contactless smart cards
• Read when held in front of a low-powered laser
4-10
Secondary Storage
Flash Memory
• Nonvolatile memory with no moving parts
– But the electronics can wear out
– Available as
• Flash memory cards
– Insert these into a flash port of a camera, handheld PC,
smartphone
• Flash memory sticks
– A form of flash memory that plugs into a memory stick
port
• Flash memory drives
– A finger-sized module of flash memory
– Plugs into the USB port of most PCs and Macintoshes
4-11
Secondary Storage
Online Secondary Storage
• Allows you to use the internet to back up
your data
– Sign up with a vendor and receive access to
software that allows you to upload your data
to that company’s server
– Files should be encrypted to maintain security
– Use only for vital files that require immediate
availability
– Use tape, removable hard disk cartridges, zip
disks, optical storage or tape for normal
backup
4-12
Future Developments in Processing &
Storage
• Moore’s Law
– Gordon Moore predicted the number of transistors on a
silicon chip will double every 18 months
– It has held up since the 1960s!
4-13
Future Developments in
Processing & Storage
New Technology
1. M-RAM
2. OUM
3. Nanotechnology
4. Optical Computing
5. DNA Computing
6. Quantum
Computing
Description of Processing Technology
1. Magnetic RAM uses miniscule magnets
rather than electrical charges
2. Ovonic Multiplied Memory stores bits by
generating different levels of low and high
resistance on a glossy material
3. Tiny machines work at a molecular level to
make nanocircuits
4. Uses lasers and light, not electricity
5. Uses strands of synthetic DNA to store data
6. Based on quantum mechanics and stores
information using particle states
4-14
Future Developments in
Processing & Storage
New Technology
1. Higher-density
disks
2. Molecular
electronics
Description of Storage Technology
1. Magnetic disk drives currently hold 100
GB of data
a.
Blank CDs are replacing floppy disks
since they hold 650MB and cost < $1
each
b. DVD disks hold up to 4.7 GB of data
currently
c. Perpendicular recording technology
allows 25% - 100% more data to be
stored on the same disk
2. Polymer memory creates chips that store
data on plastics
a. Nonvolatile memory
b. Data is stored based on polymer’s
electrical resistance
4-15
Kesimpulan
16