Advanced Information Storage 07ah566/lectures/adv07... · 2013-10-24 · Advanced Information...
Transcript of Advanced Information Storage 07ah566/lectures/adv07... · 2013-10-24 · Advanced Information...
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Department of Electronics
Advanced Information Storage 07
Atsufumi Hirohata
16:00 24/October/2013 Thursday (V 120)
Quick Review over the Last Lecture
Smooth base film (PET, PEN or PA)
70 ~ 80 % thickness
Back coating
Bottom non-magnetic layer
Top ferromagnetic layer
Servo-band Servo-signal
320
320
320
320
1280
Track width : 8.1 µm
LTO Storage :
• 12.65 mm wide tape / tracks
• Track width : µm
• Length : m
• < µm left / right distributions
• < nm surface roughness
* http://home.jeita.or.jp/
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07 Development of Magnetic Storages
• Drum memory
• Core memory
• Bubble memory
• Floppy disk
• Storage hierarchy
Punched Tape
Punched tapes were originally used for teletypes : *
• 0.1-mm thick tapes were used.
• American Standard Code for Information Interexchnage (ASCII) standardised the format in 1963.
• 1-inch wide tape
• 0.072-inch diameter holes with 0.1-inch separation
• 7-level code including feed holes
* http://www.wikipedia.org
Long lifetime
Easy to repair
No magnetic damages
Easy to dispose
× Low fidelity
× Easy to damage
× Low recording density
× Limited usage
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Punched Card
Punched cards were originally used for loom patterns : *
• In 1832, Semen Korsakov used for informatics.
• Charles Babbage proposed a calculating machine, “Number Cards.”
• Herman Hollerith invented a tabulating machine in 1890.
→ Tabulating Machine Company (1896) → IBM
• 80-column card in dollar note size
→ 80-characters column programming
* http://www.wikipedia.org
Long lifetime
Easy to sort
No magnetic damages
Easy to dispose
× Difficult to miniaturise
× Remaining punched out bits
× Low recording density
Magnetic Drum Memory
In 1932, Gustav Tauschek invented a magnetic drum memory : *
* http://austria-forum.org/af/Wissenssammlungen/Erfinder/Tauschek,%20Gustav;
• Widely used in 1950s and 60s.
• Ferromagnetic materials are coated on a drum. **
• Read / write heads are placed in one line with defining tracks.
× Slow access
× Mechanical failure
→
× Small capacity
→
** http://www.wikipedia.org/; *** http://www.computermuseum.li/Testpage/DRUM-Memory-BendixG15computer.htm
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Magnetic Core Memory
In 1949, An Wang and Way-Dong Woo invented Pulse Transfer Controlling Device : *
* http://www.wikipedia.org/
• Random access memory for a computer
• Widely used between 1955 and 75.
• Magnetic toroids, cores, store data
• Current applications to two wires write data.
• Data is read by measuring a sensing wire current.
Fast access speed
Non-volatility
Cheap
Reliable (> vacuum tube)
→
× Read-out erases data.
× Accidental data loss
Magnetic Bubble Memory
In 1967, Andrew H. Bobeck invented a magnetic bubble memory : *
* http://www.nae.edu/21856.aspx
• Widely used between 1970s and 80s
• 4,096 bits / cm 2
• Conventional stripe magnetic domains can be converted into cylindrical domains.
• The size of such cylindrical domains can be controlled by an external magnetic field.
• These domains disappear under a critical magnetic field.
→ “Magnetic bubble”
Large capacity
Non-volatility
Cheap
Robust against vibration and dust
× Accidental data loss
** http://www.wikipedia.org/
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Magnetic Bubble Memory Operation
Memory architecture : *
* http://www.decodesystems.com/tib0203.html; ** http://www.wikipedia.org/
Floppy Disk
In 1969, IBM introduced a flexible diskette : *
* http://www.wikipedia.org/
• Widely used until 1990s.
• 8-inch disk : 79.75 kB ~ 1.2 MB
• 5 ¼-inch disk : 110 kB ~ 1.2 MB
• 3 ½-inch disk : 264 kB ~ 200 MB
Removable
Basic Input / Output System (BIOS) compatible
Non-volatility
Cheap
× Fragile against vibration and dust
× Magnetic field and ultra-violet (UV) light
× High temperature and humidity
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Floppy Disk Sizes
Specifications : *
* http://www.ceramic.or.jp/museum/contents/pdf/2007_5_01.pdf
Disk diameter 8-inch 5.25-inch 3.5-inch Introduction 1970 ~ 1976 ~ 1980 ~
Developer IBM
Shugart Technology (Seagate
Technology)
Sony
Main demand Programme loading Miniaturisation High fidelity
Coercivity 300 Oe 300 Oe 720 Oe Recording density kB ( kB) MB MB Track density TPI TPI TPI Magnetic core Laminated Straddle Bulk
Floppy Disk Media
Media parts : *
* http://www.wikipedia.org/
HD indicating hole
Hub for rotation
Shutter
Plastic housing
Polyester sheet to reduce friction against the housing
Magnetically coated plastic disk
Schematic data sector
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Floppy Disk Head
A head core requires the following features : *
• Large saturation flux density
• Large magnetic permeability
• Small coercivity
• Wear-proof
* http://www.ceramic.or.jp/museum/contents/pdf/2007_5_01.pdf
ferrites ferrites
ferrites
Mag
netic
per
mea
bilit
y
Frequency (kHz)
head
Track width (TW) for ERASE
Track width (TW) for R / W data
TW for ERASE
Track width (TW) for R / W data
Read / Write (R / W) head
Partial Response, Maximum Likelihood
A method to convert ambiguous signals to digital signals : *
* http://www.datarecoverytools.co.uk/data-recovery-vocabulary/vocabulary-a-e/data-encoding-and-decoding-of-hard-disk/partial-response-maximum-likelihood-prml/
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Floppy Disk Drive
Drive parts : *
* http://www.hardwaresecrets.com/fullimage.php?image=1532
Floppy Disk and CD-ROM
Track configurations of a floppy disk and a CD-ROM disk : *
* http://www.kayoo.info/jyouhou-kiki/sozai/1506/index.html
Floppy disk CD-ROM disk
• •
• •
• (FD, HDD and MO)
• (CD, MD, DVD and BD)
× Small capacity
Fast access speed
Large capacity
× Slow access speed
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Constant Angular / Linear Velocity
Constant angular velocity : *
* http://www.wikipedia.org/
Constant linear velocity : *
Data tracks
Detecting laser / read head
Constant velocity
Data tracks
Detecting laser / read head
Variable velocity
SuperDisk
In 1996, Matsushita (Panasonic) and Imation developed a SuperDisk : *
* http://www.wikipedia.org/
• Precise tracking by laser-positioning to grooves between the tracks.
• 3.5-inch disk : 120 ~ 240 MB
• FD32MB : 1.4 MB 2HD floppy → 32 MB tracks : 80 → 777 sectors :56 ~ 36
Backward compatibility
BIOS (partially) compatible
×2 faster access speed than a FD
× Expensive
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Zip Drive
In 1994, Iomega developed a Zip drive : *
* http://www.wikipedia.org/
• 3.7-inch disk media
• First product : 100 MB
• Later 250 and 750 MB
• Magnetic thin layer : Advanced super Thin layer & high Output Metal Media (ATOMM) developed by Fujifilm.
Very fast access speed (1.0 Mbps)
Cheap drive
High data density
Direct connectability with a Parallel / SCSI port
× Expensive media as compared with a MO
× Upward compatibility A 750-MB drive cannot write a 100-MB disk.
× “Click of death” Permanent damage to the head by hitting to the protector of head movement.
Jaz Drive
In 1995, Iomega developed a Jaz drive : *
* http://www.wikipedia.org/
• 3.5-inch disk : 1 GB
• Upward compatibility : 2 GB
Fast access speed similar to a HDD (5.4 Mbps)
× Overheat
× Media stuck in a drive
× Metal slides introduces plastic debris.
× Noisy rotation
× Failure of anti-gyro system
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REV Drive
In 2003, Iomega introduced a REV drive to replace a Jaz drive : *
* http://www.wikipedia.org/
• 2.5-inch disk : 35 GB
• Upward compatibility : 70 and 120 GB
Fast access speed : 25 Mbps
Dust-proof
Anti-vibration
30-year life (> 1M times rewritability)
× Expensive
Hierarchy of Information Storage
For a Neumann machine, a central processing unit (CPU) controls the storages : *
* http://www.wikipedia.org/
• / • / non-volatile
• For volatile memories, static / dynamic
• Read/write, read only or write once
• Random / sequential access
• Location, file or content addressable
• Destructive / non-destructive read