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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