Millipede is a non-volatile computer memory that uses thousands of nano-sharp probes to punch indentations representing bits into a thin polymer film. Data can be read and written in parallel by heating the probes to alter the indentations. A prototype demonstrated storing over 1 terabit per square inch, making it suitable for very high density storage applications like mobile devices. However, progress toward commercialization has been slower than expected due to advances in competing technologies like flash drives.

1. MILLIPEDE MEMORY

2. CONTENTS
• Millipede memory Introduction.
• The Millipede concept.
• Cantilever Structure.
• Reading data.
• Writing data.
• Stored bits.
• Usage Scenarios.
• Current state of the art.
• Future challenges.
• Conclusion.

3. WHAT IS MILLIPEDE ?
• Millipede is a non-volatile computer memory.
• IBM demonstrated a prototype of millipede at CeBIT
2005.
• Data is stored as pits burned into the surface of a thin
polymer layer.
• Read and write is done by a MEMS-based probe.
• Seen as potential replacement for magnetic recordingin
hard drives.

4. HOW IT IS ?
• Millipede uses thousands of nano-sharp tips to punch
indentations representing individual bits into a thin polymer
film.
• The 'Millipede' technology is re-writeable.
• Can store more than 3 billion bits of data in the space occupied
by just one hole in a standard punchcard.
• Their layout looked like the legs of a millipede, and hence the
name.

5. NEED OF MILLIPEDE ?
• Flash memory cannot surpass 1-2 gigabytes of capacity,
whereas Millipede technology could pack 10 - 15 gigabytesof
data into the same tiny format.
• Power required will be same as that of flash memory.
• The Millipede can add tremendous data capacity tomobile
devices such as PDA, cellular phones.
• Data storage density is 1 Tb/inch^2, equivalent to storing the
content of 25 DVDs on the size of a postal stamp.

6. THE MILLIPEDE CONCEPT
• The main memory of modern computers is constructed from
number of DRAM-related devices.
• DRAM store data as the presence or absence of electrical charge.
• Hard drive store data on a metal disk.
• Data is represented as local magnetization of the material.
• Reading and writing is accomplished by a single “head”.
• The drive's performance is dependent on how fast the diskspins.

7. • Millipede storage combine the best features of both.
• Millipede uses numerous probes,for reading and writing.
• Bits are stored as a pit, in the surface of a thermo-active
polymer known as the “sled”.
• The sled is moved in a scanning pattern to bring the
requested bits under the probe, a process known asx/y
scan.
• The core components of probe storage system are
(1)A two-dimensional array of silicon probes (cantilevers)
(2)A micro-mechanical scanner which moves the storage
medium relative to the array.

9. ANIMATED VIEW OF MILLIPEDE
• An animated view of the
Millipede storage device
illustrates how an individual
tip creates an indentation in
a polymer surface (bottom)
and how a large number of
such tips are operated in
parallel (top).

10. WHAT IS A CANTILEVER ?
• Millipede has cantilever array, on which a probe has tobe
mounted,which is made of silicon.
• For reading, writing and erasing functions, the cantilever
tips are brought into contact with the storage medium.
• Most recent array design consists of an array of 64 × 64
cantilevers (4096).
• The storage medium is positioned relative to the cantilever
array.

11. READING DATA
• To accomplish a read, the probe tip is heated to around
300°C and moved in proximity to the data sled.
• If the probe is located over a pit,the surface areaincreases
in contact with the sled, and cools as heat leaks into the
sled from the probe.
• The electrical resistance of the probe is proportional ofits
temperature.
• Thus when the probe drops into a pit and cools, this
registers as a drop in resistance.
• A low resistance will be translated to a "1" bit, or a "0" bit
otherwise.

12. THERMO-MECHANICAL READING

13. WRITING DATA
• To write a bit, the tip of the probe is heated to a
temperature above the glass transition temperature of the
polymer, which is generally acrylic glass.
• The transition temperature is around 400 K.
• To write a "1", the polymer in proximity to the tip is
softened, and then the tip is gently touched to it,causing
a dent.
• To erase the bit and return it to the zero state, the tip is
instead pulled up from the surface, allowing surface
tension to pull the surface flat again

14. THERMO-MECHANICAL
WRITING

15. OVERWRITING DATA
• To over-write data, the tip makes a series of offset pits that
overlap so closely that their edges fill in the old pits,
effectively erasing the unwanted data.
• The write or overwrite cycles are limited to 1,00,000
cycles.
• Current data rates of individual tips is limited to kilobits/sec
which is few Mbits/sec for entire array.

16. STORED BITS
• Fig. shows that more than
80 percent of the 1,024
cantilevers of an
experimental setup were
able to write data (12
storage areas at right).

17. USAGE
SCENARIOS
• Micro Drives
Millipede systems can be used for micro drives, like
watches, mobile phones and personal media systems.
The very high data density of millipede systems makes
them a very good candidate to be put to thisuse.
• High-capacity hard drives
The Millipede system provides
➢ high data density,
➢ low seek times,
➢ low power consumption and,
➢ high reliability.
These features make them candidates for
building high capacity hard drives.

18. CURRENT STATE OF THE ART
• The Earlier generation millipede devices used probes10
nanometers in diameter and 70 nanometers in length,
producing pits about 40 nm in diameter on fields 92 µm x
92 µm. This is arranged in a 32 x 32 grid, the resulting 3
mm x 3 mm chip storing 500 megabits of data or 62.5 MB,
resulting in an areal density of 200 Gbit/in².
• But recent devices have used a 64 x 64 cantilever chips
with a 7 mm x 7 mm data sled, the pit size is about 10 nm,
resulting in a areal density just over 1Tbit/in².

19. CHALLENGES
 The progress of millipede storage to a commercially useful
product has been slower than expected.
 Huge advances in other competing storage systems,
notably Flash and hard drives.
 More expensive per megabyte then current technology.
 It has not been surpassed by newer generations of the
existing technologies but this can be a great challenge.

20. CONCLUSION
• Today there are many emerging markets for nanotechnology
where high density nano storage devices arerequired.
• It is a nano version of punch card butrewriteable.
• Can be used in micro devices as well as in harddrive
manufacturing.
• Millipedes read and write data parallely.
• High storage density of 1Tb/square inch.

21. REFERENCES
• http://www.seagate.com
• IBM Zurich Research
• Millipede project
• T-bit demonstration
• Millipede animation
• IBM Journal Res. Dev. paper
• www.ibm.com
• www.newscientist.com