Millipede memory
Computer memory and Computer data storage types |
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Volatile |
Non-volatile |
Millipede memory is a form of
IBM demonstrated a prototype millipede storage device at CeBIT 2005, and was trying to make the technology commercially available by the end of 2007. However, because of concurrent advances in competing storage technologies, no commercial product has been made available since then.
Technology
Basic concept
The
In contrast, hard drives store data on a disk that is covered with a magnetic material; data is represented by this material being locally magnetized. Reading and writing are accomplished by a single head, which waits for the requested memory location to pass under the head while the disk spins. As a result, a hard drive's performance is limited by the mechanical speed of the motor, and it is generally hundreds of thousands of times slower than DRAM. However, since the "cells" in a hard drive are much smaller, the storage density for hard drives is much higher than DRAM. Hard drives are non-volatile — data is retained even after power is removed.
Millipede storage attempts to combine features of both. Like a hard drive, millipede both stores data in a medium and accesses the data by moving the medium under the head. Also similar to hard drives, millipede's physical medium stores a bit in a small area, leading to high storage densities. However, millipede uses many nanoscopic heads that can read and write in parallel, thereby increasing the amount of data read at a given time.
Mechanically, millipede uses numerous
The amount of memory serviced by any one field/probe pair is fairly small, but so is its physical size. Thus, many such field/probe pairs are used to make up a memory device, and data reads and writes can be spread across many fields in parallel, increasing the throughput and improving the access times. For instance, a single
Regarding the creation of indentations, or pits, non-
Reading and writing data
Each probe in the cantilever array stores and reads data thermo-mechanically, handling one bit at a time. To accomplish a read, the probe tip is heated to around 300
To write a bit, the tip of the probe is heated to a temperature above the glass transition temperature of the polymer used to manufacture the data sled, which is generally made of
As one might expect, the need to heat the probes requires a fairly large amount of power for general operation. However, the exact amount is dependent on the speed that data is being accessed; at slower rates the cooling during read is smaller, as is the number of times the probe has to be heated to a higher temperature to write. When operated at data rates of a few megabits per second, Millipede is expected to consume about 100 milliwatts, which is in the range of flash memory technology and considerably below hard drives. However, one of the main advantages of the Millipede design is that it is highly parallel, allowing it to run at much higher speeds into the
Applications
Millipede memory was proposed as a form of non-volatile computer memory that was intended to compete with flash memory in terms of data storage, reading and writing speed, and physical size of the technology. However, other technologies have since surpassed it, and thus it does not appear to be a technology currently being pursued.
History
First devices
The earliest generation millipede devices used probes 10 nanometers in diameter and 70 nanometers in length, producing pits about 40 nm in diameter on fields 92 μm x 92 μm. Arranged in a 32 x 32 grid, the resulting 3 mm x 3 mm chip stores 500 megabits of data or 62.5 MB, resulting in an
Proposed commercial product
Devices demonstrated at the CeBIT Expo in 2005 improved on the basic design, using a 64 x 64 cantilever chips with a 7 mm x 7 mm data sled, boosting the data storage capacity to 800 Gbit/in² using smaller pits. It appears the pit size can scale to about 10 nm, resulting in a theoretical areal density just over 1Tbit/in². IBM planned to introduce devices based on this sort of density in 2007. For comparison, as of late 2011, laptop hard drives were shipping with a density of 636 Gbit/in²,[6] and it is expected that heat-assisted magnetic recording and patterned media together could support densities of 10 Tbit/in².[7] Flash reached almost 250 Gbit/in² in early 2010.[8]
Current development
As of 2015,[citation needed] because of concurrent advances in competing storage technologies, no commercial product has been made available so far.
See also
- Nanoelectromechanical systems
- Nanotechnology
- Nanolithography
- Thermal scanning probe lithography
- Punched card
References
- ISSN 0018-8646.
- ^ a b "The millipede project: A nanomechanical AFM-based data storage system". IBM Zurich Research Laboratory. Archived from the original on 2011-12-17. Retrieved 2011-09-05.
- ^ "Millipede small scale MEMS prototype shown at CeBIT". PhysOrg.com. March 12, 2005.
- ISSN 0003-6951.
- ^ .
- Hitachi Global Storage Technologies. Archived from the originalon 2011-10-26. Retrieved 2011-12-17.
- ^ Johnston, Casey (2011-05-07). "New hard drive write method packs in one terabit per inch". Ars Technica. Retrieved 2011-12-17.
- ^ Mearian, Lucas (January 31, 2010). "Intel Micron to announce world's densest flash memory". computerworld.com.