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Hub AI
Millipede memory AI simulator
(@Millipede memory_simulator)
Hub AI
Millipede memory AI simulator
(@Millipede memory_simulator)
Millipede memory
Millipede memory is a form of non-volatile computer memory. It promised a data density of more than 1 terabit per square inch (1 gigabit per square millimeter), which is about the limit of the perpendicular recording hard drives. Millipede storage technology was pursued as a potential replacement for magnetic recording in hard drives and a means of reducing the physical size of the technology to that of flash media.
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.
The main memory of modern computers is constructed from one of a number of DRAM-related devices. DRAM basically consists of a series of capacitors, which store data in terms of the presence or absence of electrical charge. Each capacitor and its associated control circuitry, referred to as a cell, holds one bit, and multiple bits can be read or written in large blocks at the same time. DRAM is volatile — data is lost when power is removed.
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 atomic force probes, each of which is responsible for reading and writing a large number of bits associated with it. These bits are stored as a pit, or the absence of one, in the surface of a thermo-active polymer, which is deposited as a thin film on a carrier known as the sled. Any one probe can only read or write a fairly small area of the sled available to it, known as a storage field. Normally the sled is moved so that the selected bits are positioned under the probe using electromechanical actuators. These actuators are similar to those that position the read/write head in a typical hard drive, however, the actual distance moved is tiny in comparison. The sled is moved in a scanning pattern to bring the requested bits under the probe, a process known as x/y scan.
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 32-bit value would normally be written as a set of single bits sent to 32 different fields. In the initial experimental devices, the probes were mounted in a 32x32 grid for a total of 1,024 probes. Given this layout looked like the legs on a millipede (animal), the name stuck. The design of the cantilever array involves making numerous mechanical cantilevers, on which a probe has to be mounted. All the cantilevers are made entirely out of silicon, using surface micromachining at the wafer surface.
Regarding the creation of indentations, or pits, non-crosslinked polymers retain a low glass temperature, around 120 °C for PMMA and if the probe tip is heated to above the glass temperature, it leaves a small indentation. Indentations are made at 3 nm lateral resolution. By heating the probe immediately next to an indentation, the polymer will re-melt and fill in the indentation, erasing it (see also: thermo-mechanical scanning probe lithography). After writing, the probe tip can be used to read the indentations. If each indentation is treated as one bit then a storage density of 0.9 Tb/in2 could theoretically be achieved.
Millipede memory
Millipede memory is a form of non-volatile computer memory. It promised a data density of more than 1 terabit per square inch (1 gigabit per square millimeter), which is about the limit of the perpendicular recording hard drives. Millipede storage technology was pursued as a potential replacement for magnetic recording in hard drives and a means of reducing the physical size of the technology to that of flash media.
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.
The main memory of modern computers is constructed from one of a number of DRAM-related devices. DRAM basically consists of a series of capacitors, which store data in terms of the presence or absence of electrical charge. Each capacitor and its associated control circuitry, referred to as a cell, holds one bit, and multiple bits can be read or written in large blocks at the same time. DRAM is volatile — data is lost when power is removed.
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 atomic force probes, each of which is responsible for reading and writing a large number of bits associated with it. These bits are stored as a pit, or the absence of one, in the surface of a thermo-active polymer, which is deposited as a thin film on a carrier known as the sled. Any one probe can only read or write a fairly small area of the sled available to it, known as a storage field. Normally the sled is moved so that the selected bits are positioned under the probe using electromechanical actuators. These actuators are similar to those that position the read/write head in a typical hard drive, however, the actual distance moved is tiny in comparison. The sled is moved in a scanning pattern to bring the requested bits under the probe, a process known as x/y scan.
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 32-bit value would normally be written as a set of single bits sent to 32 different fields. In the initial experimental devices, the probes were mounted in a 32x32 grid for a total of 1,024 probes. Given this layout looked like the legs on a millipede (animal), the name stuck. The design of the cantilever array involves making numerous mechanical cantilevers, on which a probe has to be mounted. All the cantilevers are made entirely out of silicon, using surface micromachining at the wafer surface.
Regarding the creation of indentations, or pits, non-crosslinked polymers retain a low glass temperature, around 120 °C for PMMA and if the probe tip is heated to above the glass temperature, it leaves a small indentation. Indentations are made at 3 nm lateral resolution. By heating the probe immediately next to an indentation, the polymer will re-melt and fill in the indentation, erasing it (see also: thermo-mechanical scanning probe lithography). After writing, the probe tip can be used to read the indentations. If each indentation is treated as one bit then a storage density of 0.9 Tb/in2 could theoretically be achieved.