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Magnetic Processors - Computing's New Future?
metalcoat writes "For the first time researchers have created a working prototype of a radical new chip design based on magnetism instead of electrical transistors. As transistor-based microchips hit the limits of Moore's Law, a group of electrical engineers at the University of Notre Dame has fabricated a chip that uses nanoscale magnetic "islands" to juggle the ones and zeroes of binary code.
Wolfgang Perod and his colleagues turned to the process of magnetic patterning (.pdf) to produce a new chip that uses arrays of separate magnetic domains. Each island maintains its own magnetic field. Because the chip has no wires, its device density and processing power may eventually be much higher than transistor-based devices. And it won't be nearly as power-hungry, which will translate to less heat emission and a cooler future for portable hardware like laptops."
The chip industry spends billions in R&D to extend the performance growth of silicon chips. A very large number of engineers know how to design efficient fabs for silicon. Until this technology also attracts a sufficient following of $ and manufacturing experience, I won't count silicon out.
Also, it's not clear that this technology isn't subject to same "limits of Moore's law" (if there is such a thing) as silicon chips. The use of electron-beam lithography would seem to mean that this technology is subject to the some of the same feature-size and practicality limits suffered by silicon chips.
Perhaps this technology will find a place somewhere, it just faces a major uphill battle if it is to supplant silicon.
Two wrongs don't make a right, but three lefts do.
They say that a magnetic insulator would have to be used to shield the chip from external interference.
Magnetic circuits have been studied for at least 80 years. The basic problem is one of size and speed. A dipole magnet (onr with N and S poles) has a certain minimum size, otherwise it depolarizes itself. That sets a minimum size for any magnetic device. Also it's hard to make magnetic amplifiers with more than a small fan-out. It's also really hard to distribute a clock signal-- magnetic pulses fall off at a 1/r^3 rate, and generating a fast magnetic pulse gets blocked by the inductance of the coil.
Now there *are* cigarette-pack to Taj Mahal sized magnetic voltage regulators in use. Your PC power supply may be using one to regulate the 3.3 volt output. But getting them down to IC-size is going to be really hard to impossible.
It's actually beneficial that a single 'gate' element can perform AND, OR, and INVERT
functions all in one stage. The early TTL won over other logic designs in part because
the basic gate used multiple emitters on the input transistor to get an AND function,
and multiple input transistors to get the OR function. That meant that the delay
and complexity character of AND and OR were the same, and that the complex function
of AND/OR/INVERT was available as a fast multiplexer, with the same characteristics
as a simple NAND. There was a brief attempt to use expandable gates (making
the connection point after the input transistor available on an external pin,
which was NOT TTL-logic-level compatible), but it didn't catch on.
CMOS, on the other hand, had input impedance and delay differences in the AND and
OR and other gates, so the whole 4000 series CMOS logic family only became
trouble-free to use AFTER THEY BUFFERED THE WHOLE FAMILY with an extra inverter
(and consequently extra time delay). Buffered (4000B series) is the common small
scale CMOS you see today, the unbuffered (4000A series) has been sidelined.
From a circuit-design viewpoint, the AND/OR/INVERT is a very good starting element,
for a lot of reasons that only show up when some poor engineer is perspiring over his
timing budget...