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Moore's Law

2007 Schools Wikipedia Selection. Related subjects: Computing hardware and
infrastructure

   Growth of transistor counts for Intel processors (dots) and Moore's Law
   (upper line=18 months; lower line=24 months)
   Enlarge
   Growth of transistor counts for Intel processors (dots) and Moore's Law
   (upper line=18 months; lower line=24 months)

   Moore's Law is the empirical observation made in 1965 that the number
   of transistors on an integrated circuit for minimum component cost
   doubles every 24 months. It is attributed to Gordon E. Moore (1929 —),
   a co-founder of Intel.

Earliest forms

   The term Moore's Law has been coined by Carver Mead around 1970 .
   Moore's original statement can be found in his publication "Cramming
   more components onto integrated circuits", Electronics Magazine 19
   April 1965 :


   Moore's Law

    The complexity for minimum component costs has increased at a rate of
   roughly a factor of two per year ... Certainly over the short term this
    rate can be expected to continue, if not to increase. Over the longer
    term, the rate of increase is a bit more uncertain, although there is
   no reason to believe it will not remain nearly constant for at least 10
     years. That means by 1975, the number of components per integrated
    circuit for minimum cost will be 65,000. I believe that such a large
                   circuit can be built on a single wafer.


   Moore's Law

   Under the assumption that chip "complexity" is proportional to the
   number of transistors, regardless of what they do, the law has largely
   held the test of time to date. However, one could argue that the
   per-transistor complexity is less in large RAM cache arrays than in
   execution units. From this perspective, the validity of one formulation
   of Moore's Law may be more questionable.

   Gordon Moore's observation was not named a "law" by Moore himself, but
   by the Caltech professor, VLSI pioneer, and entrepreneur Carver Mead.

   Moore may have heard Douglas Engelbart, a co- inventor of today's
   mechanical computer mouse, discuss the projected downscaling of
   integrated circuit size in a 1960 lecture. In 1975, Moore projected a
   doubling only every two years. He is adamant that he himself never said
   "every 18 months", but that is how it has been quoted. The SEMATECH
   roadmap follows a 24 month cycle.

   In April 2005 Intel offered $10,000 to purchase a copy of the original
   Electronics Magazine.

Understanding Moore's Law

   Moore's law is not about just the density of transistors that can be
   achieved, but about the density of transistors at which the cost per
   transistor is the lowest . As more transistors are made on a chip the
   cost to make each transistor reduces but the chance that the chip will
   not work due to a defect rises. If the rising cost of discarded non
   working chips is balanced against the reducing cost per transistor of
   larger chips, then as Moore observed in 1965 there is an number of
   transistors or complexity at which "a minimum cost" is achieved. He
   further observed that as transistors were made smaller through advances
   in photolithography this number would increase "a rate of roughly a
   factor of two per year" .

Formulations of Moore's Law

   PC hard disk capacity (in GB). The plot is logarithmic, so the fit line
   corresponds to exponential growth.
   Enlarge
   PC hard disk capacity (in GB). The plot is logarithmic, so the fit line
   corresponds to exponential growth.

   The most popular formulation is of the doubling of the number of
   transistors on integrated circuits (a rough measure of computer
   processing power) every 18 months. At the end of the 1970s, Moore's Law
   became known as the limit for the number of transistors on the most
   complex chips. However, it is also common to cite Moore's Law to refer
   to the rapidly continuing advance in computing power per unit cost.

   A similar law has held for hard disk storage cost per unit of
   information. The rate of progression in disk storage over the past
   decades has actually sped up more than once, corresponding to the
   utilization of error correcting codes, the magnetoresistive effect and
   the giant magnetoresistive effect. The current rate of increase in hard
   drive capacity is roughly similar to the rate of increase in transistor
   count. However, recent trends show that this rate is dropping, and has
   not been met for the last three years. See Hard disk capacity.

   Another version states that RAM storage capacity increases at the same
   rate as processing power.

An industry driver

   Although Moore's Law was initially made in the form of an observation
   and forecast, the more widely it became accepted, the more it served as
   a goal for an entire industry. This drove both marketing and
   engineering departments of semiconductor manufacturers to focus
   enormous energy aiming for the specified increase in processing power
   that it was presumed one or more of their competitors would soon
   actually attain. In this regard, it can be viewed as a self-fulfilling
   prophecy.

   The implications of Moore's Law for computer component suppliers are
   very significant. A typical major design project (such as an all-new
   CPU or hard drive) takes between two and five years to reach
   production-ready status. In consequence, component manufacturers face
   enormous timescale pressures—just a few weeks of delay in a major
   project can spell the difference between great success and massive
   losses, even bankruptcy. Expressed as "a doubling every 18 months",
   Moore's Law suggests the phenomenal progress of technology in recent
   years. Expressed on a shorter timescale, however, Moore's Law equates
   to an average performance improvement in the industry as a whole of
   over 1% per week. For a manufacturer competing in the competitive CPU
   market, a new product that is expected to take three years to develop
   and is just two or three months late is 10 to 15% slower, bulkier, or
   lower in storage capacity than the directly competing products, and is
   usually unsellable.

Future trends

   As of Q1 2006, current PC processors are fabricated at the 90  nm level
   and 65 nm chips are being introduced by Intel ( Pentium D & Intel
   Core). A decade ago, chips were built at a 500 nm level. Companies are
   working on using nanotechnology to solve the complex engineering
   problems involved in producing chips at the 45 nm, 30 nm, and even
   smaller levels—a process that will postpone the industry meeting the
   limits of Moore's Law.

   Recent computer industry technology "roadmaps" predict (as of 2001)
   that Moore's Law will continue for several chip generations. Depending
   on the doubling time used in the calculations, this could mean up to
   100 fold increase in transistor counts on a chip in a decade. The
   semiconductor industry technology roadmap uses a three-year doubling
   time for microprocessors, leading to about nine-fold increase in a
   decade.

   In early 2006 IBM researchers announced that they had developed a
   technique to print circuitry only 29.9 nm wide using deep-ultraviolet
   (DUV, 193-nanometer) optical lithography. IBM claims that this
   technique may allow chipmakers to use current methods for seven years
   while continuing to achieve results predicted by Moore's Law. New
   methods that can achieve smaller circuits are predicted to be
   substantially more expensive.

   Since the rapid exponential improvement could (in theory) put 100 GHz
   personal computers in every home and 20 GHz devices in every pocket,
   some commentators have speculated that sooner or later computers will
   meet or exceed any conceivable need for computation. This is only true
   for some problems—there are others where exponential increases in
   processing power are matched or exceeded by exponential increases in
   complexity as the problem size increases. See computational complexity
   theory and complexity classes P and NP for a (somewhat theoretical)
   discussion of such problems, which occur very commonly in applications
   such as scheduling.

   The exponential increase in frequency of operation as the only method
   of increasing computation speed is misleading. What matters is the
   exponential increase in useful work (or instructions) executed per unit
   time. In fact, newer processors are actually being made at lower clock
   speeds, with focus on larger caches and multiple computing cores. The
   reason for this is that higher clock speeds correspond to exponential
   increases in temperature, such that it becomes almost impossible to
   produce a CPU that runs reliably at speeds higher than 4.3 GHz or so.

   Extrapolation partly based on Moore's Law has led futurists such as
   Vernor Vinge, Bruce Sterling, and Ray Kurzweil to speculate about a
   technological singularity. However, on April 13, 2005, Gordon Moore
   himself stated in an interview that the law may not hold for too long,
   since transistors may reach the limits of miniaturization at atomic
   levels.


   Moore's Law

   In terms of size [of transistor] you can see that we're approaching the
   size of atoms which is a fundamental barrier, but it'll be two or three
   generations before we get that far—but that's as far out as we've ever
     been able to see. We have another 10 to 20 years before we reach a
     fundamental limit. By then they'll be able to make bigger chips and
                  have transistor budgets in the billions.


   Moore's Law

   While this time horizon for Moore's Law scaling is possible, it does
   not come without underlying engineering challenges. One of the major
   challenges in integrated circuits that use nanoscale transistors is
   increase in parameter variation and leakage currents. As a result of
   variation and leakage, the design margins available to do predictive
   design is becoming harder and additionally such systems dissipate
   considerable power even when not switching. Adaptive and statistical
   design along with leakage power reduction is critical to sustain
   scaling of CMOS. A good treatment of these topics is covered in Leakage
   in Nanometer CMOS Technologies. Other scaling challenges include:
    1. The ability to control parasitic resistance and capacitance in
       transistors,
    2. The ability to reduce resistance and capacitance in electrical
       interconnects,
    3. The ability to maintain proper transistor electrostatics that allow
       the gate terminal to control the ON/OFF behaviour,
    4. Increasing effect of line edge roughness,
    5. Dopant fluctuations,
    6. System level power delivery,
    7. Thermal design to effectively handle the dissipation of delivered
       power, and
    8. Solve all these challenges with ever-reducing cost of manufacturing
       of the overall system.

   Kurzweil expansion of Moore's Law shows that due to paradigm shifts the
   underlying trend holds true from integrated circuits to earlier
   transistors, vacuum tubes, relays and electromechanical computers.
   Enlarge
   Kurzweil expansion of Moore's Law shows that due to paradigm shifts the
   underlying trend holds true from integrated circuits to earlier
   transistors, vacuum tubes, relays and electromechanical computers.

   Kurzweil projects that a continuation of Moore's Law until 2019 will
   result in transistor features just a few atoms in width. Although this
   means that the strategy of ever finer photolithography will have run
   its course, he speculates that this does not mean the end of Moore's
   Law:


   Moore's Law

     Moore's Law of Integrated Circuits was not the first, but the fifth
    paradigm to provide accelerating price-performance. Computing devices
   have been consistently multiplying in power (per unit of time) from the
   mechanical calculating devices used in the 1890 US Census, to Turing's
    relay-based "Robinson" machine that cracked the Nazi enigma code, to
   the CBS vacuum tube computer that predicted the election of Eisenhower,
    to the transistor-based machines used in the first space launches, to
             the integrated-circuit-based personal [computers].


   Moore's Law

   Thus, Kurzweil conjectures that it is likely that some new type of
   technology will replace current integrated-circuit technology, and that
   Moore's Law will hold true long after 2020. He believes that the
   exponential growth of Moore's Law will continue beyond the use of
   integrated circuits into technologies that will lead to the
   technological singularity. The Law of Accelerating Returns described by
   Ray Kurzweil has in many ways altered the public's perception of
   Moore's Law. It is a common (but mistaken) belief that Moore's Law
   makes predictions regarding all forms of technology, when it actually
   only concerns semiconductor circuits. Many futurists still use the term
   "Moore's Law" to describe ideas like those put forth by Kurzweil.

   Krauss and Starkman announced an ultimate limit of around 600 years in
   their paper "Universal Limits of Computation", based on rigorous
   estimation of total information-processing capacity of any system in
   the Universe.

   Then again, the law has often met obstacles that appeared
   insurmountable, before soon surmounting them. In that sense, Mr. Moore
   says he now sees his law as more beautiful than he had realised.
   "Moore's Law is a violation of Murphy's Law. Everything gets better and
   better."

Other considerations

   Not all aspects of computing technology develop in capacities and speed
   according to Moore's Law. Random Access Memory (RAM) speeds and hard
   drive seek times improve at best a few percentage points each year.
   Since the capacity of RAM and hard drives is increasing much faster
   than is their access speed, intelligent use of their capacity becomes
   more and more important. It now makes sense in many cases to trade
   space for time, such as by precomputing indexes and storing them in
   ways that facilitate rapid access, at the cost of using more disk and
   memory space: space is getting cheaper relative to time.

   Another, sometimes misunderstood, point is that exponentially improved
   hardware does not necessarily imply exponentially improved software to
   go with it. The productivity of software developers most assuredly does
   not increase exponentially with the improvement in hardware, but by
   most measures has increased only slowly and fitfully over the decades.
   Software tends to get larger and more complicated over time, and
   Wirth's law even states that "Software gets slower faster than hardware
   gets faster".

   Moreover, there is popular misconception that the clock speed of a
   processor determines its speed, also known as the Megahertz Myth. This
   actually also depends on the number of instructions per tick which can
   be executed (as well as the complexity of each instruction, see MIPS,
   RISC and CISC), and so the clock speed can only be used for comparison
   between two identical circuits. Of course, other factors must be taken
   into consideration such as the bus size and speed of the peripherals.
   Therefore, most popular evaluations of "computer speed" are inherently
   biased, without an understanding of the underlying technology. This was
   especially true during the Pentium era when popular manufacturers
   played with public perceptions of speed, focusing on advertising the
   clock rate of new products.

   It is also important to note that transistor density in multi-core CPUs
   does not necessarily reflect a similar increase in practical computing
   power, due to the unparallelized nature of most applications.

   As the cost to the consumer of computer power falls, the cost for
   producers to achieve Moore's Law has the opposite trend: R&D,
   manufacturing, and test costs have increased steadily with each new
   generation of chips. As the cost of semiconductor equipment is expected
   to continue increasing, manufacturers must sell larger and larger
   quantities of chips to remain profitable. (The cost to tape-out a chip
   at 180nm was roughly $300,000 USD. The cost to tape-out a chip at 90nm
   exceeds $750,000 USD, and the cost is expected to exceed $1.0M USD for
   65nm.) In recent years, analysts have observed a decline in the number
   of "design starts" at advanced process nodes (0.13μm and below.) While
   these observations were made in the period after the 2000 economic
   downturn, the decline may be evidence that traditional manufacturers in
   the long-term global market cannot economically sustain Moore's Law.
   However, Intel was reported in 2005 as stating that the downsizing of
   silicon chips with good economics can continue for the next decade.
   Intel's prediction of increasing use of materials other than silicon,
   was verified in mid-2006, as was its intent of using trigate
   transistors around 2009. Researchers from IBM and Georgia Tech created
   a new speed record when they ran a silicon/germanium helium supercooled
   chip at 500 gigahertz (GHz). The chip operated above 500 GHz at 4.5 K
   (—451°F) and simulations showed that it could likely run at 1 THz
   (1,000 GHz), though it should be noted that this was an extremely
   simple device and that practical desktop CPUs running at this speed are
   extremely unlikely using contemporary silicon chip techniques .

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