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A possibly stupid question from a neophyte: what was the driving force behind Moore's law when it was in operation? Did it become a self-fulfilling prophecy by

by prvc 7y ago

A possibly stupid question from a neophyte: what was the driving force behind Moore's law when it was in operation? Did it become a self-fulfilling prophecy by becoming a performance goal after becoming enshrined in folklore, or is there an underlying physical reason?

aiCeivi9 7y ago
https://en.wikipedia.org/wiki/Transistor_count https://en.wikipedia.org/wiki/Transistor_count The transistor can only get so small before it stops working. There are many issues with required extreme ultraviolet light sources (lasers) and allowed amount of impurities in silicon waffer. And R&D cost for each iteration of lithography is getting higher while bringing less benefits.
- prvc 7y ago
  Yes, the existence of an upper bound on transistor count follows easily from the atomic nature of matter. The Wikipedia article on Moore's law lists multiple disparate "enabling factors" which do not seem to have much to do with one another. The conjunction of which comprise an explanation of sorts, but I'm wondering whether there's a simple observation or fact that ties them all together, apart from my Sociological theory.
wmf 7y ago
Dennard's laws explain the physics of why smaller transistors are faster and more efficient, but overall Moore's Law was closer to a self-fulfilling prophecy. There's no intrinsic reason why each generation was targeting 2x density and 18/24-month cycles are probably convenient from a business perspective but not essential.
dredmorbius 7y ago
Moore's law is part of a general set of principles regarding learning curves, see generally: https://en.wikipedia.org/wiki/Experience_curve_effects https://en.wikipedia.org/wiki/Experience_curve_effects During WWII, it was observed that each doubling of output reduced labour costs (or increased labour efficiency) by 20%. Moore's law is dependent on the density of transitors (the count doubles for a given cost every two years). Increased density => increased computing power and efficiency, and speed. Chip design is dependent on numerous factors: die size (e.g., 14 vs. 9nm photolithography dies), silicon purity, fab cleanliness (much as with cascade refrigeration, chip fabs now have multiple concentric zones of increased cleanliness), and the power and capacity of the software that's used in chip modelling itself. The law is also not entirely exogenous as it relies on market forces and demand: need for increased computing power tends to proceed at a predictable rate, and the ability to make use of more capacity is also constrained by existing practices, software, programmer skill, etc. Then there are the other non-CPU bottlenecks. Disk and memory have long been the foundations of that, increasingly it's networking. The tendency of old technology and layers not to die but to be buried in ever deeper levels of encapsulation means that efficiencies which might be gained aren't due to multiple transitions and translations -- the reason why a 1980 CPM or Apple II system had a faster response than today's digital wireless Bluetooth keyboards talking to a rendered graphical display. Bufferbloat, at the network stack, is another example. But: the main driver for Moore's law is increased density leading to increased efficiency (the same centralising tendency present in virtually all networks), bound and limited by the ability to get power in and heat out (Amdahl's observation that all problems ultimately break down to plumbing).

by prvc 7y ago

aiCeivi9 7y ago

https://en.wikipedia.org/wiki/Transistor_count https://en.wikipedia.org/wiki/Transistor_count The transistor can only get so small before it stops working. There are many issues with required extreme ultraviolet light sources (lasers) and allowed amount of impurities in silicon waffer. And R&D cost for each iteration of lithography is getting higher while bringing less benefits.

prvc 7y ago
Yes, the existence of an upper bound on transistor count follows easily from the atomic nature of matter. The Wikipedia article on Moore's law lists multiple disparate "enabling factors" which do not seem to have much to do with one another. The conjunction of which comprise an explanation of sorts, but I'm wondering whether there's a simple observation or fact that ties them all together, apart from my Sociological theory.

wmf 7y ago

Dennard's laws explain the physics of why smaller transistors are faster and more efficient, but overall Moore's Law was closer to a self-fulfilling prophecy. There's no intrinsic reason why each generation was targeting 2x density and 18/24-month cycles are probably convenient from a business perspective but not essential.

dredmorbius 7y ago

Moore's law is part of a general set of principles regarding learning curves, see generally: https://en.wikipedia.org/wiki/Experience_curve_effects https://en.wikipedia.org/wiki/Experience_curve_effects During WWII, it was observed that each doubling of output reduced labour costs (or increased labour efficiency) by 20%. Moore's law is dependent on the density of transitors (the count doubles for a given cost every two years). Increased density => increased computing power and efficiency, and speed. Chip design is dependent on numerous factors: die size (e.g., 14 vs. 9nm photolithography dies), silicon purity, fab cleanliness (much as with cascade refrigeration, chip fabs now have multiple concentric zones of increased cleanliness), and the power and capacity of the software that's used in chip modelling itself. The law is also not entirely exogenous as it relies on market forces and demand: need for increased computing power tends to proceed at a predictable rate, and the ability to make use of more capacity is also constrained by existing practices, software, programmer skill, etc. Then there are the other non-CPU bottlenecks. Disk and memory have long been the foundations of that, increasingly it's networking. The tendency of old technology and layers not to die but to be buried in ever deeper levels of encapsulation means that efficiencies which might be gained aren't due to multiple transitions and translations -- the reason why a 1980 CPM or Apple II system had a faster response than today's digital wireless Bluetooth keyboards talking to a rendered graphical display. Bufferbloat, at the network stack, is another example. But: the main driver for Moore's law is increased density leading to increased efficiency (the same centralising tendency present in virtually all networks), bound and limited by the ability to get power in and heat out (Amdahl's observation that all problems ultimately break down to plumbing).