A couple days ago, I wrote about why Twitter fascinates me and makes me feel bad at the same time. In that post I talked about how age affects how we use tools like Twitter, and I gave an example that mentioned using a PDP-8 minicomputer during my engineering school days in the late 1970's.
I also found out that as of 2008, Google was indexing one trillion web pages. This led me to wonder: Would it take more than the mass of the Earth if we used 4K (word) PDP 8's to store all of the web pages that Google links to? Based on an average size of a web page of 70K (see data sources below), I calculate that it would take 1.14 quadrillion pounds. Luckily, that's 10 orders of magnitude less than the mass of the Earth, or 1 ten-billionth of the Earth's mass. The Earth's mass, (okay,weight if in the gravity of the Earth) is 12 septillion pounds (approximately...apparently the Earth is gaining weight from space dust each day.)
So, while Earth could handle the weight of PDP8s pretty easily, the cost would be $600 quadrillion, a figure well beyond the means of our planet. We'd also have a serious issue with power. At 780 watts for each machine, and a mere 11 trillion machines needed, our 1,100 trillion pound data center would require 8.8 million gigawatts. Alas, in 2008, our entire planet generated just 20,261 of those gigawatts, leaving us 439x short.
There is hope, however. The PDP8e could have 32K words of memory, so if we upgraded to that, we'd cut our power needs to just 2.2 million gigawatts, (within a factor of 100x of world power) and our data center would only weigh about 275 trillion pounds. While our base machines would take up 2.85% our land mass, with the upgrade, we'd fit our data center in just 0.7% of the world's land mass. Without the upgrade, we would take up 25% more than the area of India. But with the upgrade, we'd fit almost perfectly in Egypt, leaving a few square kilometers for parking.
The Digital Equipment Corporation PDP8e.
Check out the size of the power supply!
Calculation Exercise: If Google Used PDP8's to store 1 Trillion Web Pages, Would They Be Heavier The Earth Itself?
Google finds one trillion Web pages: http://googleblog.blogspot.com/2008/07/we-knew-web-was-big.html
Average web page size is 70K: http://www.websiteoptimization.com/speed/tweak/average-web-page/
Weight of a PDP8: http://www.old-computers.com/MUSEUM/computer.asp?st=1&c=780
Today's Dollars converter: http://www.1soft.com/todaysdollars.htm
What's after trillion? http://answers.yahoo.com/question/index?qid=20061019213324AAU36Q9
Dec PDP-8/I Maintenance Manual Volume 1: http://www.bitsavers.org/pdf/dec/pdp8/pdp8i/DEC-8I-HR1A-D_8Imaint_Mar70.pdf
Power usage of PDP-8 (from Gordon Bell!) = 780 watts : http://www.classiccmp.org/pipermail/cctech/2009-August/108097.html
World power generation - 20,261 billion kWh = http://en.wikipedia.org/wiki/Electricity_generation#Historical_Results_of_Production_of_Electricity
Land Surface area of the Earth: 148,940,000 km squared: http://en.wikipedia.org/wiki/Earth
Land mass of countries: Russia 17M sq km; India 3.3M, http://www.mongabay.com/igapo/world_statistics_by_area.htm