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Ancient Computers, Part I - Rediscovery
Ancient Computers is an excellent introduction to the calculating methods of diverse cultures across time. A mixture of history and practical techniques for understanding and using these ancient devices brings the tools of these long-forgotten civilizations to a wide audience. Stephenson writes in an easy-to-understand and accessible manner and the use of diagrams is extensive. Want know how to use an abacus or where it came from? This is the book for you!The book is appropriate for high school audiences and above.Dag SpicerSenior CuratorComputer History MuseumMountain View, CA=====From the publisher:N.B.: The "cents" of pricing: 398 = 400 + (-2), or CCDXCIIX = CD + (-II). A demonstration of the Roman Line Abacus subtractive number representations and the inclusion of negative numbers: keys to unlocking a four millennium old mystery of how the ancients did their arithmetic calculations.-----People, especially historians, have long struggled to appreciate and understand how Ancient Romans, Greeks, Egyptians, and Babylonians, et al, were able to do their arithmetic calculations. Many say the Ancients "probably" used line abacuses or abaci, a.k.a. counting boards. But most then trivialize the possible impact that use would have on the Ancient cultures because they really don't think those abaci would be very powerful and that they would be extremely hard to use. The discovery this book documents and explores materialized from the author's experiences in engineering, with a knowledge that design compromises often have to be made; computer programming, especially the different number bases used; the hobby use of a Japanese abacus called the Soroban; and study of the Ancients' numbers and culture.The bottom line is that the Ancients had a powerful and lightning fast computer; powerful and fast compared to any other calculation method available to them in their time.Features included:- multi-base number modes: decimal, duodecimal, or sexigesimal;- operating on those numbers in two parts: a signed fraction of the base and a signed exponent of the base; - easy and low-cost expandability; and- built-in error checking!On the "standard" Ancient line abacus doing base-10 calculations, the fraction could have 10 significant digits and the exponent 4. Certainly enough for most modern engineering or scientific problems. If you need more, though, just scribe a few more lines on the abacus and add a few more pebbles to your pouch! By the way, 170 small pebbles will suffice for any problem on the "standard" line abacus. They fit in a pouch that can be easily and comfortably be carried in a man's trouser pocket.
SquareTrade 3-Year Computer Accidental Protection Warranty ($500-600)
Accidental Damage from Handling (ADH) guards you against life's little mishaps, whether you drop your cell phone on the street or splash coffee on your laptop. ADH must also be purchased within 30 days of when you bought your item. ADH coverage begins on the 31st day after the item's purchase - issues in the first 30 days are not covered. Upon purchase, you will get an email confirmation. You will not be mailed a paper contract. If you have questions, please call: 1.877.WARRANTY.
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