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News Archive - Canon 167 Introduction

Canon 167 Announcement

*Computers and Automation*, September, 1967

Note that the article very likely contains a typographical error in the
operational speed quoted for the square root operation. The article states
a time of 0.06 second
which is extraordinarily fast for a more complex operation like
square root. The correct timing is likely to be 0.6 second, or
600 milliseconds. The square root is calculated to only 8 digits behind
the decimal point. Even with the limited precision and assuming a very
efficient square root algorithm, there is no way a
machine that adds and subtracts in 10 milliseconds
can possibly complete a square root calculation in only 60 milliseconds.
Digit-by-digit calculation of square roots using the efficient
Sum of Odd Integers method
is very similar to division, performing numerous subtraction operations
to arrive at a result.
Division is quoted as taking up to 1 second with a full
15 digits of quotient, so a time of 600 milliseconds makes much more sense
to perform a square root operation with limited precision as compared to
division. It's likely that the extra zero behind the decimal point
in the quoted time of 0.06 seconds was simply a typo when the article
was prepared, and not caught in editing. The "Sum of Odd Integers"
algorithm processes the radicand two digits at a time, thus, with a
radicand of up to 15 digits, only a maximum of eight cycles through the
algorithm would be required, which is why the square root operation would
take less time than a division, which must process each digit of the
divisor one at a time.