http://www.california-gold-rush-miner.us/california-gold-rush-miner== Terms and Jargon == Seventeen or Bust uses many abbreviations and terms in the program, on the website, and in the forums that may be confusing to new users. Below is a list of common terms and abbreviations used by Seventeen or Bust.
Short for "Seventeen or Bust". Sometimes also written as "SoB".
Seventeen or Bust searches for primes of the form k * 2n + 1. It is believed that 78,557 is the smallest Sierpinski number, i.e., the least odd k such that k * 2n + 1 is not prime for all n > 0. To prove this, it must be proven that k * 2n + 1 is prime for at least one value of n for all k < 78,557. When the project began, there were only 17 values of k < 78,557 that were still in question (hence the name "Seventeen or Bust"). Since then, the number of k values still in question has been reduced to 6.
Seventeen or Bust searches for primes in the form of k * 2n + 1 using increasingly higher values of n. Once a value of n is found that makes this prime for a k in question, that number can be removed from the list of candidates for the smallest Sierpinski number. As of March 2009, the values of n being tested were around 16,000,000.
M, G, T, P
Because of the large numbers involved in testing and keeping track of project statistics, they are often abbreviated using standard SI prefixes.
M = Mega = 10^6 (1 million)
G = Giga = 10^9 (1 billion)
T = Tera = 10^12 (1 trillion)
P = Peta = 10^15 (1 quadrillion)
Numbers abbreviated in this way use the prefix letter as a suffix on the number, and that number is then multiplied by the value of the SI prefix. For example, 16M would mean 16,000,000 and 1.25T would mean 1,250,000,000,000.
jEMs stands for "jiggered Exponentiation Modulus's" and is cacluated as constant * n2 * loglogn
jEMs is the current unit of measurement for work done by the SoB client. It replaced cEMs on March 23, 2009 and all previous statistics were recomputed using this unit. This resulted in early tests being given more credit and newer tests given less credit, making credit given more fair and in-line with the actual work done.
cEMs stands for "corrected Exponentiation Modulus's" and was calculated as constant * n3
cEMs were the unit of measurement for work done by the SoB client and was used for SoB stats prior to the introduction of jEMs. It is unique to the project and not used by anyone else. The name comes from a function call that the old client program made called "exp_mod()".
The original unit of measurement was EMs (i.e. how many times exp_mod() was called), but for bigger numbers the function takes longer to execute. Therefore, a correction factor was introduced, resulting in "corrected Exponent Mods".
Later, the algorithm was replaced by a faster version which didn't slow down as much as the numbers got bigger. The correction could not be adjusted to match the new algorithm, and the cEMs unit became very inaccurate when comparing statistics. As a result, the jEM unit was created.