August 20th 2007

As you may recall, we have been attacking the first and second parts of the unbroken message separately. The main server dealt with the second part, the old server with the first part. Since the old server had just been left in place to accommodate machines running the old software, the first part has gotten considerably less attention than the second part. The approximate numbers are 10 passes for each work unit vs. 60 passes for each work unit.

In order to fix this imbalance, the roles are now reversed. The work unit overview on the M4 Project page shows the statistics for the main server dealing with the first part of the message.

Amount of work done on the second part:

Date Daily Completed Remaining

2007-08-20 1698 670730 5023270

This run was started on March 28th 2006.

Terminology:

The terminology has been an ongoing source of confusion. I hope that this analogy helps to clarify things:

Suppose that you have lost a gold coin in an area of one square kilometer. Fortunately, you have a metal detector. Unfortunately, the detector is such that you only have a 50% chance of getting an alert even if you hold it right above the coin.

You come up with a plan. Since you are a methodical person, you divide the square kilometer into 1000000 work units of one square meter each. Subsequently, you go over the whole area, processing each unit once. In 50% of the cases, you'll have found the coin. If you haven't, you'll go over the area a second time, unit by unit. Now your odds of having found the coin are 75%. And so on.

It should be clear by now that the square kilometer stands for the whole search space, which is divided up into 11388 work units. In the above statistic, we have searched each work unit about 60 times.

It should also be clear that the large number of remaining work units results from the fact that a maximum of 500 passes has been planned per work unit and the server reports the total number of units as 11388 * 500 = 5694000.