Errata

Wow! This book is insanley great! Great writing as well. I am learning so much and enjoying every page!

But I believe there is a typo in chapter 48 regarding the amount of communication channels required by a system with n=20 processes:

"Imagine that you have ten processes that must all communicate with each other to maintain cache coherency. Then there are 9 + 8 + 7 + … + 1 = 45 communication channels that the system must maintain. If the number of processes increases just by 1, to 11, then the communication channel count increases by 10, to 55. Doubling the process count from 10 to 20 increases the communication channel count from 55 to 210."

A system with 20 processes requires communication channels/lines to 19 other processes.

(19*19 + 19) / 2 = 190

Thus, a system with 20 processes requires 190 communication channels but not 210. The 210 count number would include a channel from and to the 20th process itself.

Is my assumption correct?

Thanks for this book!

Note from the Author or Editor:
Wolfgang, thank you for finding and reporting this mistake. Your assumption is correct.

"Cells F11 and F14 give you helpful advice, in an effort to try to keep you away from the far right of the hockey stick curve that shows you how bad queueing delay can get if you overdo your traffic intensity."

There are no cells F11 to F14 depicted within the provided screenshot. Column E contains the "% capacity" values. Thus, I assume it should be corrected to: "E11 to E14".

Note from the Author or Editor:
Wolfgang, I agree with your finding. Thank you for being a careful reader!