>SNIP
>>
>>For those who does not know Calvin, he is the lead programmer of Visual FoxPro at Microsoft, and without any doubt the person who knows most about how Visual FoxPro works internally. According to Ken Levy he has all the millions of source code for VFP in his head.
>
>I'll bet he **DOES** have all the source code in his head!
>
>Many many years ago, in my mainframe days, I would meet the person from IBM who wrote "HASP", which was a critical component of the operating system. When people would describe a problem to hime he would say " In the Xxxxx module, go to line 247 and change the yFunction to a zFunction and that will do it".
>The guy was amazing, and I've heard Calvin is amazing too.
>
>cheers

I had an instructor for a DEC device driver course that could do that, too. I had asked him a question on VMS, and he knew exactly which page of over 30,000 sheets of microfiche (with 16 pages of code on each sheet) to find the answer in the code. Simply amazing.