We could not complete your purchase

I have a lightly used Core 2 Duo MacBook that I thought I'd upgrade to Mountain Lion, but I encountered an unexpected issue in the App Store: "We could not complete your purchase. OS X Mountain Lion is not compatible with this computer."

Requirements: "OS X 10.6.8 or later"

About This Mac says "Mac OS X Version 10.6.8"

How did Tim know that I didn't need this and should be doing something productive?

WSAEMFILE

The error code exists so it should be interesting, right?  I wanted to force this error for Apache httpd on Windows (7 in my case), so I thought I'd create sockets in the child until it failed, then free up the last n of those so that the server could basically work but occasionally encounter socket handle limits under controlled load.  I really didn't expect this:

[Fri Jul 20 10:28:09.269300 2012] [mpm_winnt:crit] [pid 4540:tid 444] (OS 10055)An operation on a socket could not be performed because the system lacked sufficient buffer space or because a queue was full.  : error on last socket create request, after creating 1328724

I was able to successfully create 1.3 million AF_INET/SOCK_STREAM sockets before encountering WSAENOBUFS. So much for trivially forcing a real WSAEMFILE error... If I understand a few web resources correctly, there's no socket handle limit other than limitations on resources associated with the socket.

Woo hoo! Compilers is done

Earlier this week, after a Friday-Monday a.m. heads down stint, I finished the last programming assignment — MIPS code generation for the Cool language — for Coursera's Compilers class.  Just now I finished taking the final, so I'm DONE.  What a relief!

The last programming assignment was great fun.  At the point that "Hello, world" actually ran on the MIPS emulator I started using the grading script and its testcases to identify the next bug or feature to implement.  The first run was 0 points out of 63 possible, and getting more than 1 or 2 points took quite a few hours :)   As I slowly filled in the implementation, each time I passed another testcase I ran around the house and high-fived anyone home. Finally, fixing a bug with calculating dispatch table offsets for overridden methods brought the score to 63/63 and I was done.  (No one will ever look at that blatantly unrefactored code I hope.)

Now, on to those things I'm behind on :)