Hard Disk Wipe

Yesterday I returned home from class to find my MacBook Pro unresponsive. I did manage to coerce it into booting, but it would abruptly restart about 3 minutes after the booting process was complete. The charging indicator stayed green, never the orange of charging; the battery indicator turned into a X.

Today I took the 2010 MacBook Pro to the Apple Store here in Indianapolis, where they ran tests to find the file hierarchy was destroyed. That might be why the Mac would not even countenance Alsoft's Disk Warrior, on which I once relied. Problem identified, I brought the Mac back, wiped the hard disk, partitioned it again, and installed the free Mac OS X 10.9, Mavericks. It still sucks: three kernel panics alone tonight with only the basic system installed and Microsoft Office 2011. It seems Macericks itself is the problem.

A Matter of Convolution

Today we students in ECE202 at IUPUI got our third tests back. I was very pleased to see a 100, especially since I had been rather concerned about the first two problems. They were both convolution problems for the same problem. However #1 wanted us to solve the convolution graphically, while #2 wanted a mathematical solution using Laplace transforms.

The graphic below is a crude rendering of the problem. Mathematically, it was:

x\left(t\right)=u\left(t-1\right)-u\left(t-3\right)
and
h\left(t\right)=3e^{-t}

20140424-225400.jpg

When tests are returned, students often ask about the average and answers to certain problems. This morning I asked how many people solved the convolution graphically by folding the exponential curve instead of the box. Out of perhaps 35 people, I was the only one.

What does it mean? Probably nothing. However, I found it an interesting fact.