## Using harpoon vector symbol in LaTeX

My favorite vector symbol is a harpoon, but the harpoon package defaults to text mode, which will fail when math characters like \ell are used in the math mode.

 \usepackage{harpoon} \newcommand*{\vect}[1]{\overrightharp{\ensuremath{#1}}} 

then
 $\vect{d\ell}$ 

will work.

reference: http://tex.stackexchange.com/questions/66723/nudging-overset-characters-downwards

## Manually putting external USB drives into standby

You can manually put a USB HDD that doesn’t automatically spin-down after inactivity to sleep with the following command:

sg_start 0 --pc=3 /dev/sdc

where I assumed your HDD was at /dev/sdc. You can determine which /dev/sd* you’re at with the command
df

The HDD should automatically spring back to active spinning mode when you write a file to it, etc.

You can install the sg_start program via:
 sudo apt-get install sg3-utils

The reason you might want to do this include that the HDDs put out some substantial heat when they’re not spun down. You don’t want to spin up/down too frequently (like every 5 minutes) but if you’re not using the drive for the night or a few days, it might be worthwhile to spin them down if heating is an issue.

## Using Phoronix Test Suite 5

1. Prerequisites
2. sudo apt-get install php5-cli php5-curl php-fpdf

3. install
sudo gdebi phoronix-test-suite_5*.deb

if you don’t have gdebi, you can install gdebi on Ubuntu 14.04 by:
 sudo apt-get install gdebi-core 

5. run tests (from terminal)
6. phoronix-test-suite benchmark c-ray phoronix-test-suite benchmark hpcc phoronix-test-suite benchmark scimark2 phoronix-test-suite benchmark xonotic

7. Listing all results on this PC
8.  phoronix-test-suite list-saved-results

9. Converting results to PDF
10. phoronix-test-suite result-file-to-pdf myTest

## Matlab Compiler tbb.dll errors

Even with a fresh install of Windows 7 x64 and Matlab R2013b, I was getting tbb.dll related errors after compiling M-scripts using Matlab Compiler deploytool. The exe would compile, but upon running it would issue various tbb.dll errors.

This problem happened across multiple PCs. To fix this problem, I followed this process:

cd c:\tbb\tbb*\bin tbbvars intel64 all