Arduino Transistor Identification and Transfer Curve Tester - Part 1

At prokopyshen.com, we have a lot of transistors collected over the years.  Many are unmarked and we are not always sure if the device is functional or has sufficient gain for our projects.  Our solution was to build an Arduino based test device that wil positively identify each lead, the type (PNP vs NPN), material (Silicon or Germanium), and then collect enough data points for us to determine the gain and DC transfer characteristics. 

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When adding virtual CPU cores is the wrong thing to do

I was recently involved in a trouble shooting exercise where an application was giving terrible response times and frequent connection timeouts to visitors.  This particular application has peak traffic demands during the business day and very few users overnight.  From the checks I made using top and process status reports, it was easy to see that this virtual linux machine was saturated.  Multiple virtual CPUs running 99% user+system and a run queue length over 30.
 
Click read more for why adding more vCPUs was not a good idea.

Runnning XEN on ASUS X54C under Debian

I had a need to verify a new puppet configuration and wanted my own puppet master and client server to do this.  And, I wanted to be able to work on this when I was mobile.  
 
Solution: Run a debian XEN host and two Virtual Machines on the ASUS X54C laptop.   Here are my notes for making this work.

How to get RT5390 wireless wifi card working on ASUS X54C laptop under Debian Linux

The ASUS X54C laptop is our go-to machine when we are mobile.  Our earlier article described how we made it dual boot Windows 7 and Debian Linux. 
 
The ASUS comes with a RaLink Device 5390 wireless card and support for that card is not included in Debian Linux. 
 
Read more for my notes on getting this laptop to connect to my wireless network under Debian linux.
 

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