What's in the Dalvik cache?

OSNews asks: What's in the Dalvik cache?

And one of the commenters points to interesting reference document:
http://www.netmite.com/android/mydroid/dalvik/docs/dexopt.html

How to Undo Unity

Good piece of advice:
http://www.osnews.com/story/26192/How_to_Undo_Unity

Log-off, restart and power-off in Windows 8

Recently I've installed a Release Preview of Windows 8 in virtual machine. Luckily apart from completely new Start menu, all other major features are similar to Windows 7. Also the new Windows Explorer includes the scenic ribbon, which I prefer much more than previous "hidden-until-alt-key-pressed" regular menu.

But there are some basic things in Windows 8 I needed to re-learn, even though I find it unnecessary to be so complicated (compared to previous Windows):

• Power options: (restart, hibernate and power-off)
  
• Logging off
  
• Swithing users (WinLogo+L)
  

To find how to turn off the system I needed to consult Windows Help (it proved to be helpful this time). But to find out how to use new "Sign-out" function I needed to use Google for it, but again I've found what I was looking for:

http://www.askvg.com/how-to-log-off-restart-and-shut-down-windows-8-pc/

To be honest, sign-off is now similar to web e-mail programs, where one needs to click user account image to close the session (okay, I consider this to be a slight improvement). But putting power options inside a hidden, pop-up vertical bar of new Start menu is way too complicated! Since Windows 95 a user needed just to click "Start" to find option to close the system - now it's so well hidden I suppose less experienced users will just pull the physical plug than to find where the damned power-off button is.