The original (ROM00 and ROM01) models used a '1/2 AA' battery soldered directly to the motherboard. The ROM03 uses a 1/2 AA in a patic battery holder, and is more easily replaced.
ActiveGS is an emulator for the Apple II gs, it lets you play old Apple II/II+/IIe/IIgs games on your browser. It is safe as far as I know (I do use it myself) and likely too obscure for someone to use it as an attack vector.
To extend the life of your battery for Apple Macbook Pro is to unplug the laptop and use it to run the battery down then recharge it. Apple does not recommend keeping your laptop plugged in continously as this can ruin your battery. Read more about this at http://www.apple.com/batteries/notebooks.htm
When you go to buy a battery they can tell you the correct size.
Depends on the size of the engine in the boat.
Most use a small 12 volt battery.
The fuse you use is determined by the load on the circuit and the size wiring used in that circuit not the battery voltage.
They use a 1/3N 3 volt battery. AimPoint models which do not use AA batteries also use the same battery.
AAA
NS40 or NS60
You can use modern size C
Any Walmart can tell you the correct size battery to buy.
Size A batteries are/were available for use in older laptop battery packs or hobby battery packs. The important words here are 'battery packs' so they are not available as single units.