Geek stores in Boston

[clint at neotrance.dyndns.org (Clint M. Sand)]

Someone told me shortly after moving to Boston that there's a large book
store somewhere in town that only sells tech books. Can anyone point me
to where that is? Or what it might be called so i can find it?

Also, I need to get some new RAM for a box at home, are there any stores
in the Boston area I should check out? I've found the compusa's, but
thats about it. 

Thanks

Clint