Re: [Haskell-cafe] On the purity of Haskell

On Fri, 2011-12-30 at 18:34 +0200, Artyom Kazak wrote:

I wonder: can writing to memory be called a “computational effect”? If yes, then every computation is impure. If no, then what’s the difference between memory and hard drive?

The difference is that our operating systems draw an abstraction boundary such that memory is private to a single program, while the hard drive is shared between independent entities. It's not the physical distinction (which has long been blurred by virtual memory and caches anyway), but the fact that they are on different sides of that abstraction boundary. -- Chris Smith