The Ultimate Computer
The personal computer on my desktop is hundreds of times as fast, and has thousands of times as much memory, as the mainframe computer that served my entire university when I was a student. Such advances in the processing speed and storage capacity of computers are expected to continue until the laws of physics impose certain limits. After all, we cannot shrink atoms or increase the speed of light.
Now, imagine a computer technology that eventually approaches these limits. Imagine further that every star in every galaxy in the observable universe could somehow be fashioned into computers of this ``ultimate'' type. That would be a lot of very fast computers. Or if they were connected together we could think of them as a single, massively parallel computer: call it the ``Universe Computer.''
Admittedly, there are tasks - word processing, for example - at which this imaginary computer would be no more useful than any one of its constituent computers operating independently. But for large, repetitive trial-and-error tasks, such as code breaking, the speed and power of this integrated ``Universe Computer'' would be vastly superior to anything we could ever hope to build, right?