Charles Weir wrote:Once upon a time computer memory was one of the most expensive commodities on earth, and large amounts of human ingenuity were spent trying to simulate supernova explosions with nothing more than a future Nobel prize winner and a vast array of vacuum tubes. Nowadays many people have enough computer memory to simulate the destruction of most of the galaxy in any one of their hand-held phones, digital diaries, or microwave ovens.

But at least two things have remained constant throughout the history of computing. Software design remains hard (Gamma et al. 1995), and its functionality still expands to fill the memory available (Potter 1948). This book addresses both these issues. Patterns have proved a successful format to capture knowledge about software design; these patterns in particular tackle memory requirements.

As authors we had several additional aims in writing this book. As patterns researchers and writers we wanted to learn more about patterns and pattern writing, and as software designers and architects we wanted to study existing systems to learn from them. In particular:

- we wanted to gain and share an in-depth knowledge of portable small memory techniques; techniques that work in many different environments
- we wanted to write a complete set of patterns dealing with one single force — in this case, memory requirements
- we wanted to study the relationships between patterns, and to group and order the patterns based on these mutual relationships, and lastly
- we wanted an approachable book, one to skim for fun rather than to suffer as a penance.

This book is the result. It's written for software developers and architects, like ourselves, whether or not you happen to be facing memory constraints in your immediate work.

To make the book more approachable (and more fun to write) we've taken a light-hearted slant in most of our examples for the patterns and with Duane Bibby's cartoons. If frivolity doesn't appeal to you, please ignore the cartoons and the paragraphs describing the examples: the remaining text is as rigorous as we can make it.