Software development, .Net, SQL Server, TDD, Agile, Community and other Odds and Sods
Mitch Wheat has been working as a professional programmer since 1984, graduating with a honours degree in Mathematics from Warwick University, UK in 1986. He moved to Perth in 1995, having worked in software houses in London and Rotterdam. He has worked in the areas of mining, electronics, research, defence, financial, GIS, telecommunications, engineering, and information management. Mitch has worked mainly with Microsoft technologies (since Windows version 3.0) but has also used UNIX. He holds the following Microsoft certifications: MCPD (Web and Windows) using C# and SQL Server MCITP (Admin and Developer). His preferred development environment is C#, .Net Framework and SQL Server. Mitch has worked as an independent consultant for the last 10 years, and is currently involved with helping teams improve their Software Development Life Cycle. His areas of special interest lie in performance tuning
Sunday, February 05, 2012
Bootstrapping and Reflections on Trusting Trust
The term "Bootstrapping" comes from the term "pulling yourself up by your own bootstraps" (Wikipedia). In computing parlance, a bootstrap loader is the code that initially runs when a machine starts, whose job is to load the rest of the operating system. [I can remember (just) old mainframes where the bootstrap code was entered by hand using switches on the front panel!]
If you’ve never read Ken Thompson’s “Reflections on Trusting Trust” (his Turing Award acceptance speech), it’s definitely worth reading:
How did I get onto this topic? Someone asked the question “How can you write a compiler in it's own language?”
If you were writing a new C++ compiler, you would just write it in C++ and compile it with an existing C++ compiler. If you were creating a compiler for a completely new language, you would need to write the new compiler in another language first. Usually this would be another programming language, but it can be assembly, or even machine code.
If you want to bootstrap a compiler, you would generally write a compiler for a small subset of the language. Then in this minimal version of the language, you would write a compiler for the full language. This often occurs iteratively rather than in a single pass.
There is an interesting article about bootstrapping a compiler from the ground up titled Bootstrapping a simple compiler from nothing.
MSN, Email: mitch døt wheat at gmail.com