Here are some conventions [Update: typos fix, Friday] We are concerned with state machines and sequences of events. The prefixes of a sequence include the empty sequence “null” and the sequence itself. Relative state: If “w” is the sequence of
Data structures and algebra
[Edited 9/10] There’s an easy connection between data structures and basic abstract algebra that may or may not mean anything, but keeps getting rediscovered. I’ve never seen it clearly explained (anyone with a reference or who notices an error in
Death of 1000 suboptimal solutions
The traditional path to making a slow operating system is to take a fast one and add features under the 5% rule. If a new feature does not visibly slow the system down or only slows it down 5% or
The lost wakeup problem
One basic problem in operating system design is how to make efficient blocking requests. Thread A wants something from Thread B (or ISR B) and (1) requests and (2) blocks. There are thousands of ways in which the interval between
Silver Bullets
Like many famous papers, Fred Brooks No Silver Bullet is more referenced than read but it deserves better. Here is Brooks explaining why verification hype, for example the recent vast investment in marketing supposed security levels of Common Criteria Software
Two new web sites
The FSMLabs web site is finally up with some material about new work. The web site for Finite State Research, our sister company focused on R&D and consulting is also up although it contains very little – FSR is there
OSIM Madrid and Value Manifolds
Spent a couple of very interesting days at the OSIM conference in Madrid as part of my consulting for WindRiver which has a very powerful market position in cellular handsets now – partly due to their acquisition of RTLinux for
Exciting moments in fiber
… the first truly game changing advance in bend-insensitive fiber came at the FTTH Council Europe meeting in Amsterdam early 2005, when an NTT engineer demonstrated a tough fiber that could be tied into knots. As we reported in oour
Thinking like a subcontractor
Many industries are organized so that a small group of companies controls the “product” and sit on top of a pyramid of subcontractors who provide parts and labor. It’s natural for companies at the top of the chain to prefer
Apple’s strategic brilliance
I may be reading too much into it, but Apple looks to have come up with a strategy to pass Microsoft in the next ten years. They are linking their phone, music, and PC business together to form an unavoidable