Dijkstra's paper and XVPI

1)I read dijkstra's paper mentioned in a previous post. Its amazing that serious projects such as OS360 had no notion of protection from race conditions. Its also amazing that people of the time had no mathematical solution to concurrency, and they were solving racing conditions by accurately timing the tasks and debugging the designs depending on the timing of events.

2) Now that I got a bit more beefy in device drivers and hardware peripherals, I came back to the original idea of harnessing an FPGA under a driver. Yesterday I read the paper I wrote last year on runtime reconfiguration. What I wrote now makes more sense. I read a few papers that I read last year to write my paper, they also make more sense, now that I know more on devices and their drivers. In a nutshell, a Virtex Device is configured using a bunch of pins. Xilinx Virtex Portable Interface is an API written in C that's built around a single register that maps those pins. And XHWIF is a layer on top of XVPI. That's it. So what I needed to know here was how to get a well defined FPGA run-time reconfiguration interface (via a set of registers as in USB or EHCI). I wanted it because the registers of a device is the best interface a C programmer can get for a device. So XVPI already does this. Glad I learned that. Last year I wasn't very aware of how XHWIF would work, as I didn't have any experience in real code that does the work. Now that at least I can have a first go at it.