Posts
Comments
The prevailing attitude that "Memory is Cheap" doesn't cut it in the world of Embedded Systems. I get code to fit into parts (others have picked), that are too small. I translate code between different micros and compilers. Besides the software aspects of things I also do micro design, analog design, power supply design, and board layout.
During the heyday of the Dot Com boom I was the lead author of Circuit
Cellar Online's Resource Links. Steve Ciarcia said I set the standard by which
other link sites were judged, at that time.
I was also a paid member of the Circuit Cellar AskUs staff.
From the final "Connect Time" in Circuit Cellar Issue #80, March 1997:
"I do want to thank a few individuals who have contributed above and
beyond the call over the last 10 years (and, I'm hopeful, for years to
come). Specifically, **Bob Paddock**, Pellervo Kaskinen, George Novacek,
Jim Meyer, and Ed Nisley. I could always count on one of these sharp
guys to have an intelligent, well-thought-out answer to some of the most
off-the-wall questions I've ever seen." - Ken Davidson former SYSOP/Editor-In-Chief Circuit Cellar
Magazine
When I supported the GNU compilers at Wind River, D'Anne Thompson made it clear that all global variables (both those visible to the linker and those visible throughout a source file) are volatile by *default*.
ReplyDeleteThis is because all the code in VxWorks (before version 6) is in the same address space. Every thread, driver, interrupt handler, etc. This means that between the time a function loads up a global variable and the time it trefers to it again, another thread (running code in another module or other code in the same module) may have changed it.
This situation is exactly why the keyword 'volatile' was invented.
It requires a lot of discipline to minimize or eliminate global or non-static variables from your code,
and it's worth it.