I once had a project that involved two serial devices with incompatible message format that had to send big chuncks of data back and forth. We created a simple board with a dual-UART CPU and external SRAM for buffering the large strings (this was before the days of 8051 CPUs having internal XRAM).

Another programmer took a routine from the "Embedded building blocks" that used a seemingly well written structure for an interrupt driven 2K circular buffer on both serial ports. After we got the board up and running, he turned the project over to me. When the serial buffer seemed to have problems once in a while, I asked him to look at the code for me. He started debugging the code while I set to work ripping out the serial port structures and pointers and re-writing it for one serial port, and then just duplicating and editing for the second serial port. Since I had some experience with interrupt-driven serial buffers (in both A51 and C) I had the application up and running long before the other programmer had figured out what was wrong with the structure...

-- Tom Bachmann