Robin2:
When you remember post a link to it and I will look at it. In the meantime I will continue to avoid Strings.Because of the way Strings work I don't think the problem is fixable. They work fine when there is 2GB of SRAM but not when there is 2K. I use the concept all the time when I write Python code on my PC, but never in my Arduino code.
...R
When I last looked at the Arduino String class, it expanded the buffer by one byte every time a character was appended to it, and it expanded the buffer by the exact amount of space required when appending a string. It would be better to expand the buffer exponentially (by, say, 50%) to avoid memory fragmentation. So I believe the String class can be improved to possibly reduce memory fragmentation to some extent.