I'm just beyond the concept phase for a data logging and control project that once started will have minimal to no downtime in order to remove the SD card to retrieve the data. Reading the data log from the card will be done via wireless USB module. The system will also be logging to the card at the same time as data is being read. The plan is to read several lines into a transmit buffer then close the file and allow for the file to be appended. When the transmit buffer is empty, I need to remove the first number of already transmitted lines from the file. This is where I'm stuck. How do I remove data from a file on an SD card? Whether it is at the beginning (like this situation), in the middle or at the end?
(Before you ask, I don't have a working sketch yet. I'm still gathering the pieces of code necessary to make it work, let alone compile)