I am not sure if this is a vampire related issue or coffin or it's my fault, but the amiga programmers handbook 2 states that when reading from serial.device the structure IOExtSer contains a ser variable of type IOStdReq.
IOStdReq holds a io_Actual variable that contains the number of characters read, stating from pag 151"The results of command execution are found in io_Actual and io_Error. The io_Ac-
tual parameter indicates the number of characters actually read." Now take a look at my code at
https://github.com/Ozzyboshi/alsfsAmigaServer/blob/master/alsfssrv.c:723 On my unvampirized amiga the io_Actual holds the value 1 everytime as I expected reading from the manual.
I have another A600 with vampire 2.1 and coffin r51, and this value is always zero.
However it seems that the DoIO() call succeedes because I find the correct read character on DataReadBuffer variable. It is very likely that this piece of code is broken, I am an amateur programmer, but at the end this program works on my vampirized amiga, I just get the on screen warning. I assumed this information could be of interest of the apollo team that's why I am posting.
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Documentation about the Vampire hardware