Yes, I am using a device, a hard drive specifically. Strange that it worked for you, I did my own test to see if it was a problem with the functions, the storing of the file handle, or somewhere else. Basically I did a sysseek and sysread in the new function, it worked then failed later when getblocks was called, so the open file handle works fine in the constructor, but dies somewhere before I call getblocks.

I also tried standard open,read,write,seek and got the same problem.

I need to access devices (whole point of the code) and I need to use sysread and syswrite because I want to bypass the buffered IO.