2008/2/1 Galchin Vasili :

I wrote a simple program to read the contents of a cdrom:

(Note that this is a terribly inefficient way of reading large amounts of binary data. Of course, if this is just meant as an example, that's fine. Otherwise, see the struff about ByteStrings at http://www.haskell.org/haskellwiki/DealingWithBinaryData) The error you are seeing comes from the operating system. You could run the resulting Haskell program under strace to see the exact error, but what's happening is that the kernel is getting an error from the CD drive itself. This is pretty much unique to CDs I guess. If you were reading a hard drive, the kernel knows exactly how large the disk is (see /proc/partitions) and would return EOF (zero bytes). As an aside, hitting EOF in your code would result in an infinite loop, since you don't handle actualByteCount == 0. You can catch and handle the resulting exception with the functions in: http://haskell.org/ghc/docs/latest/html/libraries/base/Control-Exception.htm... AGL -- Adam Langley agl@imperialviolet.org http://www.imperialviolet.org 650-283-9641