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On some systems , reading a large amount of data from a character special file can also fail with EAGAIN if the kernel cannot find enough physical memory to lock down the user 's pages . The first time you do this , you may get a number of errors as the kernel cannot find the special drivers . On some systems , writing a large amount of data from a character special file can also fail with EAGAIN if the kernel cannot find enough physical memory to lock down the user 's pages .