That's kind of what I was thinking of, but I would prefer to modify the open statement to include a die statement, such as below:

open (IN,"<",$file) || die "Unable to open file '$file':  $!\n";
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Also, I would think that the sleep statements in the OP are actually "slowing" it down by making it run longer. Based on the code provided, it doesn't look like the sleep statements are needed. Of course, since I have never used sysread, I may be completely wrong about this.