tags 8294 moreinfo close 8294 thanks Paul Eggert wrote: > On 03/19/2011 11:26 AM, John Morris wrote: >> On a 64bit platform shouldn't the following command have done the >> expected thing instead of quietly clipping to 231? > > It depends on what your platform's 64-bit 'read' > system call does. My guess is that your platform's > 'read' syscall refuses to read more than > 2**31 - 2**12 bytes at a time from /dev/zero, > so the problem (if any :-) is with 'read', not > with 'dd'.
Thanks for replying, Paul. John, If the read system call were failing and dd were ignoring that failure, that would be a bug. However, dd is careful to check for that sort of thing. Here, read is returning after readling less than a full block, and that's fine. It's a so-called short read. If you want dd to accumulate full blocks, use GNU dd's iflag=fullblock option.
