io library bug?

[N.M. Maclaren]

On May 27 2010, Arjen Markus wrote:
>>
>> The real question is: Do you really need record sizes of 6.4 GiB? I can
>> see reasons to store data of several hundreds of GiB - but I fail to
>> come up with a good application where one accesses blocks of data
>> consisting of several GiB.

Checkpoint/restart for a program with multi-GB arrays, for a start.

>Nitpicking:
>If the record size of an _unformatted_ file exceeds 4GB, how is the
>record header and trailer handled by gfortran? (I have never come
>across that problem myself, but with the ever-increasing memory
>sizes, you never know)

Some compilers have the option to select between 4- and 8-byte header
and trailers.  Of course, one could use the technique used on IBM MVT
(now zOS) from the 1960s onwards, which has no limit - anyone interested
should contact an old fogey (such as yours truly) :-)  But, in practice,
a 4/8-byte option is what compilers do nowadays.


Regards,
Nick Maclaren.