[erlang-patches] Optimize communication with file io server

Björn Gustavsson <>
Tue Apr 9 12:12:00 CEST 2013

The patch looks fine and it would be a good thing to do.

Unfortunately, there is the pesky question of backward

Someone can open a file on an R15 system, send the
file descriptor (=a pid) to an R16B01 system with your
patch and the R16B01 system will attempt to do file
operations on the file.

The backward compatible way to do this is to first introduce
a file_io_server module that can handle both the new
and the old messages. Two releases later the file module
can be changed to use the new message format.

Strictly speaking, two releases forward means R19
to allow the original R16B release to communicate
with an R18 release.


On Fri, Apr 5, 2013 at 12:56 PM, Anthony Ramine <> wrote:

> Hello,
> This patch adds the monitor references to the file io protocol to optimize
> the receive expressions in the 'file' module.
>         git fetch https://github.com/nox/otp.git file-receive-optim
> https://github.com/nox/otp/compare/erlang:maint...file-receive-optim
> https://github.com/nox/otp/compare/erlang:maint...file-receive-optim.patch
> Regards,
> --
> Anthony Ramine
> _______________________________________________
> erlang-patches mailing list
> http://erlang.org/mailman/listinfo/erlang-patches

Björn Gustavsson, Erlang/OTP, Ericsson AB
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