On Tue, Jul 29, 2008 at 8:04 AM, Alexander Sychev <santucco@gmail.com>wrote:

> On Tue, 29 Jul 2008 12:52:14 +0400, Enrico Weigelt <weigelt@metux.de>
> wrote:
>
> Hi!
>
>  an full mmap() is a really nice thing. It can make a lot things
>> easier if you just map the whole file into the process' memory and
>> let the kernel handle the actual IO.
>>
>
> Yes, it is comfortable. But just think a bit - what will you do in the mmap
> implementation when you had mapped a remote file (in Plan9 you can't be sure
> some file is local or it is really just a file), and the connection has just
> been broken? Surprise!


>
> For example, in Windows you will have an "access violation". It is very
> funny to rewrite a code for using the good old file i/o instead of mmap.
> In Linux you can't map a non-regular file.
>
> Yes, you can read entire the file into the memory, but a size of the file
> can be very big and you will destroy the main advantage of mmap - the
> reading of only needed pieces of the file, not entire.
>

And if you read it in in pieces, how can you be sure the file isn't changing
on the system it's hosted on while you're looking at it?


>
> I beleive, mmap is not for distributed systems.
>
> --
> Best regards,
>        santucco
>
>