Version française
Home     About     Download     Resources     Contact us    
Browse thread
Estimating the size of the ocaml community
[ Home ] [ Index: by date | by threads ]
[ Search: ]

[ Message by date: previous | next ] [ Message in thread: previous | next ] [ Thread: previous | next ]
Date: -- (:)
From: Frédéric_Gava <frederic.gava@w...>
Subject: Re: [Caml-list] Estimating the size of the ocaml community
> AFAIK Marshal.{to,from}_channel isn't limited by the maximum string
> length.
>...
>    Olivier

OK. Right but you can not all the time used channels... For TCP/IP, that is
possible, but for low level libraries (as MPI, PVM, PUB etc...) you need
strings and you are blocked by this limitation (except if you read the
values from a file but in this case it is not a fast solution).

>It's a problem of the implementation, but one which looks hard to
>change.  The reason it arises is because each OCaml value has a 4
>byte[*] header, divided into a 1 byte tag, 2 bits for the GC, and the
>remaining 22 bits to store the size of the value in words.  Since
>strings are stored directly in the value (which is very efficient),
>they are limited to 4 * (2^22 - 1) bytes ~ 16 MB in size.
>...
>Richard Jones, CTO Merjis Ltd.
Sure it is a hard problem. But I thinks that in the futur (now my bench are
not bench of true applications but bench of the limits of the language,
values that exceed 16Mo are rare), true scientific applications will need to
serialize big values...(big graphs for example)


Frédéric Gava