Re: [boost] Random Access to Files (RAF) - any interest ?

From: Martin Bonner (martin.bonner_at_[hidden])
Date: 2006-05-24 04:33:25

----Original Message----
From: boost-bounces_at_[hidden]
[mailto:boost-bounces_at_[hidden]] On Behalf Of Slava, Alex Sent:
23 May 2006 22:32 To: boost_at_[hidden]
Subject: Re: [boost] Random Access to Files (RAF) - any interest ?

>> On 5/22/06, Tomas Puverle <Tomas.Puverle_at_[hidden]> wrote:
> ...
>>> There are filesystems out there that support 128 bits for file
>>> sizes.  So I think there needs to be a more general solution.
>>> 
> 
> Totally agree about more general solution.

Another reason for wanting a more general solution, is coping with the
user wanting many RAF objects at once.

That also means that the user needs to be able to specify whether to map
the whole file or a window.  (The implementation might think there is
nothing wrong with mapping the whole of this 1G file on a 32-bit
operating system, but the user may be about to open another three such
files - which won't fit!)
> 
> That does not change anything, but just out of curiosity some
> calculations were made: the number of atoms in the graphite of a
> pencil is < 2^72,
> 
> http://www.madsci.org/posts/archives/oct98/905633072.As.r.html
> 
> so the storage providing capacity to hold files with 128-bit offset
> would have to contain at least as many atoms as 8*2^56 = 2^59 pencil
> leads ! Hundreds of tons of material that should be. And this is with
> just 1 atom per bit of information. Seems a bit too much for any
> conceivable technology... What FS would need to provide support for
> such capacities ?

-- 
Martin Bonner
Martin.Bonner_at_[hidden]
Pi Technology, Milton Hall, Ely Road, Milton, Cambridge, CB4 6WZ,
ENGLAND Tel: [phone]