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From: Terry Lambert <tlambert@primenet.com>
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Subject: Re: Proposal to include iconv library in the base system.
To: ache@nagual.pp.ru (Andrey A. Chernov)
Date: Fri, 1 Sep 2000 18:14:20 +0000 (GMT)
Cc: bp@butya.kz (Boris Popov), freebsd-arch@FreeBSD.ORG,
	freebsd-i18n@FreeBSD.ORG,
	Konstantin.Chuguev@dante.org.uk (Konstantin Chuguev)
In-Reply-To: <20000901185945.A29804@nagual.pp.ru> from "Andrey A. Chernov" at Sep 01, 2000 06:59:46 PM
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> On Thu, Aug 24, 2000 at 05:39:39PM +0700, Boris Popov wrote:
> > FreeBSD already contains a few character conversion schemes for
> > msdosfs, nwfs, cd9660fs and syscon mapping tables.  However, the usage
> 
> We need XLAT converters for them, not Unicode one, as I understand Unicode
> data loaded into kernel will be too big.

You can mmap a file into a pageable region in the kernel; it's
just a pain requiring a lot of glue, and eats KVM address space
(same problem with SYSV SHM).

You could change the approach to "window" it, but you'd really
want to only enforce that in low KVM situations.

It's useful to have the tables in the kernel when you are, for
example, trying to deal with NTFS or another modern FS which
uses Unicode as the on disk storage format for directory data.

Likewise, it would allow you to do translation between (for example)
ISO 8859-1 and ISO 8859-5 character sets between a machine which
is exporting ISO 8859-1 to the user space (via the directory entry
operations) and a remote system which has an NFS volume containing
ISO 8859-5.

My personal preference would be to move most of the POSIX interfaces
into a library, and go to Unicode for the native FreeBSD system calls.

If that happened, you'd still need translation for Linux and other
ABI compatability, since they would be pushing a particular 8-bit
character set over the user/kernel boundary.


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.


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