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Date:      Thu, 15 Jul 1999 02:10:11 +0000 (GMT)
From:      Terry Lambert <>
To: (David Schwartz)
Cc:,,,, chat@FreeBSD.ORG
Subject:   Re: Known MMAP() race conditions ... ?
Message-ID:  <>
In-Reply-To: <000001bece24$65a5c5e0$> from "David Schwartz" at Jul 14, 99 11:12:13 am

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> 	Large RAID arrays.

You mean software RAID, right?  SCSI cables don't care what they
are connected to.  Hmmm.  I could do a SCSI commercial:

	"So you want a RAID array?  Well, at RAID-arrays-R-us,
	 they do RAID the way you like it.  But bring your SCSI
	 card, because they don't do untagged commands, and they
	 don't accept IDE... SCSI: It's everywhere you want your
	 data to be"

>       4-way SMP.

We know this one.  8-).

> Applications requiring large numbers of threads.

Balk.  "Rodents of unusual size?  I don't believe they exist...".

> There's nothing I know of in any UNIX that comes close to NT's
> completion ports for efficient network I/O.

I want whatever you're smoking confiscated.

Completion ports are no more, and no less, than VMS AST's.  Just
like aio* in FreeBSD, and much of the POSIX crap that's passing
for standards these days.

They may make it easier to code, by calling your callbacks, but
the idea that network buffers should be in user space instead of
on the kernel side of the protection domain barrier is just
plain nuts.

> I won't bother listing NT's problems -- we all know them. But it doesn't do
> us any good to ignore its strengths.

The anti-NT sentiment wasn't mine.  On equivalent hardware, it
handily beats FreeBSD's SMB server performance (one of the major
impetus' for the work Kirk is now doing).  I've address some of
that in another posting, from my experience optimizing a similar
hosted server for NetWare on Solaris, UnixWare, Dell UNIX, VMS,
and AIX.  The problems are correctable, but require work to be
done, and code to be committed.

					Terry Lambert
Any opinions in this posting are my own and not those of my present
or previous employers.

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