Date: Tue, 26 Sep 2000 20:11:23 +0200 (CEST) From: =?ISO-8859-1?Q?G=E9rard_Roudier?= <groudier@club-internet.fr> To: Joe McGuckin <joe@via.net> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: What's the difference between the ncr0 and sym0 drivers? Message-ID: <Pine.LNX.4.10.10009261925340.1161-100000@linux.local> In-Reply-To: <200009260216.TAA25565@monk.via.net>
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On Mon, 25 Sep 2000, Joe McGuckin wrote:
> Is one preferable?
Here's the history:
BSD ncr -> Linux ncr53c8xx -> Linux sym53c8xx -> FreeBSD sym
The ncr is minimally maintained mainly against O/S changes since the
latest real improvement that has been the support of 875/895/896 Ultra
chips:
- Ultra, Ultra 2
- On-chip RAM
These changes came from the Linux ncr53c8xx driver, as I am using both
Linux and FreeBSD since 1995.
Note that Linux ncr53c8xx is now also minimally maintained.
Only `sym53c8xx' and `sym' support phase mismatch handling from SCRIPTS,
Ultra3 chips (SYM53C1010), residual calculation, completion queue (rather
than walking CCB lists), etc ... (would be too long :) ).
Speaking about Linux + FreeBSD + FreeEtc..., my main project at the
moment is `sym' for all. Btw, this is not an original strategy. :-)
It seems that a new driver is developped from scratch in the NetBSD
project. That's a courageous effort. Just the `from scratch' approach has
been a bad idea, in my opinion.
About the `sym' driver, I try to maintain it up-to-date regarding both O/S
features and chips features. It seems extremally stable in practice and is
both very fast and scale perfectly with the number of simulatenous IOs, at
least in theory :).
Just a number: I have measured a bit more that 16000 small IOs per second
(512 bytes READs) using a single old SYM53C895 chip, which let me think
that theory should match practice here. :)
Gérard.
PS: LSILogic supports actively sym53c8xx and sym drivers development by
providing me with controllers, documentations and hardware upgrades.
> Thanks,
>
> Joe
>
>
>
> --
>
> Joe McGuckin
>
> ViaNet Communications
> 994 San Antonio Road
> Palo Alto, CA 94303
>
> Phone: 650-969-2203
> Cell: 650-207-0372
> Fax: 650-969-2124
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