Subject: Re: 2940 & netbsd-current
To: Michael L. VanLoon -- HeadCandy.com <michaelv@HeadCandy.com>
From: Justin T. Gibbs <email@example.com>
Date: 03/29/1996 12:44:09
Some of the comments you make here are incorrect or missleading.
Let me try to clear the air.
>Uh, I hate to sound like a repetitive commercial. But, Adaptec isn't
>the only company that makes SCSI controllers that work with *BSD. I
>don't make any commission off preaching BusLogic, but people seem to
>continue following Adaptec like little lemmings, in spite of the
>problems with the controllers under *BSD. Adaptec controllers are
>proprietary. As new versions come out that are sufficiently
>different, they will continue to have to be reverse engineered, and
>drivers updated. I don't know why everyone is so eager to support
>Adaptec, still, when they really couldn't care less about the free
Adaptec is no saint, but their attitude is much the same as with NCR.
They don't want their HIM code (aka firmware) to be distributed in
source form so that other SCSI adapter companies can take advantage of
their many years of experience in making their cards compatible with 99% of
the peripherlas on the market. They will give you all the documentation to
write your own HIM layer (basically what John Aycock and myself have done
for the aic7xxx cards and Stephan Esser has done for the NCR). Neither
driver was reversed engineered, they were just more difficult to write.
As for Buslogic, their cards (until the Flashpoint) do not use downloaded
firmware so the driver can use a well defined, high level, interface to the
card. This is just the same way the 1542 and 1742 cards were designed, and
since both Buslogic and Adaptec can give free software driver writers the
information to talk to that high-level interface without exposing their
"trade secrets" in the firmware, they do so. With the FlashPoint, Buslogic
is moving to use the same strategy as Adaptec has in its aic7xxx product
line and as you may know, is doing the exact same thing as Adaptec
has: It will not release its firmware so the FlashPoint will not be
supported by any Free un*x until someone rewrites the firmware.
>The only reasons I push BusLogic as the best alternative is: 1) they
>are the only one with drivers as mature as the Adaptec drivers in *BSD
>(actually, much more mature than the Adaptec 2xxx) drivers;
The Buslogic driver is so mature that it doesn't support tagged-queuing,
use all of the mail boxes on the card, etc. The Linux driver does better,
but you can't avoid the fact that the Buslogic has 5 times the command
overhead of the aic7xxx boards and 3 times that of the NCR 8XX boards.
The only advantage they have is the support for 32 tags per target, but
you can approach that with a 3940 anyway since it allows 255 concurrent
transactions per bus (the 2940 only does 16). Since the BSD driver only
does 2 transactions per unit, its not even an issue until someone enhances
the bt driver.
>are the only company with cards that work on all busses, with the same
Okay, so the aic7xxx driver only works for EISA/VLB/PCI cards. So what?
>3) and they are the only company that makes cards that are as
>powerful as the Adaptec cards (the NCR 53c8xx cards are close, but
>don't quite have the high-end processing muscle, from my experience).
>I would be happy to quote a second and third alternative to Adaptec,
>if there were a good one to quote. Unfortunately, I don't know of any
They simply aren't as powerfull. The only company that does as well, and
in some cases better than Adaptec is Advasys and since it was founded by
former Adaptec employees, its not too difficult to tell why.
>You don't *have* *to* buy Adaptec cards and use the buggy driver.
>There *are* other controllers that are just as good. I've been
>incredibly satisfied with both of my BusLogic (EISA and PCI)
The driver in NetBSD is buggy. It doesn't have to be buggy and infact
I've been repeating the fact that a driver that will make these problems
"go away" is already availble in FreeBSD.
You're right though. You do have a choice. If you want the best
performance, you buy an Adaptec. If you don't like Adaptec or
don't want the best, buy a Buslogic.
> Michael L. VanLoon michaelv@HeadCandy.com
> --< Free your mind and your machine -- NetBSD free un*x >--
> NetBSD working ports: 386+PC, Mac 68k, Amiga, HP300, Sun3, Sun4,
> DEC PMAX (MIPS), DEC Alpha, PC532
> NetBSD ports in progress: VAX, Atari 68k, others...
Justin T. Gibbs
FreeBSD: Turning PCs into workstations