Date: Wed, 11 Sep 1996 21:11:43 -0700 From: "Michael L. VanLoon -- HeadCandy.com" <michaelv@MindBender.serv.net> To: brianc@pobox.com Cc: freebsd-hackers@freebsd.org (FreeBSD Hackers) Subject: Re: IDE and ASUS P/I-P6NP5 Message-ID: <199609120411.VAA24398@MindBender.serv.net> In-Reply-To: Your message of Wed, 11 Sep 96 21:41:35 -0400. <199609120141.VAA00555@ottawa.net>
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>> I think the problem is still that it is impossible to reliably detect
>> support for the mode without crashing older (WD1007, etc.?) hardware.
>And Terry clearly has a problem with IDE in general.
Well, Terry isn't the only one...
>Nonetheless I'd really love to have a bus-mastering IDE driver
>available. I could care less if it automatically detects older
>hardware, although other operating systems manage to do this.
Yes, I agree this would be great. We should make the most of all our
hardware...
>I'd be happy to manually specify that my IDE chipset and drive were
>"DMA capable" for the dual benefit of freeing up the CPU for more
>useful tasks and increased throughput.
But you still shouldn't kid yourself that it would be "as good as"
SCSI. All the design deficiencies of IDE aside, the single most
important benefit to asynchronous high speed drive through-put that I
have found in my testing, is tagged-command-queuing. Even over the
same high end SCSI board (AHC-2940UW or BT956c) on the same drives,
with tagged-command-queuing simply disabled.
I may be mistaken, but I don't believe I have heard of EIDE even
attempting to address something on that level.
So, once again, I agree that it would be a really great win to have
this EIDE functionality (especially for all the existing hardware
already out there), but I still recommend that you stick to SCSI from
the start, if there is any way you can do so.
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Michael L. VanLoon michaelv@MindBender.serv.net
--< Free your mind and your machine -- NetBSD free un*x >--
NetBSD working ports: 386+PC, Mac 68k, Amiga, Atari 68k, HP300, Sun3,
Sun4/4c/4m, DEC MIPS, DEC Alpha, PC532, VAX, MVME68k, arm32...
NetBSD ports in progress: PICA, others...
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