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Date:      Sun, 26 Oct 2008 16:31:20 -0700
From:      Jeremy Chadwick <koitsu@FreeBSD.org>
To:        Louis Mamakos <louie@transsys.com>
Cc:        Charles Sprickman <spork@bway.net>, freebsd-hardware@freebsd.org
Subject:   Re: PCI-X SATA Card + Server Recommendation
Message-ID:  <20081026233120.GA5517@icarus.home.lan>
In-Reply-To: <53B2E924-A690-4DAE-B937-076B1DA89F8E@transsys.com>
References:  <Pine.OSX.4.64.0810260112010.4630@toasty.nat.fasttrackmonkey.com> <20081026125017.GA88016@icarus.home.lan> <Pine.OSX.4.64.0810261502011.4630@toasty.nat.fasttrackmonkey.com> <20081026204935.GA2429@icarus.home.lan> <53B2E924-A690-4DAE-B937-076B1DA89F8E@transsys.com>

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On Sun, Oct 26, 2008 at 05:58:07PM -0400, Louis Mamakos wrote:
> On Oct 26, 2008, at 4:49 PM, Jeremy Chadwick wrote:
>
>> On Sun, Oct 26, 2008 at 03:30:11PM -0400, Charles Sprickman wrote:
>>> On Sun, 26 Oct 2008, Jeremy Chadwick wrote:
>>>
>>> Ouch.  I was thinking more along the lines of a dead-simple SATA  
>>> card in
>>> the under $50 range.  I'm not up at all on PCI-X stuff, but I assume 
>>> I
>>> can go with a normal PCI card, right?  Or 64-bit PCI (or is that  
>>> PCI-X)?
>>> What kind of performance hit would I have going from a PCI-X card to
>>> something else, and if I remove the PCI-X restriction, is there  
>>> another
>>> recommended card?
>>
>> Any PCI 2.x or 3.x revision card should work fine in a PCI-X slot.  Of
>> course, the card will only run at 33MHz 32-bit (vs. 133MHz 64-bit,  
>> which is
>> what native PCI-X is), but it'll still work.  Most PCI cards are 32- 
>> bit
>> 33MHz, but a 64-bit 33MHz PCI card should also work.
>>
>> The only PCI 1.x cards will probably fry your motherboard; they use a 
>> 5V
>> bus, not a 3.3V bus.  :-)
>
>
> This has been a concern of mine.  I just bought a Dell Poweredge 2650
> off of eBay, and was going to outfit it with a USB2/Firewire PCI card
> so I can attach some cheap bulk storage to it for backup purposes.  The
> Dell has PCI-X slots; backwards compatible with PCI, right?  Try to
> find a USB PCI board that doesn't require a 5V capable PCI slot..
>
> I haven't been able to; of course it's pretty obvious in that the USB
> host is supposed to supply 5V power to the peripherals.. D'oh!  Oh well.

Why do you think think the voltage provided on the USB bus is directly
proportional to the voltage provided across the PCI bus?  A PCI 3.3V
expansion card (for USB ports) card *most definitely* provides 5V to the
USB bus.  The voltage increase is done with a very small amount of
circuitry on the card itself.  (I've confirmed this with two separate EE
folks I know; I showed them your message, and they're equally as
confused why you think that.)

Maybe what you're trying to say is that your PowerEdge 2650 box only has
the old 5V PCI slots, thus you need a USB PCI card that works in such
scenarios?  If so, I'm baffled as to why you're having such difficulty.
Many PCI cards (including PCI USB cards -- I've Googled and found many!)
are "Universal PCI" cards (keyed to work on both 3.3V and 5V PCI slots),
and those will work fine.  How to determine what's what:

http://en.wikipedia.org/wiki/Image:PCI_Keying.png

The Dell PowerEdge 2650 Systems Installation and Troubleshooting Guide
indicates that the mainboard uses a riser board to provide three (3)
PCI-X slots:

http://support.dell.com/support/edocs/systems/pe2650/en/it/5g375aa0.htm#1046001

Googling around for a few minutes turns up some photos of the 6H580
riser board, which confirm the slots are 64-bit PCI-X 3.3V:

http://cgi.ebay.com/Dell-6H580-PowerEdge-2650-PCI-Riser-Board-Card-TESTED_W0QQitemZ200218132010QQcmdZViewItem

But what revision of PCI-X?  Well, the speeds (MHz) available for each
slot change depending upon what's installed where.  Here's that
reference:

http://support.dell.com/support/edocs/systems/pe2650/en/it/5g375c60.htm#1059976

Which says the maximum rate is 133MHz, confirming these are PCI-X 1.0
slots.

Have fun.  :-)

-- 
| Jeremy Chadwick                                jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |




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