Date: Sun, 26 Oct 2008 21:27:10 -0400 From: Louis Mamakos <louie@transsys.com> To: Jeremy Chadwick <koitsu@freebsd.org> Cc: Charles Sprickman <spork@bway.net>, freebsd-hardware@freebsd.org Subject: Re: PCI-X SATA Card + Server Recommendation Message-ID: <2F0DB513-B639-46CB-8D8F-E6D9410FE401@transsys.com> In-Reply-To: <20081026233120.GA5517@icarus.home.lan> 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> <20081026233120.GA5517@icarus.home.lan>
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On Oct 26, 2008, at 7:31 PM, Jeremy Chadwick wrote: >> >> 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.) I'm well aware of the existence of switching power supply regulators; however the selection of USB/Firewire boards I was able to find didn't appear to be universal cards -- at least based on the photos provided of the actual products. The last board I bought for another system didn't have any on-board power source -- other than PTC fuses, the power just came off the PCI backplane connector. It's the easy and obvious solution. Perhaps not quite as obvious these days with 3.3V only buses. > > 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 2650 only has 3.3V slots. This determined by the physical keying of the connectors on the riser. I looked a bunch of boards on Amazon, and they didn't appear to be universal PCI cards. And if you look at the photos, there's nothing there that would appear to be a small switcher to generate the +5V for the USB interface. > > > 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. My bandwidth needs are modest, just to run the USB/Firewire interfaces. The 2650 is pretty cost effective on ebay these days, though you're constrained to using SCA SCSI drives which are somewhat more expensive than your generic SATA drives these days. I've got 5 bays populated with 73GB drives which is sufficient for the usual email/www server, I'd like to drop some larger, less performant drives for over-the-net backup use. The search continues.. louie > > > 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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