This is more of a purely education-seeking question; no troubleshooting required.

I have been using lspci, dmidecode, and mpt-status to get hardware information on my Dell 1950 running Ubuntu 8.10. One thing that is sticking in my mind is difficulty in understanding the output, likely due to some fundamental missing piece in my hardware understanding.

I'm pretty sure my server is using an embedded SCSI RAID controller from info I got from Dell's site:
1 CR679 Assembly, Card, SAS6IR, Integrated, Sled
1 TX846 Assembly, Cable, Controller SAS, POWEREDGE EXPANDABLE RAID CONTROLLER

When I run lspci I see:
01:00.0 SCSI storage controller: LSI Logic / Symbios Logic SAS1068E PCI-Express Fusion-MPT SAS (rev 08)

PCI-Express is an actual...well, PCI card, right? But dmidecode shows that I have two x8 PCI Express slots that are both available. Sooo...I'm missing something. How am I running a PCI Express SCSI controller without using a PCI Express slot? In the event of not having the kind of info that I did (i.e. the service tag) how would I be able to tell at a glance whether a component like my RAID controller was embedded or not?

Thanks in advance.

Well the simple way to tell, is to open up the case and take a look. I'd be willing to bed its an expansion card which maybe connected permanently onto the motherboard. The PCI-Express bit is the way it communicates/appears to the system, doesn't have to mean its got the physical attributes of a normal PCI-Express card.

Yeah, if I could just pop open the top of my server that would definitely provide a quick answer to the question. The challenge is for situations where I cannot do that (such as in this case where the server is physically inaccessible and also a production server so I wouldn't be powering it down for something like that anyway). It is news to me that there is such a thing as an expansion card permanently connected to a motherboard. I thought devices were either attached via slots (PCI, PCI Express, etc) or soldered(?) on. Didn't know you could take a PCI device and attach it permanently. Just as I figured: there was a major gap in my hardware knowledge. So, sounds like the best way to know this info from the shell is comparing the output of multiple commands like these. Thanks for the info.

It's not because you see PCI Express that it is a card sitting in a PCI-E slot.
The controller is connected thru the PCI express bus but it can be onboard.
I guess the only way to be sure is to open the box.

You often see this kind of description for embedded ethernet controllers or onboard VGA.

I get this entry for example on a linux box :
While I am 100% sure it's onboard and not a seperate controller

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Look in back?

Pretty sure there is a way to id the pci pci-e slots used by some command.

Randomly one of my servers claims to have 3 memory slots, yet on inspection it only has two. Simply the manufacturer hasn't bothered to connect up the 3rd slot. Same kind of thing, however in your case its connected, and embedded into the board, but is STILL a pci-e device.

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Thanks all! That about clarifies it.