When we build a bleeding-edge system, things seldom work as expected. That was true of this system, in spades.
We encountered our first gotcha when we carried the system back to our bench to install Windows and Linux and test the system. The nVIDIA 6800 GT video adapter provides two DVI connectors, as shown in Figure 28.
Figure 28. The dual DVI connectors on the nVIDIA 6800 GT video adapter
The nVIDIA 6800 GT does not, unfortunately, provide a standard analog DB15 VGA connector. That was a problem, because the monitor on our bench has only a standard VGA cable. We searched the nVIDIA box, expecting to find a VGA-to-DVI adapter, but none was included. (This card is an engineering sample; a card you buy may well include an adapter.)
So we went off in search of a VGA-to-DVI adapter. Indeed, we found one, nestled in our Miscellaneous Small Parts box. The one we found was an ATi part. We half expected the nVIDIA card and ATi adapter to scream when we mated them. Alas, they refused to mate, as shown in Figure 29. The body of the adapter was slightly too wide to clear the chassis frame. Hmmm.
Figure 29. Insufficient clearance for a DB15-to-DVI adapter
Rats. We couldn't move the video adapter to a different slot, because there is only one PCI Express video slot on the motherboard. We didn't want to tear down the system and rebuild it in a different case, nor did we feel like driving off in search of a thinner adapter or an adapter cable.
Fortunately, Barbara had a cunning plan. When we installed the video adapter, we secured it in the usual way, with the screw notch in the card pressed tight up against the mounting screw. Barbara realized that we might be able to loosen that screw and tilt the card slightly in the direction we needed it to go. We needed only a couple of millimeters of additional clearance. Sure enough, when we removed the mounting screw and loosened the screw for the adjacent slot, we were able to tilt the card just slightly, as shown in Figure 30. We tightened down the screw for the adjacent slot, which actually clamped the card into place, and then reinstalled the screw that is missing in the image. With that done, the ATi VGA-to-DVI adapter mated easily, as shown in Figure 31. (We didn't hear any screams, either.)
Figure 30. Tilting the PCI Express adapter to increase clearance
Figure 31. The VGA-to-DVI adapter fitting properly
Now we had the video connected, so we figured it would be all downhill from there. That turned out not to be the case.
We put our Xandros Business Edition 2.5 CD in the Plextor PX-712SA and restarted the system, assuming Xandros Setup would fire right up. Nope. All we got was an error message telling us no operating system was installed. That surprised us, because nearly all modern motherboards include the optical drive in the boot sequence. This system had no floppy drive and a blank hard drive, so it shouldn't matter what boot order was specified. The system should have tried to boot from the optical drive sooner or later. It should have, but it didn't.
So we fired up BIOS Setup to verify the boot order, and found that it was set to FDD first, hard drive second, and nothing third. We attempted to change the boot order to put the PX-712SA first, but the PX-712SA wasn't listed as an option. At that point we thought we'd forgotten to connect its data or power cable and that the system therefore didn't see the PX-712SA at all. When we checked the list of installed drives, though, the PX-712SA was listed. Hmmm. The BIOS knew the PX-712SA was installed, but it refused to allow us to use it as a boot device. Not good.
Note: While we were in BIOS Setup, we disabled Intel RAID to minimize therbligs during the initial installation of the operating system. Although it is usually thought of as hardware RAID, Intel RAID is in fact hybrid hardware/software RAID, with some RAID functions being performed in hardware by the ICH6R Southbridge and others in software by the main system processor. This complicates matters when installing an operating system, particularly an unsupported one, so we elected to disable RAID at least until we had the system up and running under Linux and Windows in non-RAID mode.
We'd used the Plextor PX-712SA successfully in other systems, including several based on Intel D865PERL and D875PBZ motherboards, so we knew the problem wasn't the drive itself. Both of those other motherboards use the Intel ICH5/ICH5R Southbridge, whereas the D925XCV uses the new ICH6/ICH6R Southbridge, so it seemed possible there might be an incompatibility between the PX-712SA drive and the D925XCV motherboard. In fact, that turned out to be the case. A web search turned up a PX-712SA compatibility list, which did not include the D925XCV.
We had some alternatives to make the system bootable, but none we were happy about. We could have installed a floppy drive, but a bleeding-edge system with a floppy drive is an oxymoron. We eventually decided to replace the PX-712SA Serial ATA drive with a PX-712A Parallel ATA model. We couldn't find a PX-712A in the stockroom, so we ended up instead installing a PX-708A to make the system bootable.
With that done, we fired up the system again and watched Xandros begin its setup procedure. Unfortunately, that aborted quickly. We've installed Xandros 2.5 successfully on many systems with S-ATA hard drives, so we suspect that Xandros didn't know how to deal with the 925X chipset, the DDR2 memory controller, the PCI Express video, or one of the other bleeding-edge technologies in this system. That's not surprising, really, because Xandros 2.5 is based on the aging 2.4.x kernel. Xandros 3.0, which we expect to ship later this year, will almost certainly be based on a 2.6.x kernel, so we should have better luck with it.
But we needed to install some form of Linux for testing, so as an interim measure we downloaded and burned the ISOs for Fedora Core 2 (Tettnang), which uses the 2.6.5 kernel. FC2 detected all the hardware and installed flawlessly. Once we'd established that, we stripped the hard drives down to bare metal and installed Windows XP, which installed successfully but failed to detect some of the hardware, including the network adapter. Fortunately, the Windows XP drivers supplied by Intel solved those problems, and we were able to get Windows XP up to speed quickly.
Over the coming weeks, we'll configure this system to dual-boot Windows XP and one or another of the Linux distros based on the 2.6.x kernel and install and tweak the drivers to achieve the fastest possible performance. Judging only by our preliminary testing, though, we can already say that this is one seriously fast system.
Robert Bruce Thompson is a coauthor of Building the Perfect PC, Astronomy Hacks, and the Illustrated Guide to Astronomical Wonders. Thompson built his first computer in 1976 from discrete chips. Since then, he has bought, built, upgraded, and repaired hundreds of PCs for himself, employers, customers, friends, and clients.
Barbara Fritchman Thompson is a coauthor of "Building the Perfect PC" and "PC Hardware in a Nutshell." She runs her own home-based consulting practice, Research Solutions.
In August 2004, O'Reilly Media, Inc., released Building the Perfect PC.
Sample Chapter 1: Fundamentals is available free online.
For more information, or to order the book, click here.
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