OK, it seems that the kernel I have (stock CentOS 4.7: 2.6.9-78.0.22.EL i686) seems to gronk the nVideo SATA controller in AHCI mode. It is NOT able to deal with the SATA DVD Burner I have. It is a "Sony Optiarc DVD Burner with LightScribe Black SATA Model AD-7241S-0B LightScribe Support". Is there some special magic I need to do? Here is the relevant bit from the boot up (SATA ports 2-6 are empty at present): Jul 26 16:29:27 sauron kernel: ACPI: PCI Interrupt 0000:00:09.0[A] -> GSI 20 (level, low) -> IRQ 201 Jul 26 16:29:27 sauron kernel: MSI INIT SUCCESS Jul 26 16:29:27 sauron kernel: ahci 0000:00:09.0: AHCI 0001.0200 32 slots 6 ports 3 Gbps 0x3f impl SATA mode Jul 26 16:29:27 sauron kernel: ahci 0000:00:09.0: flags: 64bit ncq led clo pmp pio Jul 26 16:29:27 sauron kernel: ata1: SATA max UDMA/133 cmd 0xF8874100 ctl 0x0 bmdma 0x0 irq 58 Jul 26 16:29:27 sauron kernel: ata2: SATA max UDMA/133 cmd 0xF8874180 ctl 0x0 bmdma 0x0 irq 58 Jul 26 16:29:27 sauron kernel: ata3: SATA max UDMA/133 cmd 0xF8874200 ctl 0x0 bmdma 0x0 irq 58 Jul 26 16:29:27 sauron kernel: ata4: SATA max UDMA/133 cmd 0xF8874280 ctl 0x0 bmdma 0x0 irq 58 Jul 26 16:29:27 sauron kernel: ata5: SATA max UDMA/133 cmd 0xF8874300 ctl 0x0 bmdma 0x0 irq 58 Jul 26 16:29:27 sauron kernel: ata6: SATA max UDMA/133 cmd 0xF8874380 ctl 0x0 bmdma 0x0 irq 58 Jul 26 16:29:27 sauron kernel: scsi1 : ahci Jul 26 16:29:27 sauron kernel: ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300) Jul 26 16:29:27 sauron kernel: ata1.00: qc timeout (cmd 0xec) Jul 26 16:29:27 sauron kernel: ata1.00: failed to IDENTIFY (I/O error, err_mask=0x104) Jul 26 16:29:27 sauron kernel: ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300) Jul 26 16:29:27 sauron kernel: ata1.00: qc timeout (cmd 0xa1) Jul 26 16:29:27 sauron kernel: ata1.00: failed to IDENTIFY (I/O error, err_mask=0x104) Jul 26 16:29:27 sauron kernel: ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300) Jul 26 16:29:27 sauron kernel: ata1.00: qc timeout (cmd 0xa1) Jul 26 16:29:27 sauron kernel: ata1.00: failed to IDENTIFY (I/O error, err_mask=0x104) Jul 26 16:29:27 sauron kernel: ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300) Jul 26 16:29:27 sauron kernel: scsi2 : ahci Jul 26 16:29:27 sauron kernel: ata2: SATA link down (SStatus 0 SControl 300) Jul 26 16:29:27 sauron kernel: scsi3 : ahci Jul 26 16:29:27 sauron kernel: ata3: SATA link down (SStatus 0 SControl 300) Jul 26 16:29:27 sauron kernel: scsi4 : ahci Jul 26 16:29:27 sauron kernel: ata4: SATA link down (SStatus 0 SControl 300) Jul 26 16:29:27 sauron kernel: scsi5 : ahci Jul 26 16:29:28 sauron kernel: ata5: SATA link down (SStatus 0 SControl 300) Jul 26 16:29:28 sauron kernel: scsi6 : ahci -- Robert Heller -- 978-544-6933 Deepwoods Software -- Download the Model Railroad System http://www.deepsoft.com/ -- Binaries for Linux and MS-Windows heller at deepsoft.com -- http://www.deepsoft.com/ModelRailroadSystem/