I run a 1.4.X.. And I have lot of problem when using my cdrom :

ahc1: target 4 synchronous at 20.0MHz, offset = 0x10
cd0(ahc1:4:0):  Check Condition on CDB: 0x08 03 46 f4 04 00   
SENSE KEY:  Media Error
INFO FIELD:  214772
ASC/ASCQ:  L-EC Uncorrectable Error

ahc1: target 4 synchronous at 20.0MHz, offset = 0x10
cd0(ahc1:4:0):  Check Condition on CDB: 0x08 03 46 f0 04 00
SENSE KEY:  Hardware Error
INFO FIELD:  214768

ASC/ASCQ:  Tracking Servo Failure
ahc1: target 4 synchronous at 20.0MHz, offset = 0x10
cd0(ahc1:4:0):  Check Condition on CDB: 0x08 03 46 f0 04 00
SENSE KEY:  Media Error
INFO FIELD:  214768							        
ASC/ASCQ:  L-EC Uncorrectable Error

ahc1: target 4 synchronous at 20.0MHz,offset = 0x10
cd0(ahc1:4:0):  Check Condition on CDB:0x08 03 46 f0 04 00
SENSE KEY:  Media Error
INFO FIELD:  214768
ASC/ASCQ:  Record Not Found
												

Here dmesg 
My computer has two cpu ... you ll only see one !

cpu0: family 6 model 5 step 2
cpu0: Intel Pentium II (Deschutes) (686-class)
total memory = 127 MB
avail memory = 113 MB
using 1659 buffers containing 6636 KB of memory
BIOS32 rev. 0 found at 0xfb260
mainbus0 (root)
pci0 at mainbus0 bus 0: configuration mode 1
pci0: i/o space, memory space enabled
pchb0 at pci0 dev 0 function 0
pchb0: Intel 82443BX Host Bridge/Controller (rev. 0x03)
ppb0 at pci0 dev 1 function 0: Intel 82443BX AGP Interface (rev. 0x03)
pci1 at ppb0 bus 1
pci1: i/o space, memory space enabled
vga1 at pci1 dev 0 function 0: Nvidia Corporation RIVA TNT2 (rev. 0x11)
wsdisplay0 at vga1: console (80x25, vt100 emulation)
pcib0 at pci0 dev 7 function 0
pcib0: Intel 82371AB PCI-to-ISA Bridge (PIIX4) (rev. 0x02)
pciide0 at pci0 dev 7 function 1: Intel 82371AB IDE controller (PIIX4)
pciide0: device disabled (at device)
uhci0 at pci0 dev 7 function 2: Intel 82371AB USB Host Controller (PIIX4) (rev.
0x01)
pci_intr_map: no mapping for pin D
uhci0: couldn't map interrupt
Intel 82371AB Power Management Controller (PIIX4) (miscellaneous bridge,
revision 0x02) at pci0 dev 7 function 3 not configured
ahc1 at pci0 dev 11 function 0
ahc1: interrupting at irq 9
ahc1: aic7890/91 Wide Channel A, SCSI Id=7, 16/255 SCBs
scsibus0 at ahc1 channel 0: 16 targets, 8 luns per target
ne2 at pci0 dev 13 function 0: RealTek 8029 Ethernet
ne2: 10base2, 10baseT, 10baseT-FDX, auto, default [0x03 0x30] auto
ne2: Ethernet address 52:54:00:e7:f5:a9
ne2: interrupting at irq 5
eap0 at pci0 dev 15 function 0: Ensoniq AudioPCI 97 (rev. 0x06)
eap0: interrupting at irq 11
eap0: TRA2 codec; Harman International VMAx
audio0 at eap0: full duplex, mmap, independent
midi0 at eap0: AudioPCI MIDI UART
isa0 at pcib0
ep0 at isa0 port 0x300-0x30f irq 10: 3Com 3C509 Ethernet
ep0: address 00:60:8c:75:c7:42, 8KB byte-wide FIFO, 5:3 Rx:Tx split
ep0: 10baseT, 10base5 (default 10baseT)
com0 at isa0 port 0x3f8-0x3ff irq 4: ns16550a, working fifo
pckbc0 at isa0 port 0x60-0x64
pckbd0 at pckbc0 (kbd slot)
pckbc0: using irq 1 for kbd slot
wskbd0 at pckbd0: console keyboard, using wsdisplay0
pms0 at pckbc0 (aux slot)
pckbc0: using irq 12 for aux slot
wsmouse0 at pms0 mux 0
lpt0 at isa0 port 0x378-0x37b irq 7
pcppi0 at isa0 port 0x61
midi1 at pcppi0: PC speaker
sysbeep0 at pcppi0
isapnp0 at isa0 port 0x279: ISA Plug 'n Play device support
npx0 at isa0 port 0xf0-0xff: using exception 16
fdc0 at isa0 port 0x3f0-0x3f7 irq 6 drq 2
fd0 at fdc0 drive 0: 1.44MB, 80 cyl, 2 head, 18 sec
isapnp0: no ISA Plug 'n Play devices found
biomask e34d netmask e76d ttymask f7ef
scsibus0: waiting 2 seconds for devices to settle...
ahc1: target 0 using 16bit transfers
ahc1: target 0 synchronous at 40.0MHz, offset = 0xf
ahc1: target 0 using tagged queuing
sd0 at scsibus0 target 0 lun 0: <IBM, DDRS-34560D, DC1B> SCSI2 0/direct fixed
sd0: 4357 MB, 8387 cyl, 5 head, 212 sec, 512 bytes/sect x 8925000 sectors
ahc1: target 2 using 16bit transfers
ahc1: target 2 synchronous at 40.0MHz, offset = 0x1e
ahc1: target 2 using tagged queuing
sd1 at scsibus0 target 2 lun 0: <IBM, DNES-309170W, SAH0> SCSI3 0/direct fixed
sd1: 8748 MB, 11474 cyl, 5 head, 312 sec, 512 bytes/sect x 17916240 sectors
ahc1: target 4 synchronous at 20.0MHz, offset = 0x10
cd0 at scsibus0 target 4 lun 0: <PIONEER, CD-ROM DR-966, 1.00> SCSI2 5/cdrom
removable
ahc1: target 6 synchronous at 10.0MHz, offset = 0x8
cd1 at scsibus0 target 6 lun 0: <MATSHITA, CD-R   CW-7502, 4.16> SCSI2 5/cdrom
removable
sd0: no disk label
boot device: sd1
root on sd1a dumps on sd1b
root file system type: ffs