How to decode LBOLT numbers

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The following briefly explains how to decode LBOLT numbers, to reference a specific hardware. These LBOLT numbers appear most of time when the system is experiencing SCSI errors, and is logging these errors in the /var/adm/syslog/syslog.log file.


Sep 12 17:07:47 myserver vmunix: SCSI: Unexpected Disconnect -- lbolt: 54063027, dev: bc051000, io_id:5cf6050

In this case the LBOLT number to decode is bc051000 which correspond to the device that is logging the error.

How To Decode LBOLT[edit]

In order to decode this LBOLT number, is easier to split it in 5 hex sections.

0x bc 05 10 00
s1 s2 s3 s4 s5


  • 0x = Designates the remaining as hex and is always there.


  • bc = This is the hex for the MAJOR number (188) of the SCSI character device
  • 1f = This is the hex for the MAJOR number (31) of the SCSI block device

The remaining numbers (051000) correspond to the MINOR nunmber for the device in hex.


  • 05 = First pair of MINOR in hex. Hex 05 = Decimal 05 <-Controller number


  • 10 = Third number of MINOR in hex. Hex 10 = Decimal 16 <- Target number


  • 00 = Fourth number of MINOR in hex. Hex 00 = Decimal 0 <- Disk number

A quick way to find out the dsf that belongs to a LBOLT code is to drop the MAJOR number from the LBOLT error and search with the "ll" command the disks device special files.


# ll /dev/*dsk/* | grep 051000
brw-r-----   1 bin        sys         31 0x051000 Jul 25  2006 /dev/dsk/c5t16d0
crw-r-----   1 bin        sys        188 0x051000 Jul 25  2006 /dev/rdsk/c5t16d0