pseudo: [ID 129642 kern.info] pseudo-device: vol0

Hi I have a system that gave me some messages on bootup that I was not used to seeing:
pseudo: [ID 129642 kern.info] pseudo-device: vol0
genunix: [ID 936769 kern.info] vol0 is /pseudo/vol@0
these came with these:
Feb 13 17:42:17 system1 eri: [ID 517527 kern.info] SUNW,eri0 : 100 Mbps full duplex link up
Feb 13 17:42:21 system1sendmail[197]: [ID 702911 mail.crit] My unqualified host name (system1) unknown; sleeping for retry
Feb 13 17:43:21 system1 sendmail[197]: [ID 702911 mail.alert] unable to qualify my own domain name (system1) -- using short name
Feb 13 17:43:24 system1 pseudo: [ID 129642 kern.info] pseudo-device: vol0
Feb 13 17:43:24 system1 genunix: [ID 936769 kern.info] vol0 is /pseudo/vol@0
Feb 13 17:43:25 system1 eri: [ID 517527 kern.info] SUNW,eri0 : No response from Ethernet network : Link down -- cable problem?
I know what the sendamil messages are, but the pseudo mesages I don't understand.
Can you help me?