Persistent green messages interrupting console on NetBSD 6.99.19 i386

["Thomas Mueller" <mueller6724%bellsouth.net@localhost>]

I keep getting green messages on the console, on a black background and white 
or light gray regular text, making it impossible to do anything useful.

It is practically impossible to use vi editor because of all that green 
garbage, like


May  6 23:18:38  /netbsd: sd0(umass0:0:0:0):  Check Condition on CDB: 0x35 00 
00 00 00 00 00 00 00 00
May  6 23:18:38  /netbsd:    SENSE KEY:  Vendor Unique
May  6 23:18:38  /netbsd:     ASC/ASCQ:  Logical Unit Not Ready, Cause Not 
Reportable
May  6 23:18:38  /netbsd: 
May  6 23:18:38  /netbsd: sd0(umass0:0:0:0):  Check Condition on CDB: 0x35 00 
00 00 00 00 00 00 00 00
May  6 23:18:38  /netbsd:    SENSE KEY:  Vendor Unique
May  6 23:18:38  /netbsd:     ASC/ASCQ:  Logical Unit Not Ready, Cause Not 
Reportable
May  6 23:18:38  /netbsd: 
May  6 23:18:41  /netbsd: sd0(umass0:0:0:0):  Check Condition on CDB: 0x35 00 
00 00 00 00 00 00 00 00
May  6 23:18:41  /netbsd:    SENSE KEY:  Vendor Unique
May  6 23:18:41  /netbsd:     ASC/ASCQ:  Logical Unit Not Ready, Cause Not 
Reportable
May  6 23:18:41  /netbsd: 
May  6 23:18:41  /netbsd: sd0(umass0:0:0:0):  Check Condition on CDB: 0x35 00 
00 00 00 00 00 00 00 00
May  6 23:18:41  /netbsd:    SENSE KEY:  Vendor Unique
May  6 23:18:41  /netbsd:     ASC/ASCQ:  Logical Unit Not Ready, Cause Not 
Reportable
May  6 23:18:41  /netbsd: 

All this is copied from /var/log/messages; the date, time, and "/netbsd:" did 
not appear in the green spew.

No graphical interface, and no way I could do anything with pkgsrc with all 
that interference.

Conceivably I could cross-compile pkgsrc modular xorg from FreeBSD 9.1_STABLE 
or another version of NetBSD, but I don't want to waste such effort on such an 
unstable system.

This also brings up the question, for updating the system, how would I specify, 
for build.sh, which gcc to use for cross-compiling, considering I might want to 
use a version newer, from FreeBSD ports or NetBSD pkgsrc, than what comes with 
the base NetBSD or FreeBSD system?  Would that be HOST_CC and PATH?

No immediate rush, I might wait a few months to allow more time for 
improvements, would be busy anyway with FreeBSD and Linux.

I install NetBSD to a USB stick but keep usr/src and pkgsrc on hard-drive 
partition originally used for FreeBSD 9.1_BETA1.

I might add, only one VT works; I can't go to another, even though I have 
wscons=YES in /etc/rc.conf .

CPU is Intel Sandy Bridge.

Tom