Solaris

i can bet you the Solaris isn't that clever in everything always..
Be it H/W or the OS, there are many issues. If they are so straight forward, why aren't people resolve problems themselves? Half of the time is based on experience (going through the hard way)

There is no evidence the OP is experiencing a bug or a hardware failure. On the opposite, the filesystem is reported to be mounted and he is destroying it by running fsck on it.

Looking at /etc/vfstab or /etc/mnttab wasn't the correct way to see if a filesystem was mounted. Instead, "df -k" should have been used.

The solution was due to a frantic error on my part.

# df -k
Filesystem kbytes used avail capacity Mounted on
/pci@1e,600000/ide@d/cdrom@0,0:b
178735 161584 0 100% /
/devices 0 0 0 0% /devices
ctfs 0 0 0 0% /system/contract
proc 0 0 0 0% /proc
mnttab 0 0 0 0% /etc/mnttab
swap 1966120 344 1965776 1% /etc/svc/volatile
objfs 0 0 0 0% /system/object
swap 1966328 552 1965776 1% /tmp
/tmp/dev 1966328 552 1965776 1% /dev
fd 0 0 0 0% /dev/fd
/devices/pci@1e,600000/ide@d/sd@0,0:a
2656590 2656590 0 100% /cdrom
/cdrom/Solaris_10/Tools/Boot/usr
2656590 2656590 0 100% /usr
/platform/sun4u-us3/lib/libc_psr/libc_psr_hwcap1.so.1
178735 161584 0 100% /platform/sun4u-us3/lib/libc_psr.so.1
/platform/sun4u-us3/lib/sparcv9/libc_psr/libc_psr_hwcap1.so.1
178735 161584 0 100% /platform/sun4u-us3/lib/sparcv9/libc_psr.so.1
swap 1965776 0 1965776 0% /tmp/root/var/run


# echo | format
Searching for disks...done

AVAILABLE DISK SELECTIONS:
0. c1t0d0 <SUN36G cyl 24620 alt 2 hd 27 sec 107>
/pci@1c,600000/scsi@2/sd@0,0
1. c1t1d0 <SUN36G cyl 24620 alt 2 hd 27 sec 107>
/pci@1c,600000/scsi@2/sd@1,0
Specify disk (enter its number): Specify disk (enter its number):
#

I was using drive c0t0d0s0... once I corrected it to c1t0d0s0, it worked. Thanks to everyone.