Do I need to re-create /etc/fstab?

[winger9]

Hi

Could you fine chaps help me please.

Got Knoppix distro 7.0.2, kernel release 3.3.7, on hard disk, on Acer Aspire
5755G laptop.

1. Here's a SUMMARY of what I'd like to find out thanks:

a) I did a umount of a USB memory stick, which caused a crash. I think I need to
create a new /etc/fstab because the one I've got, now has a remnant entry in it
which I don't think should be there, and is causing a problem. My present
/etc/fstab is:

# DEFAULT BASE FSTAB, UNCONFIGURED
proc /proc proc noauto 0 0
sysfs /sys sysfs noauto 0 0
/dev/sda6 / reiserfs relatime 0 0
/dev/sda5 none swap defaults 0 0
# Added by KNOPPIX
noauto,users,exec 0 0
# Added by KNOPPIX
/dev/sdb1 /media/sdb1 vfat
noauto,users,exec,umask=000,shortname=winnt,uid=kn oppix,gid=knoppix 0 0
# Added by KNOPPIX
/dev/sr0 /media/sr0 auto noauto,users,exec 0 0
# Added by KNOPPIX
/dev/sda2 /media/sda2 ntfs noauto,users,exec,umask=000,uid=knoppix,gid=knoppi x 0
0
# Added by KNOPPIX
/dev/sda1 /media/sda1 ntfs noauto,users,exec,umask=000,uid=knoppix,gid=knoppi x 0
0
# Added by KNOPPIX
/dev/sda3 /media/sda3 ntfs noauto,users,exec,umask=000,uid=knoppix,gid=knoppi x 0
0

b) The lines which I don't think should be there are:

# Added by KNOPPIX
noauto,users,exec 0 0
# Added by KNOPPIX
/dev/sdb1 /media/sdb1 vfat
noauto,users,exec,umask=000,shortname=winnt,uid=kn oppix,gid=knoppix 0 0

c) SO (*** MAIN QUESTIONS ***):

(i) AM I RIGHT ABOUT "b)"?
(ii) DO I JUST NEED TO RE-CREATE /etc/fstab, AND IF SO HOW DO I DO THAT?
(iii) BUT I THINK /etc/fstab IS GETTING THE INFO FOR LINE "/dev/sdb1 /media/sdb1
vfat ..." FROM A FILE SOMEWHERE ON THE SYSTEM, BECAUSE THERE IS *NO* MEMORY
STICK PRESENTLY IN ANY USB SLOT SINCE BOOT-UP (WHICH IS WHAT WOULD NORMALLY
CAUSE THAT LINE TO BE THERE I BELIEVE). IF IT *IS* GETTING THE INFO FROM A
FILE, HOW DO I FIX THAT PLEASE?
(iv) I THINK THIS WHOLE ISSUE MAY HAVE CAUSED 15 NEW ENTRIES TO APPEAR IN /dev,
IE /dev/sdb1 to sdb15. WHY IS THIS? AND DOES IT MATTER? (See 6.)


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Full Details:

2. a) I recently wiped (intentionally) the entire contents of a USB memory stick
using the following method:

b) Plugged 2Gb memory stick into a USB slot. I let the system detect and mount
it. "mount" returned the following info:

/dev/sdb1 on /media/sdb1 type reiserfs (rw,nosuid,nodev,relatime)

c) In a terminal I ran

dd if=/dev/zero of=/dev/sdb1

This writes all zeros to the entire memory stick.

d) I unmounted the stick with I believe

umount /dev/sdb1

But this caused the entire system to hang. Not even CTRL+ALT+BACKSPACE or
CTRL+ALT+DEL could make it respond. I realised that there was NO filesystem
anymore on the stick to be actually unmounted.

3. When I rebooted, in pcmanfm filemanager, at the left was a device icon
labelled "sdb1", but there was NO memory stick plugged in any USB socket.
"mount" gave the following info (which doesn't show "sdb1"):

/dev/root on / type reiserfs (rw,relatime)
proc on /proc type proc (rw,relatime)
sysfs on /sys type sysfs (rw,relatime)
usbfs on /proc/bus/usb type usbfs (rw,relatime)
tmpfs on /tmp type tmpfs (rw,relatime,size=2097152k)
udev on /dev type tmpfs (rw,relatime,size=20480k)
tmpfs on /dev/shm type tmpfs (rw,relatime,size=2097152k)
devpts on /dev/pts type devpts (rw,relatime,mode=1777)

4. Then I looked in /etc/fstab, which is shown at 1.a). I don't think the lines
that I've shown at 1.b) should be in /etc/fstab. In particular, it looks as
though it is the entry "/dev/sdb1 /media/sdb1 vfat ..." that is causing pcmanfm
to think that such a device is present. But there is no memory stick (or
anything else) plugged into any USB slot.

5. So the umount that I did at 2.d) (and the crash) seems to have caused this
situation.

6. Also, I've noticed that in /dev there are 15 files (block devices) called
/dev/sdb1 to sdb15. I seem to think that they weren't there before. In fact
there seem to be a lot of other entries in /dev that I don't recall being there
before, such as /dev/sdg1 to sdg15. Does this matter, and is it linked to the
umount crash?

7. I would be everso grateful if you could suggest possible answers to my
questions at 1.c).

Many thanks. John

[Werner P. Schulz]

You can delete all the entries "# Added by KNOPPIX" and reboot. After reboot, Knoppix will recollect proper entries for '/etc/fstab'.