Sky calendar 2006
Tammy Plotner created a sky calendar with the most remakable things in the night sky for 2006. You can download the PDF file on the site of Universe Today. Stunningly beautiful !
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Tammy Plotner created a sky calendar with the most remakable things in the night sky for 2006. You can download the PDF file on the site of Universe Today. Stunningly beautiful !
# w
2:51pm up 852 day(s), 18:35, 2 users, load average: 0.77, 0.61, 0.33
# init 0
I guess this is a record. I was afraid the server would reboot with fsck errors, but it came back online without a glitch. This is a Netra server running Solaris 7. My heart bleeds every time I must do this, but patching is a necessary thing...
Aaarghh ! The Aargh Page is a visual representation of the relative frequencies of aarghh. The number of ways one can write aaarghhh is aarghuable, off course. Would there be other words written like that ? Hmmmm...
Het wordt ondertussen aftellen naar het huwelijksfeest. Nog een kleine maand te gaan, en ondertussen is zowat alles geregeld. De misboekjes zijn gekopieerd, en het zelf plooien en nieten van zo'n 60 boekjes is toch wat meer werk als gedacht. Ook het noteren van wie nu komt naar de receptie en naar het avondfeest is een dagelijkse bezigheid geworden.
Net terug ook van de Lovers4ever trouwbeurs in de Mechelse Nekkerhal; de bedoeling was om wat meer adressen te krijgen voor de trouwringen, en de huwelijksreis, maar de beurs zelf was door zijn kleine opzet een beetje een ontgoocheling. Allee, we hebben toch een afspraak met een goudsmid deze week, maar qua trouwringen is het toch lastig kiezen. Niet moeilijk, als je weet dat de meeste trouwringen zo'n lelijk bladnerfmotief dragen tegenwoordig.
Do you know that deleting a file really doesn't delete the file content on your disk ? In Unix, a file delete (rm) unlinks the inode, but doesn't actually zero-out the data blocks associated with the file. How can you really destroy the contents of a file? What if you're doing a rm -r of hundreds of files? Deleting files on disk-level can be very interesting if you have highly sensitive data on your disks. Many people who are using Unix know GNU shred, but the docs state "that shred relies on a very important assumption: that the filesystem overwrites data in place." This is the traditional way to do things, but many modern filesystem designs [such as Solaris' UFS] do not satisfy this assumption. ZFS is even trickier, as it uses Copy On Write, so overwriting data actually never happens !
I'll present some ways of deleting data on your disks.
Overwrite raw device with something such as:
dd if=/dev/zero of=/dev/rdsk/c#t#d#s#
a. Remove all files of interest.
This will leave disk blocks on the free list which may contain some data that you'd rather not see leave your custody.
b. AS ROOT, run this on each filesystem where the files from (a) used to live:
yes > junk
and let it run until the filesystem is completely full. Why "as root"? Because the last 10% of the actual free space on each filesystem is reserved for root. (See "tunefs".) This allows root user to manipulate the filesystem and recover from some space exhaustion problems -- even when the filesystem appears to be "full" from the viewpoint of end users.
c. Of course, "yes > junk" is rather simple-minded and relatively slow - something that did block writes would run a heck of a lot faster. So for example, you might want to use something a notch more sophisticated, along these general lines:
touch junk
while (1)
dd if=/some/big/file/full/of/crud bs=20k >> junk
end
to do 20K writes. This should run considerably faster, and of course you could also do your variant of this with shell, perl, C, python, whatever you wish. The general idea though, is that you want to force the system to allocate every (currently) free block so that you can scribble on it. This should put recovery of the data beyond the ability of most people.