Hi Peter:
From the CD, this time I only installed the English language. (Previous I
installed all languages).
Damn! I needed you to install "All Languages"
And your OS must be set
to "English" when you do that, otherwise we have had reports in the past
that you can get a bad installation.
Question 1.
In Excel Preferences under Authoring should there also be 'Proofing Tools'?
(as there is in Word). My Excel has no Proofing Tools! no Spelling and Grammar
icon!
In Excel, there should NOT be an "Authoring" tab in its Preferences, no
Spelling and Grammar preferences at all. Excel uses the Microsoft Office
proofing tools, which are common to the whole suite.
Question 2.
What is the difference between Empty Trash and Empty Trash Securely? (apart
from the difference between the time taken to perform each).
On a Mac, the "Delete" command is simply a "rename" operation. It renames
the file so that it appears to be "In the Trash". The file hasn't actually
moved anywhere.
The "Empty Trash" command changes the first character of the File Name in
the disk file table to mark the file as "available for overwriting". That
enables the system to use the disk space occupied by that file when it finds
something that will fit there. The data still hasn't gone anywhere: the
system just hung a "For Sale" sign out the front. Actual overwriting of the
file my occur weeks or years later, when the system gets around to needing
the space.
Until the overwrite happens, with advanced tools and knowledge and a fair
bit of patience, you could conceivably reconstruct the deleted file. There
is no guarantee that you would get it all back, and you would get it in a
random order. Most files are on the disk in more than one "block". If the
file is marked as "free" the system will use whichever of its blocks are
closest to the disk head when it needs one. So one or more of the blocks
may be overwritten almost immediately, and some may never get overwritten.
A skilled person may be able to get some of it back. You would need to be
very good to re-assemble the resulting binary soup into an Excel file. But
it can be done, and the security forces of various nation states have the
technology to do so, if you attract their attention. The effort involved is
so high that most normal criminals would just give up.
The "Secure Empty Trash" command physically re-writes the individual data
bits in every byte of every block of the deleted file. The Finder actually
runs the Unix "srm" command on the file to do this.
The command srm offers the ability to overwrite each bit in the file 1, 7 or
35 times. Finder uses the middle one, seven times. This method follows the
U.S. Department of Defense standard for the sanitization of magnetic media
in ŒDoD 5220- 22-M: National Security Program Operating Manual'.
First it rewrites every bit of the file to its opposite: If it was a 0, it
becomes a 1, or it was a 1, it becomes a zero. Then it writes them all to
1. Then all to 0. Then it writes each bit four more times using patterns
generated by a random number generator.
After you do this, the data is really "gone". There are rumours that it is
possible to reconstruct the data after such treatment. But as far as I
know, if anyone has actually succeeded in doing so, they have never admitted
it (because they work for some government agency that spells its name in all
capital letters...)
If I may give you just a gentle hint: While you are off-base five hours by
jet plane from the nearest Apple shop, you are in a very bad place to be
playing around with Secure Empty Trash. I strongly suggest that you do not
use that command again until the day before you sell the machine, when you
are utterly certain that you do not want any of the data on it...
Running advanced security routines on your machine while connected to a less
than reliable power supply in far-flung outer Mongolia is thrill-seeking on
a scale that would keep me awake at night. One little blip in the power,
and your entire hard disk could be unreadable. Forever.
You know how they told you in school "Don't touch that red button!"? Well,
DON'T
Hope this helps
--
This email is my business email -- Please do not email me about forum
matters unless you intend to pay!
John McGhie, Microsoft MVP (Word, Mac Word), Consultant Technical Writer,
McGhie Information Engineering Pty Ltd
Sydney, Australia. | Ph: +61 (0)4 1209 1410
+61 4 1209 1410, mailto:
[email protected]