PCUGR Shareware SIG -
April 28, 2001
Rawls Frazier,
Facilitator
rfrazier
This month,
six of us listened to some "alternative" (digital
alternative, that is) music, did a little
"educational" exploring on the net, looked at some
innovatative digital art, took a game side trip, explored how
to really erase a file or disk and, finally, found out how to
change the "skin" of Internet Explorer.
The music
side of the meeting looked at a site that featured Real Audio
files of pop music from the 50s, 60s and 70s, in contrast to
the more widely discussed (notorious?) MP3 format. The sound
quality was definitely not CD, but most everyone agreed it
was OK and the files were certainly small enough. We also
discussed how to generate a playlist for the Real Audio basic
player and, as is typical in our meetings, that led us into a
discussion of file extensions. But, before we go there,
here's the music site:
http://www.spnt.com/~bettwitt/50s.htm
The file
extension discussion came up because the playlist file we had
created had the extension .PLS, and the icon for the file,
rather than being a Real Audio icon, happened to be for
another music player, Winamp. What this means, of course, is
that a file with the .PLS extension is associated with Winamp
and, when the .PLS file is double clicked, Winamp attempts tothe file and play the contents. Only in this specific
case, the playlist was full of Real Audio files and Winamp
was clueless on what to do with the list.
To further
drive home the point that a file association is governed by
the file extension and not the content of the file, we took
an ordinary text file (with a .TXT extension) and renamed it
to a .JPG extension and vice versa. Icon's changed per the
extensions as did the program that would attempt tothe
file. Naturally, this raised futher questions, particularly
with regard to unassociated files and how to go about
figuring what program to associate the file with.
Especially confusing was that mysterious " With" dialog box pops up when an unassociated file is
double clicked in Windows Explorer. You know, the one that
looks like this:
One strategy
offered was to select a promising candidate from the dialog
box, making sure that the "Always use this program tothis file" check box was unchecked.
That way, if the selected program wasn't correct, no harm was
done since no permanent association had been made. Of course,
if the selection was good, you just needed to double click
the file again and remake the program selection, this time
leaving the check box checked.
So what do
you do if you accidentally associate a file with the wrong
program. That's easy enough to reverse, too, if you know the
magic incantations. That is, in Windows Explorer, click View
| Folder Options... , click the "File Types" tab,
then find the type in the registered file types list and,
finally, click the "Remove" button.
Another
strategy for determining what program to associate with a
particular file type was to "peek" into the file
for clues about it's type. In this vein, we looked using the
Send To menu to "send" a file to a particular
application - in this case an editor (like Notepad), general
file viewer (like the old DOS program List) or a graphics
file viewer like Irfanview.
Also
recommended, especially for graphics and music files, was to
simplythe program you prefer to use and see if it
doesn't have an option to associate itself with the file
extension in question. We looked at the cooresponding dialog
box in Irfanview as an example.
Finally, yet
another way was to look up a list of file extensions and the
corresponding file type or application that creates/uses the
type. Here are some places to get this info:
The
cknow.com File
Extensions
(http://tomsmart.com/tempext.htm) list is really good, but
currently at a temporary location which may change - check
the cknow.com home
(http://www.cknow.com/) for up-to-date information.
(Incidentally, cknow = Computer Knowledge, a nice site for
general computer information and some tutorials.)
File
extensions on Webopedia (http://www.webopedia.com/quick_ref/fileextensions.html)
ExtSearch (http://extsearch.com/)
While we
were at it, we also looked the famous and fun "Jargon
File" - a great resouce for all those obscure terms and
geek-speak that inevitable come out when discussing PCs:
http://murrow.journalism.wisc.edu/jargon/jargon.html
Continuing
on with our educational vein, we took a look at Learnfree.com
(http://www.learnfree.com/) a site that features
"VidBooks" which are short training videos on a
variety of topics.
For
something more computer oriented, we went to FreeSkills
(http://www.freeskills.com - this has morphed to
Beginners.co.uk - http://www.beginners.co.uk/). This site
features both on-line courses and on-line tutorials. The
emphasis is toward programming, but there are enough other
computer related topics to make it generally interesting. For
example, there is a two part course on Windows 98. The
beginners course is 98 (!) pages, complete with exercises to
test your skills.
We then
looked at mysportsguru.com, a site that
features expert advice from "gurus" on various
sports. Since there were some golfers in the group, we took a
look at the golf advice, learning why all our shots were
slicing (it's those darn weak grips).
Last stop
was Project Guttenberg, a venerable
location where famous literature in the public domain is
being placed on the Internet for all to benefit. Of
particular note is the possibility that you could be
a contributor - volunteer your time to help input a book. A
nice way to read a book and share with others at the same
time!
Next up was
a look at the New
Digital Paintings of Peter Stanick, which
featured an innovative use of Shockwave Flash technology to
create both interesting art and an interesting presentation
of it.
Then, for a
little break, we went to, of all places, the Baywatch site
(yes that over-the-top TV series austensibly about lifeguards
- yeah, right). OK, truth be told, we skipped all the normal
(?) stuff and went only to the online
game
- a new version of the classic Asteroids game, only this time
the spaceship was a motor boat, the asteroids were menacing
beach balls and, to get extra points or power, the you needed
to save drowning swimmers. Lots of fun. (p.s., you need Java
enabled in your browser for this game to work.)
While we
were in fun mode, we also took a look at a cute Energizer Bunny
screensaver.
Moving on to
things more practical, we looked at what happens when a file
(or directory) gets erased and how to make sure a file is
truly gone.
Directory Snoop
Our
1st step was to get a utility that let us look at directory
entries and the disk clusters associated with the file.
Directory Snoop was designed expressely for this purpose.
With it, you can look at raw directory entries and raw
clusters. When started, the program displays an Explorer like
tree of folders on the left side and all the directory
information for the current directory on the right side,
including all the date info and intial cluster infomation.
Both long and 8.3 filenames are shown in all FAT formats
(sorry NT HPFS is not supported). After navigating to the
desired directory, double clicking the filename up a
new window which now lists disk clusters on the left and the
file contents in hex and ASCII on the right.
To
demonstrate using this program to check how completely a file
was erased, we first looked at an ordinary text file, noting
it's filename and the contents - including the stuff in the
last file cluster that didn't belong to the file proper. Next
we erased the file in Explorer - not by sending it to the
Recycle Bin, but by holding the shift key down and pressing
Delete. At this point there is no file displayed in Explorer
and it is not to be found in the Recycle Bin. With Directory
Snoop, however, we could demonstrate that the file was
actually still on the hard disk. In the directory, only the
first character of the filename had been changed (displayed
as a "?" mark by Directory Snoop) and the cluster
associated with this "erased" name was still there.
Double clicking on this "erased" name brought up
the data in that cluster as well. Some erasure, indeed! In
fact, Directory Snoop could create a blank file that you
could manually add clusters to and reconstruct the file - a
sort of manual unerase. (Except in the most desperate
circumstances, this is not recommended. Commercial unerase
programs like Norton's Unerase do the work automatically with
good results and are much easier to use.) Anyway, a file
erased in this way is not really gone. The space it used to
use is marked available by the operating system and, until
written over, can be recovered.
For our
exploring and review, we used Directory Snoop, version 2.1,
the last freeware version. Current versions are shareware
($30) and can be found at:
http://www.briggsoft.com/dsnoop.htm
So, what if
we really want to erase the file? The trick is to overwrite
the actual data and to replace the filenames. With a utility
like Directory Snoop, we can check to see how well a utility
that purports to do that works. We looked a two such file
"wiper" programs to demonstrate the difference.
SDelete
This
free command line program can delete individual files, groups
of files via filename wildcards and directories (including
recursing down through the subdirectories). For the really
paranoid, multiple overwrite passes can be specified to help
thwart even the most sophisticated file recovery techniques.
Another feature was an option to "erase" free space
on the disk - areas marked as available by the operating
system but could still have fragments of file information. We
did our test as before and verified with Directory Snoop that
the filename had been modified so it wasn't so obvious what
was there before. However, the initial cluster connected to
the file remained and we could look at the information in it.
We did find the information to be overwritten, but only in
the space allocated to the file. Probably good enough, but
our next file wiper did a more thorough job. One other very
good feature of this program, however, was that the source
code was available. This meant one could see exactly how it
worked and modify it if more capability was needed.
http://www.sysinternals.com
Eraser
This is a GUI program which can erase files and folders or
clean the disk free space - on demand, at scheduled times
(for example, making a clean up sweep at night), via the
right click Explorer menu (a.k.a., as a Shell Extension) and
from the command line. In ordinary interactive use (e.g.,
"On-demand"), one creates a task in a dialog box,
choosing whether to clean disk free space, erase a folder
(and, optionally, its subfolders) or a file (wildcards
allowed and the program can look for matching files in
subfolders). Once the task is created, the
"On-demand" button is pressed to erase the files at
once or the Scheduler button is pressed to schedule a
deferred erasure. By default, the program implements the
"Gutmann" method, which is a very sophisticated
overwriting protocol with a set of special bit patterns to
insure a secure erasure. Two other faster, but less secure
overwrite methods are supported as well. Also by default, the
file name is removed and the unallocated space in the last
cluster (so called "cluster tip") is erased.
In our
testing, we found this program to be exceptionally thorough.
Not only was the data overwritten with the special bit
pattern, the filename was truncated to one random character
and the initial cluster allocation was removed. There was
essentially no way to associate the directory entry with any
particular cluster.
To top off
this fine program, it came with an excellent help file. The
program was fully explained, including the locations of all
the installed files. There is a short tutorial, a great
explanation of what happens when files are erased, how the
various erasure methods implemented in the program work, and
even the complete text of P. Guttman's "Secure Deletion
of Data from Magnetic and Solid-State Memory".
The program
is free for use, however the author, Sami Tolvanen,
encourages a donation ($10 suggested). Source code is also
available.
http://www.tolvanen.com/eraser/
For those
who want to know more about secure file deletion and a review
of file wipers, check out this link:
http://www.fortunecity.com/skyscraper/true/882/Comparison_Shredders.htm
The last
item on our list was a disk wiper. This, called simply enough
Wipe, is a small (19K) DOS command line program that you put
on a floppy. To use it, boot the computer with a bootable
floppy, issue the wipe command with a command line parameter
to specify which physical hard drive (0 through 7) to erase
and let it rip. This program doesn't know anything about
partitions or file systems. It simply writes zeros (00h) to EVERY
sector of the disk. Works with IDE and SCSI disks up to 8GB
in size. Free from IBM.
http://www.storage.ibm.com/techsup/hddtech/welcome.htm
Internet
Explorer Personalizer
Tired of the same old boring look of IE? With freeware IE
Personalizer you can change the name that appears in the
title bar, the spinning logo at the top right corner,
personalize the toolbar with the graphic or photo of your
choice and more. If you don't like what you see, you can
revert back to the default setup (but you may have to reboot
to see it take effect).
http://accesscodes.hypermart.net/
Hotbar
Another approach to customizing IE is to use the web based
Hotbar application. First step is to download and install
their software (free) and then, from the Hotbar website,
choose from 50,000 skins to change your browser look.
Installed at the same time is their custom toolbar (hence the
name Hotbar). Great selection of skins, but you may or may
not care for the other customizations. Undoing things
requires uninstalling the hotbar application.
http://www.hotbar.com
A BIG thanks
to Ben Pietsch for faithfully bringing the projector to these
meetings and to Bernie Stepan for the meeting room and
Internet connection at RE/MAX Marina, Petaluma.
RE/MAX Marina
775 Baywood Dr. #100
Petaluma, CA
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