Maine Antique Digest April 2015

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Maine Antique Digest, April 2015 17-A
Computer Column #316
DATA DISPOSAL,
BACKUP POWER, AND
MOBILE WEB SITES
by John P. Reid,
- COMPUTER COLUMN #316-
Disposing of data CDs with sen-
sitive information, Internet sur-
vival in bad weather, and adapt-
ing a Web site for mobile devices will be
covered.
Shred CDs and DVDs
While purging old computer records,
we found recordable CDs and DVDs with
sensitive data—old federal tax records,
password lists, and financial records.
Even though rewritable CDs and DVDs
can be erased by computer, do not trust
this when identity thieves are about. A
way to “shred” the data is needed, but
the tough polycarbonate disks would jam
a regular paper shredder (some newer
shredders can accommodate disks).
The data stored on a CD or DVD is
just under the label on the top side of the
disk. The laser of the reader is below the
clear side. The laser beam travels through
the thickness of the clear plastic to read
the data under the label. This is true of
both computer-written recordable and
rewritable disks as well as mechanically
stamped commercial music and data
disks. On-line searches give contradic-
tory and possibly dangerous suggestions
for disposal.
Bad suggestion number one is breaking
the disk. This is nearly impossible with
bare hands, so we tried holding two sides
with Vise-Grip brand pliers and bend-
ing. The disk shattered with a loud bang.
Sharp plastic shards flew all over the
room. Wrapping in a towel was clumsy.
Bad suggestion number two is zapping
the disk in a microwave oven for a brief
but seldom specified time. This sounds
clever, but on-line comments say it leaves
a bad smell, makes the oven unfit for
food, can damage the oven’s electronics,
and does not always destroy the data.
There also were bad suggestions to
cloud the bottom surface or remove the
top surface with acetone. We tried ace-
tone, lacquer thinner, and paint stripper
(all nasty stuff) with little effect.
The suggestion that worked was ordi-
nary sandpaper. Sanding away all or part
of the label to the center hole makes a CD
or DVD unreadable with a minute’s work.
A power hand sander might be useful for
a large number of disks. Do the job out-
doors or wear a dust mask. The recordable
surface includes organic chemicals and a
microscopic protective layer of gold or
silver, the dust of which may not be good
to breathe or eat.
Bad Weather
We have just been through another
winter. This is a good time to get ready
for summer storms and next winter’s
weather. Many antiquers have a backup,
standby, or uninterruptible power supply
for their desktop computers. These back-
ups store standby power in a large internal
battery. Costing $100 and up, they keep a
computer running for half an hour, more
or less, during a power outage. That is
perhaps enough time to check the e-mail,
complete a shop sale, bid at an on-line
auction, or keep up to date on a social
network.
Of course, these things can be done on a
tablet or smartphone until the battery runs
down. Keeping a second backup power
supply for charging mobile devices may
pay off. A smaller, less expensive unit can
charge several mobile devices for days.
Do not mention it to the neighbors unless
you want them tramping in with muddy
boots, dead cell phone in hand, during the
next power outage.
Incidentally, the internal storage batter-
ies of backup power supplies need to be
replaced every few years. The maker will
often send a reminder if the purchase is
registered.
Cell phones that use the cell phone net-
work for data will do fine during a power
outage. Tablets usually need Wi-Fi for
data, including e-mail. Those who get
Wi-Fi from the phone company by voice
or fiberoptic line can buy a slightly larger
second backup power supply to run the
router or gateway box while charging
phones. Turning it off while not in use
may enable connections for days. Those
who get Wi-Fi from cable television or
dish antenna should talk to the supplier
about maintaining an Internet connection
during an outage.
Of course, if the phone, cable, and
fiberoptic lines all come crashing down
in a storm, the usual Wi-Fi sources will
not work. There is one possible solution
called “tethering,” which depends only
on working cell phone towers. Cell tow-
ers are tough. Tethering allows some
cell phones to pick up data from the cell
phone network and rebroadcast it as a
local Wi-Fi hotspot. The Wi-Fi can serve
Android, iOS, BlackBerry, Windows,
Macintosh, and many other devices. Teth-
ering is not possible with all cell phones,
especially older ones. Some cell phone
networks charge extra for using tethering,
and others disallow it. All charge for the
data at their usual rate.
Setting up tethering is complicated and
should be done well in advance of the need.
There is a good introduction on Wikipedia
).
Avoid the tethering methods that require
“rooting” or “jail breaking” the phones.
Web Sites for Mobile
Column #282 in the Maine Antique
Digest for June 2012 described making
my 150-page Web site for collectors of
old and rare Delaware books accessible
to smartphones and small tablets. The
human viewer was asked to tell the site
that a mobile device was in use. That
switched the viewer to a duplicate site that
used a dif-
ferent page
layout. However, it is a nuisance to have
to update two pages when one change was
made. An alternative is for the Web page
to try to detect what browser is in use and
format accordingly. This is fraught with
pitfalls.
The new HTML5 Web language and
its CSS format language mentioned last
month have simplified things. It is now
possible for the Web page to ask the
receiving device for its screen dimensions
without bothering the human viewer. The
mechanism is called a “media query” and
is inserted in the Web page’s style defini-
tions without bothering the viewer.
CSS stands for Cascading Style Sheet.
There is a pecking order for style com-
mands for elements such as titles, para-
graphs, pictures, boxes, and the like. Each
element has a built-in default style that can
be overridden by a style command in a sep-
arate style file or in the Web page itself. If
there are conflicting commands in the style
file or Web page, the last one wins.
The usual pattern is to define styles for
Web pages suitable for display on a desk-
top computer. Then, insert a media query.
If the query says the device’s screen is too
small, new styles are defined. Being last
in the cascade, this styling will win out
during this connection.
For most Web pages, the styles for
handheld devices should not use multi-
ple columns. Elements should follow one
another vertically in a single column to
fit the screen. Clickable links should be
displayed as boxes to fit human fingers.
Picture sizes may need to be reduced, and
tables kept simple.
If you hire out your Web design or use
the apocryphal teenage whiz, consult the
designer. If you manage your own Web site,
go to the w3schools example of a media
query
pr_mediaquery.asp). Click the “Try it your-
self” button to see the story. There is more
help in HTML5: The Missing Manual, 2nd
edition, by Matthew MacDonald. Check the
subjects of media query, viewport, and fluid
layout in the index.
Sanding away all or part of the label
to the center hole makes a CD or DVD
unreadable by identity thieves.
Peggy McClard
Americana & Folk Art
By Appointment &
On the Internet
Houston, Texas
(713) 880-2572
E-mail
Attributed to Susannah Paine
(1792-1862)
American Oil on Wood Panel
Period Gilt Frames 39" x 34"