Please correct errors!
MUG
Backing Up to an External Disk Drive
Dan Crutcher & attendees
September 26, 2006
Notes plus some ideas original & not mentioned at the meeting.
1. Laptops get stolen, so back them up often. You
can prevent most thieves from reading your stuff
by setting the operating system NOT to
automatically log you in when you turn the
computer on. See: System Preferences/ Security/
Automatic Log-in. When you set computer so, the
turner-oner is presented with two blanks, one for
the user name and the other for the password, and
no clues about either.
2. Uninteruptable Power Supply: i.e. a battery
between your computer and the wall outlet keeps
your computer from stopping in the middle of
critical tasks, and may protect it from power
surges.
3. But, during thunderstorms, disconnect your
computer from power, cable and telefone lines
anyway.
4. Similarly, why keep your back-up HD connected when it's not backing up.
5. You need not only a back-up, but an off-site
back-up, so when the house burns down...
6. So your hard disk fails. No sweat. You attach
your external HD. Then the same problem that
fried the first HD fries the second. What now?
Consider having three back-ups, with one at home
and one away and one in transit or connected to
your computer. Rotate them; overwrite the oldest
with the new.
7. Consider encrypting your back-ups.
BACK-UP WHAT??
Most programs that make copies, including Mac OS
X, will not copy all files. Some files are
protected by the system, or by the authors to
prevent unauthorized duplication. If you buy an
external HD and copy your internal HD onto it,
likely you will NOT be able to boot from the
external drive. This may relate to "permissions".
You can change permissions on any file by hitting
[command] [i] and checking boxes for read only,
or read and write, or whatever, but DON'T DO IT.
Doing so may really mess up your computer. If you
feel you must, make a copy of the file to be
copied. Move it to the desktop. Change it's
permissions. Copy it as desired, then delete it.
That said, those files don't change often, and need not be backed up weekly.
"Hot" (frequently changing) files are mostly data
files which can be easily copied. So, many
persons just back-up their Home folder: USERS/
YourUserName. That typically will protect your
pictures, documents, music & movies, but not your
programs, settings, preferences, etc., and does
not make a bootable back-up.
BACK-UP TO WHERE?
.Mac includes some storage space, but many fewer
gb than your HD, and backing up over the internet
is _s_l_o_w_, altho if you do it while asleep,
who cares. Some back-up their email daily, or
most precious files only.
CD's make a non-magnetic back-up, but you must
sit next to the computer and put a new one in
every 20+/- minutes. When you're filling 20 CDs,
13g+/-, that's a long time to sit by the
computer. CDs do not cost much, but cannot be
re-used, so you must keep buying more. I have a
back-up of over 350 CDs. (see 3. below). But, not
being able to re-use CDs also means that when you
attempt to restore from them, you do not risk
erasing them (as you do with magnetic media).
Re-writable CDs are not reliable; do not use them.
DVDs hold something like 10x as much as CDs, so
you need not sit by the computer changing them
every 20 minutes, but writing on them takes
longer. If you leave your computer backing up to
a DVD and go to bed, who cares whether it's fast
or slow. Like CDs, DVDs do not cost much, but
cannot be re-used. You must keep buying more. Not
being able to re-use DVDs also means that when
you attempt to restore from them, you do not risk
erasing them (as you do with magnetic media).
EXPECT soon products that will hold much more than DVDs, e.g. BlueRay.
TAPE drives are expensive and temperamental, and
intended for backing up many computers over a
network. Retrospect, qv, was written to do this.
EXTERNAL HARD DRIVEs now cost about 2gb/$1, and
unlike CDs & DVDs can be reliably erased &
re-used. Newer Macs use Firewire. PCs mostly use
USB2. You can buy HD's with USB2, or for $10
more, with Firewire, or both. If you plan to use
the HD with both PCs and Macs, buy a HD with
both. Any HD is capable of writing data faster
than CDs & DVDs. All in all, an external HD seems
the quickest, easiest, cheapest solution. NB:
USB, which Macs have, (not USB2) is _s_l_o_w_ and
UNSUITABLE for backing up gigabytes. [Firewire
box + parallel ATA]
BACKING-UP HOW?
1. Start by backing up everything, making a
simple "mirror image" of your current boot disk.
Note: many programs cannot make a bootable copy,
even tho they look as if they're backing up
everything.
Most then switch to
2. INCREMENTAL back-ups copy only files that have
changed since the last back-up, which is
certainly cheaper and faster than copying
everything every time. I can imagine two ways to
do this:
a) keep the old back-ups and add the
newer editions, so that everything that was ever
on your computer is now available to you, even
tho you erased it from your computer a month ago.
This may not reproduce your folder structure, and
may spread files adjacent on your computer into
many different folders. This is common, perhaps
the norm, and leads to #3.
b) over-write edited old files with their
newer editions, making a "mirror image" like #1,
without having to copy everything. I'm sure some
programs do this, but I don't know which and
cannot name one.
3. Doing this builds a back-up many times larger
than the HD backed up. After a while, the
incremental files grow and get cumbersome, so
most persons REPEAT #1, then delete previous
back-ups and incremental back-ups. Then #2a make
incremental back-ups, then #3 start over.
SYNCRONIZING differs from backing up, by writing
on both HDs. It puts the newer files on either HD
on the other, over-writing any older version.
BACK-UP PROGRAMS
BACK-UP comes from Apple with a (dot)Mac
subscription, and backs up to most media (likely
not tape) and to (dot)Mac. It copies from the
internal HD, but I could not figure out how to
use it to back-up from one external HD to
another. You can schedule it to back-up any time
you want, e.g. 3:00 A.M.
CARBON COPY CLONER: donationware ($5 suggested),
can make a bootable disk image, either an "exact"
or a "sparse" copy of any bootable disk.
http://www.bombich.com/software/ccc.html
CHRONOSYNC "file & folder synchronization &
backup for Mac OS X, automatically synchronizes
files & foldrs between your laptop and desktop
volumes or schedule automatic simple backups of
important files, $30 "at
http://www.econtechnologies.com/site/index.html
was recommended, but I missed the details.
RETROSPECT, was long considered "the best," but
some up-dates have made problems. At least four
persons at the meeting "used to use" Retrospect,
but do not any more. It lets you select files to
copy (or not to copy), e.g. don't copy files
whose names contain "cache" or "trash", or files
in folders with similar names, saving time,
media, etc. After making a back-up, it will, if
asked, compare the new with the old and report
errors. Very useful. Very slow. Tape decks
require complicated drivers, because the tape
must be moving at the specified speed for writing
and reading. The tape drive may periodically have
to stop. When it does, it must rewind slightly
and get a running start, so that when the
critical spot on the tape passes the read/write
head, it does so at the right speed. Retrospect
runs tape drives as well as other media, and
costs much, as do tape drives. Tape, however, is
cheap and re-usable. Unless you're running many
computers on a network, forget it.
RETROSPECT EXPRESS does not write to tape, but
does write to other media. If it lets you select
categories of files to copy (or not), I have not
found how to do it. It will, however, compare
the new with the old and report errors. Very
useful. Very slow. Nonetheless, it's a cheap
program which allows you to make back-ups
described in both #1 and #2a above. I do not know
whether it's back-ups can be booted. available as
part of CheckIt System Performance Suite from
Allume. including SpringCleaning?, TechTool?
Platinum, Retrospect Express? "regularly $100,
but often on sale for $80
SILVER_KEEPER, free from LaCie at ?
silverkeeper.com, lets you schedule total or
incremental backups to any HD, & presumably CDs,
DVDs. http://www.lacie.com/silverkeeper/
SUPER-DUPER: shareware costing about $27.95, lets
you schedule total bootable backups, or
incremental backups. Recommended by a user.
http://www.shirt-pocket.com/SuperDuper/SuperDuperDescription.html
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