Safe, Secure and Polite Macin’ — Things You Should Practice
How to Completely Erase the Hard Disk — Tips to Avoid Data Theft When Donating a
Computer System {Even to your kids}
A
new column by Harry {doc} Babad ©
2009
As I occasionally go through my old files, including downloaded or
scanned magazine columns. I usually find, around the 20th of the
month the macC article due date, some fine archived articles many that are as
fresh as they were 3-7 years ago. The Macintosh moves on — focus areas change. We’re finally
starting to get some respect from the PC community, members of which are either
switching of dual platform using their computers. I’ve recently spent a little
time talking with friends who’ve taken the PC to Mac plunge or new users. I found they had very little concept of
how to compute responsibly, efficiently and safety. The PC users were to busy
staying alive and keeping ahead on their tasks to care. And the newbies were…
Therefore, this column.
Acknowledgements: Unless otherwise noted
I have provided the source of the material in these articles. I also found
materials in the many notes I’ve stashed for future articles, that certain
themes keep coming up, that parallel what I’ve read or practiced. In most cases I have acknowledged as
well as significantly modified the original document(s) to personalize them for
our readers. It’s called research as long as credit is given where it’s due.
Introduction
Perhaps
you have decided to forgo system upgrades and get rid of your computer system
and purchase a new one. Although focused on a newer oldie that can use OS X,
the suggestions also makes sense for a real oldie — as long as you tell
the beneficiary of your classic Macintosh its limitations. Alternatively,
you’re in a pass down mode but don’t want to spend the time clearing out your
sensitive files, obscure shareware or your highly customized software that no
one else can figure out. All of
this before your sister-in-law or teenage son, the beginning gamer,
inherits. After all, that older
but perfectly good Macintosh is still a good productivity machine for most
users and alas worth very little when sold. …And you did add a larger hard
drive, max it out on memory and kept, up to this point, all your systems
software up to date.
They Say Charity Begins
at Home — However, if you’ve decided to donate your old computer to a
charity, local group or school, it’s important to make sure your computer’s hard
drive is completely free of data.
In
the no good deed ever goes unpunished department, you need to
ensure that you don’t donate more than you planned. The last thing you want to
do is to pass on a computer containing
sensitive business information, your ‘secrete” love letters, or even personal
information such as stored passwords, personal documents, and credit card
numbers. All of this information and more you’ve forgotten about can be
retrieved and used to harm you.
When you donate a computer, you really don’t know where
it may end up, or if it will go through the hands of a malicious person with
the capability to restore previously recorded and deleted data. You did know
that simply deleting information (Command-T) only erases the address of that
material so the finder and spotlight ignore it. The trashed file, or parts of it
remain on you hard drive until it gets overwritten with new material.
There are many ways to go about ensuring your data can
never be retrieved. Obviously, you can choose to physically smash the drive,
but there are alternatives that enable you to keep the system intact so you can
donate a complete system a computer and its OS.
First some definitions so you can talk
the talk before you try to walk the walk.
Key Terms To Understanding Disk
Wiping
Disk
Formatting — “The process of preparing a hard disk or
other storage medium for use, including setting up an empty file system. When you format a disk, the operating system erases all
bookkeeping (addressing) information on the disk, tests the disk to make sure
all sectors are reliable, marks bad sectors (that is, those that are scratched
or otherwise damaged), and creates internal address tables that it later uses
to locate information.
“Large disks can be partitioned, that is, divided
into distinct sections that are formatted with their own individual file systems.
This is normally only done on hard disks because of the small sizes of other
disk types, as well as compatibility issues.
“A corrupted operating system can be reverted to a clean
state by formatting the disk and reinstalling the OS, as a drastic way of
combating a software problem or malware infection. Obviously, important files
should be backed up beforehand.”
{Wikipedia} If you’re
getting rid of the computer, and want to keep your data, backups become even
more essential. You really don’t want to loose those passwords, financial
records, bank account numbers, social security numbers and tax records. And
hmm… those love letters.
Hard
Drive — A hard disk
drive (HDD), commonly referred to, as a hard
drive, hard disk, or fixed disk drive, is a non-volatile storage device, which
stores digitally encoded data on rapidly rotating platters with magnetic
surfaces (e.g., its platter). Strictly speaking, "drive" refers to a
device distinct from its medium, such as a tape drive and its tape, or a floppy
disk drive and its floppy disk.
Early HDDs had removable media; however, an HDD
today is typically a sealed unit (except for a filtered vent hole to equalize
air pressure) with fixed media.
{Wikipedia}
We now even have a better, but more expensive storage called a solid-state
memory drive, which has no moving parts, for enhanced durability. Never the
less whether its an external drive, or a built in one, the concepts remains
that it’s the place your computer stored the data and applications you use.
Okay Down to Business —
Sterilize that Hard Drive or at Least it’s Data
Erasing and Reformatting — Simply >erasing (trashing) all the data on your hard drive or
formatting it is not enough security. You could spend hours going through your
hard drive and deleting all the files and documents you don’t want to share
with the computers new owner. Don’t, that does not protect you. Trashing a file
or application basically only removes the shortcuts to the files, making them
invisible to casual users.
Deleted files still lives and hides on your hard drive.
Indeed there are many services available that will recover data; most of it
from a really trashed (e.g., Katrina soaked) hard drive but are very pricy. But
that is not our objective — I got carried away.
However the software tools provided by Apple for free,
or third party developers do an excellent job of assuring trashed information
stays trashed.
![](SafeSecure_files/image010.png)
|
Apple Erase Disk
Security Options accessed from Disk Utility |
Checking your
favorite software supplier or doing a quick Google search will identify many
software tools for trashed file recovery will allow anyone to restore that
data. You can even read the reviews on both how well they work and their ease
of use. Why-Who Needs It? Oh you accidentally trashed that term paper or the
draft of your new book you were working against the clock to complete. Your
backups our out of date, so where do you turn? Hard disk recovery tools of
course. The same tool gave the capability to bulletproof your drive that even a
supper computer will have trouble getting at your data.
Caveat: this works only if the data has not been
over-written. This statement, as you’ll se later is not completely true, but is
valid if you overwrite all the data many times. But then you system is also dead
and gone. Is there a middle ground — read on!
Reformatting the hard drive is a bit more secure than
simply erasing the files. Formatting a disk does not erase the data on the
disk, only the address tables. It makes it much more difficult to recover the
files. However a computer specialist would be able to recover most or all the
data that was on the disk before the reformat.
For those who accidentally reformat a hard disk, being
able to recover most or all the data that was on the disk is a good thing.
However, if you’re preparing a system for retirement to a charity or other
organization, this obviously makes you more vulnerable to data theft.
For some individual users and businesses, a disk format
may be something you consider secure enough depending, of course, on the type
of data and information you saved to your computer. As long as people
understand that formatting is not a 100 percent secure way to completely remove
all data from your computer, then they are able to make the choice between formatting
and even more secure methods. If you have decided a disk format is a good
choice, at the very least you should do a full format rather than a quick
format.
Disk Wiping Options (aka a Data
Dump)
Disk wiping is an even more secure process than reformatting.
The term “disk wiping” is not only used in reference to hard drives but any
storage device such as CDs, RAIDs, thumb drives, and others. Disk wiping is a
secure method of ensuring that data, including company and individually
licensed software on your computer and storage devices, is irrecoverably
deleted before recycling or donating the equipment.
Because
previously stored data can be brought back with the right software and
applications, the disk wiping process will actually overwrite your entire hard
drive several times with data. Once you wipe your disk, you will find it all
but impossible to retrieve the data that was on the drive before doing so.
While disk-wiping algorithms differ from product to
product, they all will generally write the entire disk with a number (zero or
one), then reformat the disk. The more times the disk is overwritten and
formatted, the more secure the disk wipe is, but the trade-off is the extra
time to perform additional rewrites. Disk wipe applications will typically
overwrite the master boot record, partition table, and every sector of the hard
drive.
The government standard (DoD 5220.22-M), considered a
medium security level, specifies three full iterations to completely overwrite
a hard drive. Each iteration makes two write-passes over the entire drive; the
first pass inscribes ones (1) over the drive surface and the second inscribes
zeros (0) onto the surface. After the third iteration, a government-designated
code of 246 is written across the drive, and then it is verified by a final
pass that uses a read-verify process.
There are a variety of products available for different
operating systems that you can purchase or freely downloaded online to perform
more secure disk wipes. If time to perform the disk wipe is a consideration,
there are also tech security companies who offer disk wipe services.
Did
You Know? In 2003 two MIT students purchased 158 used disk drives
from various locations and found more than 5,000 credit card numbers, medical
reports, detailed personal and corporate financial information, and several
gigabytes worth of personal email and pornography on those drives.
Drive Genius 2.1.x
The only product I
know enough to share is Drive Genius. My pre OS X favorite a
Norton Product was discontinued.
Requirements: Mac OS
X 10.2 or higher. Shareware $99
Drive Genius is an OS X utility designed to provide
storage management. Featuring an easy-to-use interface, Drive Genius is packed
with powerful tools such as a drive optimizer, a comprehensive repair facility
for analyzing, repairing and rebuilding volumes, plus excellent testing
capabilities with media surface scanning, performance benchmarking and data
integrity checking. It can be used to initialize drives, create and delete
partitions, and erases them securely as per Department of Defenses standard.
Hard Drive Erasing
To erase a Macintosh hard drive, boot with a Mac OS X
install CD and use the Disk Utility on the drive. Apple Tech Note 107437 gives
this procedure for Mac OS X Systems:
Note: This refers to a full
Mac OS X 10.4.9 or later CD included with a computer, not to the update-only
10.2.3 CD. However the software is available to work with older OX X systems
from Prosoft Engineering, its developer.
Steps for Zeroing Data Using Apples
Disk Utility Software
Note to erase your boot volume you must
mount the Disk Utility containing disk, since the software can not erase its on
operating system.
These steps assume you have a Mac OS X 10.2.3 or later
CD:
- Insert the Mac OS X CD.
- Restart the computer.
- Immediately after the startup sound, press and hold the
“C” key to start up from CD.
- When the Installer screen appears, do not click
“Continue.” Instead, choose “Installer > Open Disk Utilities.”
- Select the hard drive to erase.
- Click the “Erase” tab.
- Select the volume format from the “Volume Format” pop-up
menu.
- Click “Options.”
- Select the checkbox for “Zero all data.”
- Click “OK.”
- Erase.
For a more secure method of erasing of data, you can
select the checkbox “8 Way Random Write Format” instead of or in addition to
selecting “Zero all data.” This process could take several hours.
For those wanting to “Clean” individual files, note this
section from Apple’s technical note: Secure Empty Trash You
can securely empty the Trash in Mac OS X. While in the Finder, from the File
menu choose “Secure Empty Trash.”
Note: When you securely empty the Trash, the deleted data cannot be recovered by disk
utilities. You should only do this if you have a backup or you are sure you
will never need the data again.
For machines which boot only Mac OS 9 or less, use Drive
Setup, Apple HD SC Setup, or Internal HD Format, and select the option to zero
out and/or low level format the disk. These programs are usually in the
Utilities Folder on the install CDs for the various versions of the Mac OS.
Apple Tech Note 21103 has more information.
A Shareware Option — ShredIt
is cross-platform: it is an ideal choice for the multi-platform office. There
is a ShredIt version for Mac OS X, Mac OS 9, Mac OS 8, Mac OS 7, Windows 95,
Windows 98, Windows NT, Windows 2000, Windows ME, and Windows XP. You can wipe
a file or erase a hard drive with this easy-to-use File Shredder —
computer privacy software that shreds data so it can’t be recovered. It’s
available on a CD-ROM for $34.95 or $25.95 for the download. Users who need to
dispose of confidential data on an ongoing basis appreciate how easy ShredIt is
to use. Just drag the file on to the ShredIt icon and ShredIt File Shredder
will wipe the file data so it can’t be recovered. If your not sure you need a
shredding tool check out “Do you need a File
Shredder? Take
the ShredIt Data Shredder Test. It takes less than 2
minutes, to find out.”
I’ve tested the software in trial mode, and it appears to
be a fine product, but full testing will wait my having more time. Of
importance to me is that ShredIt shreds everything. It will erase a file,
folders, disk free space, files you’ve already deleted, whole hard drives,
external hard drives, thumb ‘flash’ drives and even a floppy or a Zip disk. Now
I do the later medium with an old tape degausser, left
over from my reel-to-reel days.
Remember:
Throwing data in the computer trash does not remove the file contents from the
hard drive; the data can be recovered by someone else. Users who want to erase
a hard drive before disposing of a an old computer can be confident that using
ShredIt Hard Drive Cleaner will erase the hard drive so the data cannot be
recovered by the next owner.
In Part from Apple Barrel, Ridgecrest, CA
Harry Babad, macCompanion
From Paul Taylor’s Hints and Tips
Newsletter – October 2007
PS
I can’t let a thought flyaway undocumented, so back to
restore simply trashed data. Check your favorite software supplier or do a
quick Google or MacUser search to identify many of software tools for trashed
file recovery will allow anyone to restore that data. Do read the review
carefully because a bad tool can do more damage that you should bargain for.
Focus on both how well they work and their ease of use. Check blogs to see what
havoc they a product might have caused — remember the software vendor is
not liable to Caveat emptor.
Why - Who Needs It?
Oh, you accidentally trashed that term paper or the draft of your new book you
were working against the clock to complete. Your backups our out of date, so
where do you turn? Hard disk recovery tools of course. The same tool gave the
capability to bulletproof your drive that even a supper computer will have
trouble getting at your data. Examples of available product include Data Rescue II
and low-rated Disk Doctors Mac Data Recovery 1.0. There’s one I’d not heard of before [Macintosh
Data Recovery which
seem to be associated with a data recovery service. Despite the seemingly
similar titles, they seem to be different products.
PPS
Next month: eMail
Etiquette — based on what fills my inbox, no not spam, you have
not heard it all yet!