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                                                                         PT-49
                                                                  October 1992
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1.  Product Description:  LockDisk is a public domain control panel device
(CDEV) for the Macintosh to write-protect a system hard drive.  This product
test addresses version 1.0.

2.  Product Acquisition:  The author of LockDisk is Brian Bechtel.  Mr.
Bechtel's Internet address is:  blob@apple.com.  The program is available from
several Internet sites as well as Apple User Groups.

3.  Product Tester:  Chris Mc Donald, Computer Systems Analyst, Information
Systems Command, White Sands Missile Range, NM  88002-5506, DSN 258-1408, DDN:
cmcdonal@wsmr-emh03.army.mil or cmcdonald@wsmr-simtel20.army.mil.

4.  Product Test:

    a.  I obtained a copy of LockDisk from Mr. Rollo Rogers, Naval Ocean
Systems Center, in September 1992.  Product testing occurred on a Mac IIcx, OS
6.0.5, and extended from 29 September to 2 October, 1992.

    b.  One installs the CDEV by copying it to the system folder and restarting
the system.  

    c.  One activates write-protection by selecting Control Panel from the
Apple Menu.  One clicks on the LockDisk icon and receives two button
selections:  unlocked and locked.  If one selects the locked option, the CDEV
"sets the vcbAtrb flag that indicates . . . the disk in question is hardware
locked".  A user may choose the unlocked option and remove write-protection
without the requirement to restart.

    d.  Installation of the CDEV took 10-15 seconds to drag the LockDisk icon
into the system folder and restart the Macintosh.  Testing confirmed the
effectiveness of the CDEV to write-protect the hard drive.  There were no
anomalies or failures experienced over dozens of tests which included the
following exercises.

    (1)  I created text files under three different word processors and
attempted to save the files to the hard drive.  In every case it was impossible
to save the files if the system was locked.

    (2)  I attempted to invoke the communications program White Knight, which
requires the hard drive to be writable in order to function.  Every invocation
failed when White Knight detected that the hard drive was write-protected.

    (3)  I attempted to edit existing files on the hard drive with Central
Point's MacTools Disk Editor.  All attempts to save the editing changes were
unsuccessful on a locked system.

    (4)  I attempted to print files with programs that I knew created temporary
files on the hard drive.  Whenever the system was locked, printing failed.

    (5)  I attempted to create new folders from the Desktop.  This was never
possible with the system locked.

5.  Product Advantages:

    a.  LockDisk appears to perform as documented.  Activation and deactivation
of write-protection is extremely flexible.

    b.  The program is free as public domain software.

6.  Product Disadvantages:

    a.  The author comments that one should use LockDisk with a "certain sense
of caution".  Certain programs may crash; others may not function.  If a
program creates temporary files on the hard drive, it may be necessary to have
the program save the file in memory rather than on the drive, if this is
feasible.  In extreme cases where write-protection is a necessity, one might
have to choose another program for the sake of compatibility with LockDisk.

    b.  There are many organizations which prohibit the use of public domain
software.  Although the cost of LockDisk is an advantage for some, it
paradoxically can be a disadvantage for others.  There are commercial programs,
such as NightWatch II, which can provide the same capability for a price.

    c.  Any user can disable write-protection by opening the Control Panel and
selecting the unlocked button.

7.  Comments:

    There exist environments in which it is desirable to prohibit the storage
of classified, proprietary, and/or sensitive information on a system hard
drive.  LockDisk provides a discretionary control to implement write-
protection and to encourage users to save their information on removable
media.

    Since this is a discretionary tool, however, a user could intentionally
disable the feature.  If the trustworthiness of users is suspect, then LockDisk
may not be a good choice.  It may be necessary to select a commercial program
in which an administrator, not each individual user, can enable and disable
write-protection.






[The opinions expressed in this evaluation are those of the author, and should
not be taken as representing official Department of Army positions or a
commercial endorsement.]





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