Software // Enterprise Applications
Commentary
4/27/2006
01:51 PM
Fred Langa
Fred Langa
Commentary
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Langa Letter: The OS Inside The OS

Fred Langa shows how a simple tweak turns XP's low-level Recovery Console into a complete, standalone mini-operating system--in effect, an XP DOS!

SETting It Up
Of course, before you can tweak the Recovery Console, you have to install it.

We've covered the Recovery Console thoroughly in the past (see this and this). So for the rest of this article, we'll assume your target PC has the Recovery Console installed on the hard drive. If you need further help on getting it set up, see "Description of the Windows XP Recovery Console" and "How to install and use the Recovery Console in Windows XP."

Now to get us all on the same page, let's take a quick look at the Recovery Console's default behavior. If you want to follow along on your own PC, reboot, select the Recovery Console, and log in if required to do so.

Switch to the root directory (type "CD \" without the quotes and hit enter); Recovery Console should allow this. But now try switching to, say, the Documents and Settings folder and see what happens: You can't. As shown in Screen 1, you simply get an "access is denied" message, with no further explanation.


By default, the Recovery Console is very limited, with severe restrictions on where you can go on the hard drive and what you can do. For example, you can't even access the Documents and Settings folder.

(click image for larger view)

Screen One
By default, the Recovery Console is very limited, with severe restrictions on where you can go on the hard drive and what you can do. For example, you can't even access the Documents and Settings folder.

If you try the built-in documentation to resolve the "access is denied" message, you'll find that Microsoft has left a number of unfinished areas and rough spots in Recovery Console. (Don't worry-- we'll show you how to avoid them.)

For example, unrestricted access to the hard drive is controlled by a variable called "AllowAllPaths." In XP (just as in the days of DOS), "environmental variables" like these are controlled via the SET command. According to Microsoft's documentation on the Recovery Console, all you have to do is type:

SET AllowAllPaths = TRUE

and you'll be able to navigate anywhere on your hard drive. Sounds great! Let's try it.


Screen Two
Following Microsoft's instructions on overcoming Recovery Console's limitations can lead to initial failures, with error messages telling you additional prep work is needed.

(click image for larger view)

Following Microsoft's instructions on overcoming Recovery Console's limitations can lead to initial failures, with error messages telling you additional prep work is needed.

Unfortunately, as shown in Screen 2, the SET command doesn't work. Unless you've already performed a necessary prior tweak, all you'll get is an error message:

The SET command is currently disabled. The SET command is an optional Recovery console command that can only be enabled by using the the Security Configuration and Analysis snap-in.

Note the typo in the error message--the repeated word "the" (as in "...the the Security Configuration..."). That, plus Microsoft's failure to mention the necessary tweak beforehand, plus the fact that the error message is wrong (there's a much easier way to enable the SET command), very strongly suggests to me that we're in an unpolished, only roughly finished area of the Recovery Console.

Things don't get much better if you pursue the built-in help further. Normally, you can get assistance for any command by typing the command followed by " /?" as shown in Screen 3.


Before we were told to use ''the the Security Configuration and Analysis snap-in'' (see Screen 2), and now we're told to use the ''Group Policy snap-in'' with no further explanation. But don't worry, we'll show you the right (and much easier) way in a moment.

(click image for larger view)

Screen Three
Before we were told to use "the the Security Configuration and Analysis snap-in" (see Screen 2), and now we're told to use the "Group Policy snap-in" with no further explanation. But don't worry, we'll show you the right (and much easier) way in a moment.

The query doesn't do much in this instance. Typing "SET ?/" lists the commands that aren't yet available to you, plus one new bit of information: "The SET command is an optional Recovery Console command that can only be enabled by using the Group Policy snap-in." No further information is provided.

OK, let's quickly review: Microsoft has told us to use the SET command, and in trying that we're informed that before SET will work, we have to use either "the the Security Configuration and Analysis snap-in" and/or the "Group Policy snap-in." Confused yet? (I was, when I first encountered this.) But hold on--we're just about done with the confusion and ready to show you the simple, straightforward way of getting SET to work.

But first, there's one more bit of Microsoftian fumbling: If you go hunting for information in the Microsoft Knowledge Base, you'll find "How to add more power to Recovery Console by using Group Policy in Windows XP Professional," but that too turns out to be a disappointment. While that document will indeed show you how to enable the SET command in Recovery Console, it does so with a lot of needless complexity. In fact, Microsoft's documentation blows right past the much easier method, which I find simpler and faster. Here it is:

1) Start the Registry Editor (click Start/Run and type "REGEDIT" in the Run box).

2) Click your way down the HKEY_LOCAL_MACHINE tree to:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\
Setup\RecoveryConsole

3) Double-click on "SetCommand" in the right-hand pane and type the numeral "1" in the "value data" box that will open. (See Screen 4.)


Screen Four
All it really takes to remove the restrictions in Recovery Console is to change this "value data" from the default zero to one. That's it--you're done! (See text for more detail.)

(click image for larger view)

All it really takes to remove the restrictions in Recovery Console is to change this

That's it. Exit Regedit, and you're done. No muss, no fuss, no weird gyrations. Just those three quick steps, and you're finished. Now when you enter the Recovery Console, the SET command will work. It's that simple--although Microsoft's convoluted, contradictory instructions sure make it seem harder.

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