re: Restoring files deleted from a compressed drive
Tuesday, April 14, 2009 at 6:25 pm
Windows 95 Annoyances Discussion Forum
Posted by thattoo
(10 messages posted)
>I'm understanding you to say that you can read all the contents of drvspace.000.
Not exactly. What I'm saying is that I can read all of the files that can be
restored by either DriveSpace3 or PC Inspector File Recovery—i.e., the data
that, through the use of those two programs, can be copied to a never-compressed
drive as files that have intact file information, or that have filenames whose first
character only was replaced with an underscore, or that have been assigned a 'cluster
[some number]' filename because the file recovery program found whatever kind of
metadata it happened to be looking for, wherever it happened to be looking for it.
(I don't know exactly what it does and does not try to find; it is freeware, but
it's not open source.) Many of the files I did restore are corrupted, apparently
as a result of a common problem described in the documentation for that 'DriveSpace
3 Disaster Recovery Kit' software.
I don't know how to read the rest of the decompressed raw data from the area within
that DRVSPACE.000 file. With that freeware file recovery program, I was able to
retrieve only about 700MB out of nearly 900MB total. When that software copies the
data to a separate drive to restore the files, it's not smart enough to replace gibberish
characters with valid file information to prevent Windows from assuming that the
destination hard drive is full (despite that drive's having a whole 5GB of free space,
compared to less than 1GB of decompressed data that could possibly need to be stored
on it).
That corrupted file information prevents me from retrieving any deleted files
from at least two directories. One is the root directory, not a good one to do without
when I want to reinstall the OS on an unfamiliar machine; and the other, alas, is
the folder containing my friend's personal data.
I can't decompress the drive and expect to retrieve all of the free space, because
most of the free space is exactly what the DriveSpace program is likely to discard
to make room for the files it believes to exist, which take up 390MB out of just
a little over 400. But because I do have a backup image of the whole drive, I will
try it once, just in case some bug or fluke makes a 'My Documents' folder magically
appear out of nowhere. (When I mount the drive, all that shows up in an Explorer
window is the same thing I pulled up with 'DIR' at the DOS prompt on her machine
when I booted C: and had to tell what was left of the OS that the command interpreter
was on a floppy: about 100MBs' worth of mostly useless files, and I do have the
folder options set to display every file that Explorer will let me display.)
If I want to help her, I need to start with the assumption that at least some
of her personal files were not overwritten. I might be able to read the
rest by going through the data, one tiny piece at a time, with that 'Disaster Recovery
Kit' program, because the problem I'm having here seems to be just the sort of problem
that that software was written to solve.
But I'm really hoping that, after all these years, someone would know
of some easier way that just wouldn't happen to occur to me when I haven't been using
Windows much lately.
Now I'm in the middle of finding out whether the Cygwin port of dd can interpret
a mounted 'drive' as a real drive and write the whole file's decompressed contents
to a drive image file. I don't want to get my hopes up too high there, but it does
seem possible.
I've also found an old Linux kernel module called 'dmsdos' that's said to have
had some success in reading those sadistic DRVSPACE.### files, but I haven't
seen anything said about its being able to recover arbitrary raw data when the FAT
has been mangled.
Is my situation a little clearer now?
You've been kind, ancien.
~~~ The people out to get you are paranoid. ~~~
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