[comp.sys.ibm.pc] Help! Accidental Erasure of Hard Disk

yeung@reed.UUCP (Woodrow Yeung) (01/31/89)

Could anyone please tell me how a hard disk partition that was formatted can
be recovered?  I connected a second hard disk to my friends pc clone to test
if it still works.  He tried to format it (it was an ex macintosh
Hyperdrive) as drive D but forgot about his own d partition.  What sort of
utilities can recover it.  I believe that during a format of a hard disk the
information is not destroyed but rather the directory changed, so this
situation is not hopeless.  

How does one format a second disk?  Trying to format it as drive e did not
work.  Please send e-mail to inform me of what to do.  Thanks in advance.

Woody Yeung
yeung@reed
tektronix!reed!yeung

silver@eniac.seas.upenn.edu (Andy Silverman) (02/01/89)

The only way to really recover a formatted disk is to have been using a tool
PRIOR to the accidental formatting like PCTools' MIRROR/REBUILD or Norton's
or Mace's Unformat.  When you format a disk the FAT and root directory are
wiped, and on a big hard drive FAT reconstruction can be really nasty.  I
believe that most of these tools can also attempt a reconstruction even
without using the tool prior to the format, but with less chance of success...

Andy Silverman
silver@eniac.seas.upenn.edu

marc@rna.UUCP (Marc Johnson) (02/08/89)

In article <11654@reed.UUCP> yeung@reed.UUCP (Woodrow Yeung) writes:
>Could anyone please tell me how a hard disk partition that was formatted can
>be recovered?  ...

If you only did a "format" (rather than a low-level sector format), you can
recover it using the Paul MACE utilities.  There are probably other manual
ways using Norton Utilities, but MACE does it automatically, so I suggest you
try that.

>
>How does one format a second disk?  Trying to format it as drive e did not
>work.  Please send e-mail to inform me of what to do.  Thanks in advance.
>
>Woody Yeung
>yeung@reed
>tektronix!reed!yeung

Unless your system knows about the second drive, based either on your
CMOS setup (if on an AT or AT clone) or the contoller switches or AUTO-Config
via DEBUG on XTs, you won't be able to talk to a drive D or E.  Go into
SETUP (this is done many ways depending on the machine--check your manual),
add the 2nd drive with the proper parameters (drive type= heads/cylinders),
then attach the 2nd drive and reboot. It should be recognized, although the
system will probably complain about a bad partition or somesuch.  That's
okay.  Then use FINIT (or equivalent) to do a low-level format of the 2nd
drive (should be known as D: unless you have more than 1 logical drive on
your first disk), then an FDISK (or equiv.) to partition it and make it
DOS-happy, and finally a FORMAT D: (don't forget the D:!) to do the high-level
format.  If this is confusing, e-mail me with specifics (hardware models
and sizes, DOS version, etc.) and I'll try to help.

marc

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silver@eniac.seas.upenn.edu (Andy Silverman) (02/09/89)

I would like to point out that the Norton Utils WILL do an automatic
unformatting of a disk, as opposed to the suggestion in a previous post
that Mace will do this but Norton won't.  Take a look at the advanced utils
4.5...

Disclaimer: I have no personal interest one way or the other in either Mace
or Norton.

Andy Silverman
Internet: silver@eniac.seas.upenn.edu
CompuServe: 72261,531

malloy@nprdc.arpa (Sean Malloy) (02/10/89)

In article <338@rna.UUCP> marc@rna.UUCP (Marc Johnson) writes:
>>How does one format a second disk?  Trying to format it as drive e did not
>>work.  Please send e-mail to inform me of what to do.  Thanks in advance.

> . . . Then use FINIT (or equivalent) to do a low-level format of the 2nd
>drive (should be known as D: unless you have more than 1 logical drive on
>your first disk),  .  .  .

Not true. I added a disk to my system since the last weekend, and it
doesn't work in that order -- the second physical drive is _always_ 'D:'. 

I have a Perstor PS180, and had a 20Mb disk formatted to 38Mb and
split into two 19Mb partitions. I was adding a 40Mb disk to be
formatted to 78Mb, split into three partitions. I expected the drive
assignments to be:

	C:  first logical drive on drive unit 0
	D:  second logical drive on drive unit 0
	E:  third logical drive on drive unit 0
	F:  first logical drive on drive unit 1
	G:  second logical drive on drive unit 1

What I got was:

	C:  first logical drive on drive unit 0
	D:  first logical drive on drive unit 1
	E:  second logical drive on drive unit 0
	F:  third logical drive on drive unit 0
	G:  second logical drive on drive unit 1

Actually, I originally had the 20Mb disk as unit 0, so the disks were
assigned drives as [Unit 0: C:, E:] and [Unit 1: D:, F:, G:], but it
still works the same way. DOS assigns drive letters to the physical
drives _first_, then assigns drive numbers to any logical drives in
extended partitions.


	Sean Malloy
	Navy Personnel Research & Development Center
	San Diego, CA 92152-6800
	malloy@nprdc.arpa