🚀 go-pugleaf

Marcello Scala,

> How can i do it?
>

If you want to write your own data to a specific sector on the disk 
then roughly the process would be:

  1)Open the device using CreateFile()
  2)Read the target sector into a buffer using SPTI (SCSI Pass 
Through Interface)
  3)Modify the buffer contents to include your data
  4)Write the buffer back to the disk
  5)Close the device.

Notes:

a)If you don't pick your sector carefully you could overwrite file 
system structures and corrupt your disk. Worse case scenario is that 
you could render your disk innaccessible. Actually no. The worse case 
scenario is that you render your customer's disk innaccessible.

Aside from being poor PR (Public Relations) you should consider that 
some of our customers have been prepared to pay six figure sums to 
get their data back. If you are culpable you could end up being 
passed that kind of bill.

b)SPTI is documented but is very convoluted.

c)SPTI only works under WinNT or higher. For Win9x you need something 
completely different.

d)Sector are addressed by number (zero based) not 
Cylinder/Header/Sector. If you have a C:H:S address to write to then 
you'll have fun and games trying to convert it into the PSN you need.

I develop data recovery and computer forensic software and 'grew up' 
as a data recovery engineer. I understand the design and layout of 
over a dozen file systems and write/maintain file system driver code 
for our own utilities. I WOULD DO EVERYTHING POSSIBLE TO AVOID 
WRITING MY OWN DATA DIRECT TO A DISK.

The risks are appalling and the work required to guard against 
corruption is extensive.
--
Andrue Cope
[Bicester, UK]