Computer Help and Support

it should be done before, and then burned to a rescue disc
or on the side on another machine and burned to a rescue disc

anything else is kinda like calling AAA and getting a membership when you are on the roadside broken down

compile from source (any forensic or data recovery starts before it's needed by preparing for the task)
btw..if you can come up with a way, to create a binary download (non interpreted (perl lua python) ) that is
universally applicable to different linux systems(arm/ppc/x86-32/64/sparc // then add in the other hw configuration, scsi, sata, pata) you'll beat everyone in the linux community

that being said,i didn't suggest that YOU compile from source. i pointed out that i came from that area.

for forensic or datarecovery use one of the big live cd / dvd rescue discs..they usually have scalpel
and ddrescue (and dd3rescue or any of the forensically enhanced dd's) or at least dd which will let you image the hdd, from which image you'll then work

kali linux being one(live cd/dvd) that has some forensic tools (and others) (doesn't at last check have scalpel but does have foremost which does pretty much the same) it is not 'beginner easy to use'

http://www.howtogeek.com/howto/15761/recover-data-like-a-forensics-expert-using-an-ubuntu-live-cd/
is step by step on ubuntu

i've tried to drop a fast intro course on you here in these posts
however data rescue, forensics are not 'average tasks' in general, the are programmer/specialist/sysadmin tasks (primarily the 2 latter)