ethan.dicks at gmail.com
Fri Nov 5 14:08:18 CDT 2010
On 11/5/10, Jason T <silent700 at gmail.com> wrote:
> On Fri, Nov 5, 2010 at 11:45 AM, Dave McGuire <mcguire at neurotica.com> wrote:
>> Preserving/snapshotting the contents of a SCSI drive is as simple as
>> hooking it to a UNIX box and running a "dd" command.
> For us n00bs, what's the next step? If it's a drive from a (for
> example) SunOS box, you hook it up to a Solaris machine, mount it,
> identify it as something you want, dd it and it is preserved.
> What if you have (as I and probably most of you do) a pile of
> completely unknown SCSI drives? So you hook it to your nearest *nix
> machine, dd it to a file, and the drive is free to head crash and
> become scrap. Now what do you do with that image?
Dump it, scan it, poke at it, etc.
> I'd guess the next step is to try to mount that dd'd image somewhere.
> Is there an easy way to ID the filesystem of a foreign drive, or is it
> trial-and-error at that point?
There's some guided trial-and-error needed, most likely. If it truly
is an "unknown" filesystem, there are two tools I'd start with to
investigate what the image is about...
'od' (octal dump) and 'strings' (search binary images for sequences of
Between the two tools, you can do a lot to wade through raw piles of
disk blocks, and if you use 'dd' as a scalpel (to carve out sections
to dump that start at exactly byte XXXX and are exactly YYYY blocks
long), it's even convenient to follow filesystem structures to help
confirm your earlier suspicions about what sort of filesystem it
Some environments are more flexible than others. Linux supports many
recent filesystem types, but I wouldn't want to try to dig through a
Solaris disk on a VMS machine. Once I knew what the filesystem of my
image was, I'd see if I had a compatible machine, either real or
virtual, to at least be able to browse the filesystem at a file level.
For me, sometimes that's real hardware, sometimes that's simh,
sometimes it's something else. It all depends on what I find (in my
house, odds are a hard disk or floppy image is going to be AmigaDOS
(FFS or OFS), MacOS (HFS), DOS/Windows (FAT or NTFS), RT-11, OS/8,
CP/M, TRSDOS, VMS (ODS-1), SunOS 4, Solaris, Linux (ext2 or ext3), or
perhaps some flavor of BSD - I'm sure others here have greater a
lesser chances for those and more).
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