[Aboriginal] Building a floppy rescue set like BG did?

[Christopher Barry]

On Tue, 14 Mar 2017 16:05:55 +1100
Philip Rhoades <phil at pricom.com.au> wrote:

>People,
>
>As an exercise, I want to create a VM image (or at least backup of all 
>the files with rsync) from a SCSI drive in an old Red Hat (NOT 
>Enterprise) v5.2 Linux 486 machine (circa 1999 that does have rsync on 
>it but it has protocol problems talking to my server).  The 486 has:
>
>- an ISA Adaptec 1542 SCSI controller attached to a Seagate 2GB drive 
>with 6 partitions
>
>- an ISA ne2000 network card
>
>- a 1.44MB FD
>
>So, to be able to create the image of the 2GB SCSI drive that is in
>the 486, I need to boot the 486 on one or more floppy disks and dd the 
>/dev/sda drive over SSH to a file on my big Fedora 25 x86_64 
>workstation.  I now have Basic Linux booting from floppies but it is 
>still 2005 vintage and uses SSH1 and I haven't been able to get the
>old Ciphers, MACs and KexAlgorithms working with my Fedora 25 x86_64
>server 
>- so I still can't ssh or rsync to it from the 486.  BL does not have 
>any rshd that rsync could use . . so I am thinking that AL should be 
>more up to date but I will have to build my own system it seems.  I
>got BG's disks going:
>
>   http://www.giannone.ch/rescue/current
>
>but they didn't have support for the SCSI controller - I sent him a 
>couple of emails (and even rang him from Australia!) about getting his 
>custom build scripts of AL to modify . . but he didn't get back to
>me . .
>
>Has anyone here already produced a floppy boot set?  I have just
>cloned the git repo and am building for the 486 but it would be nice
>if someone could make my learning curve less steep . .
>
>Thanks!
>
>Phil.

Q: does the 486 boot at all on it's own? That's not clear to me from
this email. If it does boot, then I assume you are worried about open
files not transferring.

If it can boot on it's own, then I also assume you can see the disk and
and all the files and the network too.

If you have nc (netcat command) you can simply use dd over netcat to
backup the system. It's the simplest way to backup a disk image to
another host over the network.

start nc listening on port 9000 for connections in a shell on the f25
boxen first:

# nc -l -p 9000 | dd of=/somewhere/486-rh-backup.img
It will hang there waiting...
(-p may or may not be needed on your f25 box)

then on the 486, boot to single user mode with networking (if an
option), or telinit S to get into single mode and start networking if
needed.

From the 486 command line, dd off the entire disk (I assume it's called
sda here):

# dd if=/dev/sda | nc ip.of.fedora.box:9000


This sends data in the clear though, no encryption. Being in single user
mode, there will be very few if any important files open during the
transfer (e.g. some logfiles may be truncated), and you should be fine.

Here's the netcat source code if you need to build it on the 486.
ftp://ftp.debian.org/debian/pool/main/n/netcat/netcat_1.10.orig.tar.bz2

-- 
Regards,
Christopher