Sep 27th 2011 - Transfer data between virtual machine and host without network

Today I needed to transfer data between a virtual machine and the host.

The main problem was the lack of networking support in MINIX v3.1.0 (the virtual machine) so I could not scp or ftp anything between the systems.

I came to rescue the day with the idea of a special sneakernet between the virtual machine and the host.

On the host

• Create the floppy image on the host.
  
  % dd if=/dev/zero of=floppy.img bs=1024 count=1440
  



• Attach the floppy image to the virtual machine.
  
  The process depends on the virtualization software so is left as exercise to the reader.
  

On the virtual machine

• cd to the data (let's call it payload, shall we?.
  
  $ cd /home/tonejito/payload
  



• tar the relevant files into the floppy device (/dev/fd0)
  
  $ tar cvvf /dev/fd0 file file file ...
  

On the host

• Detach the floppy image from the virtual machine
  
  Another exercise left to the reader
  


• Extract the files
  % tar xvvf floppy.img
  


• List the contents
  
  % ls
floppy.img file file file
  

That's all

ssh write failed: broken pipe

I hate when this kind of things so I surfed the net looking for an answer [1], the cause of the problem was the inactivity in the ssh session, so a keep-alive must be implemented somewhere.

It turned out in the manpages of ssh_config and sshd_config there were a couple keep alive settings:

/etc/ssh/ssh_config
ServerAliveInterval 30
TCPKeepAlive yes

/etc/ssh/sshd_config
ClientAliveInterval 30
TCPKeepAlive yes

Server/Client Alive interval are protocol-specific settings, and TCP is a connection-specific setting.

[1] https://bbs.archlinux.org/viewtopic.php?id=97003

[2] LIDSOL website

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