[Beowulf] passwordless "rsh" login

[Trent Piepho]

On Fri, 9 Jul 2004, Robert G. Brown wrote:
> this three or four times.  Things wrong with rsh:
>  a) no security (as in "bleeding wound" in an open network)
>  b) no environment passing
>  c) no tunnelling/port forwarding
>  d) no intrinsic X11 support
>  e) archaic and easily spoofed/snooped authentication mechanism (see a))
>  f) terrible passwordless login control
>  g) more or less frozen, unsupported code

For starting jobs on a cluster with a private network, only b and g really
matter, and then not that much.

> Things good about rsh:
> 
>  h) relatively fast

For passing data over gigabit ethernet, rsh/rcp vs ssh/scp is about four times
faster, depending on the CPU.

> Things bad about ssh:
> 
>  i) relatively slow
>  j) cannot select "no encryption" as option even on secure networks
>  k) evil tty disconnect "feature" that requires ~. escapes (nested yet)
> to leave a job backgrounded from an ssh session.

What is so annoying about these things is that they didn't used to be
problems with ssh.  They were "features" added intentionally.  I cannot
stand the "we know what's best for you" attitude.