\section{Using Magneto-Optical (MO) Disks at ISAS}\index{MO disks}\index{magneto-optical disks}

A complete archive of the Yohkoh data for the whole mission is available
on Magneto-Optical (MO) disks at ISAS.

A Unix script and associated alias is available to mount and dismount MO 
(magneto optical) disks at ISAS.  An IDL interface routine is also provided
to allow MO mounts and dismounts from within an IDL session or callable
from other IDL routines.  Once mounted, access to data on these drives is 
identical to other magnetic disks --- standard Unix operations (ex: ls) are 
permitted.  For MO disks containing Yohkoh data, the standard IDL functions 
(ex: yodat access) are available.

MO disks are available on several machines of the SUN machines at ISAS.
including flare3, flare4, flare6, flare13, flare14, flare15.  The first
(and in most case, only) MO drive on any machine is referred to as drive 0.
Some machines may have a second drive (drive 1) --- all drives are clearly
marked with a drive number. Find an available (empty) drive and insert
your disk --- if you intend to write, verify that the write protect switch
allows writing.  By default, the mount is executed on the machine which 
contains the MO driver.  If that machine is different than the machine 
which executes the command, then the MO disk is automatically 'exported' 
and mounted on the local machine.  Use the /all switch to force mounting
on all ISAS machines.

\subsection{Mounting MO Disks From Unix}

The alias {\it momount} executes the script which performs all MO operations.
Parameters and switches allow specification of machine name, drive number, 
access mode, dismounts, etc.  Options include {\it /write /umount /eject /1}
and {\it /all}.
Some sample calling sequences are:
%
\ultrixinputA{3}{momount flare13 			}{\# mount flare13 , drive 0, readonly}
\ultrixinputB{3}{momount flare13 /umount		}{\# dismount same}
\ultrixinputB{3}{momount flare4  /1 /write		}{\# mount flare4, drive 1, read/write}
\ultrixinputB{3}{momount flare4  /1 /eject		}{\# dismount and eject same}
\ultrixinputC{3}{momount flare15 /all			}{\# mount flare15, drive 0, on all nodes}

\subsection{Mounting MO Disks From IDL}

An IDL driver sets up the parameters and spawns a call to the same script
file described above to allow IDL MO control (interactive or via routine).
Keyword options similar to the Unix script are available with the IDL
routine.  Some examples are:
%
\idlinputA{3}{momount,'flare13'			}{; mount flare13 , drive 0, readonly}
\idlinputB{3}{momount,'flare13',/umount		}{; dismount same}
\idlinputB{3}{momount,'flare4', /one, /write	}{; mount flare4, drive 1, read/write}
\idlinputC{3}{momount,'flare4', /one, /eject    }{; dismount and eject same}
