In the 20101007 version of Echidna spine allocation software, it is
known that there are a few issues as below. Please keep them in mind
in using this version:

 * It accepts only 1-9 priorities to targets, while the latest version
   (20110630 version) does 1-15.

 * If you use it on Mac, please comment out the "if" statement as
   below on line 52 in canvasBalloon.tcl:

   ---
   if [string match $::tcl_platform(os) "Darwin" ] {
              ::tk::unsupported::MacWindowStyle style $b floatSideProc
              }
   ---

 * If you use it on Mac OS X 10.7 "Lion", you may encounter a trouble
   where, when you open the pull-down menu from the top of the GUI,
   the list looks blank (no characters or messages are visible). The
   reason for this is still unknown. A workaround for this is to place
   a mouse pointer on the pull-down menu (then the messages become
   visible).

 * There is a bug in the single fiber allocation: If one tries to
   allocate a single fiber, the other one(s) that has(have) already
   been allocated may be de-allocated and this looks apparently hard
   to predict. So please do not use this function.

 * There is another bug in the allocation of spines to dummy objects
   with the minimum separation considered. To minimize the effect of
   this bug, please keep in mind that you should adopt a large BS
   offset (30 arcsec should be fine)

 * Please do not duplicate a single object in a .fld file. If a single
   object is registered with more than one entry in a .fld file, the
   software sometimes allocate two spines to it interpreting they are
   different objects.

   [NOTE] No spine is assigned to "K"-type object (Coodiante
   Calibration Star), so double registration should be possible if one
   entry is as "K".

 * On Allocation setup, users can set the number of flux calibration
   stars ("C") and/or those for atmospheric absorption correction
   ("Z"). This number is supposed to be "per spectrograph", but in
   reality the software seems to interpret it as the "total" number of
   stars and perform spine allocation accordingly. For example, if you
   want to observe 3 Z stars per spectrograph and input "3" on
   Allocation setup, spines will be allocated to only 3 stars in
   total, so the number of stars observed by each spectrograph will be
   2 or less (maybe none). And you will see an error message pop up
   requesting to prepare more stars in the input object list (the
   error condition seems still judged by the number of stars with
   spines allocated per spectrograph).

   The only workaround to this is to input a larger number on
   Allocation setup. For example, if you want to observe 3 Z stars per
   spectrograph, then you should input 6 or even more. Although this
   does not guarantee 3 stars per spectrograph, 6 spines will be
   allocated to 6 stars, so it will be more likely that more stars can
   be observed by each spectrograph. If the split of stars between
   IRS1 and IRS2 is so uneven (e.g. only one star is observed by IRS1
   while all the others are for IRS2), one would have to try to adjust
   field center and/or PA, and add more stars in the input list.