SPACEDIR  PROGRAM
			      Richard DeJordy
		       American Mathematical Society


   The SPACEDIR program was written to help track the usage of disk space
   on an ODS2 volume.  (Also, because I was preparing a session on ODS2
   Volume Structures for a session at a symposim and wanted a real-live
   program for it.)

   The program opens (without any locking), the INDEXF.SYS file of a volume
   specified on the command line as the first (and only) parameter.  The
   home block is located (only as the second block of the file) and the
   offset to the file headers calculated.  Then, for each file header, it
   determines if the file is a directory (FH2$V_DIRECTORY bit in
   FH2$L_FILECHAR is set).  If it is a directory, it makes and entry into a
   quadrouply linked list of directory files on the device.  The links are
   forward and backward by file number and forward and backward by back
   link point, i.e. the file number of the directory in which this directory
   appears on the disk.

   After creating the list, it goes through the INDEXF.SYS file again, this
   time recording the number of files and aggregate size of each file into
   fields in the appropriate directories entry on the linked list.

   After this, each entry's individual entries are aggregated into each
   directory which is above it in the disk "directory structure".

   Finally, the list is output in alphabetical order by directry,
   completing all subdirectories before moving to a new directory (much
   like one might see on a backup listing).  The one exception to this is
   that the [000000] is always listed first, even if there is another
   directory off the main level of the device that starts with a $.  This
   allows the first line to show the aggregate totals (number of files,
   blocks used, and blocks allocated) for the device.

   Each output line is described as

   # [dirname] # allocated, # files.  Cum: # files, #/# blocks used/allocated.

   If the [dirname] is 40 characters or less, the lines are justified such
   that all the colums line up.  If the [dirname] is more than 40
   characters, there is no padding or alignment.

   The program can rubn on an RA90 in pretty poor shape, with 1762
   directories and 75223 files in under 10 minutes on a 6320 with a
   moderate load.

   Enhancements to speed (such as btrees instead of linked lists),
   cosmetics, and flexibility (user defined output), are creeping into mind
   as I write this (2:30am one day before I leave for the Symposium).
   Please feel free to send comments, suggestion, or money to:

   		Rich DeJordy
   		American Mathematical Society
   		P.O. Box 6248
   		Providence, RI 02940
   		(401)455-4029

   		Internet;  RAD@MATH.AMS.COM