***** File SUMMARY.TXT The volume of ground-based Halley data archived by the nine IHW Disciplines is sufficiently large that, even when the Large-Scale Phenomena (L-SP) image arrays have been substantially subsampled, five CD-ROMs (IHW Volumes 19-23) are required to hold the data. The full-resolution L-SP images themselves take up 18 CD-ROMs (Volumes 1-18). Not including the separate header (extension=.HDR) and PDS label (.LBL) files, the number of datafiles on the so-called "mixed discs" (Volumes 19-23) is 37,844. Due to the archiving of multiple observations within FITS tables by some of the Disciplines, the number of individual IHW observations is substantially greater than the file count just mentioned, however. The table below lists the number of observations for each of the IHW Disciplines and sub-Disciplines: TABLE I NUMBER OF INDIVIDUAL OBSERVATIONS FOR EACH IHW DISCIPLINE DISCIPLINE Sub-DISCIPLINE NUMBER Astrometry 6475 Infrared Studies Image 95 Photometry 2204 Polarimetry 137 Spectroscopy 84 Large-Scale Phenomena 3383 Meteor Studies Radar 6962 Visual 1624 Near Nucleus Studies 3523 Photometry & Polarimetry Broad Band 3318 Narrow Band 18495 Polarimetry 752 Stokes Parameter 164 Radio Studies Continuum 97 Occultation 6 OH (molecule) 1657 Radar 1 Spectral Line 189 Spectroscopy & Spectrophotometry 3368 Amateur Observations Drawing 1294 Photography 2170 Spectroscopy 45 Visual 11641 The actual number of files is larger than 37,844 because that count does not include FITS headers and PDS label files. There are 5468 "dataless" observations (header and label files only), making the total data-related file count (2*5,468 + 3*32,376) = 108,064. Also, there are 2717 directory files not included in the counts. On these mixed discs (Volumes 19-23) the Halley and Halley-related data are located in chronological directories. The directory names are based on date, specified by the year, month, UT day and hours; not all directory names include all these time parameters. The naming of data directories by time means that the disc "time splits" can be shown by listing the first and last data directories for each CD-ROM Volume: Chronological Range of "Mixed" CD-ROMs disc start date stop date 19 /Y1981/ /Y1985/M12/D08/ 20 /Y1985/M12/D09/ /Y1986/M02/D09/ 21 /Y1986/M02/D10/ /Y1986/M04/D13/ 22 /Y1986/M04/D14/ /Y1987/M04/D03/ 23 /Y1987/M04/D04/ /Y1989/M04/D12/ Some Disciplines submitted non-Halley data, which include filter tables, non-comet images, flat fields, and laboratory spectra. While many of these have been placed in the standard (chronologically-based) data directories, they have also been located in separate directories on Volume 23: specifically, CALIB and IR_FILTR. Finally, Astrometry data sets for the apparitions of 1835 and 1909 are contained in separate directories on Volumes 19-23, and the entire Meteor Studies Discipline dataset is contained in a dedicated directory on Volume 23. The IHW dataset collection includes images, spectra, data tables, textual descriptions, and indices; as indicated earlier, some "dataless" files only point to existing observations but do not include data. To provide the Archive user the ability to conduct sophisticated searches based on time, IHW Discipline, or any in a wide variety of FITS keywords, several types of indices have been placed on these discs. The so-called "Quick Look Indices", whose files are named QUIK_0nn.* (where nn=19-23), contain all the mandatory IHW keywords for each of the archived datafiles (including dataless); these indices are located in the /INDEX directory on each disc, and corrected versions of all five indices have been placed in the /SUMMARY/INDEX directory of this disc (Volume 23). Several of the Disciplines wished to index more than just the mandatory keyword set and constructed "Discipline-specific indices", which contain entries for nearly all of the FITS keywords present in the respective headers. These indices, which bear the generic name NET*.*, are contained in the /INDEX/NETABLES directory of each mixed disc, as are indices containing parameters which may be published in the so-called "Printed Archive". Of the latter (Printed Archive) indices, there is with one exception (Radio Studies Spectral Line index, which includes OH data) one index table per Discipline or sub-Discipline, and contained in some of these indices are actual data. Thus, such indices are directly useable (without referring to the original datafiles), to plot light curves, extract positions, and identify meteor trails, for example. Production of these IHW CD-ROMs took place at the NASA/Goddard Space Flight Center after all the IHW data were transferred from the IHW Lead Center at JPL to NASA/GSFC in 1990-1991. The actual production benefited from a number of factors: use of the National Space Science Data Center's (NSSDC) CD-ROM pre-mastering facility; a number of outside peer reviews of two prototype test discs; and the generation of CD-ROM Write Once discs at the Data Distribution Lab of the PDS at JPL. A more complete discussion of how the final CD-ROMs were made is contained in the files ACKNWLDG.TXT and VOLINFO.TXT on this disc. Finally, there are two important printed volumes to mention. The Comet Halley Archive Summary Volume edited by Sekanina and Fry (1) contains chapters from each of the Discipline Specialist Teams describing the collection and processing of the data. Other articles enumerate activites associated with actual production of the CD-ROMs, from which this discussion has been drawn. A second production (2) due out is the IHW Atlas of Large-Scale Phenomena (Brandt, Niedner, and Rahe, 1992) that is being produced at the University of Colorado/Laboratory for Atmospheric and Space Physics (a comet subnode of PDS Small Bodies Node). There has been no decision regarding an independent Printed Archive volume(s); however, now that the data have been transferred to NASA/Goddard Space Flight Center (cf. ACKNWLDG.TXT and VOLINFO.TXT files on this disc), there are renewed discussions to make a version of the Printed Archive to complement the IHW CD-ROMs. 1. Sekanina, Z. and Fry, L. (1991), The Comet Halley Archive Summary Volume, JPL 400-450, Jet Propulsion Laboratory, Pasadena, California, August, 1991. 2. Brandt, J. C., Niedner, M. B., and Rahe, J. (1992), IHW Atlas of Large-Scale Phenomena, in press.