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DOCUMENTATION FOR THE ASTRONOMICAL DATA CENTER CD ROM TEST DISK Document Number STX-T-1-3002-3007-88 Lee E. Brotzman Contract NAS5-28752 Prepared for: National Aeronautics and Space Administration Goddard Space Flight Center Greenbelt, MD 20771 Prepared by: ST Systems Corp. 4400 Forbes Blvd. Lanham, MD 20706 TABLE OF CONTENTS _________________ 1.0 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2.0 THE ASTRONOMICAL DATA CENTER (ADC) . . . . . . . . . . . . . . . . . 2 3.0 THE ADC CD ROM TEST DISK . . . . . . . . . . . . . . . . . . . . . . 3 3.1 Hardware and Software Requirements . . . . . . . . . . . . . . . . . 3 3.2 Directory Layout . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3.3 File formats and naming conventions . . . . . . . . . . . . . . . . 5 4.0 THE ADC CD ROM STUDY . . . . . . . . . . . . . . . . . . . . . . . . 8 4.1 Deciding on the Technology . . . . . . . . . . . . . . . . . . . . . 8 4.2 Selecting the Data . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.3 Selecting the Data Format . . . . . . . . . . . . . . . . . . . . . 9 4.4 Test Disk Data Processing . . . . . . . . . . . . . . . . . . . . . 10 4.4.1 Catalog Files . . . . . . . . . . . . . . . . . . . . . . . . . 10 4.4.2 Documentation . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.4.3 Pre-Mastering . . . . . . . . . . . . . . . . . . . . . . . . . 12 4.5 Future Projects . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5.0 COMPACT DISK READ ONLY MEMORY . . . . . . . . . . . . . . . . . . . 15 5.1 CD ROM Disks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 5.1.1 Physical Characteristics . . . . . . . . . . . . . . . . . . . . 15 5.1.2 Logical Characteristics. . . . . . . . . . . . . . . . . . . . . 16 5.1.3 Production . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 5.2 CD ROM Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . 18 5.3 CD ROM Software . . . . . . . . . . . . . . . . . . . . . . . . . . 20 6.0 ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . 21 APPENDIX A. TEST DISK REFERENCES AND NOTES . . . . . . . . . . . . . . . 22 APPENDIX B. HAVING PROBLEMS? . . . . . . . . . . . . . . . . . . . . . . 29 APPENDIX C. USER COMMENT FORM . . . . . . . . . . . . . . . . . . . . . . 30 Table of Contents ii 1.0 INTRODUCTION _________________ In August, 1987, the Astronomical Data Center (ADC), headed by Dr. Jaylee M. Mead (Code 630, NASA/GSFC), began to study the feasibility of placing a set of astronomical catalogs onto a Compact Disk Read-Only-Memory (CD ROM). After acquainting ourselves with the advantages and tradeoffs associated with CD ROM technology, the basic design of a single "test disk" was drawn up. A catalog selection list was drafted, the directory and data file structures decided on, and facilities for producing the disk located. After several revisions to the original plan a test disk has been produced. The purpose of this document is to provide information about the contents and format of the ADC CD ROM Test Disk. Section 2 provides a brief overview of the Astronomical Data Center itself. Section 3 describes the overall contents and format of the Test Disk, while Appendix A gives individual catalog references and production notes. Section 4 goes into the study, design and data processing that resulted in the production of the Test Disk. Section 5 is a short introduction to CD ROM technology, including: physical characteristics of CD ROM disks; logical characteristics, primarily the ISO 9660 Standard volume and directory format; how CD ROMs are made; and the hardware and software required to access them. Sections 3 and 4 assume that the reader has some knowledge of CD ROMs and the terminology associated with them. If you are unfamiliar with the medium, we suggest that you scan Section 5 first so that the rest of the document will be more easily understood. Introduction 1 2.0 THE ASTRONOMICAL DATA CENTER (ADC) _______________________________________ The ADC acquires, verifies, modifies, documents, and distributes astronomical catalogs in computer-readable form. It also develops and maintains software tools to access these data. Currently, the ADC archives hold some 450 catalogs of astrometry, photometry, spectroscopy, and other miscellaneous data for stellar and nonstellar objects. To date, the ADC has distributed more than 6000 catalogs on tape, microfiche, and paper to more than 800 individual requesters. The ADC has provided data and software to several NASA space astronomy working groups including those for the Infrared Astronomical Satellite (IRAS), the International Ultraviolet Explorer (IUE), the Hubble Space Telescope (HST), the Cosmic Background Explorer (COBE), and the ASTRO Ultraviolet Astronomy Mission. The ADC maintains a dial-up service that allows users to interactively search for bibliographical references by entering the names of individual astronomical objects. For the last year and a half, the ADC has been using the BITNET and SPAN computer networks to distribute astronomical data, avoiding the hassles and time delays of sending magnetic tapes through the mail. The ADC consists of two cooperative groups working under separate contracts to the Space Data and Computing Division (Code 630) at NASA Goddard Space Flight Center. One group, headed by Dr. Wayne H. Warren Jr., works under the auspices of the National Space Science Data Center (NSSDC) and its supporting contractor, Science Applications Research (SAR). This group is mostly responsible for acquisition, verification, documentation, and distribution of catalogs, and has developed an on-line program to request data over SPAN. The other group, headed by Mr. Lee E. Brotzman, ST Systems Corp. (STX), was originally a part of the Laboratory for Astronomy and Solar Physics, but was moved to the Space Data and Computing Division when Dr. Mead took a position there. This group is responsible for catalog verification and documentation, software development and maintenance, and development of new tools and methods for dealing with technological advancements. The Astronomical Data Center (ADC) 2 3.0 THE ADC CD ROM TEST DISK _____________________________ This section discusses the hardware and software requirements, general layout, naming conventions, and file formats for the Test Disk. See "Appendix A. Test Disk References and Notes" on page 22 for complete references and production notes for each of the catalogs on the disk. 3.1 HARDWARE AND SOFTWARE REQUIREMENTS _______________________________________ As outlined in "Compact Disk Read Only Memory" on page 15, there can be quite a bit of variation in the host computers, operating systems, CD ROM readers, and driver software. How you go about opening, reading, and closing files on the CD ROM depends on the particular set-up at your site. In general, though, it is important to know that the ADC CD ROM has been made to the volume and directory specifications laid down in the ISO 9660 Standard, not its precursor called High Sierra Format. For users of MS-DOS computers, this means that you must have Microsoft CD ROM Extensions Version 2.0 or later in order to read the disk. Users of Sun or MicroVAX computers should check to make sure that the driver software they have is compatible with the ISO 9660 Standard. There are no executable programs or any other binary data on the CD ROM; all the data are in the form of ASCII characters. After the CD ROM reader and its driver software have been installed, all of the data files should be accessible to ordinary tools that manipulate character data, such as browse and list programs. 3.2 DIRECTORY LAYOUT _____________________ The Test Disk is divided into five major subdirectories, each one corresponding to a different astronomical discipline. Within each discipline subdirectory, each catalog resides in its own individual subdirectory. Subdirectory pathnames are given below: ASTROM Astrometry AGK3 AGK3 Catalogue YTP Yale Catalog of Trigonometric Parallaxes SAO SAO Star Catalog The ADC CD ROM Test Disk 3 PHOTOM Photometry ANS ANS Ultraviolet Photometry UBV86 UBV Photoelectric Photometry IRASPSC IRAS Point Source Catalog Version 2.0 IRASSSC IRAS Serendipitous Survey Catalog CIO Catalog of Infrared Observations GCVS4 General Catalog of Variable Stars, 4th ed. NSV New Catalog of Suspected Variables SPECTRO Spectroscopy and spectrophotometry MHD1 Mich. 2-D Spectral Types for HD Stars, Vol. 1 MHD2 Mich. 2-D Spectral Types for HD Stars, Vol. 2 MHD3 Mich. 2-D Spectral Types for HD Stars, Vol. 3 MHD4 Mich. 2-D Spectral Types for HD Stars, Vol. 4 MKEXT MK Classification Extension ATLAS Stellar Spectrophotometric Atlas 3130 - 10800 A LIBRARY Library of Stellar Spectra HD Henry Draper Catalog and Extension NONSTELL Nonstellar and extended objects, galactic and extragalactic RNGC Revised New General Catalogue PLN Strasbourg Catalogue of Planetary Nebulae UGC Uppsala General Catalog of Galaxies ESOUPP ESO/Uppsala Survey of the ESO(B) Atlas RADIO4C Fourth Cambridge Survey of Radio Sources IRASSSS IRAS Small Scale Structures Catalog MERCG Merged Catalogue of Galaxies QAGN3 Catalogue of Quasars and Active Galactic Nuclei The ADC CD ROM Test Disk 4 MISC Combined and derived data from various sources SAOXIDX SAO-HD-GC-DM Cross Index BSC4 Bright Star Catalogue, 4th Revised Ed. BSC4S Supplement to the Bright Star Catalogue CLAS Combined List of Astronomical Sources ISOCHRON Revised Yale Isochrones and Luminosity Functions The manner in which these subdirectories are referenced depends on the specific host computer, operating system, and CD ROM driver software being used. In the remainder of this document, MS-DOS directory names will be used, without the specific drive letter specification. For example, \ASTROM\AGK3\AGK3.DOC is the pathname of the document file for the AGK3 Catalogue. If the CD ROM reader is installed as drive F, the full name should be prefixed with "F:". Under the UNIX operating system, this file may be called /cd/astrom/agk3/agk3.doc, whereas under the VMS operating system it may be SYS$CDROM:[ASTROM.AGK3]AGK3.DOC. You should refer to the system documentation for your particular computer set-up to determine how to navigate the CD ROM directory structure. 3.3 FILE FORMATS AND NAMING CONVENTIONS ________________________________________ Within each catalog subdirectory, file names are restricted to no more than eight characters plus a three character extension. This follows the naming rules for Level 1 of the ISO 9660 Standard (see "Compact Disk Read Only Memory" on page 15). There are only two basic file formats on the Test Disk: MS-DOS text files and FITS tables. In text files, all the records are separated from each other by an end-of-line sequence consisting of a carriage return (decimal value 13; hex 0D) and a linefeed (decimal value 10; hex 0A). References to the end-of-line sequence will be abbreviated as CR/LF throughout the rest of this document. The end-of-file mark is a Control-Z (decimal value 26; hex 1A). FITS tables adhere to the rules for tables extensions described in Harten, R.H., Grosbol, P., Greisen, E.W., and Wells, D.C. 1988, Astron. Astrophys. Suppl. 73, 365. These files are byte streams which can be thought of as 2880-byte fixed-length records without any intervening CR/LF sequences or other carriage control. The file extension denotes the kind of information that can be found in a particular file, as follows: The ADC CD ROM Test Disk 5 DOC Catalog documentation file. The documents describe in detail the individual fields for each catalog file, as well as overall characteristics like the record length and the number of records. It is strongly recommended that the documentation be printed and studied thoroughly before work with a catalog begins. Catalog documents are text files with variable-length records. Page separators are indicated by the form-feed character (decimal value 12; hex 0C). The documents can be printed on any laser, dot-matrix, or impact printer that accepts ASCII carriage control characters. The recommended printer settings are: 12 characters per inch horizontal spacing, 60 lines per page, and a left margin of 5 characters. The catalog documents contain only standard ASCII characters. There are no special character codes for Greek letters, super- or subscripts, mathematical formulae, etc. The original documentation came from many different sources (see "Documentation" on page 11), so the amount of information and the way it is layed out in the text file varies. No effort was made to expunge older documents of references to "tape files" or "tape formats", although for the CD ROM the word "tape" is clearly not relevant. TXT These are the catalog files themselves, in text file format. Trailing blanks at the end of the catalog records were left intact, so the records are of fixed length. The actual record length is two bytes longer than that given in the catalog documentation, because of the CR/LF sequence between each record. For example, the record length of the file of references for the UBV Photoelectric Photometry Catalogue (\PHOTOM\UBV86\REFS.TXT) is given in the documentation as 80 bytes. The actual record length on the Test Disk would then be 82 bytes, including the CR/LF. You would use this information if you wished to write a program that performed direct access reads of file records keyed by record number. To find the starting position of a record, R, given the record length, L, you can use the formula POS = (R-1)*(L+2) assuming that byte position 0 is the first character in the file. HDR This is a copy of the FITS table extension header for the catalog file of the same name, for instance, SAO.HDR is the FITS header which describes SAO.TXT. Header files are in text file format with 82-byte records (80 bytes data plus CR/LF). The header records have been included here so that they can be inspected easily without writing programs to manipulate the FITS tables themselves. FIT This is a standard FITS table extension file for the catalog. In the case of catalogs which have more than one table (file), all tables are concatenated into a single FITS file, as outlined in the papers describing FITS generalized extensions and the FITS tables The ADC CD ROM Test Disk 6 extensions published in the Astronomy and Astrophysics Supplement. (Copies of these papers in the form of input files for the LATEX text processing program are provided in the root directory of the Test Disk.) The FITS files are meant to be used mainly for loading the catalogs into the major astronomical data analysis packages such as AIPS, MIDAS and STSDAS. The MS-DOS FITS browsing software provided with the Test Disk allows users of IBM PCs and clones to "leaf through" these files more easily. The ADC CD ROM Test Disk 7 4.0 THE ADC CD ROM STUDY _________________________ 4.1 DECIDING ON THE TECHNOLOGY _______________________________ The ADC began investigating the use of optical media for distributing astronomical catalogs in August, 1987. Several ADC members attended the Capitol Microcomputer User's Forum, which hosted a conference to introduce interested parties to CD ROM technology. Everything we heard was encouraging. The overall cost of CD ROMs was not as high as expected: mastering the disk would cost about $10,000 with each replica costing about $20. The cost of the hardware was low: drives were then going for around $1000. Since that time, costs have dropped dramatically: to less than $2000 for mastering and $2 per disk for replication, and drives selling for under $700. Experts in preparing data for CD ROM also stated that regular tabular data with simple uniform formats was the easiest type to use: all the ADC catalogs fall into this category. Our research into other optical media like video discs and Write Once Read Many (WORM) drives revealed several problems. These systems were costly and have no accepted industry standard for volume, directory, or file formats. The performance of many of these systems is superior to CD ROM, however, in both the amount of available storage and in access speed. The final decision to support CD ROMs over other optical mass storage media was based primarily on the lack of broadly accepted format standards for the latter. Access to data stored on CD ROM is cheaper for the end user as well. The unit cost of a CD ROM disk is much less than other optical media and the hardware that reads it is generally an order of magnitude less expensive. 4.2 SELECTING THE DATA _______________________ The ADC archives hold more than 500 astronomical catalogs containing many different types of data. Users of the data come from a variety of disciplines. The selection criteria to choose a few catalogs from the complete archive had to take this into account while at the same time limiting the number of selections to a reasonable quantity. First, an analysis of our requests from the last three years was used to pick out those catalogs that are asked for most often. Any catalog requested four or more times was automatically placed on the selection list. Then the "Status Report on Machine-Readable Astronomical Catalogs", the document which describes the ADC's catalog inventory, was consulted to select other catalogs based on the scientific value and quality of the data. The ADC CD ROM Study 8 A total of 31 catalogs, nearly 300 Megabytes of data altogether, was placed onto the final selection list. "Appendix A. Test Disk References and Notes" on page 22 gives complete references and production notes for the catalogs, listed by the name of the discipline subdirectory and catalog subdirectory where each can be located on the Test Disk. 4.3 SELECTING THE DATA FORMAT ______________________________ After selecting the individual data files to put onto the CD ROM disk, it became necessary to decide on the file format they would be stored in. In the fall of 1987, NASA hosted the Second Astrophysics Data Systems Workshop in Columbia, Maryland. At this meeting, Dr. Mead presented our initial plans for the ADC CD ROM project. The plan called for the first disk to have the catalogs in regular fixed-length record format, provide a moderate amount of data indexing for the files, and include some supporting software for MS-DOS desktop computers. After gaining experience in the technology, a second disk would be prepared which contained catalogs formatted as FITS tables, used more extensive data indexing, and had enhanced access and retrieval software. Several workshop participants advocated FITS tables format for any CD ROM produced by the ADC. FITS (for Flexible Image Transport System) was created in the late 1970's to provide a standard storage and distribution format for image data. FITS was adopted by the International Astronomical Union (IAU) as the standard distribution format for images in September 1982. Extensions to FITS for handling uniform tabular data were written and presented to the IAU for adoption in mid-1987. The attendees at the Astrophysics Data Workshop strongly urged the ADC to follow the guidelines they set down regarding distribution of astronomical data, namely FITS tables should be supported immediately. Since FITS tables were relatively new and not well supported by the major astronomical data analysis packages, the ADC had not yet moved to support them. The effort that would be needed to create accurate FITS headers (the data records that describe the numerical format of each field of a catalog), convert catalog files into FITS format, and check the conversion with one of the astronomical data analysis packages seemed to be beyond the scope of the limited plan for the first ADC CD ROM. In order to get more information, and explain the position the ADC was in, ADC personnel hosted a round-robin exchange of electronic mail over the SPAN network with several of the principals in the FITS and CD ROM arenas. The participants included the ADC staff, Dr. Don Wells of NRAO and co-author of the FITS standard, Dr. Bob Hanisch of STScI and president of the AAS Working Group on Astronomical Software (WGAS), Dr. Peter Shames also of STScI, Mr. Mike Martin of the JPL Planetary Data Systems Group who has already produced several CD ROM disks, Mr. Archie Warnock of the International Halley Watch (IHW), and Dr. Ed Grayzeck also from IHW and an advisor to the ADC on CD ROM technology. The ADC CD ROM Study 9 The "CD ROM Discussion Group", as we came to call ourselves, spent most of January 1988 talking back and forth about FITS format versus plain fixed-length text files and supporting desktop machines versus larger workstations able to run the large analysis packages. CD ROM technology is mostly employed on desktop machines like IBM PCs, which have no software that makes use of FITS tables. The more powerful workstations, like Sun and MicroVAX, have FITS-reading software, but CD ROM disks have not been well supported. It was difficult to find one solution that satisfied all points of view. Also in January 1988, the ADC mailed a survey to 450 requesters of digital data from the last three years. The survey asked about basic services, use of computer networks for catalog distribution, interest in astronomical catalogs on CD ROM, and use of FITS tables for ADC catalogs. The ADC received 160 responses to the questionnaire. Roughly half of those responding expressed an interest in receiving a CD ROM containing astronomical catalogs. Of those, only 15% said they would actually prefer the catalogs to be in FITS format and an additional 6% said they would prefer both FITS tables and regular flat text files. The results of the E-mail discussion and the ADC User Survey made it apparent that to produce a disk using only one file format would needlessly exclude a large portion of the community. In order to service as many users as possible, it was decided to amend our original plan for two disks - one with text files and one with FITS files - to include both formats on the same disk. As explained in Section 3, the ADC CD ROM Test Disk contains a mixture of text files, FITS headers, and "pure" FITS files. MS-DOS software has been provided to allow PC users to browse the FITS files. 4.4 TEST DISK DATA PROCESSING ______________________________ 4.4.1 CATALOG FILES ____________________ The decision to provide FITS capability on the ADC CD ROM first required that we learn how to create FITS tables, and to make sure that the methods we developed were correct and workable. Although FITS files are sometimes called "self-documenting", it was immediately apparent that the ADC could not include within the confines of the FITS header itself the kind of complete scientific documentation we normally provide with our catalogs. Therefore, it was decided that the FITS headers would contain simply the normal field format information (e.g. field start position and FORTRAN format) with perhaps some small amount of further information when appropriate. Comment records were added to direct the user to the complete hardcopy documentation for questions about the contents of the fields. The ADC CD ROM Study 10 In order to test the FITS tables, a tape was prepared containing the following catalogs: 1. The Bright Star Catalog, 4th Ed. 2. Uppsala General Catalog of Galaxies 3. Smithsonian Astrophysical Observatory Star Catalog 4. AGK3 Catalogue of Positions and Proper Motions 5. Combined List of Astronomical Sources, Version 3.1 The tape was sent to the software development teams for all of the major astronomical data analysis packages: AIPS, IRAF, STSDAS, MIDAS, and PDS. After some small problems were ironed out, the FITS tables were found to be correct and in a usable form. Work was begun immediately to create FITS headers for the remaining 26 catalogs on the CD ROM catalog selection list. At the same time, FORTRAN source code for testing, validation and verification of FITS tables was obtained from Dr. Preben Grosbol at the European Southern Observatory, in Garching, Federal Republic of Germany. The code was modified slightly to work as a background job on the NASA Space and Earth Sciences Computing Center (NSESCC) IBM 3081. This speeded up the test phase significantly, since the data were already archived in the tape library for that system and the IBM 3081 has much greater processing power than the available VAXen. Finally, a short program was written that converted the catalogs as stored in the ADC archives (fixed-length EBCDIC character files) to a form that was acceptable to the CD ROM pre-mastering workstation (ASCII character files with records terminated by CR/LF end-of-line sequences). 4.4.2 DOCUMENTATION ____________________ The question of how to document the individual catalogs was particulary thorny. It is inappropriate and unreasonable to send a stack of thirty-some hardcopy catalog documents with the CD ROM. On the other hand, none of the catalog documentation was in a form that would be useful if placed onto the CD ROM. Some of the documents were produced on obsolete word processors and no longer existed in machine-readable form. Others were stored on floppy disks for a word processor soon to be retired. A handful of documents had been written by the original authors and were only available in hardcopy. The rest were stored on the NSESCC IBM 3081 as input files for the SCRIPT/VS text processing system. It was decided to create plain ASCII text files from each of the above sources of documentation, rather than convert the whole set to some word processing format. While the documents lose some of the ease of expression The ADC CD ROM Study 11 of scientific notation, they have the advantage of being universally readable and understandable. Simple ASCII text files can be called up directly to one's terminal and scanned easily, while word processor-specific files and the input files for text processing programs such as SCRIPT and TEX are generally only readable after printing. The documents available only in hardcopy form were simply retyped into text files. The other word processor documents were stripped of the special notation for such things as Greek letters, superscripts, and subscripts and downloaded to an IBM PC/AT for final conversion into text files. The SCRIPT/VS input files were formatted to disk file targets, after being modified to eliminate the aforementioned special notation. 4.4.3 PRE-MASTERING ____________________ The ADC CD ROM Test Disk was pre-mastered using the NSSDC's CD Publisher (tm) workstation from Meridian Data, Inc. This workstation has a 6250 BPI nine-track tape drive and 1.2 Gigabytes of hard disk storage, which can be formatted in MS-DOS, High Sierra, or ISO 9660 partitions of up to 660 Megabytes each. An IBM PC/AT is used to control the unit, running programs that load the CD ROM data, make tape backups of the hard drives, and create the pre-mastered tape copies of the CD ROM in whatever format is required by the CD mastering and pressing facilities. The most important feature of the CD Publisher is its ability to perform real-time simulations of a variety of CD ROM drives. This gives a developer the chance to look at the data files and access software and, if necessary, change the disk layout and/or software to optimize performance. This happens before money is spent on pressing the CD ROM. The catalog, FITS header, and FITS table files were copied to a set of five input tapes in the same format and in the same order that they were to be copied to the CD Publisher's hard disks. The document files were put onto a set of floppy disks, then copied to a subdirectory on the hard disk of the IBM PC/AT controlling computer. The process of building the CD ROM proceeded as follows: 1. A 630 Megabyte MS-DOS partition and a 640 Megabyte ISO 9660 partition were created on the CD Publisher. 2. The primary document files were copied to the root directory of the MS-DOS partition. 3. For each major discipline subdirectory: a. The discipline subdirectory was created. b. For each catalog in the discipline: The ADC CD ROM Study 12 1) The catalog subdirectory was created. 2) The catalog document file was copied from the IBM PC/AT hard disk to the subdirectory. 3) The catalog, FITS header, and FITS files were copied from the appropriate input tape. 4) A set of test and browsing programs was run to ensure that the files placed in the subdirectory had the correct size, record length, and record format. 4. The MS-DOS partition was copied as a whole to the ISO 9660 partition. 5. The Publisher was put into simulation mode and the test and browsing software was run on randomly selected files to ensure that the Test Disk was correct. 6. The ISO 9660 partition was copied to a set of pre-master output tapes for shipping to the CD ROM mastering and replication plant. 4.5 FUTURE PROJECTS ____________________ After the ADC CD ROM Test Disk has been tested and reviewed by the community, the ADC hopes to apply the technology to other areas. A partial list of the possibilities follows, but please bear in mind that no firm plans have been made to implement any of these ideas. o ADC Library. A library of all ADC catalogs that are of A-status, meaning those catalogs which have been through our verification and documentation process. Currently about half of the archived catalogs fall into this category. The file formats used in the Library disks would depend on the results of the Test Disk review. Since catalogs are constantly being added, deleted, and/or superseded, some periodic updates to the CD ROM library would be necessary. o DISCO. The ADC has produced an index of data from orbiting astronomical platforms called the Data Inventory of Space-Based Celestial Observations. A CD ROM containing this master index and all of the original data files would be a useful tool for future space astronomy mission planning. o CLAS. The Combined List of Astronomical Sources is like DISCO in that it represents a compilation of data from many different catalogs. The CLAS provides names, coordinates, brightnesses, and extent on the sky in a uniform format for objects such as galaxies, planetary nebulae, X-ray sources, and variable stars. Together with the complete original catalogs, CLAS could be very useful for planning observing runs and making plots of sky fields. The ADC CD ROM Study 13 o SIMBAD. The Centre de Donnees Astronomique de Strasbourg (CDS) maintains an extremely large, complete, and up to date database of astronomical data and references which is accessed through its own software. The CDS has considered releasing a subset of the database on tape for distribution by other data centers. It would be an interesting project to place these data onto a CD ROM and to create SIMBAD-like supporting software, thus reducing the need to perform costly overseas network connections on a regular basis. As with the ADC Library, the SIMBAD CD ROM would need periodic update. In addition, the ADC, through the experience gained as a result of the ADC CD ROM study, plans to provide assistance to other groups that are interested in using the technology. The ADC CD ROM Study 14 5.0 COMPACT DISK READ ONLY MEMORY __________________________________ CD ROM technology gives the ADC an entirely new way to archive and distribute large volumes of data. The high storage capacity and low error rate of CD ROM disks make for a very effective data storage and retrieval medium. The following sections give a brief overview of CD ROMs, the hardware and software needed to access them, and costs associated with publishing the disks. For more detailed information, refer to CD ROM 2: Optical Publishing (Microsoft Press 1987), from which much of the following information was taken. 5.1 CD ROM DISKS _________________ 5.1.1 PHYSICAL CHARACTERISTICS _______________________________ The CD ROM disk is an optical read-only storage medium that can hold up to 680 Megabytes of data. The "physical format" of the disk describes how the tiny pits in the medium are translated into data bits; lays down the size and location of data sectors; defines error detection and correction codes; and describes all other attributes of the physical medium. It is completely described in a document written by Philips and Sony called the Yellow Book. The Yellow Book specification has been accepted as an industry-wide standard, which means that a disk made to these specifications will be readable at the data-sector level in any manufacturer's drive. The data sectors on magnetic disks are usually arranged in concentric circles or tracks, with a fixed number of sectors in each track. The disk drives spin at a constant rate, or "constant angular velocity" (CAV). The recording medium at the outer edge of the disk passes under the read/write mechanism faster than at the inner edge. This means that the bits stored on the outer part of the disk must be farther apart from each other; i.e., the data sectors are physically longer, than bits stored on the inner edge. The sectors on a CD ROM are arranged in a tight spiral growing outward from the center of the disk, like the groove on an LP record. CD ROM disks are accessed with "constant linear velocity" (CLV). When the read head moves toward the outer edge of the disk, the spin rate of the disk slows down. The rotational rate is specified in the Yellow Book to be 200 rpm at the outer radius of the disk and 530 rpm at the inner radius. With the CLV approach, the sectors are all the same physical length, which means that more sectors can be packed onto the disk than would be possible Compact Disk Read Only Memory 15 using CAV. One cannot escape from the traditional space vs. time tradeoff, however. More data can be stored on a CD ROM, but access times become slower. The measurement of the time needed to seek from an inner sector to an outer sector must not only take into account the time to move the reading machanism, but also the time to change the spin rate. Seek times are discussed more thoroughly in a later section. Each CD ROM data sector contains 2352 bytes of information divided up as follows: ----------------------------------------------------------------------------- Synchronization Data 12 bytes Header Data 4 bytes User Data 2048 bytes Error Detection Code (EDC) 4 bytes Unused Space 8 bytes Error Correction Code (ECC) 276 bytes ----------------------------------------------------------------------------- As you can see, each sector holds 2 kilobytes of user data. The header data hold the sector address, which is a reflection of the CD ROM's origins in CD audio. A sector address is split up into "minutes," "seconds," and "sectors." A minute has, of course, 60 seconds, and a second is divided into 75 sectors. The address of the first sector on the disk is defined as 00:00:00, the address of the 152nd sector is 00:02:01, and so forth. Each disk typically can hold 60 minutes of data which translates into 270,000 sectors (60 x 60 x 75), or 540 Megabytes. It is possible to produce disks with up to 70 or 75 minutes of data. One advantage of CD ROM over magnetic media is in the error detection and correction codes provided in every sector. The EDC and ECC are used by a sophisticated algorithm based on the Reed-Solomon error correction scheme. This allows the CD ROM to maintain an error rate of 1.0E-12 bits, or about 1 unrecoverable bit error in every 2000 disks. The current shelf-life of a CD ROM is rated at around ten years, or roughly twice as long as magnetic tape. The actual shelf-life is dependent on the care with which the CD ROMs are produced, and how harshly they are handled in the field. 5.1.2 LOGICAL CHARACTERISTICS. _______________________________ As stated above, the physical format of the CD ROM disk is completely defined and accepted throughout the industry. It is not something the end user needs to be concerned with, or even aware of. The "logical format" of a disk, however, is another matter. While it is possible for any CD ROM drive to read any CD ROM at the sector level, the way that the data in each sector are interpreted depends on the logical format selected for the disk. Compact Disk Read Only Memory 16 In the early history of CD ROMs (which was only a few years ago), several companies developed their own proprietary logical formats for the disks they published. Some were patterned after the "hierarchical" file structures of popular operating systems like MS-DOS, VMS, and UNIX. Others were more exotic, specialized formats such as "hashed file organization" or "tree directories". Incompatibilities between systems and the mounting confusion and frustration of end users led a group of industry leaders to converge on a single, standardized logical format. In 1985, all the companies working in the CD ROM field were invited to send representatives to a meeting at the High Sierra Casino and Hotel in Lake Tahoe, Nevada, to write a proposal for a standard CD ROM file structure. The result of their effort has come to be known as "High Sierra Group Format Description", or just High Sierra format for short. High Sierra format is now supported by most CD ROM hardware and software vendors. In February 1988, High Sierra format was accepted, with some minor modifications, by the International Standards Organization as the ISO 9660 Standard. ISO 9660 is expected to be adopted by the American National Standards Institute (ANSI) in the near future. ISO 9660 format separates the logical format of the disk into two parts, the "volume table of contents" (VTOC), which is a description of the disk as a whole, and the "directory structure" that describes and locates individual files on the volume. In order to allow for maximum portability and future advancements in technology, ISO 9660 format removes itself from the physical characteristics of the disk as much as possible. The standard uses the terms "logical sectors" and "logical blocks" to describe how specific pieces of information are addressed. As it stands now, a logical sector is equivalent to a physical sector, 2048 bytes, but the physical format can change without affecting the overall logical organization of a volume. The ISO 9660 standard establishes the rules for the structure of files, file identifiers, directories, volume descriptors, and multi-volume sets of disks in a manner that is independant of the operating system being used. Three levels of implementation, called "levels of interchange", are provided for. Level 1 is the simplest level, designed primarily for compatibility with MS-DOS machines. Any CD ROM system that claims to be ISO 9660 compatible must be able to read this format. Levels 2 and 3 provide additional features that most developers on UNIX and VMS systems will find useful, such as 31-character file names, interleaving of file sectors, file extents, and multi-volume sets. One problem with heirarchical directory structures is that they can require many seeks to locate a file in a deeply nested subdirectory. ISO 9660 provides a solution called the "Path Table". The Path Table contains a list of all the subdirectories on the disk and holds the logical block number where that subdirectory can be found. If the Path Table is kept in RAM, only one seek is required to access any subdirectory on the disk. One of the more compelling features of ISO 9660 format is the ability to extend and supplement the directory structure through the use of Extended Compact Disk Read Only Memory 17 Attribute Records (XARs). By placing supplementary data into XARs, ISO 9660 directory records can be kept small, boosting the overall performance of the CD ROM system. XARs can be used by the operating system or application program to hold file protection information, record attributes such as format and record length, file creation and expiration dates, and other application-specific information. Since directories are also files on the CD ROM disk, they may have XARs of their own, providing the CD ROM developer a powerful tool for custom-tailoring a disk to his own needs. 5.1.3 PRODUCTION _________________ The process of creating a set of CD ROMs is split up into several phases: pre-mastering, mastering, and replication. Pre-mastering involves reading in the data files, setting up directories and subdirectories, and verifying the data. It can be done either in-house with a pre-mastering workstation, or by contracting out to a service bureau that specializes in the production of CD ROM disks. CD ROM pre-mastering workstations are equipped with a nine-track tape drive and several high-capacity Winchester disk drives to store the data. Most have a real-time emulation mode to test different disk layouts and application programs before the data are committed irreversibly to read-only optical media. Workstation prices are in the neighborhood of $30,000, depending on the processing power and amount of mass storage desired. A service bureau can be cheaper if one only wishes to produce a few individual CD ROM products, but for long-term projects, the flexibility of in-house production is more economical. The output of the pre-mastering phase is a set of tapes that describes the logical organization of the CD ROM. At the CD ROM production plant, the pre-mastered data tapes are used to create a bit-for-bit image of the final disk, including all the EDC and ECC codes, synchronization data, etc. In a clean-room environment, the CD ROM bit image is "burned" into a glass master disk covered with a photo-resistant chemical layer. The master is developed, silvered, and used to create the "stamper" disk, which is a negative image of the master. Finally, the stamper is used to create the polymer replicas as the final products. Throughout the procedure, the disks are checked for contamination or other sources of error to ensure a high-quality set of replicas. Costs for mastering vary from $1,500 to $3,000 and replicas can range from $2 to $10 apiece. These costs depend on the turnaround time desired, the material used, the artwork on the front of the disk, and the total number of disks to be produced. Compact Disk Read Only Memory 18 5.2 CD ROM HARDWARE ____________________ The hardware required to read the data stored on a CD ROM consists of two components: the drive or "player", and the controller card. CD ROM drives are quite similar to their CD audio counterparts. They use the same laser optics to read the disks, but have faster tracking servos and other electronic differences in order to minimize seek time between tracks and increase data transfer rates. Drives are available in freestanding models that have their own housing and power supply, and internal models that save cost by using the computer's power supply. Some drives are equipped with audio ports which allow developers to create CD ROM multi-media presentations such as computer generated "slide shows" accompanied by narration and/or music. One sore point that arises when dealing with CD ROM systems is that they are slow compared to Winchester magnetic disks. As was mentioned earlier, this is a by-product of using constant linear velocity to access the CD ROM. The average access time of Winchester disks can vary from 30 to 300 msec, whereas the CD ROM drives vary from 300 to 1000 msec. Data transfer rates are also slow. A hard disk can read data at more than 600 kilobits/sec while CD ROM drives are limited to only 150 kilobits/sec. The seek time figures can be a little misleading, however. To read files from magnetic disks, quite often the read head must scan back and forth across the disk to read a file that has been written to many scattered sectors. On a CD ROM, the files are carefully laid out ahead of time in order to keep seek time to a minimum. Most of the computer workstations that prepare data files for CD ROM have a real-time emulation mode so that several different arrangements can be tested and compared BEFORE the CD ROM is manufactured. Statistical programs perform an analysis of the test runs and provide help in selecting the most advantageous layout. The low data transfer rates are more difficult to overcome, but future advancements in technology are sure to speed up both aspects of accessing the disks. Controller cards are attached inside the host computer and cabled to the CD ROM drive. They contain the logic circuitry to control the motion of the laser reading mechanism, perform error detection and correction, and transfer the data to the computer through a standardized hardware interface. Most controller cards are built for the IBM PC/AT/XT data bus or the Small Computer System Interface (SCSI). The SCSI controllers can be attached to Sun workstations and Apple Macintosh computers as well as IBM PCs. Controller cards are also available for MicroVAX, Apple IIe, and other proprietary system buses. As of this writing, external CD ROM drives and controller cards are commonly available for less than $700 retail. Internal full-height and half-height drives for the IBM PC are available on an OEM basis for $500 to $1,000. These prices should continue to drop dramatically through 1989 as more CD ROM applications become available. Compact Disk Read Only Memory 19 5.3 CD ROM SOFTWARE ____________________ Once a person has purchased a CD ROM drive and controller card and one or more CD ROM application disks, he needs to have software to access the data. As with the CD ROM hardware, CD ROM software can be divided into two parts: the device driver, or computer interface, and the application program, or user interface. Device driver software is used to provide a standard interface between a specific computer operating system and a CD ROM system, which consists of a drive, controller card, and the CD ROM disk itself. The device driver translates operating system commands, such as "open a file" or "read a record", into commands for the CD ROM drive/controller card based on the logical format of the CD ROM disk. The price and features of a device driver depend heavily on the host computer. For the IBM PC, the most popular device driver and operating system interface is the Microsoft CD ROM Extensions to MS-DOS, which is included at no extra cost with many CD ROM drives and application disks. Using Microsoft Extensions, Version 2.0, and a ISO 9660-formatted disk, the CD ROM drive looks like another hard drive. There are some restrictions on the DOS commands available, but one can read directories, copy files, type files to the screen or printer, and run programs. Device drivers for Sun workstations and MicroVAX computers are more expensive, and support for ISO 9660 CD ROM disks has only recently been made available. ISO 9660 drivers for MicroVAXen running VMS are expected to be announced in early 1989, but no details are known at the time of this writing. The driver currently available for Sun workstations is very expensive, on the order of $2,000 per copy, and it basically treats the CD ROM as a sequential access device, like a tape drive, rather than as a random access device. A more fully functional Sun driver for ISO 9660 is now at beta test sites around the country and should be available for general use sometime in 1989 at the same price as the previous version. Application software for CD ROMs is generally provided by the vendors of the disks themselves, either directly on the CD ROM or on floppy disk. These software products often use commercial database programs or other proprietary software that is written specifically to work on the data on the respective CD ROMs. It is through these "shell" programs that the user finally gets to individual data items. Application software can vary from rudimentary directory search and file retrieval, to advanced full-text database programs. Almost all applications rely on some form of data indexing in order to minimize the number of read operations required to find an item. The more advanced systems are very impressive, searching an entire encyclopedia's-worth of information in just a few seconds. Compact Disk Read Only Memory 20 6.0 ACKNOWLEDGMENTS ____________________ I would like to take this opportunity to thank a few people for all their help: Ed Grayzeck, for his time and patience in teaching me about CD ROMs, and all his good counsel to the ADC; Mike Martin, for his help with understanding the technology and creating new ways to deal with it; Jerry McFaul, at the U.S. Geological Survey, for allowing us to test our methods on his CD Publisher; Preben Grosbol, at ESO, for the programs that made the creation of FITS tables for the Test Disk much less painful, and for the FITS papers reproduced on our CD ROM; all the members of the CD ROM discussion group for the show of enthusiasm and the stimulating (electronic) conversation; Joe King, for his continued support and the use of the NSSDC CD Publisher; Wayne Warren for his advice on the catalog selection list and for providing the bulk of the catalog documentation for the CD ROM; and finally Jaylee Mead, for without her none of this would be happening. CD Publisher is a trademark of Meridian Data, Inc. IBM PC/AT/XT is a trademark of International Business Machines Corporation. MS-DOS is a trademark of Microsoft Corporation. VAX and VMS are trademarks of Digital Equipment Corporation. Acknowledgments 21 APPENDIX A. TEST DISK REFERENCES AND NOTES __________________________________________ Listed below are references to the astronomical catalogs which appear on the ADC CD ROM Test Disk and some notes about aspects of the data processing that differed from the norm for some of the catalogs. Pathnames are fully qualified subdirectory and/or file names using MS-DOS naming conventions (file names are indicated by a three-character extension). PATHNAME REFERENCES AND NOTES ADCCDROM.DOC Text file version of this document. COMMENT.TXT Text file version of the user comment form appearing at the end of this document. CDTREE.TXT An illustration of the directory structure of the Test Disk, giving all discipline directories, catalog subdirectories and catalog file names. The file is formatted for printing (pages are separated by formfeed characters) at 10 or 12 characters per inch, 60 lines per page. FITSTBLE.TEX AND FITSEXTN.TEX These are copies of the papers describing the FITS tables extension and generalized extensions to FITS which were published in the Astronomy and Astrophysics Supplement Series. They are input files for the LATEX text processing program. NULL.HDR An example of the "null image" header which must appear as the first 2880-byte record in any FITS table extension file. The file is given here because null image headers are not attached to the sample headers in the catalog subdirectories. \ASTROM\AGK3 NAME: AGK3 Star Catalogue of Positions and Proper Motions North of -2.5 Degrees Declination REFERENCE: Heckmann, O. and Dieckvoss, W. 1975, Hamburg- Bergedorf; see also Warren 1978, CDS Bull. No. 15, p. 116. Appendix A. Test Disk References and Notes 22 \ASTROM\YTP NAME: General Catalogue of Trigonometric Stellar Parallaxes and Supplement REFERENCE: Jenkins, L.F. 1963 (New Haven: Yale University Observatory). With corrections and Supplement data added, USNO 1982. \ASTROM\SAO NAME: Smithsonian Astrophysical Observatory Star Catalog, Positions and Proper Motions of 258,997 Stars for the Epoch and Equinox of 1950.0 REFERENCE: Smithsonian Astrophysical Observatory Staff 1966, Pub. of the Smithsonian Institution of Washington, D.C. No. 4652 (Washington: Smithsonian Institution). Revised by the ADC Staff 1984. \PHOTOM\ANS NAME: ANS Ultraviolet Photometry Catalogue of Point Sources REFERENCE: Wesselius, P.R., van Duinen, R.J., de Jonge, A.R.W., Aalders, J.W.G., Luinge, W. and Wildeman, K.J. 1982, Astron. Astrophys. Suppl. 49, 427. \PHOTOM\UBV86 NAME: UBV Photoelectric Photometry Catalogue (1986) REFERENCE: Mermilliod, J.-C. 1987, Astron. Astrophys. Suppl. 71, 413. \PHOTOM\IRASPSC NAME: Infrared Astronomical Satellite Catalog of Point Sources, Version 2.0 REFERENCE: Infrared Processing and Analysis Center [IPAC], 1987 March NOTES: The IRAS PSC appears in three different formats. First, the catalog is given in its original 80-byte record format (PSC.TXT). This format was unsuitable for putting the catalog into FITS tables format, so the original catalog was split into two files, one with the primary source data, another with the source associations alone (SOURCES.TXT and ASSOC.TXT, respectively). These two files were then put into FITS tables format (PSC.FIT). Appendix A. Test Disk References and Notes 23 Catalog documentation, in the form of Wordstar word processing files for Chapters X and XII, was kindly provided by Ms. Rosanne Hernandez, IPAC Librarian. The Introduction to the Explanatory Supplement was typed in at the ADC, and a brief discussion of the FITS formatting of the IRAS PSC was authored at the ADC and included at the end of the document file. \PHOTOM\IRASSSC NAME: IRAS Serendipitous Survey Catalog REFERENCE: Infrared Processing and Analysis Center [IPAC], 1986 December NOTES: Like the IRAS PSC, the Serendipitous Survey Catalog is in three different formats: the original 80-byte record format (SSC.TXT); three files containing the field headers, primary source data, and associations (FIELDS.TXT, SOURCES.TXT, and ASSOC.TXT, respectively); and a FITS file (SSC.FIT). The catalog documentation file was typed in at the ADC and consists of excerpts from the "Explanatory Supplement to the IRAS Serendipitous Survey". The documentation includes the Introduction, Sections V.A and V.B, which describe the machine-readable version of the SSC, and a brief discussion of the FITS formatting of the IRAS SSC that was authored at the ADC. \PHOTOM\CIO NAME: Catalog of Infrared Observations REFERENCE: Gezari, D.Y., Schmitz, M. and Mead, J.M. 1987, NASA Ref. Pub. 1196. NOTES: The documentation file is an updated and extended version of the hardcopy version which accompanied the previous (1984) version of the CIO, written in collaboration with Mr. Schmitz. \PHOTOM\GCVS4 NAME: General Catalogue of Variable Stars, 4th Edition REFERENCE: Kholopov, P.N., Samus', N.N., Frolov, M.S., Goranskij, V.P., Gorynya, N.A., Kireeva, N.N., Kukarkina, N.P., Kurochkin, N.E., Medvedeva, G.I., Perova, N.B., and Shugarov, S.Yu. 1985-1988 (Moscow: Nauka Publishing House). Appendix A. Test Disk References and Notes 24 NOTES: The catalog documentation was derived from a SCRIPT/VS text processor input file, which was written at the ADC. The document contained much scientific notation that had to be annotated for the text file version, and a table which defines the Johnson UBV spectral bandpasses was deleted. \PHOTOM\NSV NAME: New Catalogue of Suspected Variable Stars REFERENCE: Kukarkin, B.V., Kholopov, P.N., Artiukhina, N.M., Fedorovich, V.P., Frolov, M.S., Goranskij, V.P., Gorynya, N.A., Karitskaya, E.A., Kireeva, N.N., Kukarkina, N.P., Kurochkin, N.E., Medvedeva, G.I., Perova, N.B., Ponomareva, G.A., Samus', N.N., and Shugarov, S.Yu. 1982 (Moscow: Nauka Publishing Office). NOTES: See the notes for the GCVS4 above. \SPECTRO\MHD1 NAME: Michigan Catalogue of 2-Dimensional Spectral Types for the HD Stars, Vol. 1 (Declinations -89 to -53 Degrees) REFERENCE: Houk, N. and Cowley, A.P. 1975 (Ann Arbor: Department of Astronomy, University of Michigan). \SPECTRO\MHD2 NAME: Michigan Catalogue of 2-Dimensional Spectral Types for the HD Stars, Vol. 2 (Declinations -53 to -40 Degrees) REFERENCE: Houk, N. 1978 (Ann Arbor: Department of Astronomy, University of Michigan). \SPECTRO\MHD3 NAME: Michigan Catalogue of 2-Dimensional Spectral Types for the HD Stars, Vol. 3 (Declinations -40 to -26 Degrees) REFERENCE: Houk, N. 1982 (Ann Arbor: Department of Astronomy, University of Michigan). \SPECTRO\MHD4 NAME: Michigan Catalogue of 2-Dimensional Spectral Types for the HD Stars, Vol. 4 (Declinations -26 to -12 Degrees) REFERENCE: Houk, N. and Smith-Moore, M. 1988 (Ann Arbor: Department of Astronomy, University of Michigan). Appendix A. Test Disk References and Notes 25 \SPECTRO\MKEXT NAME: MK Classification Extension Catalogue REFERENCE: Morris-Kennedy, P. 1983, Mt. Stromlo Observatory, unpublished. \SPECTRO\ATLAS NAME: Stellar Spectrophotometric Atlas 3130 - 10800 A REFERENCE: Gunn, J.E. and Stryker, L.L. 1983, Astrophys. J. Suppl. 52, 121. NOTES: The catalog is in a form that cannot be translated into FITS-tables format, nor can the format be easily modified to accommodate FITS. Therefore it appears only in text file form, as described in the documentation file. \SPECTRO\LIBRARY NAME: A Library of Stellar Spectra REFERENCE: Jacoby, G.H., Hunter, D. A. and Christian, C.A. 1984, Astrophys. J. Suppl. 56, 257. NOTES: See the notes for the Stellar Spectrophotometric Atlas above. \SPECTRO\HD NAME: Henry Draper Catalogue and Extension REFERENCE: Cannon, A.J. and Pickering, E.C. 1918-1924, Ann. Astron. Obs. Harvard College 91-99; Cannon, A.J. 1924-1936, Ann. Astron. Obs. Harvard College 100. \NONSTELL\RNGC NAME: Revised New General Catalogue of Nonstellar Astronomical Objects REFERENCE: Sulentic, J.W. and Tifft, W.G. 1973 (Tucson: The University of Arizona Press). \NONSTELL\PLN NAME: Strasbourg Catalog of Galactic Planetary Nebulae REFERENCE: Acker, A., Marcout, J., Ochsenbein, F. 1981, Astron. Astrophys. Suppl. 43, 265. Appendix A. Test Disk References and Notes 26 \NONSTELL\UGC NAME: Uppsala General Catalogue of Galaxies REFERENCE: Nilson, P. 1973, Uppsala Astron. Obs. Ann. 6. \NONSTELL\ESOUPP NAME: The ESO/Uppsala Survey of the ESO(B) Atlas REFERENCE: Lauberts, A. 1982, European Southern Observatory. \NONSTELL\RADIO4C NAME: The Fourth Cambridge Survey of Radio Sources REFERENCE: Gower, J.F.R., Scott, P.F., and Wills, D. 1967, Mem. Roy. Astron. Soc. 71, 49; Pilkington, J.D.H. and Scott, P.F. 1965, Mem. Roy. Astron. Soc. 69, 183. \NONSTELL\IRASSSS NAME: IRAS Small Scale Structure Catalog REFERENCE: Helou, G. and Walker, D. W. 1985, Jet Propulsion Laboratory. NOTES: Like the IRAS PSC, the Small Scale Structure Catalog is in three different formats: the original 80-byte record format (SSS.TXT); two files containing the primary source data and associations (SOURCES.TXT and ASSOC.TXT, respectively); and a FITS file (SSS.FIT). The catalog documentation file was typed in at the ADC and consists of excerpts from the hardcopy documentation which was written at IPAC. The documentation includes the Introduction, Section VII.A, which describes the machine-readable version of the SSS, and a brief discussion of the FITS formatting of the IRAS SSS that was authored at the ADC. \NONSTELL\MERCG NAME: Merged Catalogue of Galaxies REFERENCE: Kogoshvili, N.G. 1986: see Kogoshvili, N.G. 1975, Bull. Abastumani Astrophys. Obs. 46, 133; 1981, IAU Colloquium No. 64, Automated Data Retrieval in Astronomy, Dordrecht: Reidel, p. 273; CDS Bull. No. 29, p. 89 for reference, but this is a newer version than described in 1985. NOTES: The document file for this catalog was particularly difficult to translate into simple ASCII text. The original documentation contained many special symbols which are used as Appendix A. Test Disk References and Notes 27 descriptors in the Morphological Catalogue of Galaxies, some of which were even impossible to reproduce with the SCRIPT/VS text processing system. Hopefully all of the special symbols have been described adequately, but if you are confused by the documentation it might be worthwhile to request a hardcopy version from the ADC. \NONSTELL\QAGN3 NAME: A Catalogue of Quasars and Active Galactic Nuclei REFERENCE: Veron-Cetty, M.-P. and Veron, P. 1987, ESO Scientific Report No. 5. \MISC\SAOXIDX NAME: SAO-HD-GC-DM Cross Index REFERENCE: Morin, D. 1973, Obs. de Meudon; substantially corrected and enhanced at the ADC; see the catalog documentation. \MISC\BSC4 NAME: The Bright Star Catalogue, 4th Revised Ed. REFERENCE: Hoffleit, D. (with the collaboration of Jaschek, C.) 1982, (New Haven: Yale University Observatory); see also Hoffleit, D. and Warren Jr., W.H. 1983, Astron. Data Center Bull. 1, 174. \MISC\BSC4S NAME: A Supplement to the Bright Star Catalogue REFERENCE: Hoffleit, D., Saladyga, M. and Wlasuk, P. 1984, (New Haven: Yale University Observatory). \MISC\CLAS NAME: Combined List of Astronomical Sources, Version 3.1 REFERENCE: Mead, J.M. and Hill, R.S. 1983, Astron. Data Center Bull 1, 217. \MISC\ISOCHRON NAME: The Revised Yale Isochrones and Luminosity Functions REFERENCE: Green, E.M., Demarque, P. and King, C.R. 1986, Yale University. NOTES: See the notes for the Stellar Spectrophotometric Atlas above. Appendix A. Test Disk References and Notes 28 APPENDIX B. HAVING PROBLEMS? ____________________________ If you are having trouble reading the ADC CD ROM Test Disk, here are a few things you can do to localize the problem. MS-DOS COMPUTERS 1. If your CD ROM drive can't read any CD ROMs: a. Check all wires and cards to be sure they are seated properly. b. Check that the proper device driver software for your CD ROM drive is installed. c. Check to see that the name given to the device driver in CONFIG.SYS matches that given in the "/D:" parameter when MS-DOS CD ROM Extensions (MSCDEX) is executed. d. Make sure you are specifying the correct device letter. Use the "/L:" parameter on MSCDEX to explicitly specify the drive letter if you are not sure what the correct one is. 2. If you have problems reading only the ADC CD ROM: a. Make sure that you have MSCDEX Version 2.0. The ADC CD ROM is mastered in ISO 9660, and the latest version of MSCDEX is required. b. If you do not have MSCDEX Version 2.0, you should contact the manufactorer of your drive for an update. OTHER COMPUTERS Make sure that the driver software you are using can access ISO 9660 CD ROMs. Commercial ISO 9660 drivers for Sun workstations and DEC MicroVAX computers are not openly available as of the time of this writing. You may wish to contact your local service representative to request the latest driver software. An ISO 9660 driver has been announced for the Macintosh line of computers, but the author has not seen the technical notes for the software. Contact your local service representative for more information. If all else fails, you may contact the author at the following address: Mr. Lee E. Brotzman (301) 286-695 FTS: 888-6953 ST Systems Corp. BITNET: ZMLEB@SCFVM Code 630.3 Internet: zmleb@scfvm.gsfc.nasa.gov NASA Goddard Space Flight Center SPAN: CHAMP::BROTZMAN Greenbelt, MD 20771 USA Appendix B. Having Problems? 29 APPENDIX C. USER COMMENT FORM _____________________________ After you have had a chance to use the ADC CD ROM Test Disk, we would appreciate hearing what you think of it. Tell us what you like, and more importantly, tell us what you don't like. Your comments will serve an important role in deciding the future course of CD ROM technology at the ADC. Feel free to use the back of the sheet if additional space is required. Return the completed forms to the address listed in "Appendix B. Having Problems?". If you prefer to respond via E-Mail, a text file version of the comment form is included in the root directory of the CD ROM. Appendix C. User Comment Form 30 ADC CD ROM Test Disk User Comment Form ______________________________________ Name: _________________________________________________ Address: _________________________________________________ _________________________________________________ _________________________________________________ _________________________________________________ Phone: _________________________________________________ E-mail address: ______________________________________________ Network for above: ___________________________________________ (Internet, BITNET, etc.) 1. Describe your CD ROM system. (Computer, CD-ROM drive, driver software, etc.)? 2. Which catalogs did you use? (You may simply list the subdirectory names.) 3. Which form of the catalogs did you use: text files, FITS files, or both? 4. Should future editions of ADC CD ROMs use text files only, FITS files only, both, or some other form? 5. If you used the FITS table browse software, please comment on functionality, ease of use, bugs encountered, etc. 6. Any other comments or suggestions? Appendix C. User Comment Form 31