In 1991 NASA released a CD-ROM with the 114 most requested astronomical catalogs. A list of errata is available via anonymous FTP from hypatia.gsfc.nasa.gov:pub/cdrom/adc_cdrom.errata, or by sending e-mail to listserv@hypatia.gsfc.nasa.gov, with the one line in the body of the message: get pub adc_cdrom.errata.
Numerous other CD-ROMs have been issued, e.g., the Guide Star Catalog (2 CDs), and a CD with sample scans from the STScI plate scans of the Palomar Sky Survey. At the time of writing this paper the first set of a total of 101 CD-ROMs with digitized optical surveys of the full sky is being distributed by ASP. There are 31 different CD-ROMs with X-ray data from the EINSTEIN satellite, and four CD-ROMs containing the IRAS high ecliptic latitude Sky Survey Images. Two CD-ROMs with radio images and source catalogs have been issued by NRAO. The ``PGC-ROM'' with the Principal Galaxy Catalogue (Paturel, Bottinelli and Gouguenheim 1993) includes stand-alone search software. There is one CD-ROM each on ``ROSAT, The Images'', and on ``The Extreme Ultraviolet Explorer Science Archive''. A 24-volume set of CDs was issued by NASA-GSFC in September 1992 with data from the Comet Halley Archive. It has already been mentioned that the bulk of the tabular data published in the main North American journals is issued on CD-ROM regularly. The NSSDC On-Line Service (see §3.1.1.) maintains a list of CD-ROMs of astronomical interest, and other compilations have been given by Davenhall (1993b) and within the MediaTheque project of CDS (Heck 1994a).