CD-ROM Information System

Installing public data at a new site

Installing your own data for Internet access

The following instructions apply to both:

public data you wish to make generally available

private data to be shared among Internet users at your site

Your data can reside on any hardware (e.g. magnetic disk, CD-ROM) under any operating system. The data must be exported via Sun's NFS (Network File System) protocol, to all client machines where the data will be used. Data to be publicly shared should be exported to "everyone".

Some NFS clients, e.g. Novell and Hummingbird, require an NFS authorization server which is running PCNFSD. The authorization server need not be the same machine which serves the data. If you want to share your data with "everyone" and you do NOT wish to authorize users from your own server, do NOT install PCNFSD in the server which exports the data.

If your data are exported from an SGI computer, you may need to apply a software patch which is available from Silicon Graphics Advantage Online . For mercury.census.gov and venus.census.gov, which are SGI Indy computers running VMS 5.3, NFS patch SG0000920 was required (3/28/96). Contact chris.stuber@census.gov for more information.

Additionally, for data files which will be used with MS-DOS:

1. In addition to complying with the ISO standard, the file names must be MS-DOS compatible (for example, "readme.dat" or "readme", but not "readme." or "README.DAT" or "README"). To check, examine file names in your public file system, from a PC client computer.

2. Both the carriage return and the line feed (^M^J) at the end of text lines must be present and must be properly exported via NFS. To check, type an MS-DOS BAT file in your public file system, using a PC NFS client computer. Make sure each line is left adjusted on the screen.

3. If (and only if) the files are to be used by the Census program EXTRACT, they need to be mounted world-writeable (rwxrwxrwx), which constitutes a security risk if your files are disk copies rather than physical CD-ROMs. (They could be modified by users who have login privilege to your host computer). This ugliness is due to a bug in EXTRACT. There is no problem with GO, DBUTIL, LOOKUP, etc. The Census Bureau has been asked for a policy decision, as to whether the Bureau will fix EXTRACT so it can read files which are mounted read-only. No answer yet.

   To check (from a UNIX server) type "ls -al ." in the root directory of of your public file system. Make sure that all files including "." have permissions "rwxrwsrwx".

showmount -e mercury.census.gov

If possible, access the exported file systems from a PC NFS client (for example with PC/NFS) to make sure the file names and formats are compatible with MS-DOS.

Following installation of your data for Internet access, it is recommended (but not required) that you integrate your public data into the CD-ROM Information System.

Pioneer 6-disk CD changers

Regarding particular hardware and software, LBNL has experience with Pioneer DRM-600 and DRM-604X six-disk CD changers, which cost approximately $900 and $1200 respectively as of 1993. The prices are coming down rapidly. The cheaper DRM-600 are slower and larger but more reliable than the DRM-604X. Though no longer in production, the DRM-600 are still available through some vendors.

LBNL has had bad experience with the (quad speed) DRM-604X manufactured around 1993. More than half of LBNL's DRM-604X malfunctioned and required repairs. The problems may be cured in DRM-604X manufactured at later dates.

There is a newer double speed DRM-602X drive. LBNL has no experience with this model.

LBNL has successfully mounted six-disk DRM drives on Sun Sparc-1, Sparc-2, and Sparc-10 workstations. With two extra SCSI interfaces, up to 21 six-disk DRMs can be mounted on a single Sparc station under SunOS. NFS export is accomplished with software drivers from Tracer Technologies Inc. The Tracer drivers cost about $500 per workstation, depending upon the type of workstation. Drivers are available for the Solaris operating system, but the number of CDs that can be mounted on one workstation is much more limited. For further information contact Paul Vongsathorn (paulv@cs.umd.edu).

UC DATA has experience with Pioneer six-disk DRM-600 and 18-disk DRM-1800 CD changers, on a Sun Sparc-2 and Sparc-20. UC DATA also has experimented with copies of STF3A files on a magnetic disk. For further information contact Raphe Berry (raphe@ucdata.berkeley.edu) or Fred Gey (gey@ucdata.berkeley.edu).

The Bureau of the Census has experience with single-CD drives under Unix on a PC. For further information contact Chris Stuber (chris.stuber@census.gov).

In summary, the experience with Pioneer DRM-600 drives, with Tracer drivers under SunOS is generally satisfactory. Other models, and Solaris, should be approached with caution. The six-disk drives have two important advantages over larger models: larger ratio of drives to CDs, and much less disruption to the system when one drive fails.

For our application, where use is intermittent, the sharing of six CDs by one drive is satisfactory. The slower speed of the DRM-600s is not a problem. The greatest problem is reliability of the drives. In the future, magnetic disk may be a preferred alternative to CD-ROM drives if costs are not excessive.

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