What will a user actually find on the CD-ROM?
Where can I find the navigation and geophysical
data?
What do the data file names mean?
What are the `rpt' files in the data directories?
What additional information is on the CD-ROM?
What is a green sheet?
Where can I find the data format descriptions?
What is an "end-of-reel" indicator
mentioned in some of the data format descriptions?
What information is contained in the data listings?
What does a checkmark indicate in the HTML data
listings?
What does a bomb indicate in the HTML data
listings?
What does a green document indicate in the
HTML data listings?
What information is contained in the HTML cruise
reports?
What will a user actually find on the CD-ROM?
The main purpose of creating the R/V FAY CD-ROM was to archive the navigation and geophysical data (gravity, magnetics and bathymetry) collected and processed from the R/V FAY cruises which occurred during the field season of 1975 and 1976. In addition to the navigation and geophysical data stored on this CD-ROM, the user will find items such as individual cruise reports, cross-referenced lists to locate the desired data, data format descriptions, and various PostScript generated plots illustrating the ship’s track.
Where can I find the navigation and geophysical data?
The navigation and geophysical data can be found in the directory which is located at the top-level of the CD-ROM. Below that directory, there are nine sub-directories. These directories reflect the format of the archived data. The data transcribed from the 9-track tape drives can be found in these various sub-directories.
It is recommended that the user browse these directories with a WWW client. For additional information the user may proceed to the section entitled Browsing the R/V FAY CD-ROM with a WWW client. To go directly to the data listings selection now, click HERE.
What do the data file names mean?
The individual navigation and geophysical data files stored on disk were named to correspond to the numeric tape identifier assigned by the Center's Data Library and from which the data were transcribed. In the majority of cases, those tapes contained only one data file and would be named txxxx.dat where xxxx is the numeric identifier of the 9-track tape. For example, data transcribed from tape identifier 1105 with CALCM data would be identified as t1105.dat in directory data/calcm.
Additionally, the names of data files read from multiple file tapes were created to identify the tape and file from which the data were copied. As an example of a multiple file tape, consider the three files transferred from tape 873. These files can be found in directory data/seag and are identified as t0873f1.dat, t0873f2.dat, t0873f3.dat. Creating the data file name from the Data Library tape identifier allowed easier cross-referencing of the processed data, ensuring all available data tapes were transcribed. Utilizing the data cross-reference listings, rather than simply accessing an unknown data file directly, will help identify the cruise and processing status of the individual files.
What are the 'rpt' files in the data directories?
The rpt files are summary report files generated after the data were transcribed from tape to disk. To ensure that the data tapes were read accurately, each data file was checked individually after it had been copied to disk. The summary report files were generated by analyzing the data files with a data format specific program to verify that the date, time and, if available, ship position information were within a legitimate range. The program also checked the date and time of the data files to verify that the data were in ascending time sequence. For data formats containing geophysical data, the summary report would also contain the appropriate minimum and maximum data value. The summary report files were named to correspond to the data file from which the summary information was generated. For example, t1105.rpt corresponds to data file t1105.dat.
What additional information is on the CD-ROM?
A green sheet was a form entitled Digital Data Processing Record that accompanied a 9-track tape when it was submitted to the Data Library for archive. Originally, the green sheet was printed on a pale green paper stock and hence it's nickname. The green sheets were designed to provide information about the specific tape for future reference and each tape submitted to the Data Library was to be accompanied with a green sheet. The form was designed to include information such as when, how and on what computer system the tape was created as well as tape density, data format, and processing, if any, the data may have undergone. The intent of the green sheets was to have the person responsible for creating the tape document it adequately and to provide the Data Library with significant information about the tape so the tape, when accessed in the future, would prove useful. Unfortunately not all archived tapes have a green sheet. The green sheets that could be located for the transcribed tapes have been scanned and included on the CD-ROM as GIF and PostScript formatted files for viewing.
The full resolution green sheets can be found in the doc/grnsheet directory from the top level directory of the CD-ROM. Three sub-directories, gif, ps and pdf, can be found below that directory. The gif directory contains the full 300dpi resolution GIF formatted image of the scanned green sheets. The ps directory contains a PostScript version of the green sheet ready for hard copy output on any black & white PostScript compatible printer. The pdf directory contains the green sheets in ADOBE's PDF format. This format was added for the convenience for those user who have an ADOBE Acrobat reader available and who may not have a PostScript viewer available.
To view the PostScript version of the green sheets, the user may select the Green Sheets entry below the Documentation heading from the R/V FAY homepage or clicking HERE to go directly to the Green Sheet page now.
Additionally, green sheets in a reduced GIF format have been created and compiled under directory htmldocs/grnsheet/figs. Attempts to load the 300dpi resolution GIF images for viewing resulted in significant time delays and were therefore reduced to quicker viewing. These smaller images of the doc/grnsheet/300dpi images were reduced approximately 30% and are linked for viewing from the various Cross-referenced data listings. Originally, the full resolution 300dpi PostScript images were linked with the cross-referenced data listings, but concern for systems that may not be configured with PostScript viewers resulted in changing the linkage to the reduced GIF formatted files. As noted, for users who have a PostScript viewer configured with their WWW browsers, the full resolution PostScript images may be accessed through the Green Sheet page.
Where can I find the data format descriptions?
The data format descriptions may be found by selecting the Data Formats and Processing Programs icon from the home page or clicking HERE to go directly to the data format descriptions now. ASCII versions of the data format descriptions may also be found in the directory from the top-level directory of the CD-ROM.
What is an "end-of-reel" indicator mentioned in some of the data format descriptions?
An end-of-reel indicator was used as a way to indicate the end of a data file for those magnetic tapes that did not have a standard end-of-file indicator written. Various data processing programs tested for this end-of-reel indicator. Why include an end-of-reel indicator with the actual data rather than rely on a standard end-of-file indicator on tape? Well, during some data acquisition and processing methods, end-of-file indicators did not get written to the magnetic tapes. These days, the possibility of having a tape without a proper end-of-file indicator would seem unbelievable to the average computer users. But, for a moment, consider the circumstances under which these older tapes were created. These tapes were created by early data acquisition programs that required more user attention than the state-of-art acquisition systems currently being utilized. These early acquisition programs and hardware systems required an operator to manually instruct the computer system to write a standard end-of-file on the magnetic tape. In some cases, the operator would forget or a computer system crash would prevent them from writing the end-of-file marker. Since the computer software could not ensure an end-of-file marker on the tape, their safety net consisted of adding an end-of-reel indicator as the last record in the data files.
The end-of-reel indicators are no longer needed. They have been removed from the data files, and are included in the data format descriptions for historical purposes.
What information is contained in the data listings?
Data cross-reference listings were developed to aid the user in locating and selecting specific data files. The data listings contain information such as tape identifier, cruise identifier, data format edit status and notes. This information was extracted from the Center's Data Library digital tape listings.
Accessing the data using the HTML formatted data listing eases the process of identifying the data files for the user. To view a selected data file, the user need only click on the tape identifier to view the data file. By utilizing a WWW client, the user may select to save or load to disk their selected files.
In addition to the specific information listed, the HTML formatted data listings include cross-reference links to Data Summary reports, and the PostScript formats of the tape green sheet.
What does a checkmark indicate in the HTML data listings?
A checkmark (
)
under the Data Summary column of the data listings indicates
a data summary report is available for that tape. The report includes information
such as the number of records in the data file, and the date and time of
the first and last record in the data file. In addition, format specific
information such as minimum and maximum geophysical data value ranges may
also be included as appropriate.
What does a bomb indicate in the HTML data listings?
A bomb (
)
in the Data Summary column of the data listings indicates that
the tape could not be read and, therefore, no Data Summary report is available
for that tape. If the user clicks on the bomb, information suggesting
an alternate source of data will be displayed.
What does a green document indicate in the HTML data listings?
As with the other icons contained in the HTML data listings, the green
document (
)
provides a Hyper-Text link to additional information. By clicking
on the green document, a reduced GIF image of the green
sheet for that tape will be displayed for the user.
What information is contained in the HTML cruise reports?
The post-cruise reports provided by the Chief Scientists for each cruise were scanned and converted to text files via OCR conversion. Some cruise reports provide extensive information, while other reports provide very little. In addition, there was no standardized format for these reports. The ASCII text files were then converted to an HTML version to standardize the format and provide quick links to important information. In addition, links to scanned cruise report attachments stored as GIF images, and newly generated cruise track maps have been added for the user's reference.
[an error occurred while processing this directive]