NOTICE:
This Legacy journal article was published in Volume 4, February 1994, and has not been
updated since publication. Please use the search facility above to find regularly-updated information about
this topic elsewhere on the HEASARC site.
|
Access to the HEASARC
on legacy via BROWSE
Stephen Drake, Song Yom,
and Andrew Pollock
HEASARC
The data and software archive that is being maintained by the NASA/Goddard
Space Flight Center's HEASARC (High Energy Astrophysics Science Archival
Research Center) is being moved from its previous location (the NSSDC's NDADSA
computer) to the HEASARC's own DEC/System 5000 legacy computer. This
switch from a VMS to an Ultrix (DEC Unix) operating system should improve
system performance, and has enabled us to redesign our XOBSERVER software to
make it mimic a Unix type environment, which is important since the majority of
our users are now on Unix systems; it also has enabled to centralize all of our
data access methods such as ftp, gopher, WWW/Mosaic, as well as our on-line
service BROWSE, on a single computer, legacy. The 'new' archive can be
reached by visiting the web site http://heasarc.gsfc.nasa.gov/W3Browse/
(Other ways of accessing the archive
are discussed in the companion article by Drake et al. immediately preceeding
this article.)
A test version of the XOBSERVER/BROWSE software is already available on
legacy , and users can explore the new system: please report any
problems that are encountered by leaving a comment when prompted at the end of
the session, so that we can eliminate as many bugs as possible prior to the
deactivation of the NDADSA XRAY account.
Differences Between the XOBSERVER Commands on NDADSA and legacy
We refer to the command level that you reach once you log in as xray (notice
that on legacy the captive account has to be written in lower case), and
answer the series of queries with which you are then prompted, as the XOBSERVER
environment. Most people who log in to XRAY probably immediately after they get
in, type BROWSE DATA_BASE, where DATA_BASE is the name of the database in which
they are interested, and enter the BROWSE program, but there are in fact quite
a few other possible XOBSERVER commands. In the table below, we list only
those commands which are different (in either name or functionality), defunct,
and/or new to the version of XOBSERVER on legacy. (For a full list of
applications which can be called from the XOBSERVER enviroment on
legacy, type 'la'). Notice that in many cases we have retained the VMS
name of a command as an alias of the actual Ultrix command.
XOBSERVER Commands
| on NDADSA
| on legacy
|
| ASC
| See Note
|
| BROWSE BULLETIN
| bulletin
|
| COPY
| cp (or copy)
|
| CREATE/DIR
| mkdir
|
| DELETE
| rm (or delete)
|
| DIR
| ls (or dir)
|
| FITS IMAGE
| No legacy equivalent
|
| LOGOUT
| exit (or logout)
|
| MKLEPHA
| Not implemented on legacy
|
| PURGE
| No legacy equivalent
|
| RDPHA
| See Note
|
| RDRSP
| See Note
|
| RENAME
| mv
|
| SEND
| put (or send)
|
| SET/DISPLAY
| cpd
|
| SET DEF
| cd
|
| TYPE
| cat (or type)
|
| TYPE /P
| more
|
| VIMAT
| No legacy equivalent
|
| ZOO/UNZOO
| compress/uncompress
|
Note: Special purpose commands such as these to translate data files in binary
formats into ASCII formatted files are not needed on legacy. The
XOBSERVER environment contains the FTOOLS applications such as 'fdump', which
can read and extract specific data from FITS files.
New XOBSERVER Commands on legacy
email change user's E-mail address
The 'email address' command changes the user's E-mail address in the
registration database.
env display current session characteristics
The 'env' command displays the following session parameters: XOBSERVER
username, E-mail address, registration date, last login date, home
directory path, and graphics plot device if any. This command is
identical to the 'show' command.
get copy file from user's remote machine
The 'get file ...' command copies file from user's remote machine.
Multiple files must be separated by spaces. This command is identical
to the 'recv' command.
la list applications
The 'la' command prints names of available external applications.
mail mail a file to your email address
The 'mail file ...' command sends a file to the user's E-mail address.
Multiple files must be separated by spaces.
pwd print current working directory path
The 'pwd' command displays the current working directory path.
rmdir delete a directory
The 'rmdir directory ...' command deletes a subdirectory. Multiple
directories must be separated by spaces.
BROWSE on legacy
Once inside BROWSE, the user will not find many apparent differences. Most
commands that worked in BROWSE on NDADSA work here also, and in precisely the
same way. Only a few things are different, such as a couple of archaic BROWSE
commands that are specific to EXOSAT data (i.e., FOTREQ and LIC) that have been
discontinued. As of the date of this writing (January 5, 1994), not all data
files have been moved to legacy, so some databases (such as the EXOSAT
ones) can be browsed on legacy, but do not yet have their data products
available: this situation will soon be rectified: in this interim period, in
such cases the user should revert to the XRAY account on NDADSA to get the
relevant data. By the date on which the captive account on NDADSA is scheduled
to be terminated (March 1, 1994), the database on legacy will be fully
populated. The data files on legacy, as mentioned above, are actually
going be in FITS formats, i.e., be fully transportable between different
computers without any need of translation or conversion, as opposed to the
files on NDADSA that are mostly in a hodge-podge of obscure, often binary,
formats. This, we believe, is a considerable improvement! The new FITS files
and their formats will be discussed in the next Legacy issue by Lorella
Angelini and Ian George. The important thing as far as the XOBSERVER
environment and its various tools are concerned is that this major change in
the data files formats will be completely transparent to the user: e.g., the
command pp/sp 1 in BROWSE will plot a spectrum of selection 1 just as it always
did.
E-Mail Server
HEASARC Database Request E-Mail Server provides a non-interactive user
interface to the HEASARC's BROWSE and SQL applications.
The software allows three types of access to the HEASARC DBMS: generic, native,
and information. The generic type access provides an intuitive command line
interface to perform either cone (coordinate) or name search. The native type
access provides the user the flexibility of specifying either BROWSE or SQL
native commands. Finally, the information type access provides efficient
retrieval of either all archived database or specific database content
listing.
The access to the service is via the electronic mail. The server's e-mail
address is hdbreq@legacy.gsfc.nasa.gov.
When an empty or otherwise invalid message is sent to the server, the server
sends back a reply message composed of the text describing in detail the valid
command syntax and some useful examples. Otherwise, the reply message sent
back to sender is the actual requested data.
If you have any questions about this service, please contact:
Song Yom
yom@astd3.gsfc.nasa.gov
lheavx::yom
301-286-1364
Summary
There will doubtless be some teething problems with our new XOBSERVER/BROWSE
set-up. Please tell us about any problems that you encounter or make
suggestions as to enhancements/changes that you would like to see implemented
by either leaving a message when you log out of XRAY or by e-mailing the
authors directly (drake@lheavx.gsfc.nasa.gov, yom@heagip.gsfc.nasa.gov). We
will keep users posted on updates and enhancements to the legacy
database through the welcome message that appears after login and in future
articles in this journal.
Proceed to the next article
Return to the previous article
Select another article
HEASARC Home |
Observatories |
Archive |
Calibration |
Software |
Tools |
Students/Teachers/Public
Last modified: Monday, 19-Jun-2006 11:40:52 EDT
|
