Versions of IRAF at STScI
15 May 1997

The existence of several different versions of IRAF at STScI sometimes leads to confusion about which version to use. This document briefly summarizes the differences between the various versions, explains the primary uses of each version, and explains how to switch between versions. We also discuss the future plans for how the various versions of IRAF at STScI will evolve.

Characteristics of Different IRAF Versions

Sorted by system:

                      |IRAF Version|      FITS kernel version    |     Operations Applications    |  Applications  
System  OS      Name  |2.10.4 2.11b|None 20aug96b 24jan97b 2.11b1|Baseline Develop Test Operations|Baseline Develop
------  --      ----  +------ -----+---- -------- -------- ------+-------- ------- ---- ----------+-------- -------
Ra      Solaris irafx |         X  |                          X  |            X                   |            X 
Ra      Solaris iraft |   X        |         X                   |                  (X)     X     |            X* 
Ra      Solaris irafo |   X        |                 X           |            X                   |            X 

Hydra   Solaris iraf  |   X        |  X                          |   X                            |    X         
Hydra   Solaris irafx |   X        |                          X  |            X                   |            X 
Hydra   Solaris iraft |   X        |         X                   |                  (X)     X     |            X*
Hydra   Solaris irafo |         X  |                 X           |            X                   |            X 

Scivax  VMS     iraf  |   X        |  X                          |   X                            |    X         
Scivax  VMS     irafx |   X        |                 X           |            X                   |            X 
Scivax  VMS     irafy |   X        |         X                   |                  (X)     X     |            X 

OPUS    VMS     iraft |   X        |         X                   |                          X     |    -       - 
HDA     VMS     iraft |   X        |         X                   |                          X     |    -       -

Sorted by IRAF version characteristics:

                      |IRAF Version|      FITS kernel version    |     Operations Applications    |  Applications  
System  OS      Name  |2.10.4 2.11b|None 20aug96b 24jan97b 2.11b1|Baseline Develop Test Operations|Baseline Develop
------  --      ----  +------ -----+---- -------- -------- ------+-------- ------- ---- ----------+-------- -------
Hydra   Solaris iraf  |   X        |  X                          |   X                            |    X         
Scivax  VMS     iraf  |   X        |  X                          |   X                            |    X         
Ra      Solaris irafx |        X   |                          X  |            X                   |            X 
Hydra   Solaris irafx |        X   |                          X  |            X                   |            X 
Scivax  VMS     irafx |   X        |                 X           |            X                   |            X 
Ra      Solaris iraft |   X        |         X                   |                  (X)     X     |            X*
Hydra   Solaris iraft |   X        |         X                   |                  (X)     X     |            X*
Scivax  VMS     irafy |   X        |         X                   |                  (X)     X     |            X 
OPUS    VMS     iraft |   X        |         X                   |                          X     |    -       - 
HDA     VMS     iraft |   X        |         X                   |                          X     |    -       - 
Ra      Solaris irafo |   X        |                 X        X  |            X                   |            X 
Hydra   Solaris irafo |   X        |                 X        X  |            X                   |            X

The IRAFT versions of applications packages are essentially snapshots of the IRAFX application versions when the IRAFT installations were created (when IRAFX was still version 2.10.4 IRAF). They do not get updated unless an updated version of an application is required for operations (e.g., for paper products). These entries are marked with 'X*'.

Summary of Differences and Uses of IRAF Versions

The following summarizes the essential differences between the different versions of IRAF and who the intended users are for each version.

IRAF
This is a baseline version of IRAF/STSDAS/TABLES and represents the version of each as most recently released. No local changes have been made to the released versions. This is the version users should use if they want certainty that nothing will change between releases of IRAF/STSDAS/TABLES. The FITS kernel is not available on this version.
Ordinarly most general users at STScI use the IRAF version only when a problem is encountered in IRAFX.
IRAFX
This is the development version of IRAF/STSDAS/TABLES. Changes are made continuously to the STSDAS/TABLES software to add new tasks, enhance existing tasks, or fix bugs. Changes may be made to system level software (IRAF or TABLES) as needed to support development. This is the version most users will use. It will be the version with the most capabilities and most recent fixes to problems. IRAFX was updated to the beta version of IRAF 2.11 on 5-June-97 (and the IRAFX as it existed prior to that date became IRAFO). Most users should use IRAFX with two possible exceptions: 1) if they plan to create .imh files and use them on older versions of IRAF they may find it too inconvenient since the new .imh format files cannot be accessed from older versions of IRAF because their format has changed. (But accessing old .imh files from IRAF 2.11 is not a problem.) Although the new format is portable across different machines, that is of little practical use now since IRAF 2.11 is currently only available for Sun computers. 2) Users in the middle of large projects may prefer to continue using the 'old' IRAFX (now IRAFO) to minimize any risk. All user code written for IRAF 2.10.4 must be recompiled for this version.
IRAFO
This is the 'old' IRAFX as it existed prior to the update of IRAFX to IRAF v2.11 beta. This version will continue to be updated weekly as it had been in the past. Users are encouraged to use IRAFX unless they fall into one of the two categories mentioned in the description for IRAFX in which case they may consider using IRAFO. This version has an earlier, buggier version of the FITS kernel than exists in the current IRAFX
IRAFT
This is the IRAF version used by operations. On Ra and Hydra this version is called IRAFT; on the VMS science cluster it is called IRAFY (this inconsistency may be resolved in the near future by renaming the VMS science cluster version to IRAFT.) This is the only version of IRAF available on in the test and operations version in OPUS and test and operations versions in HDA.
This version of IRAF will remain at IRAF 2.10.4 level until IRAF 2.11 is released for VMS. The only updates to applications software are those needed for operations. It does not have, in general, all the latest versions of applications that appear in the development version. Users should use this only for the purposes of testing software in the operations environment.
The versions of the operational software (the calibration pipelines, paper products, etc.) in IRAFT are ordinarily identical to the software currently being run in the operational system. The only exception to this is when a new version of the operational software has been delivered for testing prior to its installation on the operational systems. In that case the software on the science clusters may be newer than that installed in operations. This should only be a temporary situation, which is resolved either by approving the new version for installation (so that the operational systems are brought into sync with the science clusters) or by finding a problem in the new version (in which case the science cluster software is rolled back to the operational version until another new version is ready for testing.)

Switching Between Different IRAF Versions

A new system is being put in place to make it easy to select a default version of IRAF and to switch between different versions of IRAF. First, on the Unix systems your .envrc startup file (in your home directory) can include a Package command to select which version of IRAF you want to use by default. For example, include:

	Package: irafx

to use the IRAFX version as your default.

All the science systems and the ra cluster will also have aliases (or command procedures) implemented to make it possible to switch versions by simply typing the version name followed by the usual command to start the cl. For example, suppose a user's .envrc file defaults to IRAFX. The user could run IRAFX and then switch to IRAFT temporarily as follows:

	% cl
	cl> 
	.
	. 
	.
	cl> log
	% iraft
	% cl
	cl>
	.
	. 
	.
	cl> log
	% irafx
	% cl
	cl>
	.
	. 
	.

The startup message for each version of iraf will be modified to make clear which version of IRAF the user is running (IRAF, IRAFX, IRAFO, or IRAFT).

This system has already been implemented on Ra; if no problems are encountered, it will be implemented on the Hydra cluster this week.

Future Plans for IRAF Versions

At the moment, the mercurial nature of the FITS kernel (on which the STIS and NICMOS pipelines depend) makes things complicated, with 3 different FITS kernels in use (20aug96b in operations, 24jan97b in IRAFO, and 2.11b1 in IRAFX). These different versions are necessary because the 20aug96b kernel is known to have some problems affecting interactive use, but has been found to be robust and to have no problems in the operational pipelines. On the other hand, newer versions of the FITS kernel have been changing too frequently to be used in the operational systems, because it has not been practical to repeat all the time-consuming testing of the operational software with each new version. Consequently, we have chosen to freeze the FITS kernel in operations and to make only minimal changes when problems are discovered.

Once IRAF version 2.11 is released, we will be able to simplify the system of IRAF versions. IRAF 2.11 will be released around the end of May for Solaris and other Unix operating systems; a VMS version of 2.11 should be released around August or September. With the Unix release of 2.11, and the subsequent STSDAS release (in June), we will make the following changes in the versions described above on all Unix systems:

IRAFX: The development version will be based on IRAF 2.11 and will have the same FITS kernel as IRAF.
IRAF: IRAF 2.11 and the new STSDAS release will become the baseline version.
IRAFO: The old development version of IRAF will disappear.
IRAFT: The operational version of IRAF will continue to be based on IRAF 2.10.4 with the 20aug96b FITS kernel.

The VMS systems (including the science VMS cluster and the operational computers) will not change with the 2.11 Unix release. However, with the VMS release of IRAF 2.11, we will be able to make these additional simplifications:

IRAF: IRAF 2.11 and the new STSDAS release will become the baseline version on the science VMS cluster.
IRAFX: The development version will be based on IRAF 2.11 and will have the same FITS kernel as IRAF on the science VMS cluster.
IRAFT: IRAF on the operational systems will be upgraded to IRAF 2.11. IRAFT on the science systems (Unix and VMS) will be eliminated (or equivalently, will be identical to IRAFX.) The operational, test, and development versions of the pipeline and paper products software will be made available as separate packages within IRAFX, since the system software will be the same on the operational and science machines.

Once these changes have been made, we will have reached our goal of having only one basic IRAF system (IRAF 2.11) and one FITS kernel on all our IRAF installations at STScI. The development version will continue to exist to reflect the latest changes to software applications, but system changes are expected to be much rarer and so the entire environment will be more stable and easier for users (and programmers) to understand.

Richard L. White, rlw@stsci.edu
1997 June 5

Versions of IRAF at STScI 15 May 1997

Characteristics of Different IRAF Versions

Summary of Differences and Uses of IRAF Versions

Switching Between Different IRAF Versions

Future Plans for IRAF Versions

Versions of IRAF at STScI
15 May 1997