7. Multi-architecture support

preliminary location of this page is at IFCTR

interim     location of this page should be at ITESRE

final       location of this page should be at SAX-SDC

It is very easy to run XAS from several machines running the same operating system, just install XAS on one machine, and make sure that all other machines see (e.g. via a NFS mount) the relevant disk.

However ...

this page is concerned with the case you want to run XAS from several machines with different operating systems. Of course you always can make separate installations but ...

This is possible also...

doing some sort of simplified installation. Essentially :

all system independent source code is installed and mantained on one machine only
only the system dependent directories are duplicated on one machine per architecture
system dependent source code is the one contained in the system-independent kit
system dependent directories are those flagged as such in the typical XAS tree, namely vos, lib, local, bin and external.
the case of the config directory is explained below.

If you have a VMS system and some Unix systems...

install the VMS system first (in full, i.e. all kits)
on Unix go to $XASTOP
install the three system-dependent kits ONLY
soft-link all system-independent source directories to the VMS disk e.g.
```
ln -s /yourvax/dir/include include
```
the above assumes the VAX disk is NFS-mounted as /yourvax

The above combination allows you to save the duplication of source code space. It has been tested succesfully for a long time in conjunction with manual recompilation (it is possible to compile a source file residing on the Vax NFS-mounted onto the Unix system)
HOWEVER usage of NFS-mounted VMS disks is likely not to be compatible with Unix make (which is used by xasbuild).
There are two difficulties with make. One requires the two system clocks to be synchronized, and to be in the same timezone (the VMS TCP-IP implementation of time-zones is installation dependent), which possibly could be arranged.
The second one is that make does Unix system calls to change directory, and these will not work when the parent directory is not an Unix disk.

Therefore usage of xasbuild with VMS NFS-mounted disk is unsupported

If you have several Unix systems...

install one of the systems (master) first (in full, i.e. all kits)
on the other systems go to $XASTOP
install the Unix-system-dependent source kit and the system-dependent binary kit.
soft-link all system-independent source directories to the master system disk e.g.
```
ln -s /master/dir/include include
```
the above assumes the master system disk is NFS-mounted as /master
soft-link the config directory to the master system disk e.g.
```
ln -s /master/dir/config config
```
the local directory may either be soft-linked, or exist in a separate form on the two systems, according to local needs
the vos directory MUST exist in separate form on each system (as installed from the Unix-system-dependent kit) which however has not installed the files common to all Unixes
the vos directory on the secondary systems must be populated further
- either copying from the master systems all source files not already present after installation of the Unix-system-dependent source kit
- or soft-linking such files one by one to the master system e.g.
```
ln -s /master/dir/vos/z_get_global vos/z_get_global
```
- be careful not to overwrite the files coming from the Unix-system-dependent source kit
do the xasbuild configuration on each of the systems.

The above combination allows to save duplication of source code, and to handle updates in a single physical copy. The arrangement with NFS-mounted disks is fully compatible with xasbuild provided the two system clocks are kept synchronized (otherwise make may occasionally fail).

to be checked, also for other xasbuild possibilities, by Daniele Dal Fiume