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HP OpenVMS Systemsask the wizard |
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The Question is: What we are trying to accomplish is to have a common code library in CMS on the Alpha and centralize object libraries on the Alpha but allow programmers to compile code on the vax without having to copy many files over to the vax. Can you have the link li brary logicals pointing to .OLB files on the Alpha? I am able to do a Lib/lis and lib/extract command with no problems. The Answer is : First, please ignore the error messages and the problems reported with the current approach, and consider the implications of your current approach. First, think how OpenVMS libraries are processed. The LINKER must read through the library "index" several times attempting to resolve the symbols. For any resolved symbol, it must then locate and load the object module. Now consider the way that a programmer will typically work. Typically, an application will cucle through the compile/link/test cycle numerous times. Now think about the nature of the "standard" libraries. Hopefully, they are relatively stable (and are organized into shareable images whenever possible -- please see the Shareable Image Cookbook for details; see the OpenVMS FAQ for pointers). When the libraries reside on another system accessed via a network file specification, the LINKER process effectively must copy parts of the file across the network, potentially multiple times per link -- the exact number of copies depends on the efficiency of the host buffering. This must be repeated for each LINKER operation. You will also need to start network FAL processes on the remote node to service the incoming file request, potentially one process per network file. It doesn't much matter what disks or network hardware you have, it's almost certain that the network I/O will be substantially slower than I/O from a local disk. So, unless the updates to the libraries are very frequent, or the libraries contain very large numbers of routines that are rarely referenced, then you're almost certainly better off copying the libraries once a day or once a week depending on their update frequency. The more LINKER operations performed by programmers, the performance more you win by maintaining local copies. It's a very simple matter to create a small DCL procedure to synchronize local copies with your master copy on a known host. (hint: use the F$CVTIME(F$FILE_ATTRIBUTES(file,"RDT")) to compare revision dates.) Regarding platforms... Alpha, VAX and Itanium object modules (and hence libraries) have different formats. You can certainly store VAX object libraries on Alpha systems, and you should be able to access them via a network file address -- it's all just bits to the Alpha system. However, for best performance, the OpenVMS Wizard would tend recommend against this approach. The OpenVMS Wizard has performed some simple experiments with network file specifications and link libraries, but is unable to reproduce the error message you describe. If you wish to persue the issue, please log a case with your local customer support centre, and be prepared to provide example code to reproduce the condition. Probably the easiest solution here is to cluster at least one OpenVMS VAX and one OpenVMS Alpha host together -- the CMS libraries can be common, as can the build and test procedures. No copying, and direct access to the files.
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