Re: Backup/Copy tree with alias file

From: Paul Sture (p_sture_at_elias.decus.ch)
Date: 09/06/03 

Date: 6 Sep 03 11:25:04 +0200

In article <01L09NHE98K2AOOLBD@sysdev.deutsche-boerse.com>, Phillip Helbig <HELBPHI@sysdev.deutsche-boerse.com> writes:
>> > Suppose I now copy a higher-level directory [...] which contains A and B
>> > to, say, another disk. If I do an IMAGE backup, then I can have B as
>> > the alias entry for A, or I have DOUBLE COPIES OF ALL THE FILES,
>> > depending on /ALIAS or /NOALIAS. However, if I DON'T do an image
>> > backup, the only option is to have all the files duplicated, or I have
>> > to just copy one of the directories and do the SET FILE/ENTER by hand
>> > again.
>>
>> What is the advantage to using ALIAS?
>> I am an old horse familiar with using OpenVMS symbols or logical names
>> as short cuts to files, and to use a logical name for a "Directory
>> list" that includes multiple directories or multiple disks.
>> So far, using an ALIAS sounds very difficult to manage and may create
>> undesirable backup save sets.
>>
>> Can someone from H.P. chime in with "good practices", "avoid at all
>> costs", and a reasonable use for ALIAS?
>> So far I am glad users and I have not yet used that feature.
>
> Well, DISK:[SYSn]SYSCOMMON.DIR is an alias for
> DISK:[000000]VMS$COMMON.DIR. (Actually, since both of these occur in
> logicals defined as search lists, I've never understood why this is
> necessary; perhaps it goes back to the very old days of VMS, before
> search-list logicals were implemented?
>

IIRC, going back to V2.n and RSX compatibility mode stuff, the system
directories and their numeric equivalents were aliased (though I cannot
remember in which direction). For example, [001004] (representing
UIC [1,4]) was aliased to [SYSMGR].

> I think the most common use of it is to allow a directory to be accessed
> by more than one name since some NEW application requires this, but it
> would be too much trouble to rewrite OLD applications to be compatible.

Relevant Pages

  • SYS$SYSROOT and similar logical names
    ... an alias for VMS$COMMON:in the first place. ... add a third translation for SYS$SYSROOT, ... rather than defining SYSUAF and all the other logicals explicitly. ... system disk so that it is used by all nodes booting from that system ...
    (comp.os.vms)
  • Re: Backup/Copy tree with alias file
    ... >> to, say, another disk. ... If I do an IMAGE backup, then I can have B as ... >> the alias entry for A, or I have DOUBLE COPIES OF ALL THE FILES, ... logicals defined as search lists, I've never understood why this is ...
    (comp.os.vms)
  • Re: Backup/Copy tree with alias file
    ... >>in logicals defined as search lists, ... This dates back to V3/V4 days and the initial cluster code that would ...
    (comp.os.vms)
  • Re: Backup/Copy tree with alias file
    ... >logicals defined as search lists, I've never understood why this is ... perhaps it goes back to the very old days of VMS, ... Computer Sciences Corporation ...
    (comp.os.vms)
  • Re: Backup/Copy tree with alias file
    ... >> SYS$SYSROOT defined as a search list, I don't see any reason why ... > This dates back to V3/V4 days and the initial cluster code that would ... > at the time the code did this, logicals had not been initialised. ... Search lists existed, but ...
    (comp.os.vms)