Aux List
NeXtMidas looks for a file by searching a collection of
auxiliaries, or the read AUX list. The AUXILIARY
command establishes NeXtMidas
auxiliary disk/path assignments for writing and locating data files. An
auxiliary, or aux, may be a directory or a URL; it may be a short string or
numbers in string form. In general, NeXtMidas auxes are named, not numbered,
and are not restricted to being on the local file system. These features
simplify NeXtMidas access to files identified by URL.
EXPL
AUXILIARY
(or AUX
)
provides a list of standard auxiliaries for the NeXtMidas system.
READ
and WRITE
are special reserved names which define the list of AUX names currently in use.
There are three special auxiliaries:
-
CWD
- Always points to the current directory and changes as the current
directory changes.
- HOMEPATH - Points to the current user macro homepath and changes as the homepath
changes (see also
EXPLAIN HOMEPATH
from the NeXtMidas command prompt)
DAT
- Points to a special global data directory
The <read aux
> parameters define or alter the path list used to
locate Midas data files. The syntax of <read aux
> is as follows:
n1|n2|n3
- An ordered search list of one or more aux
names separated by vertical bars or as separate arguments.
ALL
- Defines the read aux list to include all
paths in the AUX table except READ, WRITE, CWD, DAT, HOME.
-AUX
- Removes aux from the current read aux list
+AUX
- Adds aux to the end of the current read aux list.
AUX+
- Adds aux to the front of the current read aux list.
When any file is opened, whether for read or write, all
disks in the current auxiliary read list are searched. Therefore, the longer
the aux list, the longer it takes to open a file, particularly if the aux list
includes networked disks. If the application requires reopening a file
frequently, try using its full pathname. When the pathname is detected, the aux
list is not searched.
Examples:
AUX
- Display the current aux settings and associated paths
AUX 1 ALL
- Write new files to aux 1 and read from all available
disks
AUX 1 DAT
- Write to aux 1 and read from aux DAT. A minimal read list reduces search time.
AUX CWD
- Write to the current directory (read aux is unchanged)
AUX ,, -CWD
- Remove aux CWD from the current read list, write aux
unchanged
AUX ,, +DAT
- Add aux DAT to the end of the current read list