WELCOME, and they in turn contain files of their own. In case you hadn't

noticed, this diagram mimics the directory hierarchy of the Welcome disc, and

you can use *CAT to see the contents of '$' for yourself.

When you first start up the ADFS, or issue a *MOUNT command, the '$'

directory automatically becomes the 'Currently Selected Directory' or CSD.

When you type *CAT the ADFS produces a catalogue of the CSD, but you may

instead request catalogues of other directories by following the *CAT command

with the name of a directory, e.g:

*CAT LIBRARY or

*CAT WELCOME

Using *CAT in this way only allows you to see what is in another directory; you

need to be more specific before you can load a file from a sub-directory because

normally the ADFS assumes you are looking for a file in your Currently

Selected Directory.

Earlier you saved a file called TEST in directory '$'. To fully specify where this

file is to be found we need to use its full name, or pathname. In the case of

TEST it is written '$.TEST'. The full stop is used to separate the filename from

the directory name, and you can use as many of them as necessary. Here are

some examples from the diagram above:

$.WELCOME The sub-directory 'WELCOME' in directory '$'

$.LIBRARY .PANEL The file 'PANEL' in directory $.LIBRARY

The CSD's name is assumed to prefix any filename that does not start with '$',

and you can include it explicitly in a pathname by using the symbol '@'.

Using the directory hierarchy

For directories to be useful you need to be able to 'move around' (i.e. change

your current directory) and to create new directories. The *DIR command is

used to change the CSD; for example either of the following commands will

make the root directory your CSD:

*DIR

*DIR $

In fact you can use pathnames of any length, e.g.:

*DIR $.LIBRARY.BASIC

Sometimes you may want to move to the 'parent' of your CSD, that is the

directory which contains it. You can do this by including the circumflex symbol

'^' whose similarity to an upward-facing arrow is not coincidental. Suppose

your CSD is deep down in a hierarchy, for example it has the pathname

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