The disc address is used internally by the ADFS to find the file on the disc's

surface, and it is not usually of interest to users. Directories have only their disc

address displayed, the other information being meaningless.

A special form of the *EX command, *LEX, exists to produce detailed

information about files in the CSL.

Wildcards

The ADFS supports a facility for using special characters, known as wildcards

in filenames. These characters can be used to specify an ambiguous filename

which can match several real names and thus perform actions on several files

with only one command. The single character wildcard '#' indicates one

unspecified character, whilst the multiple character wildcard is '*'. Examples of

filenames incorporating wildcards are:

Chapter# (e.g. 'Chapterl', 'ChaptertG')

DAY ## (e.g. 'DAYaa', 'DAY36')

$. LETTERS . * (any file in '$.LETTERS')

PHYSICS .*Joules* (any filename in 'PHYSICS' with 'Joules' in it)

The way in which filenames incorporating wildcards are interpreted depends

on the command with which they are used. Most commands will act on the first

file that satisfies the given wildcard pattern in alphabetical order. The *CAT

command works like this so, for example:

*CAT Q*

will catalogue the first directory in the CSD that begins with a 'Q' or a 'q'

(remember the ADFS takes no notice of the case of letters).

Other commands will act on all filenames which match the pattern, for

example *INFO. Thus:

*INFO Chapter*

will display information about all files whose names begin with 'Chapter'.

A third group of commands do not permit wildcards at all, and they produce the

'Wildcards' error message if you try to employ them. Such a command is

*DELETE, which we shall come to shortly.

Access codes and the *ACCESS command

*CAT, *INFO and their associated commands print letters between the

filename and the sequence number which describe the kind of operations

permitted on the file. There are five such possible letters, each of which may be

'set' (and therefore printed by *CAT/*INFO) or 'unset' (and not printed):

F 15