Data files in ADAM are stored in an hierarchical format (HDS). This cannot be read by just typing the file at the terminal or spooling it to a printer—a special application is required. Now rather than writing separate code to read a variety of structures, this application is sufficiently general to examine almost all HDS structures or objects. The examination may also be written to an text file as well as being reported to the user.

The version number of the HDS data format used by the supplied file may also be displayed. See parameter VERSION.

For the specified ADAM data-system object ($X$) there are three cases which are handled:

1) $X$ is a primitive object. The value, or the first and last few values of $X$ are listed.

2) $X$ is a structure. The contents of the structure are listed. If a component is encountered which is itself a structure then its contents are listed down to a level of six nested structures.

3) $X$ is an array of structures. All elements will be listed if Parameter FULL is set to TRUE; only the first element will be listed when Parameter FULL is set to FALSE (default).

Listings are in the following order: name; dimensions, if any; type; and value or comment. Comments are enclosed in braces.

The values are normally listed at the end of each line, but may start on a new line. The maximum number of lines of data values may also be set. For all but the smallest arrays where the values of all elements can be displayed in the space provided, the last few values in the array as well as the first few are presented. The last few values appear on a new line, indented the same as the line above with the ellipsis notation to indicate any missing values. Note the number of elements shown depends on the number of characters that will fit on the line. The ellipsis notation is also used for long character values where there is only room to show the first and last few characters. Bad values appear as asterisks.

The exact layout may be adjusted and is controlled by four additional parameters: a) the indentation of the type string with respect to the beginning of the name string; b) indentation of the value(s) (if not on a new line) with respect to the beginning of the type string; and c) the width of the output. If the name and dimensions do not fit within the space given by parameters a) and b), the alignment will be lost because at least two spaces will separate the name from the type, or the type from the value(s). The fourth parameter defines how character arrays are arranged. The default is that character-array elements are concatenated to fill the available space delimited by commas. The alternative is to write the value of each element on a new line. This improves readability for long strings.

EACHLINE = _LOGICAL (Read)

FULL = _LOGICAL (Read)

HDSVERSION = _INTEGER (Write)

LOGFILE = FILENAME (Read)

NEWLINE = _LOGICAL (Read)

NLINES = LITERAL (Read)

OBJECT = UNIV (Read)

SORTED = _LOGICAL (Read)

TYPIND = _INTEGER (Read)

VALIND = _INTEGER (Read)

VERSION = _LOGICAL (Read)

WIDEPAGE = _LOGICAL (Read)

WIDTH = _INTEGER (Read)

This application allows far more flexibility in layout than earlier applications like LS and the original TRACE, though the order of the attributes of an object has been fixed and rearranged for standardisation, particularly for documentation purposes.