Common Output Area and Log File

The Common Output Area (COA) on the terminal screen is the remaining top area of the terminal screen not used for the User Command Area or Task Status Area. It is a viewport on the log file. Hermes treats the log file as a ``book'' with numbered pages. Normally Hermes shows the current page of the book, that is the page on which output is currently being written.

Modes of operation

The COA has two modes of operation: page mode and non-page mode. In non-page mode the page on the screen is always the current page. If necessary, Hermes will flip the page. The current page number is displayed at the extreme right of the Task Status Area. In page mode the information on the screen will stay there until the user instructs Hermes to change the page. Though the user does not see it, output can still be written to the log file. In page mode the number of the displayed page is shown to the left of the current page number. Page mode can be switched on and off by pressing CTRL-P.

Example: 2900  2901

Here page 2901 is the last page, i.e. the page to which is being written, and page number 2900 is currently displayed in the COA.

Scroll mode

When in non-page mode, Hermes can also scroll the COA instead of flipping pages. This scroll mode can be switched on and off by typing CTRL-X S. In scroll mode output is much slower than in `flip mode'. Therefore this mode is not recommended for use with slow terminals.

Traversing the log file

The log file can be traversed in backwards direction by pressing the CTRL-Z key (or on ANSI keyboards the PageUp key). Paging forward is done with the CTRL-V key (or ANSI PageDown).

Searching the log file

Text search in the log file is done by pressing CTRL-R (reverse) or CTRL-S (forward). Hermes then prompts the user for a search string. (See example below.) Searching in Hermes is case-insensitive.

Going to a page

A specific page number can be brought to the screen by typing ESC G, whereafter Hermes prompts for a page number:

Page number:

Signed numbers are treated as relative page numbers.

Printing pages

Sections of the log file can be printed by typing the ESC H sequence. (H from Hardcopy) Hermes then prompts for a range of pages to be printed:

The range can be specified as a single number, in which case only that page will be printed, or using the format `start:end'. Either start or end may be omitted, in which case the number of the currently displayed page will be used instead. The default range is the page currently displayed and the preceding two pages. The printer can be selected by typing ESC P, which causes a menu to be presented from wich a printer can be chosen.

The printer to be used can be pre-set in the Hermes defaults file. It is also possible to redirect the printer output to a file. Option ``F'' in the printer selection menu will prompt for a file name. It is not possible to pre-set this file name in the Hermes defaults file.

The statement that the COA is a viewport on the log file is not quite true. In fact the log file and the COA are different output streams to which tasks can send information selectively. Most tasks however send the same information to both the log file and the COA.

Command summary

enter or leave page mode
display previous page and enter page mode
display next page
search forward for text string
search backwards for text string
toggle scroll mode
go to specified page number
make hardcopy of specified page numbers
select a printer for the hardcopy print command
go to first page
go to last page

Hermes GIPSY