SWAC Menu is the control and communications center of all the second-generation SWAC Linux systems. The Menu starts, controls and exits
all applications delivered with SWAC Linux systems.
This application can be configured to trigger hardware or software watchdogs which would reboot the system if
they are not triggered for a certain time. It can also be configured to trigger a watchdog by request from a
running application or to act as the watchdog for an application (to restart it if not triggerd for some time).
Messages from the Kernel, system tools, drivers and applications are continually scanned for signs
of a failure, in which case the SWAC Menu can be configured to do something about it, including restarting
kernel modules and applications or even rebooting. SWAC Menu also scans the USB and PCI bus and can be configured
to reboot if a device is no longer present (in case a necessary part of the usb-hardware is plugged).
SWAC Menu is also used to keep the system secure. If the administrator logs out, SWAC Menu keeps critical applications
hidden, allowing access only if the administrator logs in again (by RFID Chip, Password or Security Key).
A logwindow can be optionally activated to provide an automated logging service using ring-buffers so that the filesystem will never
overflow. Messages from the kernel and applications are physically stored on a writable partition of the CF card so that they are
not lost during reboot.
An easy to use interprocess communications facility allows all processes started by SWAC Menu to talk with each other
simply by sending messages to the standard input/output channels which every application has by default. Applications can create and
subscribe named communication channels, getting only the information they are interested in.
Even simple shell scripts started by the 'Processes' subwindow can communicate this way by using the 'echo' command.
The Module-loading tool allows the user to select, configure and install additional drivers. Help information is automatically displayed
upon selecting a driver. And the systems is kept safe as the application will not allow the user to remove critical drivers (like the USB subsystem).
The Filesystem subwindow allows the admin to fine-tune paramaters like synchronized or async mounting, and it can mount
whole filesystem images over the read-only root filesystem with the Linux UnionFS driver, allowing transparent write-access
to read-only partitions.
The admin can get access to the powerful Linux CRON service which automatically starts processes at given dates. Complicated settings like
'only the 13th March if it's a Friday or Saturday' are possible.
Last but not least, the SWAC Menu includes a Shell window with up to five shells and a virtual keyboard.