Linux and CATS proved to be a good match. System reliability and performance met and exceeded our expectations with amazingly predictable results. CAE now has a full-blown aircraft simulation, with graphics and aural warnings, running in a Linux environment. Our Linux development environment consisted of a Pentium II Intel 350MHz CPU with 128MB of memory and a Toshiba 233 MMX Portege 320CT laptop with 32MB memory. As described previously, the CATS comes in three flavors: one-, three- and seven-screen versions. Under AIX CATS, the IBM host drives three separate X workstations, with each screen displaying different information. Under a single-screen configuration, one X workstation provides functionality for all graphics pages while using a cockpit navigational panel as shown in Figure 16. The top right-hand quick-reference panel is a small graphical representation of the aircraft cockpit. When one of the panels is selected, the system displays the selected panel in a designated portion of the single screen, with the seven-screen CATS being displayed on seven separate X workstations. Each displays a full graphical representation of all the aircraft panels (Forward, Overhead, Pedestal and Side panels, Figure 8). With Linux, the hardware configuration is a bit different. The graphics display is the same (one-, three- or seven-screen configurations); the difference is in how and where we display the graphical pages. Under Linux, we use a graphics card called Evolution 4.
This card is manufactured by Color Graphics Systems in the UK. It allows us to display four simultaneous X display outputs using Xi Graphics' Multi-Headed X server. AcceleratedX is an excellent product, allowing us to drive up to 16 X displays (using four Evolution 4 Video cards) simultaneously. The hardware cost is reduced significantly when compared to three IBM X workstations with an RS6000 IBM host CPU and a Linux PC with one Evolution 4 video card.
In a MINI CATS version (single-screen configuration), we now have the option to install the CATS on a standard PC laptop using the Xfree86 X server included with every Linux distribution. Distribution and installation of CATS has also been addressed. Customers did not want to install a dedicated Linux system on a previously preloaded Microsoft operating system. So, we developed a CD-ROM that would boot into a Linux environment, set up a small virtual Linux file system in memory, and loaded all the required CAE CATS software without installing any software on the local hard disk. This also has proven to be successful. Bombardier can now distribute their CATS systems on a pre-configured bootable CD-ROM. Booting and loading CATS in the field now requires no previous knowledge of or experience in the Linux operating system—no more file corruption or accidental file deletions by the customer. The primary reason for developing PC-based CATS for Bombardier was cost and portability, portability being Bombardier's top priority for their training instructors in the field. All these factors translate into a more affordable CATS for Bombardier and their customers.
Linux has proven without a doubt that it is a reliable and stable development platform for delivering commercial-grade simulation products to the airline training industry. CAE has recognized the potential in Linux and its potential in future CAE simulation products. CAE may even explore the possibility of running a full-flight simulator on Linux one day. Job well-done, Linus Torvalds.