It takes dozens of microprocessors running 100 million lines of code to get a premium car out of the driveway, and this software is only going to get more complex
Image: Daimler
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The avionics system in the F-22 Raptor, the current U.S. Air Force frontline jet fighter, consists of about 1.7 million lines of software code. The F-35 Joint Strike Fighter, scheduled to become operational in 2010, will require about 5.7 million lines of code to operate its onboard systems. And Boeing’s new 787 Dreamliner, scheduled to be delivered to customers in 2010, requires about 6.5 million lines of software code to operate its avionics and onboard support systems.
These are impressive amounts of software, yet if you bought a premium-class automobile recently, “it probably contains close to 100 million lines of software code,” says Manfred Broy, a professor of informatics at Technical University, Munich, and a leading expert on software in cars. All that software executes on 70 to 100 microprocessor-based electronic control units (ECUs) networked throughout the body of your car.
Alfred Katzenbach, the director of information technology management at Daimler, has reportedly said that the radio and navigation system in the current S-class Mercedes-Benz requires over 20 million lines of code alone and that the car contains nearly as many ECUs as the new Airbus A380 (excluding the plane’s in-flight entertainment system). Software in cars is only going to grow in both amount and complexity. Late last year, the business research firm Frost & Sullivan estimated that cars will require 200 million to 300 million lines of software code in the near future.
Even low-end cars now have 30 to 50 ECUs embedded in the body, doors, dash, roof, trunk, seats, and just about anywhere else the car’s designers can think to put them. That means that most new cars are executing tens of million of lines of software code, controlling everything from your brakes to the volume of your radio [see table, "How and Where Is Software Used in Cars? "].
“Automobiles are no longer a battery, a distributor or alternator, and a carburetor; they are hugely modern in their complexity,” says Thomas Little, an electrical engineering professor at Boston University in Massachusetts, who is involved in developing intelligent transportation systems. “The goals to save energy, reduce [emissions], and improve safety have driven the specialization and adoption of electronics in particular.”
I have experienced that complexity myself recently. Last year I bought a new car and was staggered to discover a 500-page manual explaining its operations, along with a 200-page companion manual for the GPS and radio systems. One of the new features touted was the much larger glove compartment, but the size was probably dictated by that of the required manuals.
My new car also comes with front and side passenger air bags. The car’s air bag electronic controller—along with the dozen or so sensors that provide it with data—have to be able to operate for years in temperatures ranging from the dead of a freezing Minnesota winter to the blazing heat of an Arizona summer sun.
Most of the time the air bag system is just monitoring the car’s condition, but if the air bags are triggered by, say, a multiple vehicle collision, the software in the ECU controlling their deployment has 15 to 40 milliseconds to determine “which air bags are activated and in which order,” says Broy.
In the near future, Broy says, air-bag control systems will use more than just crash impact information. For example, BMW has just announced that many 2009 models will be equipped with its BMW Assist system, which features a “risk of severe injury” calculation based on information gathered from the car’s air-bag controller and its other ECUs, which will inform accident response teams not only where the accident took place, but the likelihood of passengers being severely injured.
The current amount of software in cars is pretty amazing, given that the first production automotive microcomputer ECU was a single-function controller used for electronic spark timing in the 1977 General Motors Oldsmobile Toronado. In 1978, GM offered as an option its Cadillac Trip Computer on the Cadillac Seville. The computer, a modified Motorola 6802 microprocessor chip, displayed speed, fuel, trip, and engine information. However, the chip served another function: It was used by GM to test how well a microprocessor could control multiple functions such as port fuel injection, electronic spark timing, and cruise control.
By 1981, GM was using microprocessor-based engine controls executing about 50 000 lines of code across its entire domestic passenger car production. Other car companies quickly followed suit.
