1 /************************************************
  2  * Demonstration of the rectangle class.        *
  3  ************************************************/
  4 #include <iostream>
  5
  6 /************************************************
  7  * rectangle -- hold constant information about *
  8  *              a rectangle.                    *
  9  *                                              *
 10  * Members:                                     *
 11  *      area -- Area of the rectangle.          *
 12  *      width -- width of the rectangle.        *
 13  *      height - length of the rectangle.       *
 14  ************************************************/
 15 class rectangle
 16 {
 17     public:
 18         const int area;   // Rectangle's Area
 19         const int width;  // Rectangle's Width
 20         const int height; // Rectangle's Height
 21
 22     public:
 23         // Create a rectangle and assign the
 24         // initial values
 25         rectangle(
 26             const int i_width,  // Initial width
 27             const int i_height  // Initial height
 28         ) : width(i_width),
 29             height(i_height),
 30             area(width*height)
 31         {}
 32         // Destructor defaults
 33         // Copy constructor defaults
 34         // Assignment operator defaults
 35 };
 36
 37 int main()
 38 {
 39     // Rectangle to play with
 40     rectangle sample(10, 5);
 41
 42     std::cout << "Area of sample is " <<
 43         sample.area << std::endl;
 44     return (0);
 45 }

Man Bytes Computer

A system administrator for a major university was responsible for keeping several hundred DEC machines running. He quickly learned how to diagnose broken machines and figure out which board was bad. To get a steady supply of spare parts he had to purchase a service contract. This meant that a DEC service representative was supposed to come down, diagnose the machines, and figure out which board was bad and replace it. In practice, the university staff had strict orders to never let the DEC service representative near the machines.

A typical service would start with the administrator telling DEC which board was bad. The service representative would come down, find the broken board on the administrator's desk, and replace it with a good one. No running diagnostics or other work, that was all done for him.

A few years later, DEC instituted a "Smart Spares" program. The idea was that you had someone trained, on site, who could figure out which board was bad and order a replacement from DEC. Of course this suited the university, because it had been operating that way for years.

The catch was that you had to take a class, at DEC, to learn how to diagnose systems. The system administrator jumped at this opportunity. He needed the vacation. He practically slept through the two days of classes. The third day was devoted to a lab. The instructor had set up three machines. The students were divided into groups and were supposed to spend the morning finding out what was wrong with their machine.

Our hero turned on his machine, looked at the flashing lights for a minute, and then said, "Bad disk card." The instructor was a little surprised." "How do you know that?"

"Lights aren't right."

The administrator moved to the next machine, looked at it, and said, "Bad memory interface card." At the next machine, "Bad processor card."

Three machines down. This exercise was supposed to take three groups all morning, and this one guy had diagnosed all the machines in two minutes flat. (I talked to him a while back, and he told me that if he knew he was being timed, he would have worked faster.)

Undaunted, the instructor moved over to the machine reserved for the afternoon problem. This one has been set up by field service and was supposed to have a really tough problem, next to impossible to find.

The instructor knew the problem couldn't be identified by looking at the lights and waited to see what our hero would do. The guy opened the back, and even before he hit the "On" switch pointed to a board and said "That board is bad; chip U18. It'll cause an intermittent data bus parity error."

Now the instructor knew that the guy was good, but spotting a bad board without even turning the machine on? Impossible.

"How do you know it's bad?" he asked.

The administrator pointed to a small blue label in the corner. "See that dot? I put it there so I'd be sure that DEC didn't trade me back my own boards. This board is from the university. I'm the one who originally found the problem and showed it to DEC field service."

The morning and afternoon's problems now solved in the space of about 10 minutes, the class decided it was time to go out for pizza and beer.