{"id":681,"date":"2017-02-06T22:24:42","date_gmt":"2017-02-07T03:24:42","guid":{"rendered":"http:\/\/sunapi386.ca\/wordpress\/?p=681"},"modified":"2017-02-06T22:24:42","modified_gmt":"2017-02-07T03:24:42","slug":"lessons-real-time-programming-class","status":"publish","type":"post","link":"https:\/\/sunapi386.ca\/wordpress\/lessons-real-time-programming-class\/","title":{"rendered":"Lessons from Real-Time Programming class"},"content":{"rendered":"
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Lessons from Real-Time Programming class<\/h1>\n

This post is about lessons I learnt in CS452 Real-Time Programming<\/a>, a 4th year undergraduate class at the University of Waterloo. Better known as \u201ctrains\u201d or \u201crealtime\u201d class.<\/p>\n

\u201cEasy stuff! You play with trains all day (literally, maybe even night). All you need to do is write one simple program to control multiple trains so they don\u2019t crash!\u201d<\/p><\/blockquote>\n

\u2014 chko on BirdCourses.com<\/a><\/p><\/blockquote>\n

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The trains lab. Room 3018, 3rd floor Math & Computer building.<\/figcaption><\/figure>\n

The class is a bit unconventional because it indirectly teaches other topics, like time management and teamwork, by providing a large amount of work\u200a\u2014\u200aso that you have to learn these skills. I\u2019ll talk about these lessons, hoping to address a more general audience.<\/p>\n

History<\/h3>\n

This class has been around since at least the 80\u2019s. Currently Bill Cowan<\/a>teaches this class, and has been for over 20 years.<\/p>\n

The equipment have evolved since then, but the underlying challenges have not.<\/em><\/p>\n

For example, teamwork, setting priorities, and dealing with real (imperfect) systems.<\/p>\n

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Prof. Bill Cowan explains the why sensor pickup sometimes have trouble detecting slow moving trains. The gap between the contact points may cause the pickup switch to flip\u00a0twice.<\/figcaption><\/figure>\n

The early version of the QNX real-time operating system<\/a> took off from a pair of students taking this class, Gordon Bell and Dan Dodge. They decided to expand the class project into a full-fledged commercial RTOS<\/a> (real time operating system).<\/p>\n

\u201cYou should try to find a partner for this class, it\u2019ll be hard without one. Generally I\u2019ve seen two outcomes:
\n(1) you become friends with your partner, or
\n(2) you stop being friends and hate each other.
\nI recommend not starting with a partner who is your friend, because you are already friends. Don\u2019t risk it.\u201d<\/p><\/blockquote>\n

\u2014 Prof. Bill Cowan<\/p><\/blockquote>\n

Curriculum<\/h4>\n

About 65% of the class involves building a small embedded kernel, with the other 35% working on the train management application.<\/p>\n

You can choose to program in whatever language you want, because there aren\u2019t any standard libraries provided. People generally program in C, because it\u2019s known as a systems language, and the programming examples given in class. But there\u2019s no reason why you can\u2019t do it in Rust language, for example\u200a\u2014\u200aalthough godspeed, you\u2019re venturing into uncharted territory!<\/p>\n

The kernel runs on a TS-7200 embedded system<\/a>, and it talks to a M\u00e4rklin Train System<\/a> over RS232 type serial. The firmware is loaded on via RedBoot<\/a>, a bootstrap environment for embedded systems.<\/p>\n

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The M\u00e4rklin Train System<\/a>. You can see the center console where the RS232 is attached. Off to the right is the grey box that houses the\u00a0TS-7200.<\/figcaption><\/figure>\n

The final exam is a take home 24 hour long exam, where you can use any resources you want, and you only need to do 3 of the 5 questions. The assignments and kernel make up 70% of the grade.<\/p>\n

Optional Technical Info<\/h4>\n

The microkernel did very little; it<\/p>\n