School Notes

CSC372 Lecture 1

Teacher: Hamid Timorabadi (h.timorabadi@utoronto.ca)

TA: Peter McCormick (peter@pdmccormick.com), Peyman Hadi(peyman.hadi@gmail.com)

Lecture

Microprocessors are everywhere. They are any device with some level of electronics/electrical components.

Laws

Moore's Law: every 18 months, transistor density of semiconductor chips doubles. Trying to say that we will be able to pack more and more power into smaller transistors, around every 18 months.

Not so much about performance, but about the number of transistors.

Joy's Law: computer speed doubles every year.

Complexity & Slowdown

Software demand is increasing at a rapid pace, and the complexity of software is increasing just as rapidly.

Software relied on Moore's Law to achieve faster performance, but due to numerous hardware challenges, doubling up became infeasible around 2002. The designer could no longer rely on hardware improving.

Challenges

Power Density

If you look at a processor, and the amount of silicon, it's very very small. As you double transistor density, you also gain very high power density, and ventilation becomes difficult. Starts to become dangerous/unstable, and the hardware melts due to the heat.

ManyCore is the concept of having many processors per chip, apparently without limit. We can split the power between each core, reducing power density. But how do you program these chips? You could dedicate cores to different processes, leading to the idea of parallelism.

Hardware Complexity

When you look at hardware, you have a ton of manufacturers and architectures. You have to deal with different CPUs, different memory types, different I/O devices, different networking methods. So the complexity of software to interface with that hardware becomes significantly more complicated.

Shared Memory

Everything in the computer connects physically to different memory locations. Shared memory means that you have to be careful about what gets mapped where, and what needs to be accessed at different points.

Recall that with a processor, you are executing one single instruction at a time. You need to be careful to make sure that those instructions are being delegated to the most important processes at any given point, with minimal interference to the user experience.


So it's not practical to provide code for each independent task, using the required hardware for that task.

So you add an OS, which always tries to accomodate the application with the hardware and manages resources. But due to the increasing complexity, designing and implementing an OS is not easy.

This course won't be about exploring OSs or implementing complicated ones. Instead, we employ the basics of architecture to improve performance and resource management for small Microprocessor applications. We aim to develop better embedded systems to gain a better appreciation for the computer system.