Anomalous Anomaly

Why would a computer engineering degree be better than a computer science one? Computer science works in the theoretical plane. Stuff that you have to run for months on end on a supercomputer or not even solve for years. Engineering is about making things work with what you have to meet a set of constraints, and deals in milliseconds or microseconds. In game programming, you have a CPU, a GPU, memory that has a certain latency, a disk with a certain seek time, etc. You need to accomplish so much every 60th of a second given those hardware constraints or else the game will suck.

Put another way, computer science is about exploring new ideas and not having to worry about the practical implementation, which is the engineering portion. Prime numbers for example. Computer scientists love to talk about ridiculously large prime numbers and all you can do with such things, like unbreakable encryption and such. Engineering is taking that abstract algorithm and making it work on, say, a 200MHz ARM processor running on your battery-powered MP3 player, where things like battery life and response time matter.

What I’ve found is that computer science majors write really bad code. Not code that doesn’t work, but code that’s slow. They don’t know how to optimize. They can’t tell you the difference between an AMD Athlon XP and an Intel Pentium 4. They can’t explain why the new Core 2 is such a good thing. In their little abstract world of trees and lists and Java, they don’t need to understand the low level hardware. Many of them can’t ever read an x86 disassembly or tell me the first thing about how many registers in a Pentium processor or what the registers are for.

Parallelization is the big thing right now. The Xbox 360, for example, has a 6-way processor. How does one write video games when you can have 6 concurrent pieces of code running at the same time? How does that change your rendering engine? Your game logic? Memory allocation? The Playstation 3 has nine hardware threads. This totally changes the way one writes video games from now on.

Computer Science has a long standing solution to concurrency - the concept of a lock. Which in Linux and Windows are synchronization objects known as locks, mutexes, semaphores, and other names. They’re used in every operating system and just about every shipping Windows and Linux application today. Even calling malloc() is a seralizing operation on the memory heap that causes a lock. Have multiple threads calling malloc() and they basically get to stand in line (a queue data structure) and execute serially. That’s not very parallel. So once again, Computer Science has given us something that doesn’t translate well into real-world performance.

My point of this is that you should NOT go into pure computer science. You’ll rot your head with abstract ideas and end up writing very poor code. Take either computer science with electrical (or computer) engineering electives, what’s known as “CS triple E”, or take computer engineering to get the best of both worlds. If you can’t visualize an algorithm or a piece of code and understand what that touches in the microprocessor, in the memory, on the disk, and what the costs and delays of all the steps are, you’re going to write crappy code.