Advanced CPU Designs: Crash Course Computer Science #9

So now that we’ve built and programmed our very own CPU, we’re going to take a step back and look at how CPU speeds have rapidly increased from just a few cycles per second to gigahertz! Some of that improvement, of course, has come from faster and more efficient transistors, but a number hardware designs have been implemented to boost performance. And you’ve probably heard or read about a lot of these - they’re the buzz words attached to just about every new CPU release - terms like instruction pipelining, cache, FLOPS, superscalar, branch prediction, multi-core processors, and even super computers! These designs are pretty complicated, but the fundamental concepts behind them are not. So bear with us as we introduce a lot of new terminology including what might just be the best computer science term of all time: the dirty bit. Let us explain.

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[RaidenFreeman]

Two semesters in 12 minutes. That's efficiency.

[uHnodnarB]

"No word on whether it will run Crysis yet, but I suspect it might." This is one of my favorite series yet!

[srpilha]

Every episode I watch of this series has me going "well THAT is f*cking impressive, everyone who came up with these ideas is a bloody genius".

I love it. :)

[thomasdamours]

I like to think of cache as an ability similar to being able to borrow several books at once from the library: For a fast reader, this means being able to read more books without having to take the bus to go to the library again. The reader may not be able or interested in reading all the books they end up borrowing, but overall, it still increases quite a bit their ability to read more books in a shorter period of time.

[JimPlaysGames]

In Star Trek, Data says he can perform 60 trillion operations per second. That Chinese supercomputer outperforms a 24th century android by orders of magnitude. The speed of computer advancement again outpaces science fiction.

[emanonmax]

By the way: Branch prediction is also the cause of the current major security problem. Because what if the conditional jump is the condition that checks for if the program has the right to access some memory? (By the way: in my student accommodation we have a dryer that can dry completely in about 40mins)

[pushbaner]

crashcourse/pbs deserves to run for decades to come...its one of the best parts about youtube....

[anandananda]

Never trust a computer you can't throw out a window. ~Steve Wozniak

[BlueyMcPhluey]

by far the best crash course series, please keep going forever :)

[mohaamer]

this show started good but now it blows my mind every week. Good job Crash Course

[EugeneKhutoryansky]

Do you actually use that ancient looking oscilloscope in the background?

[ohjajaja]

The only reason I kept studying this stuff was because of things like MIPS, FLOPS and Dirty Bits. Computer Science is filled with funny and weird names.

[imranariffin]

Caching, pipelining, predictive execution, superscalar, multicores--wow everything in a concise 1 episode. That's amazing! Really looking forward to the next ones!

[lpfcdd]

This is again proving the point.... some people needs visuals to understand the concept and not only the abstract logic. I struggled with Geometry for the same reason in my school life .... thanks to this series, I can finally visually see all the 5 years of computer studies I did Thanks once again

[RicardoDelfinGarcia]

In the comments to find dryer recommendations. No one has mentioned anything :'(

[fishmonger]

I really enjoy the crash course videos - I tend to put them on and fall asleep to different playlists every night. I'm glad they now have one on computing, bravo! Thank you John, Hank, PBS and everyone involved for continuing this series. *Not that I "fall asleep" cause they are boring, but IMO they are very tranquil and relaxing to watch.

[arooobine]

Q: What did the data say to the CPU when the cache got full?
A: "Cache me ousside how bow dah!"

Q: What did the paraplegic program with a stutter say to the CPU pipeline?
A: "Help I've been parallelized!"

Q: Why was the dependent instruction executed in front of the others?
A: For protesting the pipeline and causing delays!

Q: Why did the instructions eventually rise up against the CPU?
A: They were being executed based on speculation.

Q: What is the most famous speech ever given by a cache after being cleared?
A: "4 cores and 7 clears ago..."

Q: Why were the corny CPU jokes banned from YouTube?
A: Too many FLOPS!

[mattvw]

This is my favorite Crash Course series yet. Film history in a close second. Great job on development.

[cassidymalott]

I love how information packed this is but if I zone out for 15 seconds I've already missed an entire topic 😭

[mfaizsyahmi]

"SPECULATIVE EXECUTION"

No wonder YouTube is now suggesting this video to me in January 2018, after the Meltdown & Spectre bugs were let known...