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LaurieWired

@lauriewired161,181 subscribers

researcher @google; serial complexity unpacker; https://t.co/Vl1seeNgYK ex @ msft & aerospace

Shorts

You’ve heard of DRAM, HBM, probably SRAM, but RDRAM…now that was a weird one. Famously used in the Sony PS2, its RDRAM had ~3x the bandwidth of your typical high end PC. If you want more memory bandwidth in a dense die, there’s (roughly) two things you can do. You can *add* many more wires (wide+close, like hbm). Or, you can make the wires *faster* and use less of them (narrow). Rambus, the creator of RDRAM, took the second bet. It was quite contrarian, but garnered some attention from Intel as well. The main issue, among others, is that RDRAM was expensive, AND high latency. For typical PC-style workloads, random access latency dominates, so it was a tough sell. Although the PS2 was a roaring success (high-bw streaming workloads made sense), it barely lasted ~3 years in the PC market. Like many ideas, Rambus+RDRAM was arguably just way, way too early. Today, CXL memory uses many of the same initial principles! If you think about a pin-efficient, high speed link, over longer distances…well, that’s kinda just CXL. Funnily enough, Rambus still exists, and is heavily involved in CXL memory controller IP these days!

You’ve heard of DRAM, HBM, probably SRAM, but RDRAM…now that was a weird one. Famously used in the Sony PS2, its RDRAM had ~3x the bandwidth of your typical high end PC. If you want more memory bandwidth in a dense die, there’s (roughly) two things you can do. You can *add* many more wires (wide+close, like hbm). Or, you can make the wires *faster* and use less of them (narrow). Rambus, the creator of RDRAM, took the second bet. It was quite contrarian, but garnered some attention from Intel as well. The main issue, among others, is that RDRAM was expensive, AND high latency. For typical PC-style workloads, random access latency dominates, so it was a tough sell. Although the PS2 was a roaring success (high-bw streaming workloads made sense), it barely lasted ~3 years in the PC market. Like many ideas, Rambus+RDRAM was arguably just way, way too early. Today, CXL memory uses many of the same initial principles! If you think about a pin-efficient, high speed link, over longer distances…well, that’s kinda just CXL. Funnily enough, Rambus still exists, and is heavily involved in CXL memory controller IP these days!

213,803 views

I think we can salvage it

I think we can salvage it

68,690 views

We take randomness for granted. Early PRNGs were BAD. Thousands of scientific papers used to rely on RANDU, created by IBM in the 1960s. In 1D space, it looks ok! Map in 3D…you start to see the issues. Now, there *was* a better solution...but it would cost you.

We take randomness for granted. Early PRNGs were BAD. Thousands of scientific papers used to rely on RANDU, created by IBM in the 1960s. In 1D space, it looks ok! Map in 3D…you start to see the issues. Now, there *was* a better solution...but it would cost you.

589,428 views

Every year shopify makes a website tracking the massive surge in compute on black friday. Right now they are tracking ~45+ million Kafka requests per second, and about 88,000 gigabytes of data per minute. (it's also just a really cool website)

Every year shopify makes a website tracking the massive surge in compute on black friday. Right now they are tracking ~45+ million Kafka requests per second, and about 88,000 gigabytes of data per minute. (it's also just a really cool website)

237,806 views

Modern tech tends to focus on “more”. More data. More bandwidth. More compute. The best software engineering happens in the “less” sphere; codec engineering. Listen to this stream with 90% packet loss. The Opus Encoder team is cracked:

Modern tech tends to focus on “more”. More data. More bandwidth. More compute. The best software engineering happens in the “less” sphere; codec engineering. Listen to this stream with 90% packet loss. The Opus Encoder team is cracked:

244,761 views

Sharks love our undersea cables. Some suspect the weak, low-frequency fields attract sharks like distressed fish. Fiber optics are particularly tasty; AT&T expressed no incidents with “old [copper] cables”. In the 80s, telecoms called the incident Jaw's Syndrome.

Sharks love our undersea cables. Some suspect the weak, low-frequency fields attract sharks like distressed fish. Fiber optics are particularly tasty; AT&T expressed no incidents with “old [copper] cables”. In the 80s, telecoms called the incident Jaw's Syndrome.

231,942 views

It's hot out there today guys. Don't forget to keep your servers cool with a nice hose-down.

It's hot out there today guys. Don't forget to keep your servers cool with a nice hose-down.

536,440 views

I promise this relates to RAM (you'll find out in my next video)

I promise this relates to RAM (you'll find out in my next video)

75,758 views

Is your compiler a boy or a MAN? Created by Donald Knuth, it’s a test to check if recursion is implemented properly. Originally written in ALGOL 60, a precursor to C, but can adapt to nearly any language. It really stresses the stack and heap, pushing insane call depths:

Is your compiler a boy or a MAN? Created by Donald Knuth, it’s a test to check if recursion is implemented properly. Originally written in ALGOL 60, a precursor to C, but can adapt to nearly any language. It really stresses the stack and heap, pushing insane call depths:

133,373 views

Absurd as it sounds, with smaller experiments it was completely worth it to: - Buy the book - Open a random page - Mark your starting point with a pen - Hand Type / Punch the data into cards

Absurd as it sounds, with smaller experiments it was completely worth it to: - Buy the book - Open a random page - Mark your starting point with a pen - Hand Type / Punch the data into cards

63,619 views

it's not every day you get to touch a Cray-2 supercomputer

it's not every day you get to touch a Cray-2 supercomputer

64,993 views

Wanna know something wild? You can still reproduce a (similar) issue on modern systems. - Open a large file on notepad (not fullscreen) - Select text while scrolling down - Wiggle the mouse and notice the speed difference

Wanna know something wild? You can still reproduce a (similar) issue on modern systems. - Open a large file on notepad (not fullscreen) - Select text while scrolling down - Wiggle the mouse and notice the speed difference

80,326 views

Of course, that fits nicely in 32-bit hardware. Only a few instructions. Apple put it in CarbonLib, FreeBSD also used it, and for a few decades it was kind of everywhere. A few years later they discovered that 48271 was a little better. Specifically, a bit more even on spectral tests up to 6 dimensions. It’s kind of funny that so few listened. FreeBSD was still using 16807 in rand() all the way until 2021! So if you ever see that constant in disassembled code…well now you know :) (side note: most rand() implementations moved on to other LCGs, or mersenne twisters and such…but it’s arguable that 16807 is still quite ubiquitous!) Original Paper if you’d like to read:

Of course, that fits nicely in 32-bit hardware. Only a few instructions. Apple put it in CarbonLib, FreeBSD also used it, and for a few decades it was kind of everywhere. A few years later they discovered that 48271 was a little better. Specifically, a bit more even on spectral tests up to 6 dimensions. It’s kind of funny that so few listened. FreeBSD was still using 16807 in rand() all the way until 2021! So if you ever see that constant in disassembled code…well now you know :) (side note: most rand() implementations moved on to other LCGs, or mersenne twisters and such…but it’s arguable that 16807 is still quite ubiquitous!) Original Paper if you’d like to read:

21,874 views

This pokemon clone is stored inside a font. Yes, an *actual* font; think Times New Roman. As expected, it's playable anywhere you use fonts. A text document, code editor, etc. The full game takes about ~20 minutes to play, an hour if you find all the secrets. But how?

This pokemon clone is stored inside a font. Yes, an *actual* font; think Times New Roman. As expected, it's playable anywhere you use fonts. A text document, code editor, etc. The full game takes about ~20 minutes to play, an hour if you find all the secrets. But how?

46,087 views

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Merry Christmas everyone!

LaurieWired

158,978 views • 8 months ago