The reason we know Radiation causes bit-flips in DRAM is pretty hilarious. In the late 70s, Intel Ram was occasionally producing soft, uncorrectable errors. Turns out, the ceramic packaging on the chip itself had a little bit of Uranium. You know, as one does.
Seriously though, the chips were a bit spicy, and it was a *problem*. AT&T was really annoyed. They had a major phone switching project, and refused delivery until Intel found the root cause. A full investigation was launched. The silicon looked…fine.
Intel’s main ceramic vendor was located in Colorado, on the Green River. Miles upstream was a…Uranium mine. Oops. Alpha particles from the ceramic were causing random, single-bit flips.
Once the root cause was found, it radically changed the industry for the better. Chipmakers quickly switched to low-alpha materials, added radiation blocking layers, and started keeping track of emission specs. The “soft error rate” (SER) in modern DRAM is a direct byproduct of
@lauriewired And then in the 90’s they noticed there are cosmic ray soft errors, and the Denver effect where soft error rates increase with altitude https://downloads.regulations....
@lauriewired Hamming Codes. Richard Hamming came to the rescue at Bell Labs!
@lauriewired I really appreciate these history tweets of yours, they're always so interesting and well written 🫡
@lauriewired When in Rom...
@lauriewired Before ceramic packaging plastics were used and they were fine until the density of IC chips went up and the heat melted those plastics. Amazing journey, isn't it!
@lauriewired I have a great idea for a random number generator chip.
@lauriewired Run into a bit-flip error recently. https://x.com/feralpacket/stat... Conditions: ... may occur when the radioactive atoms in the chip's material decay and release alpha particles into the chip. https://quickview.cloudapps.ci...
@lauriewired Spicy chips
@lauriewired You should investigate and report on what happens to our electronics as the Earths magnetic field continues to weaken during the current geomagnetic excursion (pole flip). The field is down 25-35% from the highs of the early 1900's, and declining rapidly...
@lauriewired Illustration is an EPROM not DRAM
@lauriewired Can't wait for some lead chips.
@lauriewired Who would've thought a bit of uranium would mix into '70s tech? Just another vintage tech tale to laugh at!
@lauriewired Looks like Black Masa
@lauriewired Imagine trying to debug it just to find out it was the material
@lauriewired another banger post
@lauriewired 🐞⚛️🐞
@lauriewired 😮😬
@lauriewired Love those EPROM's
@lauriewired @grok Summarize thread