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This article makes me realize how messy the underlying world of digital communication really is. As a software engineer, I send a file "into the cloud" and assu
by anticristi 6y ago
This article makes me realize how messy the underlying world of digital communication really is. As a software engineer, I send a file "into the cloud" and assume that it is going to be magically copied bit-by-bit with zero errors while going from my disk through the PCIe bus, the Ethernet cable, the fiber and similarly on the other side. Turns out "digital" is just an abstraction of messy, noisy, distorting, attenuating physical reality.
- segfaultbuserr 6y agoYou may enjoy reading the fiberglass weave effect in circuit board designs [0][1]. At multi-GHz frequencies, it turns out the grid-like microscopic structure of the circuit board creates dielectric constant and impedance variations, which can cause distortion in high-speed signals such as PCI-E. The solution? Always run the signal traces at an angle, so horizontal and vertical lines that are parallel to the microscopic grid is avoided. At this point, even the direction of the traces matters, and it's not even the cutting-edge, every commercial server motherboard is designed with this effect in mind, pretty amazing, isn't it? [0] https://www.ti.com/lit/an/spraar7h/spraar7h.pdf https://www.ti.com/lit/an/spraar7h/spraar7h.pdf see page 4. [1] https://blog.lamsimenterprises.com/2011/01/08/fiber-weave-effect-timing-skew/ https://blog.lamsimenterprises.com/2011/01/08/fiber-weave-ef...
- robotnikman 6y agoWhen you really think about it, it makes you realize its amazing it even works at all in the first place
- anticristi 6y agoRight? I'm happy someone else persevered and invented the PCIe bus. People like me would have use smoke signals to this day. :)))