You want to build a cluster of computers, but you need a high-speed network fabric that can connect anything to anything. Big bucks, right? [Fang-Pen] developed a 10 Gbps full-mesh network using USB4 that cost him under $50. The first part of the post is about selecting a low-power mini PC, but if you skip down to the “Networking” section, you’ll find the details on the cluster.
The machines selected have two USB4 ports. In theory, you can transfer 40 Gbps on these ports. In reality, the cluster only hit 11 Gbps, but that’s still well above common Ethernet speeds. [Fang-Pen] has yet to determine why he isn’t getting even faster speeds.
Since Linux is Linux, there is a module for networking over Thunderbolt, so the rest is basically set up. There are, of course, some limitations. First, it is only fully connected because the cluster has three computers. More computers would need more USB4 ports or more hardware.
In addition, the standard says you can only count on full speed with cables 0.8 meters or shorter. However, that’s the 40 Gbps number. We wondered if a 2 m cable, rated at 20 Gbps, would have still managed 11 Gbps in this setup. A 10GBASE-T network, on the other hand, should allow 100-meter cables. But for a cluster of computers, do you really care?
We’d be interested to see this idea extended to more nodes. High-speed fabric can be useful in networked disk servers, parallel computing, and probably some other scenarios. We’ve seen 10G Ethernet on the Pi, although the PCI bus limited it to about 3.6 Gbps. For reference, we saw another three computer networks with 10GBASE-T done for about $130 with similar limitations.
What in the world could possibly justify charging $129 for a USB cable? And is such a cable any better than a $10 Amazon Basics cable?
To answer that question, [Jon Bruner] fired up an industrial CT scanner to look inside various cables (Nitter), with interesting results. It perhaps comes as little surprise that the premium cable is an Apple Thunderbolt 4 Pro USB-C cable, which sports 40 Gb/s transfer rates and can deliver 100 Watts of power to a device. And it turns out there’s a lot going on with this cable from an engineering and industrial design perspective. The connector shell has a very compact and extremely complex PCB assembly inside it, with a ton of SMD components and at least one BGA chip. The PCB itself is a marvel, with nine layers, a maze of blind and buried vias, and wiggle traces to balance propagation delays. The cable itself contains 20 wires, ten of which are shielded coax, and everything is firmly anchored to a stainless steel shell inside the plastic connector body.
By way of comparison, [Jon] also looked under the hood at more affordable alternatives. None were close to the same level of engineering as the Apple cable, ranging as they did from a tenth to a mere 1/32nd of the price. While none of the cables contained such a complex PCB, the Amazon Basics cable seemed the best of the bunch, with twelve wires, decent shielding, and a sturdy crimped strain relief. The other cables — well, when you’re buying a $3 cable, you get what you pay for. But does that make the Apple cable worth the expense? That’s for the buyer to decide, but at least now we know there’s something in there aside from Apple’s marketing hype.
We’ve seen these industrial CT scanners used by none other than [Ken Shirriff] and [Curious Marc] to reverse engineer Apollo-era artifacts. If you want a closer look at the instrument itself, check out the video below
Continue reading “Using Industrial CT To Examine A $129 USB Cable”
One amazing thing about USB-C is its high-speed capabilities. The pinout gives you four high-speed differential pairs and a few more lower-speed pairs, which let you pump giant amounts of data through a connector smaller than a cent coin. Not all devices take advantage of this capability, and they’re not required to – USB-C is designed to be accessible for every portable device under the sun. When you have a device with high-speed needs exposed through USB-C, however, it’s glorious just how much USB-C can give you, and how well it can work.
The ability to get a high-speed interface out of USB-C is called an Alternate Mode, “altmode” for short. The three altmodes you can encounter nowadays are USB3, DisplayPort and Thunderbolt, there’s a few that have faded into obscurity like HDMI and VirtualLink, and some are up and coming like USB4. Most altmodes require digital USB-C communication, using a certain kind of messages over the PD channel. That said, not all of them do – the USB3 is the simplest one. Let’s go through what makes an altmode tick. Continue reading “All About USB-C: High-Speed Interfaces”
For the last decade, Macs have been running a UNIX-ish operating system on x86 processors. They’ve been fantastic developer’s machines, and the MacBook Pro is the de facto standard laptop issued to all developers, all hackathon attendees, and arguably, anyone who does real work with a computer.
This week, Apple unveiled the latest MacBook Pro and provided more evidence Steve Jobs actually knew what he was doing. Fifteen hundred bones will get you a MacBook Pro with a last-gen processor, an Escape key, a headphone jack, and two Thunderbolt 3 ports (with one port required for charging). The next model up costs $1800, ditches the Escape key for a dedicated emoji bar, and includes four Thunderbolt 3 ports.
In the past, I have defended people who choose MacBooks as their laptop of choice. A MacBook is a business-class laptop, and of course carries a higher price tag. However, Apple’s latest hardware release was underwhelming and overpriced. If you’re looking for a new laptop, you would do well to consider other brands. To that end, here’s a buyer’s guide to ThinkPads, currently the second most popular laptop I’ve seen with the dev/hacker/code cracker crowd.
Continue reading “Apple Sucks Now, Here’s A ThinkPad Buyer’s Guide”
When Intel and Apple released Thunderbolt, hallelujahs from the Apple choir were heard. Since very little in any of Apple’s hardware lineup is upgradeable, an external video card is the best of all possible world. Unfortunately, Intel doesn’t seem to be taking kindly to the idea of external GPUs. That hasn’t stopped a few creative people like [Larry Gadea] from figuring it out on their own. Right now he’s running a GTX 570 through the Thunderbolt port of his MacBook Air, and displaying everything on the internal LCD. A dream come true.
[Larry] is doing this with a few fairly specialized bits of hardware. The first is a Thunderbolt to ExpressCard/34 adapter, after that an ExpressCard to PCI-E adapter. Couple that with a power supply, GPU, and a whole lot of software configuration, and [Larry] had a real Thunderbolt GPU on his hands.
There are, of course, a few downsides to running a GPU through a Thunderbolt port. The current Thunderbolt spec is equivalent to a PCI-E 4X slot, a quarter of what is needed to get all the horsepower out of high-end GPUs. That being said, it is an elegant-yet-kludgy way for better graphics performance on the MBA,
Demo video below.
Continue reading “A Macbook Air And A Thunderbolt GPU”