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andrewcchen

155 karma · joined September 24, 2017

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andrewcchen··on A theoretical way to circumvent Android developer verification
So like LiveContainer[1] which works around ios's signing requirements

[1] https://github.com/LiveContainer/LiveContainer

andrewcchen··on Daylight Computer – New 60fps e-paper tablet
It's not an e-ink display, but rather a monochrome transreflective lcd. [1]

[1] https://www.reddit.com/r/eink/comments/1bk294i/comment/kvx17...

andrewcchen··on NodeMCU ESP32-C3 WiFi and BLE IoT boards show up for about $4
I'd say they are bad because they aren't very power efficient. There are boards with nrf52 chips that already have qmk support iirc.
andrewcchen··on Ampere switching to in-house CPU designs
Yes, custom cores in the sense of what apple does.
andrewcchen··on Arm Announces Neoverse V1, N2 Platforms and CPUs, CMN-700 Mesh
The cores don't serve the same purpose as the M1 cores. M1 is optimized for single thread at the cost of die size (and a bit of power). I don't have exact numbers, but say the apple M1 core takes 1.5x the die area of N2, the you'd get better performance by putting in 1.5x the number of N2 cores.
andrewcchen··on SpaceX wins contract to develop spacecraft to land astronauts on the moon
Fairing recovery is not abandoned, they decided to fish them out of the water after a soft landing instead of catching them with a net.
andrewcchen··on MiSTer, an open-source FPGA gaming project
Digikey pricing is not indicative of actual volume pricing, especially for FPGAs where they are often many times overpriced when buying from distributors. I doubt the board is sold at an loss, probably sold at a small profit, not that's it's really significant for a low volume dev board.
andrewcchen··on Loopy Pipe Network Converts back-and-forth flow into one-way flow
The circulator[1] is an analogous component in rf, it send the incident power from any port down to the next port, so you can take one port to be the bidirectional connection, and it splits the signal into transmit and receive connections.

[1] https://en.wikipedia.org/wiki/Circulator

andrewcchen··on MOnSter 6502
The trick to doing smd soldering is reflow. On all budget all you need is a hot air gun, if you put solder and flux on the pads manually before placing the components. With a stencil and solder paste you can save the time tinning the pads, and placing a component every few seconds is quite possible. So if you work really hard and quite possibly break your back you can assemble this board in a day :)
andrewcchen··on Rotary Cellphone
It takes a combination of software and hardware to get good power consumption. In this case, assuming the author has implemented sleep modes on the microcontroller, it's probably the 3g module being not very power efficient.
andrewcchen··on Ariane is a 6-stage RISC-V CPU capable of booting Linux
This is only a cpu core. It lacks the memory controller and peripherals that make a SoC work. It will probably never make its way into a chip tapeout.
andrewcchen··on Intel’s Manufacturing Roadmap from 2019 to 2029
In recent years the node names don't correspond to any physical dimensions of the transistors anymore. But since density improvements are still being made, they just continued the naming scheme.

https://en.wikichip.org/wiki/technology_node#Meaning_lost

andrewcchen··on Writing userspace USB drivers for abandoned devices
It's in a QFN not QFP package
andrewcchen··on How to make Linux run fast again on Intel CPUs
mitigations=off is all you need on a recent kernel
andrewcchen··on Mathematician Wins $3M Prize for 'Magic Wand Theorem'
I'd love to know what makes this theorem so useful, but I doubt I will understand much considering this is in an area of math I know almost nothing about.

I imagine it must be very hard to explain the theorem while making it accessible and interesting to the general public.

andrewcchen··on Powering a Mainframe
In a previous post he said it's 8 years old
andrewcchen··on Bitcoin's First $1k Weekend Since 2017 Marks Nine-Month High
> Bitcoin appears to have greater staying power than most nations and currencies in history.

I would not make that statement so soon. Bitcoin has only existed for 10 years. Most nations and currencies, at least in recent history, have lasted for much longer than that.

andrewcchen··on SpaceX nails triple booster landing after satellite delivery
The booster's trajectory targets offshore or away from droneship in case landing burn fails. The landing burn brings the booster onto the landing pad. See CRS-16 where the booster landed in the water when the booster lost roll control when the grid fins failed.
andrewcchen··on Ghidra, NSA's reverse-engineering tool
There's a typo in launch.sh that breaks when you try launch in debug mode

> "{$DEBUG_PORT}"

andrewcchen··on Chromium blacklists Nouveau
For rendering yes. For video decoding no. Chromium needs a patch to use VA-API[1].

[1]: https://wiki.archlinux.org/index.php/Chromium#Hardware_video...

andrewcchen··on Half of lonely people think no one will notice if something bad happens to them
The title is misleading, they have most likely only been dead for a few months since their bodies were found still decomposing.
andrewcchen··on Extracting the private key from a TREZOR with an oscilloscope (2015)
You can take screenshots by plugging a usb stick into the scope
andrewcchen··on It’s Impossible to Prove Your Laptop Hasn’t Been Hacked
Most computers have an Embedded Controller (with integrated flash) that does a lot of motherboard/system specific stuff like power management, flashing leds and even scanning the keyboard matrix on laptops.
andrewcchen··on TSMC Kicks Off Volume Production of 7nm Chips
Smallest feature size no longer correlates with transistor density in recent years. So manufacturers just use the number to convey increases in transistor density.

See https://en.wikichip.org/wiki/technology_node#History

andrewcchen··on Review: Purism Librem13 laptop
That one has an i7-5557U, compared to the i7-6500U the current one is selling with, so probably an early prototype.
andrewcchen··on Review: Purism Librem13 laptop
They say on their website "Atheros 802.11n w/ Two Antenna"

Wi-fi cards are actually a huge issue if you are concerned about privacy. You have no idea what the firmware is doing, and it has access to your entire memory through the pcie interface, and the internet at the same time.

andrewcchen··on China's Xinjiang surveillance is the dystopian future nobody wants
> not going to the local police station whenever you stayed at a hotel/switched apartment/stayed at your friends/partners place

I've never heard of this and I grew up in China. Can you provide a source?

andrewcchen··on Vulnerability of Speculative Processors to Cache Timing Side-Channel Mechanism
Cortex M cores don't have MMUs, so they cannot be affected. Also in embedded applications you would only be running trusted code anyway
andrewcchen··on Does Life End at 35? (2013)
It seems like the domain expired, and now it redirects to a gambling site.
andrewcchen··on Writing a Simple Linux Kernel Module
I modified a kernel module to use the wifi enable/disable button on my hp laptop as a normal button. For some reason the bios sends an acpi event when the button is pressed, instead of just having it as a normal keyboard key, so there is a kernel driver to handle it.
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