baobrien

8 ms·

31.
by baobrien 7y ago
U-235 is the only naturally occurring fissile isotope of uranium. In raw uranium out of the ground, it makes up about 0.7%, the rest being U-238. U-233 is also fissile, but only really made in thorium breeder reactors.
32.
by baobrien 7y ago
In 1933, the Nazi regime passed a law[1] banning anyone they considered Jewish from holding any civil service job, including positions at universities. A large proportion of German academia was considered Jewish. [1] - https://en
33.
by baobrien 7y ago
If the author hasn't reached out, @zx2c4 will probably see this post. He's pretty active on wireguard-related HN posts.
34.
by baobrien 7y ago
The Raptor stuff is pretty cool, but the cost puts it well out of practical reach for most of the people calling for opening the PSP. The cheapest Blackboard+CPU combo is $1279.
35.
by baobrien 7y ago
IIRC, the injector plate on the F1 had to go through quite a few iterations to keep the engine from exploding.
36.
by baobrien 8y ago
Pretty much all clocks in modern electronics above a few MHz are generated by PLL synthesis. The synthesizers are referenced to a slower clock crystal or something along those lines. You can go way beyond just multiplication, as well, with
37.
by baobrien 8y ago
The HiFive board really isn't aimed at the hobbyist or datacenter. It's a dev board with a low volume part made on a high end process. The goal is more to get silicon in the hands of people who want to work with SiFive cores and t
38.
by baobrien 8y ago
The Risc-V board was about $1000 the last time I checked, and the microsemi expansion thing was $2000. The SiFive board is for a small run development chip and the microsemi has a big honkin' FPGA, so the prices aren't unreasonabl
39.
by baobrien 8y ago
The fifth core is actually a 64-bit core (RV64IMAC).
40.
by baobrien 8y ago
It has 16kb of instruction cache, though, unlike most M0 cores.
41.
by baobrien 8y ago
Most Roombas that I know of also have something like that -- a UART interface, published spec, and ability to drive/clean/read sensors. I'm not sure if LIDAR data is available on the higher-end ones, though. https:/&#x2
42.
by baobrien 8y ago
Also written by the same guy who did a large chunk of the open source synthesis toolchain for the FPGA mentioned above.
43.
by baobrien 8y ago
The proprietary bloated toolchains are free to use for lower end to mid range parts, even on Linux.
44.
by baobrien 8y ago
I think -- and I could be wrong here -- that gfx-rs aims to eventually implement Vulkan on D3D12 in addition to Metal, while MoltenVK only aims to work on Metal.
45.
by baobrien 8y ago
> separate hypervisor mode RISC-V, without the hypervisor extension, meets the requirements for Popek-Goldberg virtualization, unlike x86. The problem is that classic virtualization requires shadow paging for memory virtualization, which
46.
by baobrien 8y ago
Does it matter? It's still a reference encoder. AFAIK, the AV1 bitstream is barely frozen. Is he talking about the working model HEVC encoder right after they froze it, or the final reference encoder before people started working on ha
47.
by baobrien 8y ago
Yeah, the main use case for codec2 right now is over ham radio. David Rowe, along with a few others, also developed a couple of modems and a GUI program[1]. On Sunday mornings, around 10AM, they do a broadcast of something from the WIA and
48.
by baobrien 8y ago
I think 2400B support is coming to the FreeDV GUI soon. I've seen some work done on that. That'll let you use a cheap FM radio and a laptop to get on the air with something codec2 based. I'm slowly chipping away at a TDMA mod
49.
by baobrien 8y ago
Basically every CPU with a pipeline -- even simple, in-order cores -- speculate by way of branch prediction. I think with the Cortex A53 the pipeline is short enough and the branch predictor simple enough that you can't build a useful
50.
by baobrien 8y ago
I could be wrong, but I don't think BEAM really runs on microcontrollers. Erlang might be a good environment on the same sorts of micros (32 bit, dozens of KB of ram) MicroPython targets.
51.
by baobrien 8y ago
Previous discussion: https://news.ycombinator.com/item?id=17103635 The blog post the article is actually about: http://matpalm.com/blog/counting_bees/
52.
by baobrien 8y ago
Eh, in terms of floppies, it seems like everybody used different on disk formats back in those days. Commodore had one, IBM had one, Atari, etc... All incompatible to some degree.
53.
by baobrien 8y ago
Commodore also had the Amiga CD32 a few years later. I got my hands on a few CD32 games in a haul of amiga stuff. https://en.wikipedia.org/wiki/Amiga_CD32
54.
by baobrien 8y ago
Is this a kernel implementation of WireGuard for MacOS, or is it one of the two ongoing userspace implementations? I probably missed it, but I didn't see a separate repo for it at https://git.zx2c4.com/ . On that note,
55.
by baobrien 8y ago
The justification in the RISC-V spec is that it might make porting some software easier. They also say that unaligned loads/stores may be non-atomic and take much longer than aligned accesses -- allowing firmware emulation on simple im
56.
by baobrien 8y ago
Here's the blog of a group doing the same sort of things to recover rom and firmware from arcade machines: http://caps0ff.blogspot.com/
57.
RISC-V Workshop in Barcelona Proceedings(riscv.org)
4 points by baobrien 8y ago|0 comments
58.
by baobrien 8y ago
Yep. RISC-V has had easy to decode variable length instructions from day one in the compressed ISA extension. The base user-mode ISA has a set of simple encoding rules for variable-length instructions from 16b to 192b in 16b increments, and
59.
by baobrien 8y ago
The music really helps with that. The video gave me a spooky feeling.
60.
by baobrien 8y ago
I think articles like Ken Shirriff's "Cells are very fast and crowded places"[1] are good companions for visualizations like this. It helps to keep in mind that the things moving around in cells are flying around at break-nec

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