Live data from Hacker News

The $8 Linux Computer

thelittleengineerthatcould.blogspot.com

61–70 of 166 posts

Re: The $8 Linux Computer

#63
post #31
post #2

Based on a brief bit of googling about this board's CPU (the Bouffalo Lab BL808), it seems to have one RV64 and two RV32 cores. The RV64 core may be capable of running RV32 machine code, if the OS sets various flags correctly, but the reverse isn't possible without emulation. How does Linux handle this? Can you just run an executable and have it automatically scheduled onto whichever cores can execute it? Wouldn't th…

Side note, but someone linked a great talk by OS researcher Timothy Roscoe the other day about a) the increasing heterogeneity of our computing devices, b) Linux's inability to really support same, and consequently c) Linux being used on the device, because the device has to "run Linux", but in increasingly smaller and more walled-off spaces, leaving board management which you'd normally think of as an "OS task" to d…

Yet Windows ran 16-bit, 32-bit and 64-bit code on the same core for years. Huh.

Really folks. It doesn't take new research or exotic OS design ideas, to do something that has been common practice for a decade. Let's quit pretending linux is driving any innovation. It's followed behind in OS design, often by years.

Re: The $8 Linux Computer

#64
post #3

Earlier quoted context omitted.

One proposal I saw was to treat the RV32 core like a microcontroller or as a dedicated co-processor. https://www.robertlipe.com/bl808-not-symmetric/

Let me see if I have this straight ... it's a device that can run a general OS like Linux, but say, have a core that could be run real-time, with all the goodies like timers and stuff that we expect from microcontrollers? If so, then that would be pretty awesome. I think that people have been trying to get real-time working on Raspberry Pis. It seems that they get kinda close, but never manage to get all the way.

Most modern ARM SoCs capable of running Linux have one or more cortex M cores, down from M1s to M4s (I have yet to see M7s). It is precisely for what you describe.

Re: The $8 Linux Computer

#65

Can this chip output HDMI? I looked at the datasheet and it didn't look like it: https://github.com/bouffalolab/bl_docs/blob/main/BL808_DS/en...

Not directly but it seems to be able to generate video out over the MIPI, at least. Not so convenient though, converter chips are probably small and not super hobbyist-friendly (like the one from Analog a siblibg comment dug up).

Re: The $8 Linux Computer

#66

Why would you use this instead if some rpi version?

Better embedded GPIO. RPi Zero is a great little board/computer but the capabilities of the GPIO pins are lacking in a lot of ways. Speed being the biggest problem.

This little $8 board will run circles around even an RPi 4 when it comes to doing something like controlling a long strip of ws2812b RGB LEDs, as an example.

Re: The $8 Linux Computer

#68

Can this chip output HDMI? I looked at the datasheet and it didn't look like it: https://github.com/bouffalolab/bl_docs/blob/main/BL808_DS/en...

It has an RGB interface (basically parallel bus for pixels + clock), for which multiple bridges exist to HDMI. However, those are like QFN-88 packages so for soldering here be dragons. On the plus side, it avoids the mess that MIPI-DSI is...

Re: The $8 Linux Computer

#69
post #58
post #32

Earlier quoted context omitted.

I'm a bit over Raspberry Pis at this point. They're impossible to find, and their performance is terrible. I tried getting back into one of my Raspberry Pis from scratch just earlier today, and even with setting up the OS from scratch and the most up to date version, it was unbearably slow. So slow as to be unusable for even the most simple tasks. So that kickstarts forum hopping trying to figure why, and there's lau…

By the time you get a Rpi 4, a decent power supply and an external SSD, it's usually around the same price as a mini PC which you can get with a 7th/8th/9th Gen i3 or even i5 with everything included. I get that the Rpi will use less power, but I imagine many people will be like me and have it overclocked to 2.1ghz, and my heatsink was pretty warm all day long. I've recently picked up a Optiplex 3070 with a i5 9500t…

RPis are used as embedded controllers and such instead of a custom solution, which is why they are so hard to get right now -- many companies based their products on them when they were plentiful and now get priority over end-users for distribution. It is (or was) kind of a scandal as RPi's self-mandate was to provide cheap computing devices for learning, not for businesses to make products.

Re: The $8 Linux Computer

#70

Earlier quoted context omitted.

This is actually a common pattern you get from multiple vendors.

Just as a semi-random example, NXP has the i.MX series[1] with one or more application-level cores alongside a microprocessor-level core. You can get something like the i.MX 8M Nano[2] with 4x Cortex-A53 and a single Cortex-M7. Another "big-player" option is ST which has the STM32MP1[3], which features a single Cortex-A7 alongside a Cortex-M4. [1]: https://www.nxp.com/products/processors-and-microcontrollers... [2]:…

NXP's software support for the heterogenous ARM cores is abysmal. I had to abandon an architecture on the iMX7 because their RPMSG drivers were simply broken. Documentation and examples were multiple-years old and their FAE support came down to "well, the examples work." Except they didn't.

Perhaps it's better with the newer BSPs on the 8, but I wouldn't be too quick to jump back into it.

Post reply on HN