Raspberry Pi 4 can finally boot directly from USB • Hacker News Board

Re: Raspberry Pi 4 can finally boot directly from USB

#231

Post by loxias » Sat, Sep 19, 2020, 5:18 PM UTC

londons_explore wrote: post #143

MisterAV wrote: post #131

Earlier quoted context omitted.

What is the requirement for synched audio? milliseconds, microseconds, nanoseconds,... I'm currently working on devices that synchronises themselves wirelessly indoor over a large area and I'm now wondering if music could be an application I haven't though about...

10 ms is fine. 100ms works but you get odd echoes like a speaker system in a big building. You need some way to compensate for clock drift between different playback devices. Even good clocks will drift 10ms in a few hours.

1ms is barely "ok". with 1ms you'll still hear ugly comb filter effects. (see my other comments)

Re: Raspberry Pi 4 can finally boot directly from USB

#232

Post by 0xCMP » Sat, Sep 19, 2020, 5:22 PM UTC

varispeed wrote: post #204

grahamm wrote: post #82

Earlier quoted context omitted.

I think people forget what it was designed for. It was to reboot IT education which was (is) badly floundering. It's success was so good it started to be used in small commercial applications. The Foundation tried to help fill this gap in the market with the compute module. Even though there is a lot of open source features the use of the Broadcom chipset was probably driven by cost as keeping the Pi price down was a…

How exactly does it help IT education and what was wrong with it that it needed a "reboot"?

The original idea was giving kids a device they could just connect into a TV (no need to buy a new screen) and learn by screwing up like ~"we all did when computers were simpler."

iPads, iPhones, Windows, etc.

They're expensive and complicated. Kids can't take the family computer and screw up installing linux 3 times while Mom needs to do something for work. A $25 computer is something a family could easily afford and so could school districts.

Re: Raspberry Pi 4 can finally boot directly from USB

#233

Post by loxias » Sat, Sep 19, 2020, 5:23 PM UTC

agustif wrote: post #202

loxias wrote: post #172

Earlier quoted context omitted.

I've run OS X on a very low powered Debian box before. I'd wager it could be made to run on a raspi 4 (VERY SLOWLY) with sufficient effort. (you'd have to use qemu TCG, not KVM). It would be easier to run on a SBC that uses an x86_64 chip, like the Atomic Pi, or LattePanda. I'm curious though, why in the world would you ever want to run OS X so slowly?

We just need to run one app (OmniPlan) which is OS X exclusive in our Windows work machines. We would get in via RDP or such I guess?

I bet I could do that. (or otherwise solve the problem.) My email address is on my profile, send me a note if you're interested in talking more.

Re: Raspberry Pi 4 can finally boot directly from USB

#234

Post by vlowther » Sat, Sep 19, 2020, 5:23 PM UTC

pbalau wrote: post #130

LeoPanthera wrote: post #119

Earlier quoted context omitted.

The Pi doesn't use PXE. It's different, but documented here: https://www.raspberrypi.org/documentation/hardware/raspberry...

You probably should read that link, section "DHCP Request / Reply". Virtually the entire world uses PXE. Anyway, I find it funny that we are arguing about the proper name for network boot in a thread about usb boot.

The issue is that the Pi does something that is almost-but-not-quite PXE. In particular, the RPI firmware does not send anything that identifies itself as an RPI so that the DHCP server can determine what packet to send in response -- the option 60 string it sends in the DISCOVER packet claims to the DHCP server that it is an X86 server running in legacy BIOS mode. The only way the RPI will boot is if you send it that extra magic option 43. For those of us that write DHCP servers that try to be intelligent about how to respond to PXE requests, the plethora of stupid not-exactly-PXE mechanisms the various ARM SBC hobbyist boards are annoying as fuck. At least the server class ARM stuff usually has a UEFI implementation that adheres to the UEFI extensions to the PXE spec and properly identifies itself with options 60, 93, and 94.

Re: Raspberry Pi 4 can finally boot directly from USB

#235

Post by jccooper » Sat, Sep 19, 2020, 5:56 PM UTC

silicon2401 wrote: post #77

As a pi noob: does this make it more reliable/feasible to use a pi to run a home server/application/etc? I've read in the past that SD cards aren't good with repeated read/writes, which makes it somewhat unreliable in the long run. If a pi is configured to run via USB, does that make it as reliable as other consumer hardware like a pc/laptop?

You could always use a real drive for storage on some mount point, or even as an overlay on a read-only SD card. Being able now to boot directly off a SSD is more convenient, though.

Re: Raspberry Pi 4 can finally boot directly from USB

#236

Post by airbreather » Sat, Sep 19, 2020, 6:04 PM UTC

michaelt wrote: post #192

gorgoiler wrote: post #165

Earlier quoted context omitted.

Machines no longer degrade when the power is yanked. Any corruption caused by a mid-write devoltage event is handled gracefully by whatever modern filesystem of choice you are using, is it not? Is there some more fundamental hardware damage that occurs when USB devices are unplugged without prior warning to the device itself?

1. A modern filesystem will stop the filesystem getting corrupted by power loss - but a file that was mid-write, or an install process that had copied half the files it needed to, will still leave that thing incomplete. 2. SD cards can wear out (i.e. too many write-erase cycles) regardless of the filesystem. 3. SD cards have controllers running firmware, doing things like write levelling and bad block remapping. Some…

I just spent $10k on 4 Siemens 32Gig industrial SD cards for S7-1500 PLC's, in safety service.

Gauranteed 500,000 writes, probably much more, but they have "mission life" quoted at ten years on the vendor cert, so will be ditched after ten years and replaced.

Apparently they are a whole different type of logic design, hence the cost. Even the no-name or branded equivelent I could find were close to $1k each, but given use in safety service we went legit all the way anyway.

Anything with the magic S word stamped on it seems to double in price...

Re: Raspberry Pi 4 can finally boot directly from USB

#237

Post by jankiehodgpodge » Sat, Sep 19, 2020, 6:11 PM UTC

varispeed wrote: post #204

grahamm wrote: post #82

Earlier quoted context omitted.

I think people forget what it was designed for. It was to reboot IT education which was (is) badly floundering. It's success was so good it started to be used in small commercial applications. The Foundation tried to help fill this gap in the market with the compute module. Even though there is a lot of open source features the use of the Broadcom chipset was probably driven by cost as keeping the Pi price down was a…

How exactly does it help IT education and what was wrong with it that it needed a "reboot"?

Most kids only experience computers through a smart phone and a collection of social media apps.

Re: Raspberry Pi 4 can finally boot directly from USB

#238

Post by snvzz » Sat, Sep 19, 2020, 6:14 PM UTC

simongr3dal wrote: post #221

snvzz wrote: post #212

Rpi4 and still no usb version of bootloader. What am I missing? # rpi-eeprom-update BCM2711 detected BOOTLOADER: up-to-date CURRENT: Tue 10 Sep 2019 10:41:50 UTC (1568112110) LATEST: Tue 10 Sep 2019 10:41:50 UTC (1568112110) VL805: up-to-date CURRENT: 000137ab LATEST: 000137ab I wish this was better documented.

You gotta do: $ sudo apt update $ sudo apt upgrade $ sudo apt dist-upgrade Then do a restart and the bootloader should be updated, if that doesn't work you also need to do a: $ sudo rpi-update Now the eeprom should be updated and the default option should be to boot from SD, then USB.

That's the easy way for Debian or Raspbian users, sure.

But I am on archlinuxarm.

I have used rpi-eeprom-update in the past with no issue, but it won't see the update this story is about, for reasons unknown.

Re: Raspberry Pi 4 can finally boot directly from USB

#239

Post by boneitis » Sat, Sep 19, 2020, 6:17 PM UTC

MayeulC wrote: post #198

boneitis wrote: post #140

Earlier quoted context omitted.

Not related to the rest of the thread, but this popped up the other week and, honestly to my shock, worked well on my Pi3. https://news.ycombinator.com/item?id=24441112 You may or may not get some latency with video. Seemed to vary for me.

I thought this was going to be about NymphCast, an open source alternative to chromecast http://nyanko.ws/product_nymphcast.php https://github.com/MayaPosch/NymphCast

Oh, yes!

I should have remembered this one, since I am particularly interested in it.

But, I have not actually tried it myself. I wish I had the immediate chops to contribute to the project.

Re: Raspberry Pi 4 can finally boot directly from USB

#240

Post by tinus_hn » Sat, Sep 19, 2020, 6:22 PM UTC

loxias wrote: post #230

joshspankit wrote: post #106

Earlier quoted context omitted.

The different clocks is a real hurdle. I have to give credit to Apple on this one, as they had the genius idea to make the buffer >1s, and send control messages independent of the audio stream. There’s gotta be a way to do it with PTP and the same ideas but clearly it’s either an extremely difficult problem, too niche, or both.

Correct. You use PTP+NTP, the RT_PREEMPT patches, and then you have to deal with a constantly varying resampling ratio (!!) And not only that, but if you don't want nasty artifacts, the a LOT of thought also has to go into your filter design. It's hazy, but I remember using a pair of orthonormal time-varying allpass IIR QMF filters, with extra black magic I'm blanking on that allowed me to reduce the complexity of fi…

Why would you send samples? If you do any kind of compression you’re going to convert to frequencies anyway and it isn’t that much of a hassle to expand that.