New Raspberry Pi Model B+ • Hacker News Board

Re: New Raspberry Pi Model B+

#151

Post by DougWebb » Wed, Mar 14, 2018, 2:53 PM UTC

jimmies wrote: post #45

Benjamin_Dobell wrote: post #13

Earlier quoted context omitted.

If you're not a native English speaker, I imagine the video may be preferable to the article.

Before I came to the US, I studied English on my own to be able to program/do computery-stuff because people on the internets always told me to RTFM. On my first TOEFL (Test of English as a Foreign Language) test for college, I got 29/30 for my reading comprehension and a similarly high score for writing but got 15/30 for speaking and a pretty bad score (not as bad as speaking - don't remember exactly) for listening.…

I had the same experience learning French in school as a child. I did really well at reading and writing, but could never understand what the teacher was saying. A couple of years later, in a different school, my classmates were all Hatians that were taking the class for easy credit. I had even more trouble understanding their creole french, and wound up losing all of my comprehension.

Re: New Raspberry Pi Model B+

#152

Post by digi_owl » Wed, Mar 14, 2018, 3:05 PM UTC

muxator wrote: post #7

> Here’s a long post. [...] If you don’t have time to read it all, we recommend you watch this video The video is 1 minute long. The article is ~84 lines, ~8 KB of text. Is that really long?

Never mind that with text it is quite easy to skip all the fluff and get to the info one wants (in this case, the specs and other differences between the 3B and the 3Bplus).

Re: New Raspberry Pi Model B+

#153

Post by vardump » Wed, Mar 14, 2018, 3:06 PM UTC

bunderbunder wrote: post #142

vardump wrote: post #136

Earlier quoted context omitted.

> so there's not a whole lot of value in having a >4GB address space. Don't most ARMv7 CPUs (like A7, A15, etc.) have 1 TB address space? On LPAE ARM, 64-bit arch will only get you larger virtual address space, but you get same 40-bit address space in both cases. > reduction in memory consumption that comes with pointers that are half as big Nothing prevents you from running 32-bit binaries on 64-bit OS, as long as y…

What use to I have for being able to address a hypothetical 1TB of memory on a computer that's got a fixed 1GB of memory soldered to the board? I can see having a bit of headroom for virtual memory, but I wouldn't want to actually use it. The non-volatile storage on this computer is an SD card, so paging will be particularly expensive. Are you really going to have more than 3GB of swap? That's a pretty big appetite f…

My implicit point was that addressable memory size is not a factor when choosing between 32 and 64-bit ARM.

Looks like I should have communicated it more clearly.

AArch64 does have some perks, but mostly for out-of-order cores, which RPI3's Cortex A53 is not.

That said, even A53 can benefit from 31 registers in 64-bit mode. Large virtual address space is nice not only for memory mapping files, but to do lazy initialization while keeping high performance direct pointer access characteristics. That way you can have the MMU doing the check and indirection for you instead of slow explicit conditional check in code.

You can mitigate pointer size by ensuring memory accesses are PC-relative. Perhaps there could be support for something similar to x32 ABI [0] as well.

AArch64 codegen does need to generate more conditional jumps or CSELs (like cmove) though. Also function entry & exit code is larger due to lack of LDM & STM (load/store multiple). But on the other hand, stack spills are rarer, thanks to 31 general purpose registers instead of 14 on 32-bit ARM.

Where AArch64 truly shines is when you have a real out-of-order CPU core, for example Cortex A72. There are significantly more opportunities for instruction level parallelism due to dropping instruction predicates and other changes.

[0]: https://en.wikipedia.org/wiki/X32_ABI

Re: New Raspberry Pi Model B+

#154

Post by dordoka » Wed, Mar 14, 2018, 3:13 PM UTC

zdkl wrote: post #124

yipbub wrote: post #85

Earlier quoted context omitted.

You can simplify that to Pi^2

Call up Pypy, there's a marketing opportunity for next year.

Already taken! https://pypy.org/

Re: New Raspberry Pi Model B+

#155

Post by petercooper » Wed, Mar 14, 2018, 3:28 PM UTC

nikofeyn wrote: post #106

Narishma wrote: post #41

Why was the title changed? It's misleading right now since there's already a Raspberry Pi Model B+ available for ages. Should be "New Raspberry Pi 3 Model B+" just like on the blog post.

in general, i find the aggressive title changing on hacker news confusing. it’s been happening a lot recently where i can’t find a post by eye where i know i knew the title or where the title was changed away from the exact title of the linked post or article.

In another sense it's quite beautiful though, it encourages me to visit more frequently before the titles begin to decay into things I wouldn't click on.

Re: New Raspberry Pi Model B+

#156

Post by wbsun » Wed, Mar 14, 2018, 3:32 PM UTC

Feel like RPi is heading to a commercial upgrade direction: more cores, higher frequency, faster processors, faster networks, etc. Wasn't RPi originally designed to teach programming and to make a hackable gadget? With that goal, I think a simple (and therefore maybe low performance) system is easier to learn and to hack than more and more fancy and complex architecture. From that perspective, BBC Micro bit is doing the right thing IMO.

Re: New Raspberry Pi Model B+

#157

Post by flyinghamster » Wed, Mar 14, 2018, 3:41 PM UTC

wbsun wrote: post #156

Feel like RPi is heading to a commercial upgrade direction: more cores, higher frequency, faster processors, faster networks, etc. Wasn't RPi originally designed to teach programming and to make a hackable gadget? With that goal, I think a simple (and therefore maybe low performance) system is easier to learn and to hack than more and more fancy and complex architecture. From that perspective, BBC Micro bit is doing…

Why not upgrade it, though? Keeping it a system for teaching/hacking while improving performance is a win-win, as far as I'm concerned. For commercial applications, I'd think the Compute Module would be a better bet.

Re: New Raspberry Pi Model B+

#158

Post by arbitrage » Wed, Mar 14, 2018, 3:41 PM UTC

mcjiggerlog wrote: post #82

antirez wrote: post #46

A bit worried by the increased power usage for certain applications. For instance I used to power my PI with a cell phone battery pack without any trouble.

Those models still exist, along with the even lower powered pi zero.

You can also adjust the CPU power and timing frequencies to underclock your pi for better battery life.

Re: New Raspberry Pi Model B+

#159

Post by arbitrage » Wed, Mar 14, 2018, 3:42 PM UTC

Tepix wrote: post #64

cashy wrote: post #42

Happy kodi server update day

Amlogic S905X boxes are the better choice for Kodi these days. You can installi LibreElec, they are cheaper than a Raspberry Pi 3 and they support 4K & HDR and have hardware acceleration for H.265 (HEVC) and VP9.

The also cost almost twice as much, and don't have the ecosystem/community support around them that the pi has.

Re: New Raspberry Pi Model B+

#160

Post by tssva » Wed, Mar 14, 2018, 3:44 PM UTC

sp0ck wrote: post #148

What I'm missing is on board flash. Even 512MB would be such useful for many usage scenarios to put OS there. SD cards are biggest source of problems on long run RPi's without some tweaking. There are almost none SBC with built in flash (BeagleBone is shiny exception).

It doesn't exactly fill the same niches as the regular RPi but the RPi Compute Module 3 does have 4G of emmc builtin. You can get a compute module and breakout board for $136 on Amazon.