3 ms·

For NAND flash, maybe the difference is miniscule. For NOR flash, which is what many small embedded devices run from, the difference is huge: 128Mbit (16MiB): 1

by fest 6y ago

For NAND flash, maybe the difference is miniscule. For NOR flash, which is what many small embedded devices run from, the difference is huge: 128Mbit (16MiB): 1.01$ 2Gbit (256MiB): 16.38$ 2Gbit is the highest commercially available package (with very few suppliers, so it carries extra risk).

pantalaimon 6y ago
Are people running Linux of NOR flash? On MCUs you usually have other systems like Zephyr, MBedOS or RIOT.
- fest 6y ago
  Pretty much every security camera, most of the networking equipment, action cameras and set-top boxes run Linux from NOR flash (cost and simplicity reasons- no FTL, IIRC better retention). Altogether it's probably billions of devices. There are also quite a few lines of MCUs without built-in flash memory and those typically boot from external NOR flash.
- segfaultbuserr 6y ago
  NAND is the new industry standard, but most embedded systems, several billion units, produced in the early 2010s were powered by NOR flash, and many use Linux. One example was the vast majority of home routers. I once replaced the 4 MiB NOR flash in my home router to 16 MiB for OpenWrt (yes, you can run Linux with 4 MiB of NOR flash, this configuration was officially supported by OpenWrt until it's retired in 2019).
segfaultbuserr 6y ago
See also: The most expensive chip in the ARM world by Marcin Juszkiewicz [0]. It's written by a core AArch64 developer on the lack of a full-function boot ROM on most ARM single-board computers, forcing developers and users to fight with vendor-specific bootloaders. > So SBC… Which means playing with U-Boot. In the past it meant random fork of it. [...] you have bootloader(s) built. The next step is taking microsd card, finding out which offsets to use. Then put bootloader(s) at proper places so CPU can read them and boot. Usually it also means that you have to use MBR style formatting [...] The reason? A EEPROM chip is too expensive, an astronomical cost of $3! The author was half-joking, but only serious - $3 is really expensive for most single-board computers. > The solution is SPI flash chip. But it is very expensive - 3 (three) EUR for 512Mb (64MB) chip (if bought 1000 of them). Far too much for 99.99% of SBC probably. Probably 64/128Mb will be enough even. And they are cheaper (128Mb is 1.7 EUR). Still too expensive… [0] https://marcin.juszkiewicz.com.pl/2020/01/29/the-most-expensive-chip-in-the-arm-world/ https://marcin.juszkiewicz.com.pl/2020/01/29/the-most-expens...

by fest 6y ago

pantalaimon 6y ago

Are people running Linux of NOR flash? On MCUs you usually have other systems like Zephyr, MBedOS or RIOT.

fest 6y ago
Pretty much every security camera, most of the networking equipment, action cameras and set-top boxes run Linux from NOR flash (cost and simplicity reasons- no FTL, IIRC better retention). Altogether it's probably billions of devices. There are also quite a few lines of MCUs without built-in flash memory and those typically boot from external NOR flash.
segfaultbuserr 6y ago
NAND is the new industry standard, but most embedded systems, several billion units, produced in the early 2010s were powered by NOR flash, and many use Linux. One example was the vast majority of home routers. I once replaced the 4 MiB NOR flash in my home router to 16 MiB for OpenWrt (yes, you can run Linux with 4 MiB of NOR flash, this configuration was officially supported by OpenWrt until it's retired in 2019).

segfaultbuserr 6y ago

See also: The most expensive chip in the ARM world by Marcin Juszkiewicz [0]. It's written by a core AArch64 developer on the lack of a full-function boot ROM on most ARM single-board computers, forcing developers and users to fight with vendor-specific bootloaders. > So SBC… Which means playing with U-Boot. In the past it meant random fork of it. [...] you have bootloader(s) built. The next step is taking microsd card, finding out which offsets to use. Then put bootloader(s) at proper places so CPU can read them and boot. Usually it also means that you have to use MBR style formatting [...] The reason? A EEPROM chip is too expensive, an astronomical cost of $3! The author was half-joking, but only serious - $3 is really expensive for most single-board computers. > The solution is SPI flash chip. But it is very expensive - 3 (three) EUR for 512Mb (64MB) chip (if bought 1000 of them). Far too much for 99.99% of SBC probably. Probably 64/128Mb will be enough even. And they are cheaper (128Mb is 1.7 EUR). Still too expensive… [0] https://marcin.juszkiewicz.com.pl/2020/01/29/the-most-expensive-chip-in-the-arm-world/ https://marcin.juszkiewicz.com.pl/2020/01/29/the-most-expens...