On 6/2/22 19:41, enh wrote: > Oh, yeah, I think *especially* for macOS where pretty much everyone is always > on > the latest version anyway, unless your Mac equivalent of the seven year rule > is > "support the oldest macOS release that still gets security backports", there's > no reason to do this. It's pretty rare they add anything significant anyway.
If you think the mac AOSP prebuilts should require the latest macos version to run, that's your call. I don't really have a MacOS policy because I'm not familiar enough with MacOS: they actively exclude any developer who doesn't pay to play. (And sadly Darwin died in 2006, although I'll blog about that rather than blathering here.) The three macos use cases I have at the moment are "test on github", "ship AOSP prebuilt", and "random mac developer wants to use toybox", which all have slightly different requirements. There was a tentative fourth use case: back before Apple switched from bash to zsh I thought they might eventually show an interest in a finished toysh, but they did bash->zsh the same way Ubuntu went bash->dash and Canonical showed a surprisingly adamant refusal to ever admit a mistake. So my previous "might" went from ~20% chance to like 5% tops. (And their "we don't understand what vfork was for" move abandons the embedded space too.) Rob P.S. The nommu stuff is about realtime response with long battery life: digital wristwatches could run for 5 years off the same battery because the chip inside was clocked at something like 32khz, not megahertz let along gigahertz. Sure die size shrinks help power/performance ratio but it's not linear (transistor leakage current etc get _worse_ at nanoscale), plus a 5nm chip produces microwatt signals that need a 45nm interface chip to translate them so it can talk to the outside world (and not get destroyed by the power surge when somebody opens the door and moves the air in the room), and for actual direct I/O (sensors doing analog/digital conversion or driving a small motor) you often want more like a 250 nanometer chip. So the "die shrinks will solve all this for us"... isn't true. Plus a 250 nanometer mask is what, $15k? The kind of thing you can amortize over a 30k unit production run no problem. A 5 nanometer mask isn't gonna cost less than $10 million any time soon, you've gotta make a LOT of the same chip for that to make economic sense. (The sky130 fab Google partnered with is actually a bit exotic, that's a "mixed signal" process doing a different resolution on each layer of the design, which makes routing extra-fun. Jeff Dionne is trying to do a j-core chip through that which can track GPS signals in a battery powered device, but it turns out their toolchain doesn't actually work and the first couple rounds of chips that went through the fab were all duds. He thinks he's fixed up most of it...) P.P.S. Here's a 2015 presentation about running nommu Linux on a chip with 256k of SRAM and no DRAM. https://elinux.org/images/9/90/Linux_for_Microcontrollers-_From_Marginal_to_Mainstream.pdf It's a pity the Linux Foundation accidentally deleted that year's ELC videos off of youtube, his talk was nice too. Anyway, the trick is trimming kernel data structures, XIP ROMFS so your binaries only need their .data and .bss segments in RAM, and nommu not wasting memory on page tables. No DRAM means no DRAM controller spending power on refresh cycles... _______________________________________________ Toybox mailing list [email protected] http://lists.landley.net/listinfo.cgi/toybox-landley.net
