4 ms·
Probably only limiting factor in the hardware is that R-Pi does not have any meaningful high-speed low-latency IO. But on the software side there is one huge p
by dfox 9y ago
Probably only limiting factor in the hardware is that R-Pi does not have any meaningful high-speed low-latency IO.
But on the software side there is one huge problem: today's Linux kernel and userspace is incredibly bloated in comparison to early 90's SunOS. On the other hand, said SunOS probably did not support many things that everybody expects today, like scalability to large-ish SMP systems (ie. >2 CPUs), shared libraries, loadable kernel modules, threads...
- ScottBurson 9y agoSunOS definitely had shared libraries -- I think those go back at least to 4.3BSD. Anyway, how much I/O do you need to support people running terminal apps over Ethernet?
- dfox 9y agoWhat I meant by the IO is that the aforementioned sparcstation had ethernet card connected to SBus which was capable of directly producing interrupts and doing DMA, and all the modems were connected through some multiport serial card/concentrator which tried very hard to offload stuff from the CPU. Which is completely different situation than R-Pi with everything hanging off USB with it's "novel" approach to interrupts.
- tannhaeuser 9y agoSunOS/Solaris has been able to run on hosts with lots of CPUs for much longer than Linux. But then, it had to, because SPARC CPUs have been no match to X86s for almost as long.
- dfox 9y agoIt was able to, but it was not especially efficient at doing so, to some extent because the hardware platforms themselves were not scalable and only appeared to be so because of brute force (even e10k is essentially shared bus SMP machine, sun4d-style). In fact, the NUMA support in non specialized systems (one would want to say "non-IRIX") is surprisingly recent development. In Linux it is one of the things that happened in the 2.4/2.6 timeframe, which is the same timeframe when mainstream distributions started to be too bloated for lot of old or underpowered hardware.
- ChuckMcM 9y agoIt would be interesting if you could port NetBSD 2.x to the Pi. That would be a close equivalent.
- wang_li 9y agoInterestingly, the SparcStation10 would run Solaris 9 and premier support for the SS10 only ended in June 2016, even though the product EOLed in 1994 and had end of support in 1999.
- pjmlp 9y agoBesides what others commented. It definitely supported M:1 and M:N threading models while Linux was still designing NPTL and LinuxThreads models.
- dfox 9y agoI'm not saying that SunOS was somehow slow to implement these things, but that the SunOS that ran on the aforementioned SS10 shell server. Which seems about right given the fact that first Solaris with userlevel LWPs was 5.2 (dec 93) and pthread-compatibility layer was introduced in 5.5 (nov 95). And it seems quite plausible that they ran SunOS 4.x and not Solaris.