Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for embedded systems

From	Nicolas Pitre <nicolas.pitre@linaro.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for embedded systems
Date	2017-04-03 03:10 +0200
Message-ID	<trYFj-8mn-1@gated-at.bofh.it> (permalink)
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On Mon, 3 Apr 2017, Stuart Longland wrote:

> On 03/04/17 07:41, Nicolas Pitre wrote:
> >> No PTYs seems like a big limitation. This means no sshd?
> > Again, my ultimate system target is in the sub-megabyte of RAM.  I 
> > really doubt you'll be able to fit an SSH server in there even if PTYs 
> > were supported, unless sshd (or dropbear) can be made really tiny. 
> > Otherwise you most probably have sufficient resources to run the regular 
> > TTY code.
> 
> Are we talking small microcontrollers here?  The smallest machine in
> terms of RAM I ever recall running Linux on was a 386SX/25 MHz with 4MB
> RAM, and that had a MMU.

Not to repeat what I've said already, I invite you to have a look at 
https://lkml.org/lkml/2017/3/24/634

> I recall Slackware requiring that you booted with a mounted floppy (no
> ramdisk) and possibly even required that you had a second floppy drive
> formatted as swap so you'd be able to get through the install without
> oomkiller knocking on your door.

Did the oom killer even exist in those days? I don't remember.
All I remember is the stack of 73 flopies or so to install Slackware... 
and of course floppy #68 would have developed a bad sector preventing 
you from completing the installation.

> Sub-megabyte system support is a noble goal, but I'm wondering how
> practical such systems would be, and whether an embedded real-time
> kernel might be a better choice than Linux on such systems.

Obviously, you need to leave the idea of a _distribution_ behind. If you 
think of a single user app, and a kernel that only provides those 
syscalls used by that app, and the minimal subset of kernel services 
that such an app require, then nothing prevents such and app/kernel from 
using the actual Linux API. And that's where you get a big advantage 
over other RTOSes. See the link above for the full rationale.

Nicolas

Thread

[PATCH v2 0/5] minitty: a minimal TTY layer alternative for embedded systems Nicolas Pitre <nicolas.pitre@linaro.org> - 2017-04-02 00:40 +0200
  Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-04-02 15:30 +0200
    Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Nicolas Pitre <nicolas.pitre@linaro.org> - 2017-04-02 18:00 +0200
      Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Alan Cox <alan@linux.intel.com> - 2017-04-03 15:00 +0200
        Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Nicolas Pitre <nicolas.pitre@linaro.org> - 2017-04-03 18:10 +0200
          Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Alan Cox <alan@linux.intel.com> - 2017-04-03 20:10 +0200
            Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Nicolas Pitre <nicolas.pitre@linaro.org> - 2017-04-03 22:00 +0200
              Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Alan Cox <alan@linux.intel.com> - 2017-04-04 15:50 +0200
                Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Nicolas Pitre <nicolas.pitre@linaro.org> - 2017-04-04 21:30 +0200
  Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for embedded systems Andi Kleen <andi@firstfloor.org> - 2017-04-02 22:50 +0200
    Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Nicolas Pitre <nicolas.pitre@linaro.org> - 2017-04-02 23:50 +0200
      Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Stuart Longland <stuartl@longlandclan.id.au> - 2017-04-03 01:00 +0200
        Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Nicolas Pitre <nicolas.pitre@linaro.org> - 2017-04-03 03:10 +0200
          Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Stuart Longland <stuartl@longlandclan.id.au> - 2017-04-04 02:50 +0200
        Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Geert Uytterhoeven <geert@linux-m68k.org> - 2017-04-03 20:20 +0200
          Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Rob Herring <robh@kernel.org> - 2017-04-03 21:00 +0200
            Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Geert Uytterhoeven <geert@linux-m68k.org> - 2017-04-03 21:50 +0200
          Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-04-03 23:10 +0200
            Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-04-04 19:00 +0200
              Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-04-04 19:10 +0200
                Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-04-04 20:00 +0200
                Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-04-04 20:10 +0200
                Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Nicolas Pitre <nicolas.pitre@linaro.org> - 2017-04-04 20:40 +0200
                Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-04-04 22:00 +0200
                Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Nicolas Pitre <nicolas.pitre@linaro.org> - 2017-04-04 22:30 +0200
              Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Nicolas Pitre <nicolas.pitre@linaro.org> - 2017-04-04 21:00 +0200
      Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-04-03 10:00 +0200
        Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Andi Kleen <andi@firstfloor.org> - 2017-04-03 17:40 +0200
          Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Nicolas Pitre <nicolas.pitre@linaro.org> - 2017-04-03 19:30 +0200
          Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Adam Borowski <kilobyte@angband.pl> - 2017-04-03 22:00 +0200
            Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Nicolas Pitre <nicolas.pitre@linaro.org> - 2017-04-03 22:10 +0200
              Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Adam Borowski <kilobyte@angband.pl> - 2017-04-03 22:40 +0200
        Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Nicolas Pitre <nicolas.pitre@linaro.org> - 2017-04-03 18:50 +0200
  Re: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for  embedded systems Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-03 09:50 +0200

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