From owner-freebsd-embedded@freebsd.org Wed Mar 9 01:20:52 2016 Return-Path: Delivered-To: freebsd-embedded@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 3ED86AC8532 for ; Wed, 9 Mar 2016 01:20:52 +0000 (UTC) (envelope-from brad2000@gmail.com) Received: from mail-vk0-x22e.google.com (mail-vk0-x22e.google.com [IPv6:2607:f8b0:400c:c05::22e]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id EBE7586C; Wed, 9 Mar 2016 01:20:51 +0000 (UTC) (envelope-from brad2000@gmail.com) Received: by mail-vk0-x22e.google.com with SMTP id c3so38891497vkb.3; Tue, 08 Mar 2016 17:20:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc; bh=Q4+bx/rFxte/E4fDOd+w1B/QivvY8Dv1bizdVQTBvkM=; b=thryXkWaef81br8N34jK8dWyEJsLtFYd5N1WTM8HtBQFvTdZu1wDyOXELgkMgZL1CM qxTfmQsVnCsRQZSmfJ+Qpb9mYflnR13STBnLNTTpbGvR+kwWCyx/ubwbMk4s7fkpWxO3 a7Xf6/olr1jJbP6XCHhenJo5bgUItBjrxDnP/p1kGBRrKQFSR1kxxvG5wUsh6gZTWzFg 6cjeGYFeId6XHjGiY4oGOo5mK6cknwTP1h/SYrmX7QlC5LIj5kdTPTFzPDp09zSUP0xa FZDQ4FCf4qbXeKV/ZYF5nQExcawkPcWJu77T3Yuj+uQmAo1NMlopig/7ujgHpDIyykdL 0wqg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:sender:in-reply-to:references:date :message-id:subject:from:to:cc; bh=Q4+bx/rFxte/E4fDOd+w1B/QivvY8Dv1bizdVQTBvkM=; b=YD02QlSOZQwXtXkh0g6PO4Om5KjnFU68AzV26+rOjSgI+W+is10aB9zdAF6094BYPZ 66wB4d9oyLCcMg3J8oajepEubvRgJ7QwMYLda80iHc7oMflzYG+PWOn+IDa/s7M5jPve bvBarFjcRoM22srOyCg3GTQjx32seKBJ7BdIJ3+X9W6PYtqfAcTkIz9740xPUf/iIPMT jZCBHj1eLagmMGhGNL0Sh04Ui4J8uID0V11YSwDBVxKbSZ0n+Cfv3As3KFoC1t4fhJTq shmrDC5XZY2+qomV5Wbv5xdNztpniuE5WreoRUyQOdVO7XIAK2+PcJ4cNE47OsUdCTSn hRhg== X-Gm-Message-State: AD7BkJJML2nwkNHzxglXeMeEWuVkkDr6s7zI9mQlVq4Tof2XwjcJm1xshOHfx/P1GDVpLGZGklJEmnlnu5VMvg== MIME-Version: 1.0 X-Received: by 10.31.150.193 with SMTP id y184mr24283629vkd.99.1457486451027; Tue, 08 Mar 2016 17:20:51 -0800 (PST) Sender: brad2000@gmail.com Received: by 10.31.163.18 with HTTP; Tue, 8 Mar 2016 17:20:50 -0800 (PST) In-Reply-To: References: <1457473674.1406.46.camel@freebsd.org> Date: Tue, 8 Mar 2016 18:20:50 -0700 X-Google-Sender-Auth: Ayy7K9LyUQd7yAwMXcgJNPAvr3w Message-ID: Subject: Re: ? about kernel size.. From: Brad Walker To: Adrian Chadd Cc: Ian Lepore , "freebsd-embedded@freebsd.org" Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.21 X-BeenThere: freebsd-embedded@freebsd.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Dedicated and Embedded Systems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 09 Mar 2016 01:20:52 -0000 I tend to agree with your comments. I'm not certain that getting a microkernel is all that much use anymore. Sure they are tight, small and for some implementations time deterministic. But, the point is rapidly approaching where requirements are saturating what they can do. I've worked on the following microkernels: uTasker, ThreadX, ENEA Ose. But, each one has positives and negatives. But, the needs are starting to outweigh the positives and grow the negatives. For example, we have a requirement to implement SSL/TLS, BTLE, and ftp on a microkernel. By the time this is done, it will be worthwhile to look at alternatives. Not to mention, the needs just keep coming. -brad w. On Tue, Mar 8, 2016 at 4:55 PM, Adrian Chadd wrote: > Hi, > > If someone wanted to bring up freebsd on an mmu-less platform then I'd > say go for it, but you'd have to crime out a lot of code and > functionality to make it work. > > Honestly you'd likely be better off getting a microkernel type thing > going and then bring over the minimum set of useful things (say the > usb and network stacks) which don't really require much VM clue to > operate. the filesystem code may be a bit more challenging to bring in > as you're going to have to crime a bunch of VM specific things out, so > it may not be worth it. > > > -adrian >