From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.2 Received: from minnie.tuhs.org (minnie.tuhs.org [45.79.103.53]) by inbox.vuxu.org (OpenSMTPD) with ESMTP id e734b5e8 for ; Wed, 7 Aug 2019 01:22:35 +0000 (UTC) Received: by minnie.tuhs.org (Postfix, from userid 112) id 6F0D99BB3B; Wed, 7 Aug 2019 11:22:34 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id C1E129BA22; Wed, 7 Aug 2019 11:22:14 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="DrkXDU6x"; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id 67FF59BA22; Wed, 7 Aug 2019 11:22:10 +1000 (AEST) Received: from mail-ot1-f67.google.com (mail-ot1-f67.google.com [209.85.210.67]) by minnie.tuhs.org (Postfix) with ESMTPS id DF3759BA17 for ; Wed, 7 Aug 2019 11:22:09 +1000 (AEST) Received: by mail-ot1-f67.google.com with SMTP id l15so40551129oth.7 for ; Tue, 06 Aug 2019 18:22:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=621PdnOObH66+392AvDo15oL37NqXBJbN2NZX1iN1og=; b=DrkXDU6xNzCUkl+6WzEK4cD4C+nIbQ2wNDZ1yS2FmIVXXFTaWhGn5QCY9RGipgdj01 rcLMgUpdgCzzu+s3u4TNX6ena7/pXeX28bSE8MtZ7Q/KN/OQoKPK34yeh0LnIQ2HUbCs yWnxQudQEizKcTD2KZdg2zpr/horlZMgMZ94hNptwCP2iCxkuM7RBTb0AU7sx3BcJS6k OzZqP+SGX+oZAffRDzTLK9YO8vEKviZSSix0PQNesOmA5HlJxIncXl0BjOGwIq6AtGq9 D7c7Gv8eGmwKStOVX/e6A8iKMtS3SpU304Qol0Haqx6yQq4w1faG9BZdgYum0vVazi0F 6+Cw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to; bh=621PdnOObH66+392AvDo15oL37NqXBJbN2NZX1iN1og=; b=c2WxxZHW/yejf/JkeCDjOyyaBy40l07jjDSmMex9yv7rsBbJMdrsrldmifjpPOAWwM Ptrq8YTQ1w8LAzlgwQR589Gw4AbMK52agmhAPtKReOw077Ghk34o+NYQXdB6Q0tDoBsv VnClJbR6SADjlez90kNj5ts9dt10/1P8j1D3hVbv2vZHsOWxNuZiBR/8mCNpmdORDAtI 1HtJPkQWSt/fzPSf9r5MVH0v9aFLZJGOMM9lgyYJaO7Kf277V8ip3dOLpFipzCSoIC6T nc5g4NB7s0kIpSmGTrqmPbeu0sh3145i03tG+BJDU33vzjuaOUdH6Om0bX/aKwHICcoc u5Eg== X-Gm-Message-State: APjAAAWjhhQ+N6YOSgi0QQI5f2h4hOy7yRX9/vc/Rdv6k7JSf4DNwBrq 2oylk7n+0U410gHmn4QDiMspCY5KoRs8uJnkrJEllQ== X-Google-Smtp-Source: APXvYqy8pghWmwmoTmUduUOYfHfqETfrXBFpqC1reezwx69gEVZtMb8ncOCo6mXukwd8ZOfYJjta+bLSStSyyRuuZXE= X-Received: by 2002:a5d:9bc6:: with SMTP id d6mr6170839ion.160.1565140928921; Tue, 06 Aug 2019 18:22:08 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:ac0:ac4c:0:0:0:0:0 with HTTP; Tue, 6 Aug 2019 18:22:08 -0700 (PDT) In-Reply-To: <7236c9d4-40af-bc49-8aee-5c32d869d2eb@spamtrap.tnetconsulting.net> References: <7236c9d4-40af-bc49-8aee-5c32d869d2eb@spamtrap.tnetconsulting.net> From: Andrew Warkentin Date: Tue, 6 Aug 2019 19:22:08 -0600 Message-ID: To: The Unix Heritage Society Content-Type: text/plain; charset="UTF-8" Subject: Re: [TUHS] Pre-init initialization X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: The Unix Heritage Society mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" On 8/6/19, Grant Taylor via TUHS wrote: > Do, or did, anything other than Linux use a concept of an initramfs / > initrd to create a pre-(main)-init initialization environment to prepare > the system to execute the (main)-init process? > Off the top of my head I'm not aware of any other conventional Unix besides Linux that uses a memory filesystem for early userspace. Solaris does use a memory filesystem during boot, but it normally contains only kernel modules and is only read by the kernel module linker, and IIRC AIX uses a weird vaguely zImage-like format for its boot image but I can't remember if the image contains just the kernel and some modules or if there are userspace programs in it. As far as unconventional Unix-like OSes go, QNX Neutrino (but not QNX 2 and 4) and Plan 9 both use in-memory filesystems during early userspace boot, although both only load a single image from disk rather than a separate kernel and ramdisk. In QNX, the image is a page-oriented XIP filesystem that contains the kernel and early userspace as regular files, and in Plan 9 the image is the kernel executable, which contains a minimal embedded filesystem with a few user-mode programs. UX/RT, the OS that I'm writing, will also boot from a memory filesystem containing the kernel and early userspace in a similar manner to QNX (it's loosely based on QNX and Plan 9 but is not a clone of either), although currently it isn't running any real userspace programs.