From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=5.0 tests=DKIM_INVALID,DKIM_SIGNED, MAILING_LIST_MULTI,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 8093 invoked from network); 7 Jun 2022 23:41:23 -0000 Received: from minnie.tuhs.org (2600:3c01:e000:146::1) by inbox.vuxu.org with ESMTPUTF8; 7 Jun 2022 23:41:23 -0000 Received: from minnie.tuhs.org (localhost [IPv6:::1]) by minnie.tuhs.org (Postfix) with ESMTP id 23B4B40CD6; Wed, 8 Jun 2022 09:41:18 +1000 (AEST) Received: from toucan.tulip.relay.mailchannels.net (toucan.tulip.relay.mailchannels.net [23.83.218.254]) by minnie.tuhs.org (Postfix) with ESMTPS id 0E29C40CD0 for ; Wed, 8 Jun 2022 09:41:11 +1000 (AEST) X-Sender-Id: dreamhost|x-authsender|cmhanson@eschatologist.net Received: from relay.mailchannels.net (localhost [127.0.0.1]) by relay.mailchannels.net (Postfix) with ESMTP id 8E5FB4C12F8 for ; Tue, 7 Jun 2022 23:41:07 +0000 (UTC) Received: from pdx1-sub0-mail-a268.dreamhost.com (unknown [127.0.0.6]) (Authenticated sender: dreamhost) by relay.mailchannels.net (Postfix) with ESMTPA id 166514C11FC for ; Tue, 7 Jun 2022 23:41:07 +0000 (UTC) ARC-Seal: i=1; s=arc-2022; d=mailchannels.net; t=1654645267; a=rsa-sha256; cv=none; b=x5FQMbGb++QPWojNjWd3A2GupI6ytIJ7+sIDO5fxyVmOxe6crozfjwo8+cdcBJqfvMpppw coFge48FPgp5gACgBstZwaKYV4FioLjym5pTA0Nnu+JQkULLy+VmIYRXJtmSsFmBQVMW0p qeI8pNJ24xeheVkBJO6gRZvhAxTQDEyByUDXrmKKh1GISTSWC1ySc0r9CjrgfUYOvpqmF1 Sm1E+sVFUKWxPHx92beLYEftU1BLiF3kPteYfbdehAPPRenShzJqDiYG5Pt+bpHssLaIgL XbzcOQ2eQmJo9skKpRlqvrb8YTHDV06ujXU+EXr2fEAhhHrXjoVLfQdxAsGg6A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=mailchannels.net; s=arc-2022; t=1654645267; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=38CimsKDcFf8SFCH3qoU5H0+5HlZqlxTC12anzhBAE8=; b=SNKoZYhPOAbxr0yPzLmCZLHKK3pErkD7B/xomeXU85RRcPuBBr+DgyHWKzOicf32bZio85 rxJvpvIvb2xr14aTdAiL0A2iwrqiI1Y3QkN5xz+y/qqYAzGNkgZLHDCn8HT6g+/Qh9oQ50 45UhtbisW3QKMJmbh0HQkgz/+FAwo0WaJf7YLtLVHBgoY+sTpVTe4HXRUvcmgfBjWRZKt1 hWcW8C/UZ2vhmxBUS625QnmUS1KPvnTIl0/3j24V40uAFcpChielKrTmbJL9bt2BxA/bEY fs6BQh9+lRL5v7PstqRQTqgVi0nhVGzs8BuY9eGqkBP7TgUPdktatKmpLepVnw== ARC-Authentication-Results: i=1; rspamd-786f5898df-fp8zg; auth=pass smtp.auth=dreamhost smtp.mailfrom=cmhanson@eschatologist.net X-Sender-Id: dreamhost|x-authsender|cmhanson@eschatologist.net X-MC-Relay: Neutral X-MailChannels-SenderId: dreamhost|x-authsender|cmhanson@eschatologist.net X-MailChannels-Auth-Id: dreamhost X-Cold-Ruddy: 606547e44e5bae93_1654645267307_2477015999 X-MC-Loop-Signature: 1654645267307:1708168273 X-MC-Ingress-Time: 1654645267307 Received: from pdx1-sub0-mail-a268.dreamhost.com (pop.dreamhost.com [64.90.62.162]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384) by 100.96.96.51 (trex/6.7.1); Tue, 07 Jun 2022 23:41:07 +0000 Received: from smtpclient.apple (unknown [17.212.150.205]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: cmhanson@eschatologist.net) by pdx1-sub0-mail-a268.dreamhost.com (Postfix) with ESMTPSA id 4LHn1G5ffWzKn for ; Tue, 7 Jun 2022 16:41:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=eschatologist.net; s=dreamhost; t=1654645266; bh=38CimsKDcFf8SFCH3qoU5H0+5HlZqlxTC12anzhBAE8=; h=From:Content-Type:Content-Transfer-Encoding:Subject:Date:To; b=PmTbXza42INcM+29TlnviOnwgOG4TpNNjG+sGDjE+J8X8wsXeSttJI4YCo6BbkLyV mpYFrW0gOubFdWVme6w3Ix+1B1AfD0rhTMlo2dHbDo5Y/mkFGLGFGVLQW41EKkuJs0 N9bIZtHTpG5SewkGovYaOoY/zo4kxFiBKdrrbt75RwevlIvju2c27WP7/r9H+R8GlA IxgIiTaFbBXz7FocRRpyS2aUFIiAUZxbMI1QtBytmddwa60zKBBRgRFEC8XTPV0QM+ /iLEdX/zM214WUXTjlhDoad1myj7FgFTNOf1ckWaw9Jvcyd3v+1m1eIzIyN3DmfwmT wN2vN3CQ+gxCw== From: Chris Hanson Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3696.100.31\)) Date: Tue, 7 Jun 2022 16:41:06 -0700 References: <20220607152519.GN15041@mcvoy.com> To: The Eunuchs Hysterical Society In-Reply-To: Message-Id: <931C40D7-F780-454F-B51B-747C713CD31C@eschatologist.net> X-Mailer: Apple Mail (2.3696.100.31) Message-ID-Hash: 5DWYQAHGU3RJ44RRINYSQPHZQ35BXFE3 X-Message-ID-Hash: 5DWYQAHGU3RJ44RRINYSQPHZQ35BXFE3 X-MailFrom: cmhanson@eschatologist.net X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.6b1 Precedence: list Subject: [TUHS] Re: [simh] Announcing the Open SIMH project List-Id: The Unix Heritage Society mailing list Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On Jun 7, 2022, at 10:00 AM, Paul Winalski = wrote: >=20 > Windows and OS X rarely had problems with upward compatibility (newer > versions able to run executables built for older versions), but Linux > was living hell. Shared library compatibility was the biggest > problem. Not only were shared libraries often incompatible between > different Linux distributions, they were sometimes incompatible even > between different versions of the same distribution. That's because, at least when it comes to macOS (nee OS X, nee Mac OS X, = nee OPENSTEP/Mach, nee NEXTSTEP in various capitalizations) we treat = treat binary compatibility as something for the operating system as a = whole to maintain, not just the kernel or the kernel userspace. Linux's ABI compatibility is itself kind of bare-bones; it achieves = userspace compatibility by having a fixed set of system call numbers = with well-specified calling sequences that get compiled into every = binary for a particular architecture, and it doesn't even attempt to = provide the kernel ABI compatibility needed by commercial driver = vendors. We handle userspace ABI compatibility in macOS by actually putting the = syscalls on the other side of a shared library (libSystem.dylib) so the = calling sequences and syscall numbers are entirely hidden from = userspace. We've historically taken a different approach to kernel ABI = compatibility but have provided it too, though not to the same extent as = userspace. As an example of where this helps, things like Linux-derived containers = would be much faster on non-Linux platforms if the container system = could swap in its own "libsyscall.so" instead of having to run atop a VM = of some sort to handle the Linux syscall traps. -- Chris