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=-1.0 required=5.0 tests=MAILING_LIST_MULTI, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 25101 invoked from network); 8 Sep 2022 22:17:08 -0000 Received: from minnie.tuhs.org (50.116.15.146) by inbox.vuxu.org with ESMTPUTF8; 8 Sep 2022 22:17:08 -0000 Received: from minnie.tuhs.org (localhost [IPv6:::1]) by minnie.tuhs.org (Postfix) with ESMTP id 8E473422AD; Fri, 9 Sep 2022 08:16:44 +1000 (AEST) Received: from mcvoy.com (mcvoy.com [192.169.23.250]) by minnie.tuhs.org (Postfix) with ESMTPS id 26CF4422AC for ; Fri, 9 Sep 2022 08:16:40 +1000 (AEST) Received: by mcvoy.com (Postfix, from userid 3546) id 9819435E61D; Thu, 8 Sep 2022 15:16:39 -0700 (PDT) Date: Thu, 8 Sep 2022 15:16:39 -0700 From: Larry McVoy To: Clem Cole Message-ID: <20220908221639.GR11929@mcvoy.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Message-ID-Hash: I4E2UQNAHGXGVPNRT7COTBTQIKEY2YX5 X-Message-ID-Hash: I4E2UQNAHGXGVPNRT7COTBTQIKEY2YX5 X-MailFrom: lm@mcvoy.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-tuhs.tuhs.org-0; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: segaloco , TUHS X-Mailman-Version: 3.3.6b1 Precedence: list Subject: [TUHS] Re: Re-implementations/Clean-Rooms et al. List-Id: The Unix Heritage Society mailing list Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On Thu, Sep 08, 2022 at 05:50:37PM -0400, Clem Cole wrote: > > BSD is a different beast, as they were literally replacing the AT&T source > > code before their eyes, so there isn't much argument that can be made for > > 4.4BSD being a "clean-room" implementation of UNIX. > > It was not a clean-room as Arthur defined it. It was rewritten over time, > which replaced AT&T's implementation. Which is all that was ever claimed. And it's a false claim. Go look at the Bell Labs bmap() and the BSD bmap(), the last time I looked they were bit for bit identical. I looked there because I split bmap() into bmap_read() and bmap_write() because the read path is trivial and the write path is quite a bit more difficult (this was all for the work srk imagined, and I did, to get rid of the rotational delays). So I was pretty familiar with that code path and as of about 20 years ago, well past 4.4BSD, bmap() was unchanged from either v7 or 32v. The weird thing is it isn't that hard to write something that would walk the code and find other examples. Nobody seemed to care.