From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Thread: 103376,eeee56c19a542f8d X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII Path: g2news2.google.com!news3.google.com!border1.nntp.dca.giganews.com!border2.nntp.dca.giganews.com!nntp.giganews.com!peer01.cox.net!cox.net!news-out.ntli.net!newsrout1-gui.ntli.net!ntli.net!news.highwinds-media.com!newspeer1-win.ntli.net!newsfe6-win.ntli.net.POSTED!53ab2750!not-for-mail From: "Dr. Adrian Wrigley" Subject: Re: Multi-arch User-Agent: Pan/0.14.2 (This is not a psychotic episode. It's a cleansing moment of clarity.) Message-Id: Newsgroups: comp.lang.ada References: <1147857777.703653.268610@j33g2000cwa.googlegroups.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Date: Sun, 21 May 2006 16:03:04 GMT NNTP-Posting-Host: 82.10.238.153 X-Trace: newsfe6-win.ntli.net 1148227384 82.10.238.153 (Sun, 21 May 2006 17:03:04 BST) NNTP-Posting-Date: Sun, 21 May 2006 17:03:04 BST Organization: NTL Xref: g2news2.google.com comp.lang.ada:4319 Date: 2006-05-21T16:03:04+00:00 List-Id: On Thu, 18 May 2006 21:24:44 +0000, Bj�rn Persson wrote: > I understand how multi-arch is useful if you want to use proprietary > binaries that are available only for certain architectures. Otherwise I > don't see a reason to do it. I'd think free code would just be compiled > for the "native" architecture. Is multi-arch useful in an altogether > free system in some way that eludes me? Several reasons. I suggest that people who run a mixture of machines may want to share binaries across the network, but build them on their newest machines. People also want to avoid recompiling working code with another architecture, even if they have source code. You can't be sure it'll work exactly right without testing, which may be expensive. I found a couple of latent errors when builing for 64-bit. One was calling a C varargs function incorrectly from Ada. Another was caused by undocumented members of a C struct overwriting the Ada stack. Changing architectures is a risk. If you have written some code in assembly language, this will constrain the architecture until alternative code is available. Finally, some people store records directly in data files for various reasons. Changing architecture would need recreatoin of those files. It only takes one old architecture library to be a show-stopper, whether that is a third-party or handwritten codec, a buggy library or whatever. multi-arch eases the transition to a new architecture. -- Adrian