From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.5-pre1 (2020-06-20) on ip-172-31-74-118.ec2.internal X-Spam-Level: X-Spam-Status: No, score=-1.9 required=3.0 tests=BAYES_00,FREEMAIL_FROM autolearn=ham autolearn_force=no version=3.4.5-pre1 X-Received: by 2002:a05:620a:20d6:: with SMTP id f22mr2160608qka.104.1616448318068; Mon, 22 Mar 2021 14:25:18 -0700 (PDT) X-Received: by 2002:a5b:448:: with SMTP id s8mr724135ybp.363.1616448317889; Mon, 22 Mar 2021 14:25:17 -0700 (PDT) Path: eternal-september.org!reader02.eternal-september.org!weretis.net!feeder8.news.weretis.net!proxad.net!feeder1-2.proxad.net!209.85.160.216.MISMATCH!news-out.google.com!nntp.google.com!postnews.google.com!google-groups.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Mon, 22 Mar 2021 14:25:17 -0700 (PDT) In-Reply-To: Injection-Info: google-groups.googlegroups.com; posting-host=146.5.2.231; posting-account=lJ3JNwoAAAAQfH3VV9vttJLkThaxtTfC NNTP-Posting-Host: 146.5.2.231 References: User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: Subject: Re: surprise data from Ada.Sequential_IO From: Shark8 Injection-Date: Mon, 22 Mar 2021 21:25:18 +0000 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Xref: reader02.eternal-september.org comp.lang.ada:61644 List-Id: On Monday, March 22, 2021 at 1:41:59 PM UTC-6, Jeffrey R. Carter wrote: > On 3/22/21 7:14 PM, John Perry wrote:=20 > >=20 > > For Direct_IO I inferred this fact from ARM A.8.3, "the file is viewed = as a set of elements occupying consecutive positions in linear order", but = I don't see a similar indication for Sequential_IO. Is there a warning in t= he ARM about this?=20 > >=20 > > (I do see the warning in Barnes' book, which I had consulted! and saw! = and decided not to use Direct_IO as a result! but somehow read the same thi= ng about Sequential_IO & either forgot or mis-concluded something. So I ack= nowledge my stupidity here.) > The only differences between Direct_IO and Sequential_IO are that Direct_= IO=20 > allows random access and mixed input and output. In both cases the file c= ontains=20 > a sequence of binary representations of values of a single type.=20 >=20 > I don't really understand why Sequential_IO exists, since Direct_IO provi= des a=20 > superset of Sequential_IO's functionality. Going by some of the stuff where I work, most of which has foundational-stu= ff from the 80s and 90s (though not in Ada), the "Direct IO" is considered = to be raw read/write concerning hardware or UDP datagram-packets or such. S= o, I would assume that by the nomenculture [and usage] of the day Direct_IO= was meant for similar. Sequential_IO though sounds like a "and here we hav= e a file full of entries of Type X, which we made generic to save ourselves= the headache of maintaining multiple identical-except-for-type package."