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=-0.9 required=5.0 tests=BAYES_00,FORGED_GMAIL_RCVD, FREEMAIL_FROM autolearn=no autolearn_force=no version=3.4.4 X-Google-Thread: 103376,68494635acddb77e X-Google-Attributes: gid103376,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news1.google.com!postnews.google.com!m73g2000hsh.googlegroups.com!not-for-mail From: Maciej Sobczak Newsgroups: comp.lang.ada Subject: Re: File output and buffering Date: Thu, 21 Aug 2008 00:10:52 -0700 (PDT) Organization: http://groups.google.com Message-ID: <84805bfc-26f4-4507-9024-9e3558c9cb32@m73g2000hsh.googlegroups.com> References: <60a35fd4-e5a6-4aa0-a73f-6815ce7e92fc@f36g2000hsa.googlegroups.com> <4af2f934-7458-4370-b325-c38e3a4068b8@s50g2000hsb.googlegroups.com> <1jt8nguvzf1hw$.189glcey6hmht.dlg@40tude.net> NNTP-Posting-Host: 128.141.45.246 Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Trace: posting.google.com 1219302653 28363 127.0.0.1 (21 Aug 2008 07:10:53 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Thu, 21 Aug 2008 07:10:53 +0000 (UTC) Complaints-To: groups-abuse@google.com Injection-Info: m73g2000hsh.googlegroups.com; posting-host=128.141.45.246; posting-account=bMuEOQoAAACUUr_ghL3RBIi5neBZ5w_S User-Agent: G2/1.0 X-HTTP-UserAgent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.0.1) Gecko/2008070206 Firefox/3.0.1,gzip(gfe),gzip(gfe) Xref: g2news1.google.com comp.lang.ada:1706 Date: 2008-08-21T00:10:52-07:00 List-Id: On 20 Sie, 17:39, "Dmitry A. Kazakov" wrote: > Buffering is used to make I/O in an asynchronous and/or conveyered way. No, it is not asynchronous. Nothing happens in the background, the operations are only grouped. The group is (usually) transmitted in the synchronous fashion. I do not know what is "conveyered". > That does not make I/O faster in terms of latencies. It does make it faster in terms of throughput. Note: I do not imply that throughput is more valuable for optimization than latency - these can be different goals and usually are. > Any language buffer on top of numerous layered buffers, typical for an OS, > adds nothing, but overhead. It can reduce the overhead that is associated with the number of requests. System calls are not free and there is also a significant latency of the medium that is better to be avoided (like network roundtrips or disk seek times). -- Maciej Sobczak * www.msobczak.com * www.inspirel.com Database Access Library for Ada: www.inspirel.com/soci-ada