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: 103376,49eb370bfd3baa90 X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news4.google.com!news.glorb.com!news-out.ntli.net!newsrout1-gui.ntli.net!ntli.net!newsfe2-gui.ntli.net.POSTED!53ab2750!not-for-mail From: "Dr. Adrian Wrigley" Subject: Re: Memory limits in Ada where Fortran has none 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: <1110070479.250902.220540@l41g2000cwc.googlegroups.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Date: Sun, 06 Mar 2005 23:01:36 GMT NNTP-Posting-Host: 81.100.88.147 X-Complaints-To: http://www.ntlworld.com/netreport X-Trace: newsfe2-gui.ntli.net 1110150096 81.100.88.147 (Sun, 06 Mar 2005 23:01:36 GMT) NNTP-Posting-Date: Sun, 06 Mar 2005 23:01:36 GMT Organization: ntl Cablemodem News Service Xref: g2news1.google.com comp.lang.ada:8777 Date: 2005-03-06T23:01:36+00:00 List-Id: Hi! This GNAT problem is coming up more frequently now with more people wanting to use their 32-bit systems to the full :( I regularly declare and use arrays in Ada which are 1.9GB, and map directly to files (via POSIX mmap). This is amazingly fast for access to databases I need because I can directly access all the elements in memory. Unfortunately, my data sets ideally would be around 4-5GB, but my Linux box wont mmap more than 2GB :( The main caveats (IIRC) are: Don't use 'Size type attributes on large records/arrays Only use access values to the data accessing record elements whose offset is > 256MB may be a problem(?) It's a big nuisance, because you can end up with programs which compile OK, but fail at run-time. I'm hoping someone will build an Athlon64 implementation of GNAT which can make use of 64-bit access values. I'm sure it will happen one day, because 64-bit PCs will soon be ubiquitous, and the 256MB will become a total embarrassment to the GNAT/Ada community. Adrian -- Dr. Adrian Wrigley, Cambridge, UK.