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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,9f5b05b9ce8aed62 X-Google-Attributes: gid103376,public From: dewar@cs.nyu.edu (Robert Dewar) Subject: Re: gnat for DOS Date: 1996/04/25 Message-ID: #1/1 X-Deja-AN: 151333849 references: <317A8B31.CFD@easystreet.com> <4llr39$b2a@cville-srv.wam.umd.edu> organization: Courant Institute of Mathematical Sciences newsgroups: comp.lang.ada Date: 1996-04-25T00:00:00+00:00 List-Id: Scott James said: "While your comment is perhaps relevant to GUI and OS-application programming, with regards to embedded programming your repeated smirks at DOS smack of either gross ignorance or wishful thinking. Due to DOS's relatively low system overhead, straightforward access to hardware, and the proliferation of ROM DOS chips, rest assured DOS is and will remain with us as a low-end embedded OS option for many years to come. To continually bash DOS does nothing for Ada and perhaps, in the future, should be relegated to comp.os.advocacy or alt.windows.and.mice.are.really.cool or some other such group." You miss my point, I am not talking about DOS as a target environment. It is quite true that since DOS is essentially completely transparent at run time that if what you really want to do is to run on the bare board without any OS intervention, DOS is perfectly reasonable. My comment applies to DOS as a *development* environment, where it is indeed lacking, since running on a DOS extender under DOS is always problematic compared to using a proper 32-bit operating system. Note that GNAT in any case does not run under DOS directly, nor do programs that it generates. Instead they run in protected mode on a 32-bit DOS extender. Your comments about embedded programming thus don't apply directly, since in any case you do NOT have straightforward access to the hardware, and here is no question of running in the context of ROM DOS chips. It remains good advice for people doing serious development using GNAT on a PC to choose one of the many 32-bit operating systems that is supported. It is certainly true that DJGPP 2.0 alleviates some of the worst characterstics of the DOS environment (notably the exhuastion of low memory that made the use of gnatmake impossible), but still there are limitations. So my recommendations here have nothing whatever to do with operating system advocacy, and are quite relevant to this group. Although it is certainly possible to run GNAT under DOS, and even to build large programs in this environment, you are buying yourself trouble. THis is more a comment on GNAT and its system requirements than on DOS per se. FOr example, the 8+3 character limits on file names are merely a minor nuisance for most uses of DOS, but for writing large programs using GNAT, this file naming restriction can be very bothersome. That being said, we are continuing to enhance the DOS version. The next release incorporates tasking, and also uses DJGPP 2.0 (so gnatmake should finally be available).