sommar@seismo.CSS.GOV@enea.UUCP (02/18/87)
Yes, I have heard that if I you want it to go fast and yet use a high-level language, use Fortran. Fortran is the fastet language under VMS, they say. Well, it may be fastest, but it is not the nicest to program in. Especially not if you're into system programming. All those %val, %loc clutters up your code, not talking about the equivalence statements... Anyway, I have just gone into a real-time project for VMS and currently they're using Fortran and Macro. What I'd like to know if there is any one who can give me *facts* on this issue. Are the code produced by the Pascal compiler really so much slower than the one of the Fortran compiler? Especially if you are using all these fancy Fortran-8X features, which doesn't to be aimed to make quick programmes. If you have facts that are supporting my view, please give me references so I can convince the other project members. Erland Sommarskog ENEA Data, Stockholm, Sweden sommar@enea.UUCP
JOHNSON@NUHUB.ACS.NORTHEASTERN.EDU.UUCP (02/19/87)
>Yes, I have heard that if I you want it to go fast >and yet use a high-level language, use Fortran. >Fortran is the fastet language under VMS, they >say. > >Well, it may be fastest, but it is not the nicest >to program in. Especially not if you're into >system programming. All those %val, %loc clutters >up your code, not talking about the equivalence >statements... > >Anyway, I have just gone into a real-time project >for VMS and currently they're using Fortran and >Macro. What I'd like to know if there is any one >who can give me *facts* on this issue. Are the >code produced by the Pascal compiler really so >much slower than the one of the Fortran compiler? >Especially if you are using all these fancy >Fortran-8X features, which doesn't to be aimed to >make quick programmes. If you have facts that >are supporting my view, please give me references >so I can convince the other project members. > >Erland Sommarskog >ENEA Data, Stockholm, Sweden >sommar@enea.UUCP Hm . . . This is a good one. Comparing different langauges is a bit like comparing apples and oranges. Which language you use depends on what you are doing. In general, Pascal does things behind the curtain that you don't see. The VMS common code generator and optimizer is used with Pascal and does a reasonably good job at optimizing this unseen stuff. Fortran, on the other hand (last I heard any way) used it's own code generator and optimizer. The two backends do similar things but not EXACTLY the same things. If you used nested structures with lots of pointers in Pascal you could easily end up with lots of unseen support code that you wouldn't get with the usual vanilla Fortran because Fortran hasn't got all that. So it also depends on the what code you write. Something easily written is not necessarily easily executed. Try writing something simple and get both compilers to show you the generated code. You can also instrument the code with timers but remember that timing takes time itself. I'm sorry I don't have any numbers for you. I rarely get time do one thing in two different langauges. Still, if you write vanilla Fortran and simplistic Pascal they probably won't be much different in terms of speed. One last thought. You also need to consider just how time critical is your application. If it REALLY isn't very time critical then it probably doesn't matter which language you use. I have insufficient data for a better answer. Chris Johnson Northeastern University csnet: johnson@nuhub.acs.northeastern.edu arpa: johnson%nuhub.acs.northeastern.edu@relay.cs.net at&t: (617) 437-2335