[2605] in java-interest
Re: More Java performance questions
daemon@ATHENA.MIT.EDU (Arthur van Hoff)
Thu Oct 5 21:49:12 1995
Date: Thu, 5 Oct 1995 16:42:02 -0700
From: Arthur.Vanhoff@Eng.Sun.COM (Arthur van Hoff)
To: sasebb@unx.sas.com
Cc: java-interest@java.Eng.Sun.COM
Hi Edmund,
> 1. Java specifies big-endian. I assume that this will not slow
> it down to much on little-endian machines, i.e. that it stores
> data little-endian when it is not destined for a file or communications.
The exact internal layout of objects in memory is not defined. Only
the layout in class files is defined. The interpreter can be fast, but
it will have to translate when it loads classes.
> 2. When you link to external routines, it sounds like it will be
> only though a slow CORBA-style socket linkage, where all the data is
> passed back and forth (no addresses). This could be bad news for
> a BLAS (basic linear algebra) library that is intended to speed
> up matrix calculations. It won't speed it up for most things if
> it has to move the data back and forth, rather than pass addresses.
> It means that instead of just using the external routines for
> a few standardized inner loops, we would have to transfer larger,
> more specialized problems to external routines to pick up speed.
Normal Java can link in dynamic libaries and bind Java methods to
native functions. It sounds like a bad idea to me to use CORBA objects
to do matrix calculations.
> 3. What conventions does Java have to support streaming of
> it's objects? Both as string text and in binary form. Both
> with and without embedded data (deep copy). Both with and without
> self-identifying data.
There is no support for persistent objects. This is mainly because
of security reasons.
Have fun,
Arthur van Hoff
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