[ogsa-wg] Action item from mondays call

[Andrew Grimshaw]

All,

On the call Monday night I was asked to provide a few paragraphs on
provisioning versus instance instantiation and "currying".

 

To me this is pretty straight-forward.  I provision an application on my
computer by installing it. CDL is the tool for that. Every time I want to
run the program, I create a separate application instance - JSDL/BES is the
right tool for that.

 

With respect to whether a particular input is bound to the application (as
came up in the call). More formally:

 

Assume that a program is a function L(a,b,c,d, .) that maps the inputs to
some set of outputs. (We'll assume that the programs are deterministic.)  If
we bind the formal parameter "a" with a particular value (say a particular
input file), then we have effectively created a new function L'(b,c,d, ..).
L and L' are two different functions. In lambda calculus this is called
"currying" - I've also seen it called "reification" in other contexts.

 

In terms of programs like BLAST. BLAST basically takes an input sequence
database and an input sequence and generates a set of scores - usually the
top k scores. . (There are many other parameters, but lets focus on the two
major ones.) The scores are generated by comparing the input sequence
against each of the target sequences in the database. If we "bind" BLAST to
a particular target database - then we have effectively created a new BLAST,
BLASTBound_to_the_particular_database. It is not the same function any more.


 

In terms of the discussion we've been having on the differences of the roles
of CDL and JSDL/BES I think if it this way.

 

If I want to be able to run BLAST on a machine - I may use (via perhaps the
program manager) CDL to "provision" BLAST in the BES container. To run BLAST
with a particular set of input files, then I use JSDL/BES. If I am going to
be running a large number of "BLAST jobs" against a particular DB, I may
want to "provision" BLASTBound_to_the_particular_database , using CDL, and
then run a set of comparisons against particular sequences using JSDL/BES. 

 

Andrew Grimshaw

Professor of Computer Science

University of Virginia

434-982-2204

grimshaw at cs.virginia.edu

 

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