Re: Teraspace Storage Model and CEE APIs

[Scott Klement <midrange-l@xxxxxxxxxxxxxxxx>]

Hi Mihael,

I don't think the ILE CEE APIs support teraspace at all.  If you want to 
allocate memory in teraspace, why not call the teraspace APIs?  (This 
has been available in RPG since v4r4...)

Here are the prototypes:

  /if defined(*V5R2M0)
 D TS_malloc64     PR              *   ExtProc('_C_TS_malloc64')
 D   size                        20U 0 value
  /endif
 D TS_malloc       PR              *   ExtProc('_C_TS_malloc')
 D   size                        10U 0 value
 D TS_realloc      PR              *   ExtProc('_C_TS_realloc')
 D   ptr                           *   value
 D   size                        10U 0 value
 D TS_free         PR                  ExtProc('_C_TS_free')
 D   ptr                           *   value

With these, RPG can allocate terabytes of memory to a single pointer. 
You don't need the teraspace storage model to use these...

In 7.1, IBM added the teraspace storage model to RPG.  The storage model 
controls the memory used for automatic, static, and constant storage -- 
in other words, it has no impact on the stuff you allocate yourself from 
the heap!

IBM also added the ALLOC H-spec keyword in 7.1 that lets you control 
whether the ALLOC/REALLOC opcodes and %ALLOC/%REALLOC BIFs use teraspace 
or single-level storage.  However this has no impact on what happens 
when you call an API to allocate memory, it only affects the opcodes/bifs.

So if you want to use teraspace for heap storage, and you don't want to 
wait for 7.1, just call the teraspace routines.  Maybe even wrap them 
with a subprocedure, so you can switch your code between the various 
alternatives (CEE APIs, RPG opcodes, teraspace APIs, etc) without having 
to change the logic of your main program.


On 3/14/2011 2:17 AM, Schmidt, Mihael wrote:
> I got a program which uses dynamic storage (CEE APIs) to store some
> temporary data in memory. So far so good as everything is working
> fine and there is no current business case which makes my program
> exceeds the memory it can allocate. I am using the default heap.
>
> Now as I understand it IBM i 7.1 lets you compile RPG modules with
> teraspace as the storage model. Does that also mean that the CEE API
> uses memory from teraspace and does it mean that I can use 1TB with
> the same api and just a different compile setting (
> STGMDL(*TERASPACE) ) ? I have no chance to test this as we are on 6.1
> still.