Re: Explaining single level store to non i people

[Steve Richter <stephenrichter@xxxxxxxxx>]

I am not sure. I dont know enough about the memory mapping APIs in IBM
i, Unix and Windows. It does raise a larger question in my mind, which
is, if all operating systems can map memory to stream files, what is
special about SLS?

-Steve


On Thu, Aug 13, 2009 at 9:02 PM, Mark S.
Waterbury<mark.s.waterbury@xxxxxxx> wrote:
> Hi, Steve:
>
> We already have the ability in OS/400 to use the UNIX mmap() API to map
> any streamfile into teraspace. You can use mmap64()  to map files larger
> than 4GB into teraspace. This has been available almost since Teraspace
> was first introduced (around V4R4).
>
> Using this approach, you can directly address the contents of
> streamfiles via pointers.  Is this not what you are asking for? :-o
>
> Mark S. Waterbury
>
>  > Steve Richter wrote:
> > when explaining SLS to those on another platform, keep in mind r that
> > you have to be prepared to make the case of how SLS is better than a
> > traditional system. In SLS you have the same way of addressing bytes
> > in a permanent user space as in program allocated memory. However,
> > there is the 16 meg segment size limit which complicates the work of
> > coding for spaces. We have teraspace, but teraspace can only be used
> > only for progam allocated memory.
> >
> > Consider the improvements which could be made to SLS.  Without the
> > segment limit, stream files could be addressed as an array of bytes.
> > No need for teraspace, since objects on the system could be the size
> > of all the dasd on the system. Program memory could be allocated from
> > permanent user space like objects, making it possible for the system
> > to store the complete program memory state of an abended job.
> --
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