Re: Paging file

Vernon posted this site,  I would recommend reading it.

>One of a number of webpages on porting to the 400 is thispage, giving an
>>verview of 400 architecture:

<http://www-919.ibm.com/developer/factory/porting/overview.html>


With Pretty pictures too

<SNIP>

The iSeries architecture specifies a single very, very large virtual
address space known as Single-Level Storage (SLS). All objects, programs,
files, users, data, working space, database tables... everything, resides
in this storage space. This storage space is addressed using 128-bit
pointers. It is divided into sections, including Temporary and Persistent.
This distinction refers to between re-boots. For examples, a user profile
is in Persistent, and a shared memory segment is in Temporary.

Because a single page table maps all virtual addresses to physical
addresses, task switching is very efficient. Further, most SLS addresses
contain a real address, eliminating the need for address translation, and
thus speeding up data access. Additionally, OS/400 automatically spans data
objects across all available disks arms, automatically improving the speed
of paging and persistent object retrieval. For database operations, this
eliminates the need for a database and/or systems administrator to perform
petty non-business tasks like managing data spaces.

You can think of all storage (various memory, disk, tape, etc) as
"currently available" ways to store data in the vast Single-Level-Storage.
Currently, magnetic disk technology and solid-state flash memory (aux
storage) are used to hold as much of the persistent SLS as possible, and
ECC memory (main storage) is used as temporary storage and as a cache for
disk storage. As new technologies, possibly bubble and holographic
memories, emerge from IBM Research, the iSeries architecture will enable
iSeries applications to exploit these with no modification.

Note: No other computing platform has such a powerful architecture as SLS.
It's patented. As simple as it sounds, it's also an immense effort to
effectively implement. SLS is a result of some of the most forward-thinking
ideas. In fact, the design, in development, was named "FS" for Future
System

<SNIP>