Updating web content on the iseries
This was the original design feature of the System/38 (S/38) in the mid 1970s planning for future use of faster processors, memory and an expanded address space.
The operating system was rebranded as i5/OS to correspond with the introduction of POWER5 processors and the rebranding of the hardware to e Server i Series.User-mode programs contain both TIMI instructions and the machine instructions of the CPU, thus ensuring hardware independence.This is conceptually somewhat similar to the virtual machine architecture of programming environments such as Smalltalk, Java and . The key difference is that it is embedded so deeply into the AS/400's design as to make applications effectively binary-compatible across different processor families.For the 6.1 release, the operating system was again renamed to IBM i. Features include a RDBMS (DB2/400), a menu-driven interface, support for multiple users, block-oriented terminal support (IBM 5250), and printers.It supports security, communications, and web-based applications which can be executed inside the optional IBM Web Sphere Application Server or as PHP/My SQL applications inside a native port of the Apache web server.The TIMI instructions are stored within the final program object, in addition to the executable machine instructions.
This is how application objects compiled on one processor family (e.g., the original CISC AS/400 48-bit processors) could be moved to a new processor (e.g., Power PC 64-bit) without re-compilation.
For 64-bit Power PC processors, the virtual address resides in the rightmost 64 bits of a pointer while it was 48 bits in the S/38 and CISC AS/400.
The 64-bit address space references main memory and disk as a single address set which is the single-level storage concept.
One feature that has contributed to the longevity of the IBM System i platform is its high-level instruction set (called TIMI for "Technology Independent Machine Interface" by IBM), which allows application programs to take advantage of advances in hardware and software without recompilation.
TIMI is a virtual instruction set independent of the underlying machine instruction set of the CPU.
The original AS/400 CISC models used the same 48-bit address space as the S/38.