Transcript Note 3
iSeries Note3 Technology independence • Technology independence change the underlying hardware architecture and add new functionality without disrupting customers. • Other manufacturers found ways to incorporate new functions and new hardware designs. Difference existing application programs cannot use these new capabilities. • Intel [1985] added 32-bit extensions to the original 16-bit architecture. – Any 16-bit application could still run on the new 32-bit chips, but it ran in a 16-bit mode that did not use any of the 32-bit extensions. • Intel [1997] made a significant change to the architecture when it added the multimedia extension (MMX). – Older applications could run on the new chips but just couldn't use MMX. • PC industry acceptable to require applications to be rewritten to use the newest hardware functionality iSeries architecture Application programs and OS/400 programs MI [a logical, not a physical, interface to the system] •MI architecture has two components – a set of instructions and the operands upon which those instructions act •bit and byte operands + data structures [Objects] •application program interfaces (APIs) Internal details are hidden Data Structure [encapsulation] Object •highly extendable new environments System Licensed Internal Code (SLIC) [Knowledge about the hardware characteristics] Conventional Machine Interface iSeries MI Note: There is no memory at the MI The System Licensed Internal Code [Kernel] • The iSeries' operating system OS/400 [MI] + SLIC Operating System Functional Split System-wide security is in OS/400, while the authorization to system resources is in the SLIC Technology-Independent Machine Interface Objects • how the iSeries uses objects . • iSeries is an object-based system [no inheritance] • This permits only iSeries servers to make technology advances in the hardware, such as storage, memory, and processor technology, while protecting end-users' investments in existing applications Object-based system Logical partitions and many operating systems iSeries is the universal server. • OS/400 • Linux • Unix, • Windows applications all run on iSeries servers. A single server may optionally be divided into several partitions, each of which receives a dedicated set of resources, including processor and memory. The primary partition must be OS/400, but the other partitions can run, as of this writing, different versions of OS/400 and Linux. Logical partitions and many operating systems (cont.) • Linux distributions, provided by several vendors, run in logical partition(s) of an iSeries server. • Windows applications run on an iSeries server on an optional plugin Intel processor. • Rather than run an instance of a Unix operating system, applications from AIX run inside an OS/400 job, completely and seamlessly integrated into OS/400. – This option is the OS/400 Portable Application Solution Environment (OS/400 PASE). PASE provides a very easy way to drop in, often unmodified, a Unix application on iSeries.