आईबीएम आई: Difference between revisions

IBM i (एकीकृत के लिए स्थायित्व i)<ref>{{cite web|url=https://www.itjungle.com/2020/05/13/where-is-ibm-i/|title=Where is IBM i?|author=Alex Woodie|date=2020-05-13|website=itjungle.com|access-date=2021-03-01}}</ref> IBM द्वारा IBM ऊर्जा प्रणाली के लिए विकसित एक [[ऑपरेटिंग सिस्टम|संचालन प्रणाली]] है।<ref>{{cite web |title=IBM i: A platform for innovators, by innovators |url=https://www.ibm.com/it-infrastructure/power/os/ibm-i-technologies |website=ibm.com |publisher=International Business Machines |access-date=22 September 2020}}</ref> यह मूल रूप से 1988 में OS/400 के रूप में विमोचित किया गया था, IBM AS/400 प्रणाली की पंक्ति के एकमात्र संचालन प्रणाली के रूप में, 2004 में इसका नाम परिवर्तित कर i5/OS कर दिया गया था, 2008 में द्वितीय बार IBM i का नाम परिवर्तित होने से पूर्व<ref name="steve-will-presentation">{{cite web|url=https://www.youtube.com/watch?v=k6W2LHjZqjo|title=IBM i in 2020: It's Not Just AS/400|website=youtube.com|publisher=HelpSystems|author1=Steve Will|author2=Tom Huntington|date=2020-07-16|access-date=2021-03-21}}</ref><ref name="i5os">{{cite web|url=https://www-01.ibm.com/common/ssi/cgi-bin/ssialias?subtype=ca&infotype=an&appname=iSource&supplier=897&letternum=ENUS204-084|title=IBM i5/OS V5R3 — the next generation of OS/400|date=2004-05-04|publisher=IBM|access-date=2021-02-24}}</ref> यह प्रणाली/38 [[Control Program Facility|CPF]] संचालन प्रणाली का विकास है,<ref name="fortress-rochester">{{cite book|title=Fortress Rochester: the Inside Story of the IBM iSeries|author=Frank G. Soltis|isbn=978-1583040836|year=2001|publisher=System iNetwork|url=https://books.google.com/books?id=ypJmzqt7JdUC}}</ref>प्रणाली/36 [[सिस्टम सपोर्ट प्रोग्राम|SSP]] और [[IBM AIX]] अनुप्रयोगों के लिए अनुकूलता परतों के साथ<ref name="fortress-rochester" />यह प्रणाली/38 प्लेटफॉर्म से अनेक विशिष्ट विशेषताओं को प्राप्त करता है, जिसमें यंत्र अंतरपृष्‍ठ, नेटवर्किंग

IBM i सांपत्तिक IBM [[सिस्टम नेटवर्क आर्किटेक्चर|प्रणाली नेटवर्क शिल्प ज्ञान]] के अतिरिक्त TCP/IP नेटवर्क संचालन  का समर्थन करता है।<ref>{{cite web |title=TCP/IP |url=https://www.ibm.com/support/knowledgecenter/en/ssw_ibm_i_74/rzai2/rzai2kickoff.htm |website=IBM |access-date=13 May 2020}}</ref>

IBM i प्रणाली को ऐतिहासिक रूप से अभिगम किया गया और [[IBM 5250]] टर्मिनलों के माध्यम से प्रबंधित किया गया, जो [[जुड़वां अक्षीय केबलिंग]] केबलिंग के साथ प्रणाली से जुड़े थे। समर्पित टर्मिनल हार्डवेयर की गिरावट के साथ, आधुनिक  IBM आई प्रणाली को सामान्यत: 5250 [[टर्मिनल एमुलेटर]] के माध्यम से अभिगम किया जाता है। IBM, IBM i के लिए दो टर्मिनल इम्यूलेटर उत्पाद प्रदान करता है:<ref>{{cite web |title=IBM I Access Client Solutions |url=https://www.ibm.com/support/pages/node/633795 |website=IBM |access-date=13 May 2020}}</ref>

इसके अतिरिक्त, IBM एक वेब-आधारित प्रबंधन कंसोल और प्रदर्शन विश्लेषण उत्पाद प्रदान करता है जिसका नाम IBM नेविगेटर i.<ref>{{cite web |title=IBM Navigator for i |url=https://www.ibm.com/support/pages/node/633937 |website=IBM |access-date=13 May 2020}}</ref>

== History[edit] ==

See also: IBM AS/400 § Silverlake

OS/400 was developed alongside the AS/400 hardware platform beginning in December 1985. Development began in the aftermath of the failure of the Fort Knox project, which left IBM without a competitive midrange system. During the Fort Knox project, a skunkworks project was started at Rochester by engineers, who succeeded in developing code which allowed System/36 applications to run on top of the System/38, and when Fort Knox was cancelled, this project evolved into an official project to replace both the System/36 and System/38 with a single new hardware and software platform. The project became known as ''Silverlake'' (named for Silver Lake in Rochester, Minnesota).

The operating system for Silverlake was codenamed ''XPF'' (Extended CPF), and had originally begun as a port of CPF to the Fort Knox hardware. In addition to adding support for System/36 applications, some of the user interface and ease-of-use features from the System/36 were carried over to the new operating system.

Silverlake was available for field test in June 1988, and was officially announced in August of that year. By that point, it had been renamed to the ''Application System/400'', and the operating system had been named ''Operating System/400''.

See also: IBM AS/400 § The move to PowerPC

In 2006, IBM rebranded the AS/400 line one last time to ''System i''. In April 2008, IBM consolidated the System i with the System p platform to create IBM Power Systems. At the same time, i5/OS was renamed to ''IBM i'', in order to remove the association with POWER5 processors. The two most recent versions of the operating system at that time, which had been released as i5/OS V5R4 and V6R1, were renamed to IBM i 5.4 and 6.1.

Along with the rebranding to IBM i, IBM changed the versioning nomenclature for the operating system. Prior releases used a ''Version, Release, Modification'' scheme, e.g. V2R1M1. This was replaced with a ''Version.Release'' scheme, e.g. 6.1. Beginning with IBM i 7.1, IBM replaced the Modification releases with ''Technology Refreshes''. Technology Refreshes are delivered as optional PTFs for specific releases of the operating system which add new functionality or hardware support to the operating system.

== Architecture[edit] ==

When IBM i was first released as OS/400, it was split into two layers, the hardware-dependent ''System Licensed Internal Code'' (SLIC) and the hardware-independent ''Extended Control Program Facility'' (XPF). These are divided by a hardware abstraction layer called the ''Technology Independent Machine Interface'' (TIMI). Later versions of the operating system gained additional layers, including an AIX compatibility layer named ''Portable Application Solutions Environment'' (originally known as the ''Private Address Space Environment''), and the ''Advanced 36 Machine'' environment which ran System/36 SSP applications in emulation.

IBM often uses different names for the TIMI, SLIC and XPF in documentation and marketing materials, for example, the IBM i 7.4 documentation refers to them as the ''IBM i Machine Interface'', ''IBM i Licensed Internal Code'' and ''IBM i Operating System'' respectively.

The TIMI isolates users and applications from the underlying hardware. This isolation is more thorough than the hardware abstractions of other operating systems, and includes abstracting the instruction set architecture of the processor, the size of the address space and the specifics of I/O and persistence. This is accomplished through two interrelated mechanisms:

* Compilers for IBM i do not generate native machine code directly, instead they generate a high level intermediate representation defined by the TIMI. When a program is run, the operating system carries out ahead-of-time translation of the TIMI instructions into native machine code for the processor, and stores the generated machine code for future execution of the program. If the translation process changes, or a different CPU instruction set is adopted, the operating system can transparently regenerate the machine code from the TIMI instructions without needing to recompile from source code.

* Instead of operating on memory addresses, TIMI instructions operate on ''objects''. All data in IBM i, such as data files, source code, programs and regions of allocated memory, are encapsulated inside objects managed by the operating system (c.f. the "Everything is a file" model in Unix). IBM i objects have a fixed type, which defines the set of applicable operations which may be carried out on them (for example, a ''Program'' object can be executed, but cannot be edited). The object model hides whether data is stored in primary, or secondary storage. Instead, the operating system automatically handles the process of retrieving and then storing the changes to permanent storage.

The hardware isolation provided by the TIMI allowed IBM to replace the AS/400's 48-bit IMPI architecture with the 64-bit RS64 architecture in 1995. Applications compiled on systems using the IMPI instruction set could run on top of the newer RS64 systems without any code changes, recompilation or emulation, while also allowing those applications to avail of 64-bit addressing.

There are two different formats of TIMI instructions, known as the ''Original Machine Interface'' (OMI) and ''New Machine Interface'' (NMI) formats. OMI instructions are essentially the same as the System/38 Machine interface instructions, whereas NMI instructions are lower-level, resembling the ''W-code'' intermediate representation format used by IBM's compilers. IBM partially documents the OMI instructions, whereas the NMI instructions are not officially documented. OMI instructions are used by the original AS/400 compilers, whereas NMI instructions are used by the Integrated Language Environment compilers. During the PowerPC port, native support for the OMI format was removed, and replaced with a translator which converted OMI instructions into NMI instructions.

The storing of the TIMI instructions alongside the native machine code instructions is known as ''observability''. In 2008, the release of i5/OS V6R1 (later known as IBM i 6.1) introduced a number of changes to the TIMI layer which caused problems for third-party software which removed observability from the application objects shipped to customers.

=== SLIC[edit] ===

The SLIC consists of the code which implements the TIMI on top of the IBM Power architecture. In addition to containing most of the functionality typically associated with an operating system kernel, it is responsible for translating TIMI instructions into machine code, and it also implements some high level functionality which is exposed through the TIMI, such as IBM i's integrated relational database. The SLIC implements IBM i's object-based storage model on top of a single-level store addressing scheme, which does not distinguish between primary and secondary storage, and instead manages all types of storage in a single virtual address space. The SLIC is primarily implemented in C++, and replaced the HLIC and VLIC layers used in versions of OS/400 prior to V3R6.

The XPF consists of the code which implements the hardware-independent components of the operating system, which are compiled into TIMI instructions. Components of the XPF include the user interface, the Control Language, data management and query utilities, development tools and system management utilities. The XPF also contains the ''System/36 Environment'' and ''System/38 Environment'', which provide backwards compatibility APIs and utilities for applications and data migrated from SSP and CPF systems. The XPF is IBM's internal name for this layer, and as the name suggests, began as an evolution of the System/38 Control Program Facility. The XPF is mostly implemented in PL/MI, although other languages are also used.

PASE (Portable Applications Solutions Environment) provides binary compatibility for user mode AIX executables which do not interact directly with the AIX kernel, and supports the 32-bit and 64-bit AIX Application Binary Interfaces. PASE was first included in a limited and undocumented form in the V4R3 release of OS/400 to support a port of Smalltalk. It was first announced to customers at the time of the V4R5 release, by which time it had gained significant additional functionality.

PASE consists of the AIX userspace running on top of a system call interface implemented by the SLIC. The system call interfaces allows interoperability between PASE and native IBM i applications, for example, PASE applications can access the integrated database, or call native IBM i applications, and vice versa. During the creation of PASE, a new type of single level storage object named a ''Teraspace'' was added to the operating system, which allows each PASE process to have a private 1TiB space which is addressed with 64-bit pointers. This was necessary since all IBM i jobs (i.e. processes) typically share the same address space. PASE applications do not use the hardware-independent TIMI instructions, and are instead compiled directly to Power machine code.

PASE is distinct from the Qshell environment, which is an implementation of a Unix shell and associated utilities built on top of IBM i's native POSIX-compatible APIs.

=== Advanced 36 Machine[edit] ===

Introduced in 1994, the Advanced/36 platform ran unmodified System/36 applications and the SSP operating system in emulation on top of the OS/400 SLIC using hardware which was mostly identical to that of contemporary AS/400 systems. This functionality was incorporated into OS/400 itself from V3R6 through V4R4, making it possible to run up to four System/36 "virtual machines" (to use IBM's term) using the so-called ''Advanced 36 Machine'' feature of the operating system. Support was discontinued in the V4R5 release, coinciding with IBM's discontinuation of the Advanced/36 product line as a whole. The Advanced 36 Machine feature is distinct from the System/36 Environment introduced in the initial OS/400 release and still supported in current IBM i versions.

Prior to the Advanced/36, the System/36 line used two different processors in each system - the Main Storage Processor (MSP) which ran most of the SSP operating system as well as user code, and the Control Storage Processor (CSP) which ran so-called "microcode" which implemented core operating system functionality as well as I/O. The CSP microcode was invoked from the MSP through the use of the Supervisor Call (SVC) instruction. On the Advanced/36, the CSP microcode was reimplemented inside the SLIC. An MSP emulator was also built into the SLIC, sometimes referred to as the ''Technology Independent Emulation Interface''. Even with the overhead of emulation, the Advanced/36 systems were significantly faster than the original System/36 systems they replaced due to the performance of their PowerPC AS processors.

=== Database management ===

IBM i features an integrated relational database currently known as IBM Db2 for IBM i. The database evolved from the non-relational System/38 database, gaining support for the relational model and SQL. The database originally had no name, instead it was described simply as "data base support". It was given the name ''DB2/400'' in 1994 to indicate comparable functionality to IBM's other commercial databases. Despite the Db2 branding, Db2 for IBM i is an entirely separate codebase to Db2 on other platforms, and is tightly integrated into the SLIC layer of IBM i as opposed to being an optional product.