Information about Iseries

The IBM System i (formerly known as iSeries, AS/400, and Application System/400) is a minicomputer platform produced by IBM. It was officially introduced as the AS/400 in 1988. It was then renamed to the eServer iSeries in 2000 as part of IBM's e-Server branding initiative. In 2006, the platform has once again been renamed to System i.

Market positioning

As the current midrange offering, the System i platform offers features intermediate between mainframe systems and PC-based servers.

Features

The IBM System i platform extended the System/38 architecture of an object-based system with an integrated DB2 database that was designed to implement E. F. Codd's relational database model, which is based on Codd's 12 rules, in the operating system and hardware. Equally important were the virtual machine and single-level storage concepts which established the platform as the most advanced business computer in the industry.

Instruction set

One feature that contributes 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; it is not the instruction set of the underlying CPU. 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 .NET. 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.

Note that, unlike some other virtual-machine architectures in which the virtual instructions are interpreted at runtime, TIMI instructions are never interpreted. They constitute an intermediate compile time step and are translated into the processor's instruction set as the final compilation step. 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. PowerPC 64-bit) without re-compilation. An application was saved from the older 48-bit platform and restored onto the new 64-bit platform where the operating system discarded the old machine instructions and re-translated the TIMI instructions into 64-bit instructions for the new processor.

The IBM System i's instruction set defines all pointers as 128-bit. This was an original design feature of the System/38 (S/38) in the mid 1970s. For PowerPC processors, the virtual address resides in the rightmost 64 bits of a pointer (48 bits in the S/38 and CISC AS/400), leaving room for addresses to be expanded past 64 bits in future processors. The 64-bit address space addresses all of main memory and disk (the single-level storage concept).

The original AS/400 CISC models used the same 48-bit address space as the S/38. This was expanded to 64-bits in 1995 when the PowerPC RISC 64-bit CPU processor replaced the 48-bit CISC processor.

Software

The IBM System i includes an extensive library-based operating system, I5/OS, and is also capable of supporting multiple instances of AIX, Linux, Lotus Domino, Microsoft Windows 2000 and Windows Server 2003. While I5/OS, AIX, Linux and Lotus Domino are supported on the POWER processors, Windows is supported with either single-processor internal blade servers (IXS) or externally-linked multiple-processor servers (IXA).

LPAR (Logical PARtitioning), a feature introduced from IBM's mainframe computers, facilitates running multiple operating systems simultaneously on one IBM System i unit. A system configured with LPAR can run various operating systems on separate partitions while ensuring that one OS cannot run over the memory or resources of another. Each LPAR is given a portion of system resources (memory, hard disk space, and CPU time) via a system of weights that determines where unused resources are allocated at any given time. The operating systems supported (and commonly used) under the LPAR scheme are I5/OS, AIX, Linux and Lotus Domino.

Other features include an integrated DB2 database management system, a menu-driven interface, multi-user support, non-programmable terminals (IBM 5250) and printers, security, communications, client-server and web-based applications. Much of the software necessary to run the IBM System i is included and integrated in to the base operating system.

The IBM System i also supports common client-server-based technologies such as ODBC and JDBC for accessing its database from client software such as Java, Microsoft .NET languages and others.

The IBM System i also provides an environment for AIX applications to run natively on I5/OS without the need for an AIX LPAR.

Programming

Programming languages available for the AS/400 include RPG, assembly language, C, C++, Pascal, Java, Perl, Smalltalk, COBOL, SQL, BASIC, PHP, PL/I, Python and REXX. Several CASE tools are available: AllFusion Plex (see *), Synon, AS/SET, LANSA, ProGen Plus, PHP from Zend Technologies.

The IBM System i fully supports the Java language, including a 32-bit JVM and a 64-bit JVM.

Commands in the Control Language (CL) are promptable using the F4, and most provide cursor-sensitive help to make specifying command parameters simpler.

Examples:

• CRTUSRPRF - Create (verb) user (modifier) profile (noun)
• DLTLIB - Delete (verb) library (noun)
• CPYF - Copy file
• WRKACTJOB - Work with Active Jobs
• WRKSYSSTS - Work with System Status

For traditional business programming languages such as RPG, COBOL, and C, the IBM System i provides an interface to the integrated database that allows these languages to treat database files much like other platforms treat ISAM or VSAM files. Support for 5250 display operations is provided via display files.

History

The IBM System i, then known as the AS/400, was the continuation of the System/38 database machine architecture (announced by IBM in October 1978 and delivered in August 1979). The AS/400 removed capability-based addressing.^[1] The AS/400 added source compatibility with the System/36 combining the two primary computers manufactured by the IBM Rochester plant. The System/36 was IBMs most successful mini-computer but the architecture had reached its limit. The first AS/400 systems (known by the development code names and Olympic) were delivered in 1988, and the product line has been refreshed continually since then. The programmers who worked on OS/400, the operating system of the AS/400, did not have a UNIX background. Dr Frank Soltis, the chief architect, says that this is the main difference between this and any other operating system.

The AS/400 was the first general-purpose computer system to attain a C2 security rating from the NSA, and in 1995 was extended to employ a 64-bit processor and operating system.

In 2000 IBM renamed the AS/400 to iSeries, as part of its e-Server branding initiative. The product line was further extended in 2004 with the introduction of the i5 servers, the first to use the IBM POWER5 processor. The architecture of the system allows for future implementation of 128-bit processors when they become available. Existing applications can use the new hardware without modification.

Although announced in 1988, the AS/400 remains IBM's most recent major architectural shift that was developed wholly internally. Since the arrival of Lou Gerstner in 1993, IBM has viewed such colossal internal developments as too risky. Instead, IBM now prefers to make key product strides through acquisition -- e.g. the takeovers of Lotus Software and Rational Software -- and to support the development of open standards, particularly Linux. It is noteworthy that after the departure of CEO John Akers in 1993, when IBM looked likely to be split up, Bill Gates commented that the only part of IBM that Microsoft would be interested in was the AS/400 division. (At the time, many of Microsoft's internal systems ran on the AS/400 platform) ^[2]

Hardware

The AS/400 was originally based on a custom IBM CISC CPU which used a CPU architecture known as Internal MicroProgrammed Interface (IMPI) and an instruction set similar to the IBM 370. It was later migrated to a POWER-based RISC CPU family eventually known as RS64.^[3]

CPU in AS/400, iSeries, i5

The System i5 uses IBM POWER CPUs. These CPUs are developed and manufactured by IBM. The POWER 4/5/5+ chips contain two cores. There are Multi-Chip Modules (MCM) available. They have 2 CPU (4 cores) or 4 CPUs (8 cores) in one MCM.

CPU	Year	Speed	Server-Model
Cobra (A10)	since 1995	55 or 75 MHz	Model: 4xx, 5xx
Muskie (A25/A30)	since 1995	125 or 154 MHz	Model: 53x
Apache (RS64) (A35)	since 1997	125 MHz	Model: 6xx, 150
NorthStar (RS64 II)	since 1998	200, 255 or 262 MHz	Model: 170, 250, 7xx, 650, S40, SB1[4]
Pulsar (RS64 III)	since 1999	450 MHz	Model: 270, 820
IStar	since 2000	400, 500, 540 or 600 MHz	Model: 820, 830, 840, SB2, SB3
SStar (RS64 IV)	since 2001	540, 600 or 750 MHz	Model: 270, 800, 810, 820, 830, 840
POWER4	since 2002	1.3 GHz	Model: 890
POWER4	since 2003	1.1 or 1.3 GHz	Model: 825, 870
POWER5	since 2005	1.5 or 1.65 GHz	Model: i5-520; i5-550; i5-570; i5-595
POWER5	since 2006	1.9 GHz	Model: i5-595
POWER5+	since 2006	1.9 GHz 2.2 GHz	Model: i5-520, i5-550 ,i5-515, i5-525 Model: i5-570
POWER6	since 2007	4.7 GHz	Model: i5-570

Models of AS/400, iSeries, i5 systems

Model	Year	CPU Group	Base - CPW
B10, B20, B30, B35, B40, B45, B50, B60, B70	1988, 1989	P10, P20	2,9 - 20
C04, C06, C10, C20, C25	1990	P10	3,1 - 6,1
D02, D04, D06, D10, D20, D25, D35, D45, D50, D60, D70, D80	1991	P10, P20, P30	3,8 - 56,6
E02, E04, E06, E10, E20, E25, E35, E45, E50, E60, E70, E80, E90, E95	1992	P10, P20, P30, P40	4,5 - 116,6
F02, F04, F06, F10, F20, F25, F35, F45, F50, F60, F70, F80, F90, F95, F97	1993	P05, P10, P20, P30, P40	5,5 - 177,4
P01, P02, P03	1993, 1994, 1995	P05	7,3 - 16,8
150	1996	P05	10,9 - 35,0
S10, S20, S30, S40	1997	P05, P10, P20, P30, P40, P50	45,4 - 4550
SB1, SB2, SB3	1997, 2000	P30, P40	1794 - 16500
10S, 100, 135, 140	1995, 1993	P05, P10, P20	17,1 - 65,6
170	1998	P05, P10, P20,	30 - 1090
200, 20S, 236	1994	P05, P10	7,3 - 17,1
250	2000	P05	50 - 75
270	2000	P05, P10, P20	50 - 2350
300, 30S, 310	1994	P10, P20, P30, P40	11,6 - 177,4
400, 40S, 436	1995	P05, P10	13,8 - 91,0
500, 50S, 510, 530, 53S	1995	P10, P20, P30, P40	18,7 - 650
600, 620, 640, 650	1997	P05, P10, P20, P30, P40, P50	22,7 - 4550
720	1999	P10, P20, P30	240 - 1600
730	1999	P20, P30, P40	560 - 2890
740	1999	P40, P50	3660 - 4550
800	2003	P05, P10	300 - 950
810	2003	P10, P20	750 - 2700
820	2000, 2001	P05, P10, P20, P30, P40	100 - 3700
825	2003	P30	3600 - 6600
830	2000, 2002	P20, P30, P40, P50	1850 - 7350
840	2000,2001,2002	P40, P50	10000 - 20200
870	2002	P40, P50	7700 - 20000
890	2002	P50, P60	20000 - 37400
520	2004 - 2006	P05, P10, P20	500 - 7100
550	2004 - 2006	P20	3300 - 14000
570	2004 - 2006	P30, P40	3300 - 58500
595	2004 - 2006	P50, P60	24500 - 184000
515	2007	P05	3800 - 7100
525	2007	P10	3800 - 7100
570	2007	P30	5500 - 76900

See also

• AS/400 Control Language
• AS/400 Libraries
• AS/400 object
• i5/OS
• IBM 5250
• IPDS

References

External links

• IBM's System i homepage
• System iPortal
• System iNetwork
• iseries forum
• at
• midrange.com -- free online resources for System i / iSeries / AS400 users