RE: Experimental Wiki at midrange.com -- MIDRANGE-NONTECH

Wikipedia.org has been on my radar screen for the last couple of years.  I
have noticed two things.
 1) Wikipedia.org is an encyclopedia with a wealth of information on
Information Technology.  For example:
 -  International Business Machines     http://en.wikipedia.org/wiki/IBM
 -  iSeries                                             
http://en.wikipedia.org/wiki/Iseries  (quoted at bottom of
this message)

The wikipedia article on "iSeries" has more than 50 links to other wikipedia
articles.  These 50+ links help the reader understand the iSeries.

There are many thousands of definitions and articles on iSeries topics at
wikipedia.org already.
Take a look, everyone.
EricL 013-638-1049
====================================
The Application System/400 (AS/400) is an IBM minicomputer for general
business and departmental use, introduced in 1988 and still in production
under the names iSeries and i5. The AS/400 is an object based system with an
integrated database that was designed to implement E. F. Codd's relational
database model in the operating system and hardware. All software necessary
to run this computer is included and integrated. More than 2,500 business
software applications were available when the first AS/400 was delivered in
1988.

The AS/400 was the follow-on to the System/38 database machine, announced by
IBM in 1978 and delivered in 1980. The first AS/400 systems (known by the
development code names Silverlake and Olympic) were delivered in 1988, and
the product line has been refreshed continually since then. IBM renamed the
AS/400 to iSeries in 2000, as part of its e-Server branding intiative. The
product line was further extended in 2004 with the introduction of the i5
servers, the first to utilize the IBM POWER5 processor. The AS/400 was the
first general purpose computer system to attain a C2 security rating from
the NSA, and in 1995 was first to employ a 64-bit processor and operating
system. The architecture of the system allows for future implementation of
128-bit processors when they become available. Existing programs will
utilize the new hardware without modification.

Features include an extremely fast DBMS, a menu-driven interface, multi-user
support, terminals (IBM 5250) and printers, security, communications and an
extensive library-based operating system, OS/400. The big selling point is
that applications can run without modification on any model in the product
line, from small, single processor machines up to those with 64 multi-core
CPUs.

The machine was originally based on a custom IBM CISC CPU which used a CPU
architecture known as Internal MicroProgrammed Interface (IMPI). It was
later migrated to a PowerPC based RISC CPU family eventually known as RS64.
The latest models are based on the POWER5 (announced 4 May 2004) processor.

The machine survives because its ISA (called TIMI for "Technology
Independent Machine Interface" by IBM) allows the operating system and
application programs to take advantage of advances in hardware and software
without recompilation. This means that a program written and compiled on a
S/38 can be run as a native 64 bit program. The HAL allows a system that
costs $9000 to run the exact same operating system and software as a $2
million system. The system can concurrently run multiple operating systems
(i5/OS (OS/400), Linux, AIX) natively, and runs Windows Server and Linux on
one or more single cpu blade servers or externally attached mutiple cpu
servers when installed. The 64-bit design provides for the seamless
addressing of up to 16 exabytes (16 million terabytes) of storage.

The AS/400 enforces the use of the TIMI virtual instruction set for all user
mode programs; it is not possible for such programs to utilise the
instruction set of the underlying 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 all applications and even the bulk of its operating systems
binary-compatible across different processor families. The AS/400's
instruction set defines all pointers as 128-bit to allow seamless transition
from older to new processor generations.

Another feature that was recently introduced to the AS/400, LPAR, came from
IBM's mainframe line of computers. LPAR (Logical PARtitioning) facilitates
running multiple instances of operating systems simultaneously on one AS/400
unit. A system setup with LPAR can even run different operating systems on
different 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 OSes
supported (and commonly used) under the LPAR scheme are OS/400, AIX and
Linux.

Even though AIX can now be natively run in a LPAR partition, the original
implemenation was to allow AIX programs to be ported to the PASE
environment. AIX programs ARE binary compatible with OS/400 when using
OS/400's PASE (Portable Applications System Environment). PASE is
essentially "an operating system within an operating system", supporting the
most recent stable version of AIX. Binaries need to be re-compiled on the
AIX system, with 16-bit (quadword) pointer alignment enabled. Once the
program is compiled with this option, the executable can be FTP-ed to the
AS/400, and executed under the PASE Korn Shell.

Additionally, tasks such as handling record locks and queuing updates are
managed automatically by the system, making high-speed, multiuser
applications easy to create, maintain, and extremely reliable.

Programming languages available for this machine include RPG, assembly
language, C, C++, Java, COBOL, SQL, BASIC, PHP, PL/I, and REXX. Several CASE
tools are available: Synon, AS/SET, and Lansa.

Commands in the Command Language (CL) are promptable and most provide cursor
sensitive help to make entering parameters easier. A command consists of a
three letter verb and a subject part. This is intended to make it easy to
understand CL code. Examples:

    * CRTUSRPRF - Create user profile
    * DLTLIB - Delete library
    * CPYF - Copy file

It was designed as the successor of the IBM System/38 and the IBM System/36.
The programmers that worked on OS/400, the operating system of the AS/400,
did not have a UNIX background. Dr. Frank Soltis, the head architect, says
that this is the main difference between this and any other operating
system.

Despite the lack of "UNIXy" background, the AS/400 has over the years,
picked up the programming/runtime model found on UNIX, Linux, and PC
systems. Traditional AS/400 programming is a "one-stop shop", where a
programmer writes computer code, compiles the code, and then executes the
code. There is no link step that is found in other environments.

However, in 1995, that changed. IBM re-christened the one-stop shop
programming style "OPM" (for Original Programming Model) and introduced a
new language paradigm called "ILE" (for Integrated Language Environment).
ILE had significant enhancements over OPM, including the ability to create
modules (similar to .obj or .lib files), and then bind (link) the modules
together into a single executable. The executable could be created as a
program or a service program (service programs are similar to .lib or .dll
files).

The real power of the ILE environment is in the "integrated" aspect,
however. Modules in ILE-compliant languages (RPG, COBOL, C, C++, and CL)
could be created and bound together. For the first time, AS/400 programmers
could exploit the strengths of each ILE-compliant language and create
programs. Also, with the introduction of service programs, standard routines
could be externalized more easily, and increase modularity. To ensure proper
migration to the ILE environment, OPM RPG and COBOL programs could be
migrated to ILE easily.

Interoperation with the Java language is also supported, though not as
tightly as to the ILE languages. The iSeries Java implementation is
distinguished by the depth of its embedment in the operating system.
[edit]

See also

    * AS/400 Command Language
    * AS/400 Libraries
    * AS/400 object
    * OS/400
    * IBM 5250
    * iSeries Architecture