ch04.htm

this describes managing multivendor networks

for the different 5250 models might not contain all 24 CF keys.</P>
<P>Like the hosting computers, the two families of terminals are oriented toward
their respective markets. The 3270 is a more generalized workstation, suitable for
a wide variety of applications. The 5250, on the other hand, is tailored for the
menu orientation of the midrange systems and is better suited for general business
applications (although the issue is certainly arguable).</P>
<P>Some fundamental operational differences between the 5250 family and the 3270
family are the following:

<UL>
	<LI>In certain configurations, the 5250 has special capabilities that work with midrange
	software to perform such advanced word processing functions as word wrap and dual
	cursor operations. This feature is most notable under the AS/400 Office system.<BR>
	<BR>
	
	<LI>The 5250 has three special field operation keys:<BR>
	<BR>
	
	<UL>
		<LI>The field exit key clears the contents of an alphanumeric field to the right
		of the cursor and then advances to the next field.<BR>
		<BR>
		
		<LI>The field + and field exit keys are used to right-justify numbers in a numeric
		field, adding the appropriate sign (blank for positive or &quot;-&quot; for negative)
		at the right side of the number.<BR>
		<BR>
		
	</UL>
	<LI>The 5250 supports roll-up and roll-down keys that enable the terminal to scroll
	through multipage screens offered by the host.
</UL>

<P>The first position of a 5250 display (line 1, column 1) is reserved in most operations.</P>
<P>Most of these differences are minor, and simply serve to illustrate how each line
of terminal is oriented toward a specific host line (mainframe or midrange). To a
certain extent, this is one of the most unique features of the IBM terminal line--IBM
is one of the few full-line manufacturers that does not offer a single line of terminals
applicable across the entire computer line (like DEC's VT offerings or HP's terminal
line).
<H3><A NAME="Heading5"></A><FONT COLOR="#000077">Personal Computers</FONT></H3>
<P>Having stayed out the personal computer market for so long, when IBM decided to
jump, it decided to go in headfirst--and in a real hurry. Certainly its product,
the Personal Computer (PC), was no technological powerhouse.</P>
<P>Before IBM's entry in 1981, the personal computer market was loaded with products
from every manufacturer even remotely involved with electronics. Virtually every
watchmaker, TV manufacturer, or major chip vendor had a product offering in this
area. Most of these forgettable products used the CP/M operating system, and those
that did not favored proprietary operating systems that have not seen the light of
day since. The industry sadly lacked microcomputer standards.</P>
<P>Rumor has it that when IBM went shopping for an operating system, it first turned
to Digital Research. Digital Research, however, was sitting happily on what it believed
to be the top of the microcomputer heap, so it did not agree to the terms IBM offered.
Much to its surprise, IBM then went to Bill Gates at Microsoft Corporation. Mr. Gates,
in turn, went out and purchased ownership of another company's operating system.
Thus, PC-DOS--and MS-DOS--was born.</P>
<P>The IBM PC included up to 640K (kilobytes) of memory, which was ten times the
memory offered by most of the 64K CP/M machines. For storage, it featured a 5.25-inch
floppy disk drive and the inevitable interface to a cassette tape recorder. To hurry
the product to the market, IBM even turned to the Far East to supply some of the
components. To increase the availability of applications, IBM appealed to key software
companies to develop or port their products to the IBM PC.</P>
<P>IBM followed up on its original PC design with the PC/XT (Extended Technology)
in 1983. The PC/XT introduced some relatively minor design changes in the original
PC board but served to bring hard disk technology to the PC through the inclusion
of a full-height (but slow at 85 ms) 10M hard disk drive. In the same year IBM released
the scaled-down version of its the PC, called the PCjr.</P>
<P>In 1984, IBM released the IBM PC/AT (Advanced Technology). While the changes between
the original PC and PC/XT were relatively small, the changes between the PC/XT and
PC/AT were relatively large. First and foremost, the IBM PC/AT used the Intel 80286
processor instead of the PC/XT's 8088 processor. Second, the input/output bus (used
for such option boards as the display adapter and disk controller) was improved to
contain both 8-bit and 16-bit slots (the PC and PC/XT contained only 8-bit slots).</P>
<P>By 1987, the PC market had grown to unbelievable proportions, and IBM was quickly
losing market share. IBM's market was being eroded by American manufacturers such
as Compaq Computer Corp. and AT&amp;T; by a massive number of off-shore (Taiwanese
and Korean) manufacturers marketing through large companies, such as Leading Edge
Hardware Products Inc.; and by small, garage-type operations. IBM sought to retrench
its position by redesigning the architecture of the PCs, using a closed architecture
that would force other manufacturers to sign license agreements with IBM if they
wanted to use the same technology.</P>
<P>The result of IBM's research was announced in 1987 as the Micro Channel Architecture
of IBM's Personal System/2 (PS/2) line--the replacement to the PC line. Shortly after
the announcement of the PS/2 series, IBM discontinued the PC/XT and PC/AT models.
Despite this discontinuation, the ISA Bus, (based on the AT bus) is still the most
common PC bus design. The Micro Channel Architecture offers many advantages over
the ISA Bus design. It provides for a large channel bandwidth, and includes an arbitration
mechanism to prevent a single adapter from taking over the system. Other features
of the Micro Channel Architecture include automatic configuration and a streaming
technique that allows an address line to be used as an additional data line, effectively
doubling channel throughput.</P>
<P>In addition to the change in hardware architecture, the PS/2 also served as the
launching platform for a new multitasking operating system, Operating System/2 (OS/2).
Despite the announcement of OS/2, however, IBM has continued to offer the popular
PC-DOS operating system. In fact, when IBM introduced the PS/1 home computer in 1990,
PC-DOS was the only operating system option.</P>
<P>There are two families of PCs now offered by IBM--the 300 and the 700 family.
The high-end systems have a Pentium or Pentium Pro processor, PCI busmaster device
controller, 6X CD-ROM, and 4M of Video memory. Networkable with optional Ethernet
and Token Ring cards, the 700 provides networking and communications features and
enhanced graphics.
<H3><A NAME="Heading6"></A><FONT COLOR="#000077">Engineering Workstations</FONT></H3>
<P>Engineering workstations are the weakest area of the IBM product line. IBM's initial
RISC-based offering, the RT-System, was introduced in 1986 in the wake of IBM's sweeping
success in the PC market. To a certain extent, IBM was hoping that the RT would ride
on the coattails of the PC and become a success by association. The RT's alignment
with the PC family is evident in its capability to use PC/AT adapter cards. As with
many other engineering workstations, a co-processor option enables the RT to run
PC-DOS concurrently with its native operating system, AIX. Unfortunately, the RT-System
lacked sufficient innovation or price/performance advantage to rise to the top of
the heap, and it never became a commercial success.</P>
<P>The RT line used a RISC architecture. As noted, the entire line ran the AIX operating
system, IBM's version of UNIX. IBM's enhancements to AIX include support for up to
one terabyte (one trillion bytes) of virtual memory and up to 16M of real memory.
IBM has also addressed connectivity of the RT to other systems by including the SNA
Logical Unit 6.2 (LU 6.2) interface and support for both IBM Token Ring and TCP/IP
over Ethernet.</P>
<P>In early 1990, IBM totally revamped its engineering workstation line with the
introduction of the RISC System/6000 (RS/6000) family of workstations and servers.
Modern developments in RISC technology enabled the RS/6000 line to offer a dramatic
performance increase over the older RT technology. The RS/6000 family runs the AIX
operating system and is divided into two lines: Powerstation and Powerserver models.
Powerstation models are targeted at individual workstation users, while the Powerserver
models are intended to serve multiple users.


<BLOCKQUOTE>
	<P>
<HR>
<FONT COLOR="#000077"><B>The Future of the RS/6000</B></FONT><BR>
	New offerings in the RS/6000 line include a PowerPC-based workgroup and Internet
	server, and the introduction of multiple operating system options. Other new announcements
	include a multimedia software offering, which delivers multiple audio and video streams
	from the RS/6000 server to a variety of desktop clients over LANs and internetworks.
	IBM is also planning to incorporate Sun Microsystems' Java technology with the AIX
	operating system, so Java applets can be sent to clients across the corporate intranet
	or the public Internet. Another new feature will provide access to tape devices,
	and consolidate tape operations across a network of RS/6000 workstations. This creates
	a pool of tape resources, and facilitates centralized tape management. 
<HR>


</BLOCKQUOTE>

<P>The RS/6000 family runs from low-end ThinkPads, to workstations, to the high-end
symmetric multiprocessor and parallel processing computers (all running the same
version of AIX), making it one of the most scalable lines of RISC-based systems available.
The RS/6000 supports multiple operating systems, including IBM AIX, Windows NT, and
SunSoft Solaris. At the high end, the RS/6000 can function as an application or data
server, and can be optimized for transaction-oriented applications; or for graphics-intensive
workstation usage such as CAD or scientific visualization. It may also be applied
to OnLine Transaction Processing (OLTP) applications, which process transactions
in real time as they are received by the system.
<H3><A NAME="Heading7"></A><FONT COLOR="#000077">Midrange Offerings</FONT></H3>
<P>If you liked the television series M*A*S*H, then you'll love the AS/400--or so
thought IBM when they used Alan Alda in prime-time commercials and high-visibility
print ads as they brought the AS/400 to market. The early and overt commercialization
of the AS/400 shows clearly that IBM is targeting the product toward the general
business community. The emphasis is on multi-user business solutions and upward growth
(or the perception of it, anyway).</P>
<P>Understanding this orientation is significant when you evaluate IBM's midrange
offerings against Digital's and HP's. While HP and Digital offer products focused
toward the technical environment, IBM offers products focused on the business environment.
Given the scale of these types of systems, it is not at all unusual to find an IBM
midrange processor in the front office and a DEC VAX in the lab, even in smaller
businesses. Of course, the coexistence of VAX computers with IBM mainframes is commonplace
in larger businesses.</P>
<P>In those dinosaur days before the AS/400, IBM offered two lines of midrange systems--the
System/36 and the System/38. The System/36 ran an operating system called System
Support Program (SSP) that featured, among other things, a menu-driven user interface
that was simple and straightforward to use. Additionally, the System/36 featured
connectivity options specifically geared toward the integration of PC networks with
the System/36.</P>
<P>The System/38, on the other hand, was more upscale. It ran the Control Program
Facility (CPF) operating system, which featured an extensive programming environment
and an integrated relational database. The System/38 was geared for connectivity
to mainframe systems.</P>
<P>All things considered, the two offerings were very similar in many categories,
but not similar enough overall. For example, although IBM offered migration provisions
to facilitate a move from a System/36 to a System/38, this migration was just painful
enough to be avoided. To make the jump, you had to modify and recompile programs;
and worse, the two systems' databases were not totally compatible. These differences
formed a chasm wide enough to keep both product lines on the market simultaneously
(much to IBM's chagrin).</P>
<P>The AS/400 was created to provide easy migration for all midrange users. The AS/400
borrowed more from the System/38 design than it did from the System/36, although
many areas (like connectivity) are supersets of both capabilities. In a nutshell,
the AS/400 combines the easy-to-use menu-orientation of the System/36 with the programming
and database environment of the System/38.</P>
<P>Programs from the System/38 can run as is on the AS/400 (again attesting to the
closeness between the AS/400 and System/38). IBM implemented improved migration aides
for the operating system, OS/400, to enable System/36 programs to move to the AS/400
but, at a minimum, the programs have to be recompiled (and in some cases, rewritten)
first. To further garner support for the AS/400, IBM offered third-party software
developers AS/400 access and technical assistance to move their programs to the AS/400
before its official release. As a result of this effort, the 1988 AS/400 announcement
included support for thousands of ready-to-run business applications.</P>
<P>The new AS/400 Advanced 36 (See Figure 4.1) offers a gradual migration path for
S/36 users by enabling up to three System/36 configurations to run with an AS/400.
Under this configuration, System/36 users can use their existing applications while