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Client/Server Systems Development
Software
An Index Group survey found that up to 90 percent of information
technology (IT) departments' budgets are spent maintaining and enhancing
existing systems.
1: This maintenance and enhancement continues to be done
using old, inefficient, and undisciplined processes and technology. As the
number of installed systems increases, organizations find more of their efforts
being invested in maintenance. Ed Yourdon claims that the worldwide software
asset base is in excess of 150 billion lines of code. Most of this code was
developed in the 1960s and 1970s with older technologies. Thus, this code is
unstructured and undocumented, leading to what the Gartner Group is calling the
"Maintenance Crisis." We simply must find more effective ways to
maintain systems.
Business Process Reengineering (BPR) techniques help organizations achieve
competitive advantage through substantive improvements in quality, customer
service and costs. BPR must be aligned with technology strategy to be effective.
Organizations must use technology to enable the business change defined by the
BPR effort. In too many organizations technology is inhibiting change. Many CIOs
are finding that their careers are much shortened when they discover that the
business strategy identified by their organization cannot be realized because
the technical architecture employed lacks the openness to support the change.
Senior executives look for new applications of technology to achieve business
benefit. New applications must be built, installed, and made operational to
achieve the benefits. Expenses incurred in maintenance and enhancement are not
perceived to produce value. Yet, most measurements show that 66 percent of the
cost of a system is incurred after its initial production release during the
maintenance and enhancement phases. In this period of tight budgets it is
increasingly difficult to explain and justify the massive ongoing investment in
maintenance of systems that do not meet the current need.
Our challenge is to change the expenditures from ongoing maintenance to new
development. Buying off-the-shelf application solutions frequently will meet the
need. However, unless the packaged solution perfectly matches the needs of the
organization, additional and expensive maintenance will be required to modify
the package to make it fit.
Clearly, the solution is to design and build systems within a systems
development environment (SDE). Applications and systems within an SDE are built
to be maintained and enhanced. The flexibility to accept enhancements is
inherent in the design. A methodology defines the process to complete a
function. The use of a systems integration life cycle methodology ensures that
the process considers the ramifications of all decisions made from business
problem identification through and including maintenance and operation of the
resultant systems. The changes implied by BPR and the movement from
mainframe-centered development to client/server technology requires that you
adopt a methodology that considers organizational transformation.
Object-oriented technologies (OOTs) can now be used to define the necessary
methodology and development environment to dramatically improve our ability to
use technology effectively.
With effective use of Object Oriented Technologies productivity improvements of
10:1 are being measured. Systems are being built with error rates that are
one-third that of traditionally developed systems. The creation and reuse of
objects supports the enterprise on the desk through the reuse of standard
technology to support the user and developer. Object Oriented Technology allows
business specialists to work as developers assembling applications by reusing
objects previously constructed by more technical developers.
Hardware
As I mentioned ," the cost of powerful hardware for
client/server computing has declined dramatically in the last few years.
Nevertheless, this power must be packaged properly, and cost still must be
considered in the design and purchasing decision. Hardware that provides the
client/server, LAN-to-LAN, and LAN-to-WAN connectivity must be acquired for
clients, servers, data storage, and the networks.
Entry-level client workstations can range from a basic Intel-based PC to an
entry-level Apple Macintosh or an X-Terminal. These entry-level clients start at
about $1,000 and use LAN servers for printing, backup, software storage,
application execution, and WAN connectivity. High-end client workstations can
cost more than $50,000 for engineering stations that provide advanced
capabilities such as a gigabytes or more of local storage, high-resolution
graphics monitors, 100-MIPS processing, direct WAN connectivity, 1000-dpi color
printing, or professional multimedia development tools. The average client
workstation has dropped from $5000 to $2000 in the last years.
Server hardware offers the largest and most complex set of choices. Servers run
the gamut from a $30M+ traditional IBM mainframe, to a 4- to 16-way symmetric
segment multiprocessor machine, to a 32- to 32767-processor massively parallel
cluster supporting hundreds of users, to a $5,000 PC used to provide file and
connectivity services for a small LAN workgroup. Many organizations also have
client/server applications that use the services of existing IBM 370 mainframes
running VM, MVS, or VSE, DEC VAX minicomputers running VMS or Ultrix, and large
RISC-based systems running UNIX—all as high-end servers.
Other mainframe and minicomputer hardware platforms, running proprietary
operating systems, are frequently used in terminal emulation mode from the
client workstation. The non-IBM and DEC proprietary operating system platforms
rarely are used to provide other services, such as database and RPC-invoked
application services. There is a lack of tools available in these environments
to build or buy client/server applications. Servers based on the IBM, DEC, and
UNIX operating systems will provide application services using existing
applications through terminal emulation or RPC-invoked application services.
These same servers will provide connectivity and database services to the first
client/server applications in an organization.
Connectivity requires every client workstation to be connected to a LAN or
through a WAN to a remote server. In the usual situation, the workstation is
connected through an Ethernet, Token Ring, FDDI, CDDI, or occasionally a
parallel or serial interface to the LAN. The primary connection types require a
network interface card (NIC) to be inserted in the workstation to provide the
protocol processing necessary to establish and maintain the connection. The cost
of LAN connectivity has declined rapidly in parallel with the industry reduction
in workstation costs.
Cabling costs vary widely, depending on the physical difficulty of installation
and whether the network planners choose unshielded twisted-pair (UTP), shielded
twisted-pair (STP), or glass-fiber cables. Cable costs without installation run
from $1 per foot for UTP, $1.50 per foot for STP, to $3 per foot for glass
fiber. Installation costs vary from $1 per foot to $15 per foot, depending on
the physical environment and connection requirements. Glass-fiber termination
equipment is more costly than twisted-pair, although the costs are declining.
Current costs are between $100-200 for Ethernet, $300-500 for Token Ring,
$300-700 for CDDI, and $750-1250 for FDDI.
Today, many vendors provide the hardware for these connections. Each vendor
offers some advantages in terms of cost, performance, and reliability. Motorola
provides wireless Ethernet connectivity at lower speeds and higher costs than
wired connections. Wireless connections are an advantage in existing buildings
with no cable installed and with relatively low-speed communications
requirements.
WAN connectivity requires each workstation to be directly connected to the WAN
or to a communications server connected to the WAN. Most new LANs are installed
using communications servers. There are cost, performance, and especially
network management reasons for using a LAN communications server. A substantial
advantage accrues because there is no need to cable each workstation to the WAN.
Workstations that are individually connected to the WAN require an embedded
controller card for synchronous communications and either a modem or serial
connection for asynchronous communications. These typically operate at speeds of
2400-64000 bits per second (bps) through analog or digital modems. Each
workstation must have its own cable connecting it to the WAN controller.
Workstations connected to the WAN through a communications server share a
higher-speed connection, typically 14400 bps, 56000 bps, or 1.54 Mbps.
A major advantage of the communications server is its ability to multiplex a
high-speed communications line and provide bandwidth on demand to each client
workstation. Only the single LAN cable and LAN controller are needed to provide
workstation connectivity in the server implementation.
Data storage can be provided to a client from a local disk or through the file
services of the NOS. Local disk storage requires the workstation to have its own
disk devices. Server storage involves large shared server disks. In either case,
a backup capability must be provided. This can be done through local diskette or
tape devices or though a server tape, disk, or optical device.
Service and Support
Users of mainframe-based applications may grumble about
costs, response time, inflexibility, lack of user friendliness, bureaucracy, and
their particular piques in a specific environment. One thing they should not
complain about is data loss. Mainframe users expect that when a host transaction
completes, the data is reliably stored. Any subsequent application, system,
hardware, or power failure will not cause data loss. In some sites a fire,
flood, hurricane, or other natural disaster will cause minimal or no data loss.
Personal computer users historically have had different expectations. In the
past, if after an hour working on a spreadsheet the system hangs up, power
fails, or a virus reboots the machine, users certainly feel annoyed but not
really surprised.
Likewise, even with companies that have moved beyond single-user PC applications
and have embraced networking, users historically have been more tolerant of less
rigorous standards. For example, Forester Research projects that the costs to
manage distributed networks of PCs and servers will be 10 to 30 percent more
than to manage minicomputers and mainframes. Other studies have claimed costs
are double. This higher cost is the case when LANs evolve and applications are
built without an architectural view and without appropriate standards to support
the design.
With the movement to client/server computing, demand for mainframe-like
performance from client/server architectures increases. If firms are going to
move the business of the corporation into the client/server world,
mainframe-like expectations will prevail and mainframe-like support must be
provided.
Recent experience with remotely-managed LAN applications is demonstrating that
costs are equal to or less than costs for traditional mainframe applications.
Effective remote management requires systems and application architectures that
anticipate the requirement for remote management.
Training
What trips up IS spending planners most when they initiate
rightsizing? "Training, training, and training," says Henry Leingang,
vice-president and CIO at Viacom Inc., the New York entertainment and
broadcasting firm.
"It is easy to overlook the training effort required
when organizations attempt to reengineer their business processes. Managers
become accustomed to people doing their jobs in a certain way and overlook the
effort that has been expended to get them to that level of competence.
Reengineering means change—change that is fundamental and not transparent.
Change requires people to be learning to work effectively within the changed
environment. Continuous change means that a continuous program of learning must
be in place to allow people to work effectively."
Client/server computing provides an opportunity to reengineer the business
process by using technology earlier and in a more integrated manner. It does not
eliminate the need to train for the new process.
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