2. an E-type system must be
continually adapted or it becomes
progressively less satisfactory
as an E-type system evolves, its
complexity increases unless work is
done to maintain or reduce it
Lehman, Belady 1974
4. growth rate over that
Table 1 contains the
-installment authors
e products vary in
ality (for instance,
onance, oil explora-
ht management sys-
aracterized as safety
A Compound Annual Growth
Rate for Software
The last column of Table 1 states
the compound annual growth rate
(CAGR). CAGR is year-over-year
growth over some number of years. For
example, doubling in five years can be
explained by a CAGR of 1.15 (1.155 =
2.01). CAGR is often used in analysis
reports summarizing the expected fu-
ture growth of markets or revenue. The
CAGR of the six products listed fall
within a surprisingly small range. To be
clear, we didn’t cherry-pick these prod-
ucts based on their CAGRs, nor will we
in the future. The CAGR ranged from
1.11 to 1.29 for the six products listed.
growing.
6. A
lthough many firms have rapidly and
enthusiastically adopted distributed
architectures, many more are stuck
with mainframe-based mission-critical
systems that continue to isolate them from their
partner, supplier, and customer systems. Indeed,
IDC estimates there are more than 10,000 large
IBM mainframe sites worldwide with 200 billion
lines of legacy code still in use.
Most companies want to transform their appli-
cations to meet new business
demands, but because legacy
systems tend to be unwieldy,
monolithic, and inflexible,
many firms regard modern-
ization assomewhere between
improbable and impossible.
Reeling from the Y2K deba-
cle and saddled with years of
NOT A TR
But this
which is w
business a
everything
uted hete
encapsula
ness. The c
captured b
tem fit into
architectur
RescueW
from Rela
knowledge
nents.The
of objects t
have clear
faces (API
industry-st
rting a
ithic legacy
to stand-alone
nents can turn
urce of business
7. an E-type system must be
continually adapted or it becomes
progressively less satisfactory
as an E-type system evolves, its
complexity increases unless work is
done to maintain or reduce it
Lehman, Belady 1974