How to Write Programs That Will Last Forever
Future proofing your applications
Darren Self
25 October 2011
Space is big...
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Enterprise Application Facts - Size
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EA Facts – Scale of COBOL source
• Over 310 billion lines of code in use
• 1.5 million new lines written per day
• 200 times more transactions each day than Google
– 500 million cell phone connections per day
– 60 million patient records per day
– Up to 18,000 ATM transactions per minute in the UK alone
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EA Facts – Run the Business
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EA Facts – Diminishing Skills
• Original architects and programmers moved on
– Redundancy
– Retirement
• Hard to train skills
– Platform
– Corporate standards
• Often undocumented
– Ingrained knowledge
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EA Facts – Poor understanding
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What drives change?
• Technical
– Platforms/technology evolutions
• Web
• Mobile
• Cloud
– The Y2K problem
• Business priorities
– Mergers & acquisitions
– Emerging markets
• Legislative
– Sarbanes-Oxley
– FRS17
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Options for change
• Do nothing
– Stagnation
– High costs of maintenance
– Often not a viable option
• Buy off shelf
– Doesn’t always meet business needs
– 40% cancelled before going live
– Often require substantial tailoring/integration
• Rewrite
– High risk/cost
– 75% failure rate
• Reuse
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The risks
ERP Implementation Risk Factor
• Implementing new packages
takes years
– 42% either never delivered, or
more than 50% late
(source: Gartner Group)
– Package projects: years to
implement, canceled 35% of
the time & rarely fully deployed
42% never
delivered
or very late
(source: Standish Group)
• Most large AD projects never
deliver on promise
– 74% either fail, or are late and
over-budget
• Deactivating legacy systems
is almost impossible
Source: Gartner Group
Outright Project (Failure)
Exceeded estimate by over 50% (very late)
Exceeded initial estimate (late)
Package: 42% chance of failure or excessive delays
Re-write: 74% chance of failure or excessive delays
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Case Study – Hershey Foods
Magnitude of Failure
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Market Reaction
Sales fell 12% in qtr after
system went live, down 150.5
million from year before
3rd qtr profits dropped about
18.5%
Retailers and distributors forced
to order from rivals
Candy sat in warehouses on eve
of peak season
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Analysts estimated Hershey
could lose .5% market share
($65 million)
During a booming stock market,
Hershey shares ended the year
down 27% from the year high
“Retail sales lagged the industry’s growth rate as a result of
our shipping problems.”
Kenneth L. Wolfe, Chairman, Hershey Foods
Sources: USA Today, Dec. 7, 1999; CIO Magazine, June 1, 2000; Business Week Online, Sept. 2001;
www.thespot4sap.com; “Top 10 Corporate Information Technology Failures”; Hershey Foods 2000 Annual Report
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Hershey Foods – What happened?
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Candy sat in warehouses where previously it sat in shops
Issue caused by massive distribution problems following flawed
implementation of a $112 million package ERP system
Inaccurate inventory data (+ other problems) caused shipment delays,
incomplete orders during second half of 1999
Seriously affected shipments to stores in peak Halloween and preChristmas sales periods
After investing millions, things that used to worked stopped working,
resulting in financial catastrophe
Source: CIO Magazine, June 1, 2000;
“Top 10 Corporate Information Technology Failures”
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Case Study – UK Passport Agency
Magnitude of Failure
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Impact
$180 million on a new passport
system
Processing costs up by 30% per
passport
Additional staff hired to handle
the backlog
Compensation paid to thwarted
travellers
New law rushed in: free 2-year
passport extensions
•
•
•
Processing time increased 4
fold, from 10 days to 8 weeks
Over 1 million telephone calls
unanswered in 1 month alone
Lack of service forced travellers
to line up outside passport
offices demanding passports
“Senior government ministers were forced to make lengthy
explanations in the House of Commons... Home Secretary Jack Straw
promised to move ‘heaven and earth’ to get a passport to a woman for
her honeymoon.”
Source: CIO Magazine, Aug. 1, 2000
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UK Passport Agency – What happened?
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Passports which previously were being processed on time sat unprocessed
Cause was due to new system not being able to provide the throughput to
process passports in appropriate timescales
Backlog of unprocessed passports reached 538,000, 1000s of vacations
jeopardized
A PR nightmare -- thousands of angry travellers who lined up in rain
forced agency to purchase umbrellas
Officials prioritized people into “urgent”, “non-urgent” and “awfully urgent
indeed, old chap” categories
After investing millions, things that used to worked stopped working,
resulting in financial catastrophe
Source: CIO Magazine, Aug. 1, 2000
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Evolutions we’ve seen...
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User Interfaces
Platform Modernisation
Globalisation
Service Oriented Architecture
The Web
Mobile Access
The Cloud
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Case Study – History of the ATM
No screens
Limited functionality
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Case Study – History of the ATM
Buttons alongside the screen
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Case Study – History of the ATM
Touch screens & palm scanners
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Case Study – History of the ATM
What runs these systems?
Standard desktop OS’s
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Case Study - ATM Reasons for change
• Hardware
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Connectivity
Security
Robustness
Accessibility
• User expectations
– Real time access
– Full range of financial services
– Convenience
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Case Study – ATM UI Considerations
• User Interfaces change
• Back end services remain constant
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Modular
Extendable
Flexible
Robust
Secure
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Everlasting programs - 1
• Modular design
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Easier to extend
Well defined interfaces/contracts
Reusable
Flexible
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Everlasting programs - 2
• Quality
– Well documented
– Clean design
– Automated tests
• Unit
• Integration
• Graphical
– Processes
• Source control
• Build & delivery
• Continuous integration
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Everlasting programs - 3
• Maintainability
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Readable
Keep it simple
Don’t make assumptions
Design patterns
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Conclusions
• Enterprise Applications are important
– Underpin businesses
– Run the world!
• Software evolves
– Evaluate the options
– Beware the risks
• Design for re-use
– Maintainability
– Simplicity
– Modularity
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Essay Topic
Reflect on the challenges encountered and
strategies employed when long-lived Enterprise
Applications are exposed for re-use in new
environments such as the Cloud, the Web and
mobile devices.
You may want to consider such areas as
interfacing to the existing Enterprise Application,
accessing data, real-time and/or concurrent
access, testing strategies and usability.