When to Migrate

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When to Migrate

• What Issues Drive Developers to Migrate to a New
  Host, Target, Tool, or Language?

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• David Mosley
• Senior Software Engineer
• DDC-I, Inc.
• dmosley_at_ddci.com

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Agenda

• Why Migrate?
• Decision To Migrate
• Host Issues
• Target Issues
• Tool Issues
• Language Issues
• Factors Affecting The Cost Of Migration

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Why Migrate?

• Migration Is Not Undertaken Lightly And Is Often
  Driven By Outside Factors.
• Benefits of Migration gt Cost to Change

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Benefits of Change

• Extended Life of Product gt Extended Sales
  Including
• Product Enhancements
• Sales In New Projects

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Why is Change Necessary?

• The World Changes Around Us
• Such as
• Interface to a Different Component
• Provide Different Information to the User
• Environment Changes

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Why is Change Necessary?

• Cost Cutting Product Maintenance is Taken Over
  by a New Subcontractor
• Longevity of Product
• Competition Why did Apple Switch to Pentium?

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Decision to Migrate

• Why Migrate?
• Decision To Migrate
• Host Issues
• Target Issues
• Tool Issues
• Language Issues
• Factors Affecting The Cost Of Migration

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• In the Embedded Hardware/Software Domain There
  are Three Categories Affecting the Migration
  Decision
• Host Factors
• Target Factors
• Language Factors
• Also Considered Are The Software Development
  Tools Such as Compilers, Linkers, and Debuggers

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Need to Migrate

• A Product Change Is Needed
• Host And Tools Are OK
• Target Is Still Adequate
• There Is No Need To Migrate
• But If You Have Any Of The Following Problems
  Then You Need To Migrate!

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Target is Constant - Why Change the Host?

• Host is Obsolete and Non-functioning
• VAX/VMS
• Sun SPARC/SunOS
• PC/Windows NT

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Host Changes

• Perhaps the Host is Still Functioning, but
• The Handwriting is on the Wall
• Contingency Plans for when the Last Host System
  Dies

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Tool Changes

• Host is Still Viable, but Need to Acquire New
  Software Tools
• The Original Version of Software Tools is
  Unavailable

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Tool Changes

• Yearly Support Payments are a Form of Insurance
• DDC-I will Support our Tools as Long as One
  Customer Pays Maintenance.

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Tool Changes

• Acquire a New Host Platform, but the Original
  Tools are Not Available for that System

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Host Constant or ChangesTarget Changes

• Physical Constraint of the Target Might be
  Exceeded
• Memory Addressability Limitation
• Processor Throughput
• Power Consumption

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Target Changes

• Original Software Tools Not Available for the New
  Target

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Target Changes

• Changes in the Embedded Environment
• New Peripheral Devices
• New Communication Bus
• New Protocols

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Target Changes

• May Need an Embedded RTOS Where None Was Used
  Before
• New product would benefit from the additional
  capabilities provided by an RTOS

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Target Changes

• Target Hardware or Processor Becomes Obsolete
• Intel 80860, 80960
• Motorola 68000
• Mil-Std 1750A

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Target Changes

• New Standards or Certification are Imposed on the
  System
• Recoding
• Testing All Paths
• Dead Code Removal

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Target Changes

• Interoperability With Newer Systems is Required
• Production Royalties Affect the Profitability of
  the System

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Target Changes

• Expertise in the Product and/or Tools is Lost
• Product is Simply Unmaintainable
• Software Has Been Patched Repeatedly
• No One Knows How to Make a Change

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Language Changes

• The Software is Written in an Old Language Such
  as JOVIAL
• Consider Language Migrations for
• Ada 83 ? Ada 95
• Ada ? C
• JOVIAL ? C
• Others

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Cost of Migration

• Why Migrate?
• Decision To Migrate
• Host Issues
• Target Issues
• Tool Issues
• Language Issues
• Factors Affecting The Cost Of Migration

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Calculating Migration Costs

• Old Environment

Test Environment
Host Dev System
Target System
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Calculating Migration Costs

• Changing Only The Host Side
• New Development System
• New Development Tools
• Warning Target Functions Could Change

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Calculating Migration Costs

• New Development Costs for Software Tools Such as
  Compilers, Debuggers
• Concern Source Code Incompatibilities Even When
  Using the Same High-level Language

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Costs of Changing Software Tools

• Dont Expect to Simply
• Install a New Compiler
• Throw the Compilation Switch
• And Get a Working Executable!

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Costs of Changing Software Tools

• Hidden Dependencies
• For Example The Order in Which Memory is
  Initialized at Startup
• Code Size Issues
• Will Need to Work Closely With the Compiler
  Vendor

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Costs of Changing Software Tools

• Old Target System Possibly Reached a Memory or
  Performance Limit No Code Growth and No Slow
  Down
• Old Software Tuned to Old Compiler. Source
  Code Must be Tuned to the New Compiler

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Cost of Changing Software Tools

• Choosing A Mixed Language Development System
  Will
• Allow The User To Keep Most Of The Code Unchanged
  
• Implement New Functions In The New Language
• Reduce The Cost Of Migration

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Cost of Changing Software Tools

• SCORE Integrated Development Environment From
  DDC-I Offers
• Mixed Language Compilers Debuggers for Ada, C,
  Embedded C, Fortran, and JOVIAL
• Cross Development for Popular Host Platforms
  Targeting 80x86, PowerPC, Mil-Std 1750A,

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Calculating Migration Costs

• New Host System Typically PC/Windows or PC/Linux
• Other Infrastructure Costs
• Maintain Network
• Maintain Security
• Maintain Software Development Processes Such as
  CM, Problem Tracking, Etc.

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Calculating Migration Costs

• New Target Typically Modern, Faster Processor
  With Additional Memory
• Cost of Host Development System
• Cost of Software Development
• Cost of Hardware Development
• Cost of Testing Environment Change

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Calculating Migration Costs

• Moving to a New Target
• Can Still Reuse Much of the Software, but
• May Need Compiler Vendor Support
• Cost Will be Comparable to Original Development

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Moving to a New Target

• Testing Costs Will be Very High
• Especially for Safety-critical Applications
• Modified Condition/Decision Coverage Testing
• Path Testing
• FAA DO-178B (Avionics)
• FDA 501(k) (Medical)

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Migration Mitigation

• Perform an Up-Front Migration Assessment
• Survey of Existing Systems
• Comprehensive Needs Assessment
• Detailed Migration Requirements

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Migration Mitigation

• DDC-I Offers Migration Services
• Compete Migration Assessment Package
• Detailed Assessment Report Including Cost, Risk
  Factors, And Plan For Future
• Complete Migration Of Application
• Why DDC-I?
• Extensive Experience In Migrations
• Tools To Ease The Process

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Lessons Learned

• Why Migrate? Competitive Advantage
• When to Migrate? Avoid Obsolescence
• Cost to Migrate? Significant But
  Manageable

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• Thank You

David Mosley Senior Software Engineer, DDC-I,
Inc. dmosley_at_ddci.com http//www.ddci.com