1. Extending the Embedded Software Process (ESP) to DSP applications*
07/16/96
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Extending the Embedded Software Process (ESP) to DSP applications
K. Nielsen and M. R. Smith, Electrical and Computer Engineering
University of Calgary, Canada ucalgary.ca
2nd Quantitative Software Engineering Conference Banff, Canada, February 2002 *

2. Review of Embedded Software Process Copyright smithmr@ucalgary.ca
Overview of Talk
Need for Humphrey’s Personal Software Process (PSP).
Relationship between PSP and CMM.
PROBE method of estimating effort needed to implement a design.
Concept of Abowd’s Embedded Software Process (ESP)
Testing of Abowd’s ESP process
Problems of extending ESP into DSP environment
12/9/2018
Review of Embedded Software Process Copyright

3. Personal Software Process*
07/16/96
To introduce you to a process-based approach to developing software
To show you how to measure and analyze your personal software process (PSP)
To show you how to use process data to improve your personal performance
To show you how to apply these methods to your other tasks
KEY -- Ability to recognize and handle undue pressures
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4. Review of Embedded Software Process Copyright smithmr@ucalgary.ca*
PSP Principles - 1
07/16/96
The quality of a software system is governed by the quality of its worst components.
The quality of a software component is governed by the individual who developed it.
This is governed by your
knowledge
discipline
commitment
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5. Review of Embedded Software Process Copyright smithmr@ucalgary.ca
PSP Principles - 2 *
07/16/96
As software professionals you should know your own performance.
You should measure, track, and analyze your work.
You should learn from your performance variations.
You should incorporate these lessons in your personal practices.
Use the information to avoid placing “unrealistic expectations” on customer or yourself.
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6. Review of Embedded Software Process Copyright smithmr@ucalgary.ca
The CMM and the PSP - 1 *
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The capability maturity model (CMM) was developed by the SEI with the help of leading software groups to the most effective large-scale software practices.
The PSP is a modification of the CMM to provides the framework for disciplined individual work.
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7. Review of Embedded Software Process Copyright smithmr@ucalgary.ca*
The CMM and the PSP - 2
07/16/96
Level 5:
Process change management*
Technology innovation*
Defect prevention* 5
From Humphrey 4
Level 4
Quality management*
Process measurement and analysis* 3
Level 3
Peer reviews*
Intergroup coordination
Software product engineering*
Integrated software management*
Training program
Organization process definition*
Organization process focus* 2
Level 2
Software configuration management
Software quality assurance
Software subcontract management
Software project tracking and oversight*
Software project planning*
Requirements management 1
Level 1
*PSP key practices
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8. Review of Embedded Software Process Copyright smithmr@ucalgary.ca
PSP Overview - 2 *
07/16/96
PSP3
Cyclic development
From Humphrey
PSP2.1
Design templates
PSP2
Code reviews
Design reviews
PSP1.1
Task planning
Schedule planning
PSP1
Size estimating
Test report
PSP0.1
Coding standard
Size measurement
Process improvement
proposal (PIP)
PSP0
Current process
Time recording
Defect recording
Defect type standard
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9. Defect cost fixes decrease
PSP Level 3
Ad-hoc -- PSP Level 0
Modified from Humphrey
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10. Productivity is not affected by PSP?
PSP Level 3
Ad-hoc -- PSP Level 0
Modified from Humphrey
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11. The Project Planning Framework*
07/16/96
Define
Requirements
Produce
Conceptual
Design
Estimate
Size
Resources
Schedule
Develop
Product
Size, Resource
Data
Process
Analysis
Available
Productivity
Database
Delivery
Tracking
Reports
From Humphrey
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12. Review of Embedded Software Process Copyright smithmr@ucalgary.ca
Object LOC Correlation With Development Hours LOC is a “useful” proxy for effort
From Humphrey
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13. The PROBE Estimating Method*
07/16/96
Start
Conceptual
Design
From Humphrey
Identify Objects
Number of
Methods
Object
Type
Relative
Size
Reuse
Categories
Calculate Added and
Modified LOC
Estimate
Program Size
Calculate
Prediction Interval
Estimate
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14. Review of Embedded Software Process Copyright smithmr@ucalgary.ca
Conceptual Design
A conceptual design is needed
to relate the requirements to the product
to define the product elements that will produce the desired functions
to estimate the size of what will be built
For understood designs, conceptual designs can be done quickly.
If you do not understand the design, you do not know enough to make an estimate.
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15. Review of Embedded Software Process Copyright smithmr@ucalgary.ca
Identify the Objects - 1
Where possible, select application entities.
Judge how many methods each object will likely contain.
Determine the type of the object, i.e.: data, calculation, file, control, etc.
Judge the relative size of each object: very small (VS), small (S), medium (M), large (L), very large (VL).
NOTE THE NON-EXACTNESS. I feel from my past experience this will become a Large Math Module
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16. Review of Embedded Software Process Copyright smithmr@ucalgary.ca
Identify the Objects - 2
From YOUR historical object data, determine the size in LOC/method of each object.
This is what differs from “ad-hoc” approaches
Multiply by the number of methods to get the estimated object LOC.
When objects do not fit an existing type, they are frequently composites.
Ensure they are sufficiently refined
Refine those that are not elemental objects
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17. Review of Embedded Software Process Copyright smithmr@ucalgary.ca
Estimate Program Size
Total program size consists of
newly developed code (adjusted with the regression parameters calculated from historical data on prior estimated newly developed (object) LOC and actual new and changed LOC)
The completed estimate includes 70% and 90% prediction intervals -- based on the stability of your process
Use your known productivity to estimate time.
Then use your known schedule to estimate completion date
This completion date allows “pressure avoidance”
Date obtained without any coding being done
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18. Why Resource and Schedule Plans Are Needed
Provides a business basis for doing the work
establishes the price
sets the schedule
permits agreement on the work
Establishes a management framework
defines commitments
helps groups coordinate their work
allows status tracking
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19. PSP becomes DSP with ESP
PSP helps software engineers
Estimate size and time of project early in the development
Develop a higher quality project
Embedded systems have software and also hardware
PSP is not enough
Need to estimate “early in development” whether the available hardware will support the new design or permit new features to be added
RAM, ROM, cycle time
Concept comes from Peter Abowd
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20. PSP becomes DSP with ESP
On-chip memory is a very big concern
System (off-chip) memory can be a key cost issue. 10 bytes over the top of available memory means “complete new block” of memory or “project time to code crunch” and mostly available in large blocks only
Being able to accurately estimate system memory needed would reduce project risks
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21. Review of Embedded Software Process Copyright smithmr@ucalgary.ca
The Embedded PSP
Embedded PSP is an extension of PSP
Use the PSP PROBE method to convert design concepts into YOUR project LOC.
Uses LOC estimate to estimate ROM/RAM based on your OWN personal programming style
Inaccurate estimates problematic
Reduce ROM/RAM used
Late program changes introduce defects
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22. Review of Embedded Software Process Copyright smithmr@ucalgary.ca
Basis of Extension
From Abowd
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23. Is there a good correlation Between LOC and ROM/RAM?
ROM contains assembly code instructions
Most code written in C
# C LOC → Assembly LOC not consistent
Results will be processor dependent
However “C” was a “processor independent” assembly language
RAM contains variables
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24. Industry Data Memory vs. LOC (P. Abowd)
From Abowd
ROM (Program) vs LOC
RAM vs LOC
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25. Embedded PSP Application Example
Abowd attempted to test the process as follows
2 embedded engineers each develop a bicycle monitor.
Each write 6 programs
Micro Startup
Simple cyclic schedule
Read wheel sensor and calculate speed
Button matrix decode and event handling
A to D braking control
LCD output
Use results of first 3 to plan final 3 programs
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26. Review of Embedded Software Process Copyright smithmr@ucalgary.ca
Estimating ROM and RAM
Results of PSP Planning Phase
Base LOC (B), Deleted LOC (D), Modified LOC (M), and New and Changed LOC (N)
Conversion to required ROM and RAM
Deleted LOC frees utilized ROM & RAM
New & Changed LOC consumes ROM & RAM
Modified LOC has no effect (simplified)
Not always true
Total LOC = B + N – D – M
Best estimate of required ROM = β01 + β11(B + N – D – M)
Best estimate of required RAM = β02 + β12(B + N – D – M)
β0 & β1 parameters are unique to ROM and RAM and individual -- found from individuals data base.
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27. Review of Embedded Software Process Copyright smithmr@ucalgary.ca
Measures
From Abowd
Engineer A
Engineer B
ROM
RAM
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28. Review of Embedded Software Process Copyright smithmr@ucalgary.ca
How Well Does It Work?
From Abowd
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29. Issues not explained by P. Abowd
Which processor was discussed?
What happens to stack usage?
Why does it work?
The problems associated with “loops” and hence execution times were discussed by Abowd.
He did provide a “personal process engine” for automating the process
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30. Does ESP scale to DSP applications?
Consider 2106X processor Program requirements
Need off-chip ROM to store program code on start up
This ROM size can be estimated by ESP
This ROM code is then transferred to on-chip RAM program memory -- therefore that can be estimated too!
Halstead Volume correlates highly with LOC.
Halstead volume relates to the number of operations in the “C” code -- does this correlate to the number of bytes needed for code?
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31. Does ESP scale to DSP applications?
Consider 2106X processor Data requirements
Abowd examined only “control” applications
Very small amount of data Ram bytes
DSP algorithms uses large arrays for initial and final storage
Need initial design information for this?
Is there some sort of relationship between LOC and sizes of intermediate arrays needed?
PSP uses Small, medium, large estimates for data, calculation, file, control, functions etc.
Perhaps “array size” is another “function type”
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32. Does ESP scale to DSP applications?
Peter Abowd intended to estimate # of Cycles as well
Could not develop a useful model
Branching conditions and loop counts are unpredictable from LOC counts
However in DSP, the size of arrays handled is probably known ahead of time, therefore the loop size is known. Also algorithm is well known.
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33. DOES ESP scale to DSP applications?
What about parallel operations?
Can estimates “maximum usage” of resources and therefore get a theoretical lower limit on code size?
Lot of code is written directly in assembly
Depends on company
Different relationship between assembly LOC and effort? Probably not, as often stated that roughly the same amount of time for 1 line of code regardless of effort -- hence it is better to use the highest level of language possible.
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34. What sort of test needed?
We already have tools to measure
LOC and Halstead Volumes
Use of linker memory maps would provide rom and ram usage information.
Most processor manufacturers provide example code, in both “C” and assembly
Use that code to see if ROM/RAM v LOC relationship still exists
But code written by many different people!
Doug Joest has offered to try out something
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Review of Embedded Software Process Copyright

35. Review of Embedded Software Process Copyright smithmr@ucalgary.ca
Overview of Talk
Need for Humphrey’s Personal Software Process (PSP).
Relationship between PSP and CMM.
PROBE method of estimating effort needed to implement a design.
Concept of Abowd’s Embedded Software Process (ESP)
Testing of Abowd’s ESP process
Problems of extending ESP into DSP environment
12/9/2018
Review of Embedded Software Process Copyright

36. Review of Embedded Software Process Copyright smithmr@ucalgary.ca*
Credits
07/16/96
Slides from Watts Humphrey’s Disciplined Software Engineering
Software Engineering Institute, Carnegie Mellon University
Research sponsored by the U.S. Department of
Slides from P. Abowd, “Personal Process for Embedded Systems,” Presentation, Salt Lake City, 1998
Automotive electronic software engineer
10 years of experience at Ford Motor / Visteon
DSP additions from Dr. Smith
Presentation based on SENG689 project by Kraig Nielsen
Paper presented at 2nd QSE conference in Banff, Feb, 2002.
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Review of Embedded Software Process Copyright *