Requirements and Estimation Process From a CMM Level 5 Organization Alan Prosser.

Requirements and Estimation Requirements and Estimation ProcessProcess

From a CMM LevelFrom a CMM Level 5 Organization5 Organization

Alan ProsserAlan Prosser

Requirements and Estimation Requirements and Estimation

This is a sample process for requirements and cost This is a sample process for requirements and cost estimation process from a CMM level 5 organization. The estimation process from a CMM level 5 organization. The organization was for a government contract, the software organization was for a government contract, the software for the Space Shuttle Onboard computers (OBS stands for for the Space Shuttle Onboard computers (OBS stands for On Board Software). The contract has been through On Board Software). The contract has been through several companies, (IBM Federal Systems, Loral Space several companies, (IBM Federal Systems, Loral Space Systems, Lockheed Martin Space Information Systems and Systems, Lockheed Martin Space Information Systems and by now United Space Alliance). by now United Space Alliance).

Requirements and Estimation Requirements and Estimation

There were 5 different CCBs and processes for software There were 5 different CCBs and processes for software with 5-6 different risk levels and for changes vs. fixes. What with 5-6 different risk levels and for changes vs. fixes. What I describe here is a high level view of the requirements I describe here is a high level view of the requirements change process to the 2-3 higher risk levels. (Level 2-3 use change process to the 2-3 higher risk levels. (Level 2-3 use the same process from this view).the same process from this view).– 1 - Flight software - life and property depend on it1 - Flight software - life and property depend on it– 2 - Critical tools - affect 1s and 0s of FSW2 - Critical tools - affect 1s and 0s of FSW– 3 - Non-critical, deliverable tools3 - Non-critical, deliverable tools– 4 - Organization use - used by organization but not customer4 - Organization use - used by organization but not customer– 5 - Department use - helpful, but not a wide number of users5 - Department use - helpful, but not a wide number of users– 6 - Individual use tools - automation of personal, manual tasks6 - Individual use tools - automation of personal, manual tasks

Requirements and EstimationRequirements and Estimation

Basic StepsBasic Steps– Change Request (CR) goes to CCBChange Request (CR) goes to CCB– Functional Areas fill out PASS 1Functional Areas fill out PASS 1– Back to CCB for PASS 1 (Requirements) Back to CCB for PASS 1 (Requirements)

approvalapproval– Functional Areas for Development and Functional Areas for Development and

Verification fill out PASS 2 (Estimates)Verification fill out PASS 2 (Estimates)– Approval and schedule to a release by CCBApproval and schedule to a release by CCB


Change Request (CR) goes to CCBChange Request (CR) goes to CCB Someone, either external (NASA) or internal, writes a CR, which is Someone, either external (NASA) or internal, writes a CR, which is

high level, mentions some kind of justification, what applications high level, mentions some kind of justification, what applications are affected, need date, etc. This document goes to the CCB, are affected, need date, etc. This document goes to the CCB, where it gets assigned a number and is entered into the where it gets assigned a number and is entered into the Configuration Management Database (CMDB).Configuration Management Database (CMDB).

The CCB passes a copy the request on to each functional area The CCB passes a copy the request on to each functional area affected. There are representatives of all functional areas at the affected. There are representatives of all functional areas at the CCB, some individuals represent several areas.CCB, some individuals represent several areas.

If anyone notices that a functional area is missing, it will be added.If anyone notices that a functional area is missing, it will be added. Most team members at least get the CCB agendas for this purpose.Most team members at least get the CCB agendas for this purpose.


Functional Areas fill out PASS 1Functional Areas fill out PASS 1 A requirements analyst (RA) responsible for the area looks at the A requirements analyst (RA) responsible for the area looks at the

CR to see if a change of the baselined requirements are needed. If CR to see if a change of the baselined requirements are needed. If requirements will need to be changed, a cost and date estimate for requirements will need to be changed, a cost and date estimate for the requirements change is required. An online form is filled out the requirements change is required. An online form is filled out (PASS 1 Requirements) The form also has a place to reject the (PASS 1 Requirements) The form also has a place to reject the request.request.

A developer for the functional area looks at the CR and fills out a A developer for the functional area looks at the CR and fills out a form to indicate that the change is small, medium, or large, if form to indicate that the change is small, medium, or large, if changes to requirements are needed, and suggests a release that changes to requirements are needed, and suggests a release that may be possible or rejects the change with reasons. There is a may be possible or rejects the change with reasons. There is a form for development too (PASS 1 Development)form for development too (PASS 1 Development)


To CCB for PASS 1 (Requirements) To CCB for PASS 1 (Requirements) approvalapproval– The forms automatically show up on the CCB agenda, The forms automatically show up on the CCB agenda,

and if they all say approve for writing requirements, and if they all say approve for writing requirements, the requirements cycle starts for each functional area. the requirements cycle starts for each functional area.

– Requirements cycle(s) until team agrees, then Requirements cycle(s) until team agrees, then CCB can give PASS 1 approvalCCB can give PASS 1 approval

Note that CRs that also affect FSW will also go through a similar CCB Note that CRs that also affect FSW will also go through a similar CCB process there as well.process there as well.


Requirements CycleRequirements Cycle The RA does investigation and writes a version of the The RA does investigation and writes a version of the

requirements. The RA may look at any documentation, have requirements. The RA may look at any documentation, have interviews, brainstorming sessions, etc. interviews, brainstorming sessions, etc.

An internal review of the requirements is scheduled. There are An internal review of the requirements is scheduled. There are representatives for verification and development and a backup RA, representatives for verification and development and a backup RA, and a neutral (from other functional area) moderator. All major and and a neutral (from other functional area) moderator. All major and minor errors are loggedminor errors are logged

When the team has approved the requirements, it goes to the CCB When the team has approved the requirements, it goes to the CCB and customer (there is a customer rep at CCB). Any of them could and customer (there is a customer rep at CCB). Any of them could point out changes needed, sending back to begin this cycle. Large point out changes needed, sending back to begin this cycle. Large changes have multiple cycles and may take months to write.changes have multiple cycles and may take months to write.


Functional Areas for Development and Functional Areas for Development and Verification fill out PASS 2 (Estimates)Verification fill out PASS 2 (Estimates)– Developers fill out estimates (Development Developers fill out estimates (Development

PASS 2)PASS 2)– Verifiers fill out estimates (Verification PASS 2)Verifiers fill out estimates (Verification PASS 2)


Developers fill out estimates (Development Developers fill out estimates (Development PASS 2)PASS 2)– A developer generates an initial list of A developer generates an initial list of

components (modules, includes, etc) to change, components (modules, includes, etc) to change, enters a PASS 2 Development form with cost enters a PASS 2 Development form with cost and schedule estimates. and schedule estimates.

– Cost estimates are in Lines of Code and Cost estimates are in Lines of Code and schedules are to particular releases.schedules are to particular releases.


Verifiers fill out estimates (Verification PASS Verifiers fill out estimates (Verification PASS 2)2)– A verifier (often the same person as RA and A verifier (often the same person as RA and

user) plans when in the development cycle they user) plans when in the development cycle they can do their testing, with an estimate of cost. A can do their testing, with an estimate of cost. A PASS 2 Verification form is filled out.PASS 2 Verification form is filled out.


Approval and schedule to a release by CCBApproval and schedule to a release by CCB– After all PASS 2 forms and requirements are approved After all PASS 2 forms and requirements are approved

by the CCB, work can start on design and code.by the CCB, work can start on design and code.


What is the result?What is the result?– We have detailed requirements that have been We have detailed requirements that have been

reviewed or are at least visible to everyone.reviewed or are at least visible to everyone.– We have a good chance that all affected areas We have a good chance that all affected areas

are identified.are identified.– We have a fair estimate of the size of change We have a fair estimate of the size of change

and for small changes may know CIs.and for small changes may know CIs.– We have a schedule agreed to by all.We have a schedule agreed to by all.– We know when independent testing will be done We know when independent testing will be done

with an estimate of cost.with an estimate of cost.

Q & AQ & A

ReferencesReferences

Fast Company wrote an article about culture and process Fast Company wrote an article about culture and process improvement philosophy of the organization in issue 6, improvement philosophy of the organization in issue 6, 12/1996-1/1997 12/1996-1/1997 http://www.fastcompany.com/magazine/06/index.htmlhttp://www.fastcompany.com/magazine/06/index.html “They Write the Right Stuff” “They Write the Right Stuff” http://www.fastcompany.com/magazine/06/writestuff.htmlhttp://www.fastcompany.com/magazine/06/writestuff.html

http://www.alprosser19.com/alworks.htmlhttp://www.alprosser19.com/alworks.html has a summary has a summary of the work Al did in the Space programof the work Al did in the Space program

http://www.fastcompany.com/magazine/06/index.html

http://www.fastcompany.com/magazine/06/writestuff.html

http://www.alprosser19.com/alworks.html

Requirements and Estimation Process From a CMM Level 5 Organization Alan Prosser.

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