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Software Archeology & theHandbook of Software Architecture

Grady BoochIBM Fellow

© 2008 Grady Booch

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Software Archeology

What it is/what it not/why we dig

The process of archeology

Architectural reconstruction

Handbook of Software Architecture

P ti f l i ftPreservation of classic software

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How Much Software Exists In The World?

SLOC is a measure of laborOld code never diesS d i DOA

(not a measure of value)(you have to kill it)

Some code is DOASome assumptions

1 SLOC = 1 semicolonNumber of software professionals worldwide% of software professionals who cut codeSLOC/developer/yearp y$100/SLOC to develop

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Number Of Software Professional Worldwide

Number of IT professionals worldwide

y = -128.47x3 + 12800x2 - 59294x + 14662314 000 000

16,000,000

10,000,000

12,000,000

14,000,000

6,000,000

8,000,000

Number of IT professionals worldwide(assumptions)Poly. (Number of IT professionalsworldwide (assumptions))

2,000,000

4,000,000

0

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% Of Software Professionals Who Cut Code

% of IT professionals worldwide who cut code

70%

80%

50%

60%

70%

of IT professionals worldwide who cut code %

y = -0.0075x + 0.7575

20%

30%

40%

p(assumptions)Poly. (% of IT professionals worldwide who cut((code (assumptions

0%

10%

20%

45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 87 89 91 93 95 97 99 01 03 05

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SLOC/Developer/Year

New or modified source lines of code per year per developer

y = -0.0328x3 + 4.8392x2 - 67.596x + 1062.87,000

8,000

5,000

6,000

,

New or modified source lines of code per year

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4,000

p y(per developer (assumptionsPoly. (New or modified source lines of code per((year per developer (assumptions

0

1,000

2,000

45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 87 89 91 93 95 97 99 01 03 05

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New Or Modified SLOC/Year And Cumulative

New or modified source lines of code per year per developer & cumulative

700 000 000 000

800,000,000,000

500,000,000,000

600,000,000,000

700,000,000,000

300,000,000,000

400,000,000,000

New or modified source lines of code peryearCumulative source lines of code

100,000,000,000

200,000,000,000

0

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Software Archeology

The recovery of essential details about an existing system sufficient to reason about, fix, adapt, modify, harvest, and use that system itself or its parts.its parts.

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Why We Dig

To reason aboutCAATS

To fixY2K

To adaptTo adaptHomeland Security

To modifyJPL Mars Rovers

To harvestPatriot Missile SystemPatriot Missile System

To useAWACS Mid-term modernization

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The Process of Archeology

Study of the source code

Reverse engineering

Probing and other instrumentation

Review of existing documents

I t i ith t ib l l dInterviews with tribal leaders

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The process of archeology

Most design information lives in tribal memoryTypically there exists very high level architectural views and very low level design views but little in betweenlevel design views, but little in betweenReconstructing deployment and implementation views is easyReconstructing the use case view is possibleReconstructing the logical and process views is hardHarvesting patterns is harder still

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The Process of Archeology

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Architectural Reconstruction

ArchitectureThe fundamental organization of a system, embodied in its components, their relationships to each other, and the principles governing its design and p p p g g gevolution (IEEE Std 1471-2000, 2000, p. 3).

StakeholderAn individual, team, or organization (or classes thereof) with interests in, or , , g ( ) ,concerns relative to, a system (IEEE Std 1741-2000, 2000, p. 3).

ConcernThose interests which pertain to the system's development, its operation or p y p , pany other aspects that are critical or otherwise important to one or more stakeholders. Concerns include system considerations such as performance, reliability, security, distribution, and evolvability (IEEE Std 1471-2000, 2000, p. 4).1471 2000, 2000, p. 4).

ViewA representation of a whole system from the perspective of a related set of concerns (IEEE Std 1471-2000 2000 p 3)

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concerns (IEEE Std 1471 2000, 2000, p. 3).

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Representing Software Architecture

Logical View Implementation View

End-userFunctionality

ProgrammersConfiguration management

Use Case Viewy Use Case View

Process View

PerformanceS l bilit

System integrators

Deployment View

System topologyC i ti

System engineering

ScalabilityThroughput

CommunicationProvisioning

Conceptual Physical

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Source: Kruchten, “The 4+1 Model View”

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Architectural Views

Use case viewThe view of a system's architecture that encompasses the use cases that described the behavior of the system as seen by its end users and other external stakeholders.

Logical viewThe physical place where a system is developed, used, or deployed.

Process viewThe view of a system's architecture that encompasses the threads and processes that form the system's concurrency and synchronization mechanisms; a process view addresses the performance, scalability, and throughput of the system.

Implementation viewImplementation viewThe view of a system's architecture that encompasses the components used to assemble and release the physical system; an implementation view addresses the configuration management of the system's releases, made up of somewhat independent components that can be assembled in various well-structured ways to produce a p y prunning system.

Deployment viewThe view of a system's architecture that encompassesthe nodes the form the system's hardware topology on which the system executes; a deployment view addresses the

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hardware topology on which the system executes; a deployment view addresses the distribution, delivery, and installation of the parts that make up the physical system.

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Barriers To Software Archeology

Concerns over leakage of IP

Accessibility of the development team

Language

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Architecture Metamodel

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Air Traffic Control

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Source: http://www.booch.com/architecture/architecture.jsp?part=Gallery

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ATM

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Battlefield Management

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Cargo Routing

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Computational Chemistry

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Enterprise

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Games

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Games

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Google

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MetLife

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Mobile Phone

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Mozilla

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Pathfinder

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Router

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Speech Recognition

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Washing Machine

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Web Server

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Eclipse

www.eclipse.org

Eclipse was started about 2 yrs go - when IBM made a $40M t ib ti t th i d b b t i i d d t titcontribution to the main code base – but is now an independent entity

The principal architects are John Wiegand, Dave Thomson, John Duimovich all part of the OTI team which jump-started Eclipse.

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Eclipse Artifacts

Eclipse Platform Technical Overview

How to use the Eclipse API

Eclipse Overview

More detailed information exists for each of the subprojects.

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Eclipse Architecture

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Eclipse Use Case View

Check In/Out Resource

Close Perspective

Close Window

Display Help

I k N T lInvoke New Tool

Open Perspective

Open WindowOpen Window

Refresh Workspace

Shutdown Workbench

Startup Workbench

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Eclipse Implementation View

ant.jarantrunner.jarantsupport.jarantsupportlib.jarappserver jar

jdtcore.jarjface.jarjfacetext.jarjsp.jarjunit jar

servlets.jarservlets-common.jarservlets-default.jarservlets-invoker.jarservlets manager jarappserver.jar

boot.jarbootstrap.jarcatalina.jarcommons-logging.jarcompare.jar

junit.jarjunitsupport.jarlaunching.jarlaunchingsupport.jarlucene-1.2.jarnaming-common.jar

servlets-manager.jarservlets-webdav.jarslimlauncher.jarsnippetsupport.jarstartup.jarswt.jar

cvs.jardtcore.jardtui.jareditors.jarexternaltools.jarforms.jar

naming-factory.jarnaming-resources.jaroptional.jarparser.jarpde.jarpde-ant.jar

team.jarteamcvsssh.jarteamcvsui.jartomcat-coyote.jartomcat-http11.jartomcat-util.jarforms.jar

help.jarhelpworkbench.jarhelpworkbenchwin32.jarjakarta-regexp-1.2.jarjasper-compiler.jarj ti j

pde ant.jarpdebuild.jarpdebuild-ant.jarpdecore.jarpdert.jarpdeui.jard i t j

tomcat util.jartomcatwrapper.jarui.jarupdatecore.jarupdate-servlets.jarupdateui.jar

d t 32 jjasper-runtime.jarjdi.jarjdimodel.jarjdui.jarjdt.jarjdtCompilerAdapter.jar

pdeuiant.jarresources.jarresources-ant.jarruntime.jarsearch.jarservlet.jar

update32.jarversioncheck.jarviews.jarwebapp.jarworkbench.jarworkbenchwin32.jar

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Eclipse Logical View

Plugin Development Environment (PDE)

Workbench

Team

Debug

A tAnt

Help

Java Development Tools (JDT)Java Development Tools (JDT)

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PDE

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PDE

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PDE

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Workbench

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SWT

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Drag and Drop

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Widgets

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Team

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Team

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Debug

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Ant

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Core boot

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Help

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JDT

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Lessons Learned

A lot of design information lives in tribal memory

There were very high level architectural views and very low level d i i b t littl i b tdesign views, but little in between

Reconstructing the deployment and implementation views are easy

Reconstructing the use case view is possibleReconstructing the use case view is possible

Reconstructing the logical and process views are hard

Harvesting patterns is harder stillg

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Handbook of Software Architecture

No architectural reference exists for software-intensive systems

Goals of the handbookCodify the architecture of a large collection of interesting software-intensive systemsStudy these architectural patterns in the context of the engineering forces th t h d ththat shaped themSatisfy my curiosity

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Artificial IntelligenceAsimoAvidaBlondie24

Content AuthoringAvidMassiveMicrosoft Word

Entertainment and SportsDisney Hall of the PresidentsHong Kong Jockey ClubNBC control roomCYC

SwarmTrilogy

Commercial and Non Profit

Microsoft WordPhotoshopRendermanWall Street Journal

NBC control roomOlympicsSpidermanVeri-Lite

Commercial and Non-Profit AmazoneBayHome DepotLDS

Yamaha

DevelopmentEclipse

FinancialFedline bond systemGreat PlainsNYSELDS

Library of CongressSabreStarwoodTicketmaster

emacsJIT

Devices

NYSEVisaWells Fargo

GamesCommunications

5ESS911Nokia

Bernini ArtistaCocaColaFoveon cameraGeneral Electric

GamesDeep BlueDoom IIIStarCraft

Hamilton AutomationOtisSuunto watchT it

The Sims

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Triton

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S i tifiIndustrialDow ChemicalNERTOToyota

MilitaryAEGISAWACSBendix

ScientificABI PrismEarth Weather SimulaJasonToyota

LegalIdentixLexis/NexisS C t

BendixChyenne MountainF16Force XXI

Mars Exploration RoverMathematicaMona Loa observatory National Data Buoy CenterSupreme Court

MedicalCogencyMedtronics

GPSPathfinderPredatorSpace Command

National Data Buoy CenterNational Ignition FacilityNavTechProtein Data Bank

PhilipsSiemens

UtilitiesAOL Messenger

p

Operating SystemsLinuxPalm OS

SETI@home

TransportationBMWB iti h R ilAOL Messenger

BabblefishGoogleGroovesendmail

Wind River OSWindows XP

PlatformsNET

British RailCAATSEvans and SutherlandFedexsendmail .NET

J2EEFordNuTechOOCL

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Adobe Photoshop

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Second Life

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Logical View

Asset System - transport for animations, sounds, notecards, scripts, etc

A t A i t t d f h Avatar Appearance - appearance is constructed from a mesh, parameters to deform the mesh, and textures to describe clothingAvatar Profiles･Culling - octree and occlusion based culling to speed rendering

Error Logging System - command and control of debugging Error Logging System command and control of debugging outputGroups･Image System - prioritizes and decodes JPEG2000 images into OpenGL texturesimages into OpenGL textures

Texture cache - used for reading and writing texture data to the local disk cache

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Logical View

Image System - prioritizes and decodes JPEG2000 images into OpenGL textures

Texture cache used for reading and writing texture data to the Texture cache - used for reading and writing texture data to the local disk cacheImage Pipeline - fetches textures from the servers and decodes themthem

Inventory - server-side storage of assets for each userL$ System･Message System - reliable and unreliable transport over UDP

Movie System - QuickTime-based video on object surfaces

Muting Objects and Agents How the viewer manages the Muting Objects and Agents - How the viewer manages the muted object list

Rendering System - from viewer object to drawable to face

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to vertices to graphics

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Logical View

Sound System - cross platform audio based on FMOD

Tools - anything that takes effect when you click your mouse th ld ion the world view.

UI Widgets - cross platform buttons, scroll bars, etc.

UI Floaters - dialogs and windows built from XML filesUI Floaters dialogs and windows built from XML files

VFS - cached data is held in two "virtual file systems" in large files on the client

Viewer Object System - objects in scene for rendering and editing

Web Browser - the integration of the viewer with the webWeb Browser the integration of the viewer with the web.

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Process View

Main thread -- The input/output main program function (including rendering).

VFS th d Th d ibl f di / iti t th VFS thread -- Thread responsible for reading/writing to the local virtual file system.

LFS thread -- Thread responsible for some reading/writing to the local native file system.

Image thread -- Thread responsible for requesting and decoding image data･g g

Error Thread -- Thread responsible for catching exceptions, calling the (currently unused?) error handler, and retiring

Worker Threads -- Threads designed to do cpu intensive background tasks･These threads may be paused during rendering so as not to reduce performance (design in-

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progress)

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Process View

1.Initialize - newview/viewer.cppﾊ:: main()

2.Loop - newview/viewer.cppﾊ:: main_loop()

Gathers keyboard and mouse inputPumps the TCP i/o･idle()

R d th fRender the frame

Let filesystem and worker threads process

3 Shutdown3.Shutdown

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Preservation of Classic Software

No comprehensive and intentional activity has yet been undertaken to preserve software artifactsThere are a number of reasons to act nowThere are a number of reasons to act now

Many of the authors of seminal systems are still aliveMany others may have the source code or design documents for th t ll ti d t i th i ffithese systems collecting dust in their offices or garagesTime is our enemy: over time, these artifacts will become lost forever

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Goals

Preserving such artifacts for future generations is more than a valuable historical curiosity

The understanding and codification of architectural patternsThe understanding and codification of architectural patternsThe evolution of software architecture and how they were products of their timeA t t t f i t l t t th i f i dA statement of prior art relevant to the issues of proving and disproving software patents

Preserving such artifacts also provides raw materials for future generations of software archeologists, historians, and software developers who can learn from the past regarding

What worked and what didn'tWhat was brilliant and what was an utter failure

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Metahistory

I’ve been inspired by two groups:Bruce Andersen (Handbook of Software Architecture)Ward Cunningham (and the Hillside Group)

Spring 2002Survey of 500 of my closest friendsSurvey of 500 of my closest friends

Fall 2002Museum board meetingg

Fall 2003Workshop on preservation of software

CurrentEstablishment of Software Collections Committee

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Spring 2002

I'm seeking your help in preserving classic software products before they are forever lost to future generations.As Bjarne Stroustrup, the inventor of C++, has observed, "our civilization runs on computers." There are a number of organizations - most notably the Computer

Museum History Center - dedicated to preserving classic hardware, but it occurs to me (and others) that we should also preserve classic software as well.There are a number of reasons to act now. Although many of the authors of such systems are still alive and many others may have the source code or design

documents for these systems collecting dust in their offices or garages, time is our enemy and over time, these artifacts will become irretrievable. By the way, notice that I said "source code" and "design documents." Executables are interesting only insofar as we have the machines upon which to run them (and preserving running hardware is an entirely different issue), but the code and designs that these executables manifest tell us much about the state of thepreserving running hardware is an entirely different issue), but the code and designs that these executables manifest tell us much about the state of the software practice, the minds of their inventors, and the technical, social, and economic forces that shaped these products in their time. Preserving such artifacts for future generations is certainly a valuable historical curiosity, but they also offer a statement of prior art (relevant to the issues of proving/disproving software patents), the evolution of software architecture (and how they were products of their time), and the creation of architectural patterns (patterns are common solutions to common problems, and such patterns have emerged for particular domains and development cultures). Preserving such artifacts also provides the raw materials for future generations of software archeologists, historians, and software developers (the latter who can learn from the past regarding what worked and what didn't as well as what was brilliant and what was an utter failure).

What constitutes a classic software product? I can only offer the subjective criteria that such a product is one that made a seminal technical, economic, or social difference. Lisp 1.5, the Mark I Time Sharing System, Smalltalk-72, Dijkstra's THE operating system, Unix/Linux, and EMACS are all examples of technically g y j g y ysignificant products. DOS, Windows 3.1, VisiCalc, and the original Mac OS all had significant economic impact. Space War, Pong, Zork, sendmail, IM, and the original Netscape browser all wove themselves into the fabric of society.

I'm not affiliated with the Computer Museum, although, from my discussions with them, my intent is to initiate this effort but to deliver up all such artifacts to them for their preservation and care. I expect to be creative - some of you have or may know of people who have dusty card decks, listings, or disks that we'd want to scan, capture and otherwise preserve, while certain companies may have source code locked up in their vaults as precious intellectual property yet who might be open to the suggestion of putting that source code into some secure escrow so that 50 or even 100 years from now, at which time there would be zero value in that IP, we could open a time capsule of software.

You are receiving this email because you are an important contributor to the theory and/or practice of software. I've emailed about 500 such folks, ranging from ou a e ece g t s e a because you a e a po ta t co t buto to t e t eo y a d/o p act ce o so t a e e e a ed about 500 suc o s, a g g oTuring Award winners to CTOs/CEOs, and researchers. I apologize if I've spammed you, but I know of no better way to begin this effort than to connect with those people who have helped invent the present and will continue to invent the future.

To draw this message to a close, I'm only asking two things of you. At the very least, could you respond to the first? If you are so able, some help on the second would be of enormous value.

First, tell me what's in your top ten list of classic software products. What software artifacts would you want to preserve for future generations, products that made a difference in shaping the software industry?

Second, please let me know if you have access to any such artifacts or if you know of colleagues who do. I'm aware of a few related efforts to keep old software i d if k f th h ti iti l h l t i t h ith th i i I'll h il b b d d k li ti d t kirunning, and if you know of other such activities, please help me get in touch with their organizers. I'll happily absorb card decks, listings, documents, napkins

full of sketches, and the like. If your company owns the rights to some of these artifacts, let's enter into a serious dialog about how we might put those artifacts into secure escrow to save them before your company discards them by intention, neglect, or merger/economic demise. If you are or know of the original architects of these classic software products, let's also talk about capturing an oral history of their creation.

Thank you for your time in listening to my ranting. Personally, I'm doing this because the software industry has been good to me, and I simply want to give back to those who will drive our industry in the future.

Grady BoochChief Scientist

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Chief ScientistRational Software [email protected]

IBM Research

Spring 2002

Personal contactsWeb contactsCl i ftClassic softwareActions

Conduct a workshop regarding the preservation, presentation, and p g g p , p ,archeology of classic softwareInvestigate forming a public escrow for software currently under IP protectionMake contact with Microsoft, Apple, and IBM archivistsPublish a call in IEEE Software (Steve McConnell)Publish a call in the Annals of the History of Computing (TimPublish a call in the Annals of the History of Computing (Tim Bergen)Publish a call to the owners of all Web contactsS d k l d t t ll l t t

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Send an acknowledgement message to all personal contacts

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Things Collected

Altair Basic

ThingLab (Alan Borning)

MulticsMacPaint

Fortran compilers

Whirlwind

…

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The Architecture of an InterpreterThe Architecture of an InterpreterThe Altair 8080 was the first really personal computer

Its basic interpreter was written by Bill Gates and Paul AllenIts basic interpreter was written by Bill Gates and Paul AllenLots of tricks were required to save memory

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Reuben Harris

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MacPaint

Source code fell into my lap from Tim O’Reilly and Andy Herzfeld

Legal/IP issues abound

Next step is to conduct an interview

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Fall 2002

Grady Booch

John Toole

Dave Babcock (volunteer)

Sharon Brunzell (librarian)

Mik Willi (h d t )Mike Williams (head curator)

Ike Nassi (board member)

Len Shustek (board chair)Len Shustek (board chair)

Sowmya Krishnaswamy (cybermuseum)

Mike Walton (cyberexhibits)( y )

Lee Courtney (volunteer)

Bob Supnik (via phone)

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Present

Al kosskow Computer History Museum Software Curator

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The Big Questions

What systems do we preserve?What artifacts should we collect?H d k th tif t il bl ?How do we make these artifacts available?How can we create a sustainable program?

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