电子书免费下载 The Mythical Man-Month

In many ways, managing a large computer programming proj-

ect is like managing any other large undertaking—in more ways

than most programmers believe. But in many other ways

it is different—in more ways than most professional managers

expect.

The lore of the field is accumulating. There have been sev-

eral conferences, sessions at AFIPS conferences, some books,

and papers. But it is by no means yet in shape for any systematic

textbook treatment. It seems appropriate, however, to offer this

little book, reflecting essentially a personal view.

Although I originally grew up in the programming side of

computer science, I was involved chiefly in hardware architec-

ture during the years (1956-1963) that the autonomous control

program and the high-level language compiler were developed.

When in 1964 I became manager of Operating System/360, I

found a programming world quite changed by the progress of

the previous few years.

Managing OS/360 development was a very educational ex-

perience, albeit a very frustrating one. The team, including F. M.

Trapnell who succeeded me as manager, has much to be proud

of. The system contains many excellencies in design and exe-

cution, and it has been successful in achieving widespread use.

Certain ideas, most noticeably device-independent input-output

and external library management, were technical innovations now widely copied. It is now quite reliable, reasonably efficient,

and very versatile.

The effort cannot be called wholly successful, however. Any

OS/360 user is quickly aware of how much better it should be.

The flaws in design and execution pervade especially the control

program, as distinguished from the language compilers. Most of

these flaws date from the 1964-65 design period and hence must

be laid to my charge. Furthermore, the product was late, it took

more memory than planned, the costs were several times the

estimate, and it did not perform very well until several releases

after the first.

After leaving IBM in 1965 to come to Chapel Hill as origi-

nally agreed when I took over OS/360, I began to analyze the

OS/360 experience to see what management and technical les-

sons were to be learned. In particular, I wanted to explain the

quite different management experiences encountered in System/

360 hardware development and OS/360 software development.

This book is a belated answer to Tom Watson's probing ques-

tions as to why programming is hard to manage.

In this quest I have profited from long conversations with

R. P. Case, assistant manager 1964-65, and F. M. Trapnell, man-

ager 1965-68. I have compared conclusions with other managers

of jumbo programming projects, including F. J. Corbato of

M.I.T., John Harr and V. Vyssotsky of Bell Telephone Labora-

tories, Charles Portman of International Computers Limited,

A. P. Ershov of the Computation Laboratory of the Siberian Di-

vision, U.S.S.R. Academy of Sciences, and A. M. Pietrasanta of

IBM.

My own conclusions are embodied in the essays that follow,

which are intended for professional programmers, professional

managers, and especially professional managers of program-

mers.

Although written as separable essays, there is a central ar-

gument contained especially in Chapters 2-7. Briefly, I believe

that large programming projects suffer management problems different in kind from small ones, due to division of labor. I be-

lieve the critical need to be the preservation of the conceptual

integrity of the product itself. These chapters explore both the

difficulties of achieving this unity and methods for doing so.

The later chapters explore other aspects of software engineering

management.

The literature in this field is not abundant, but it is widely

scattered. Hence I have tried to give references that will both

illuminate particular points and guide the interested reader to

other useful works. Many friends have read the manuscript,

and some have prepared extensive helpful comments; where

these seemed valuable but did not fit the flow of the text, I have

included them in the notes.

Because this is a book of essays and not a text, all the ref-

erences and notes have been banished to the end of the volume,

and the reader is urged to ignore them on his first reading.

I am deeply indebted to Miss Sara Elizabeth Moore, Mr.

David Wagner, and Mrs. Rebecca Burns for their help in pre-

paring the manuscript, and to Professor Joseph C. Sloane for ad-

vice on illustration.