Mythical Man-Month, Anniversary Edition, The: Essays On Software Engineering

Most of the big last gains in software productivity have come from removing artificial barriers that have made the accidental tasks inordinately hard, such as severe hardware constraints, awkward programming languages, lack of machine time. How much of what software engineers now do is still devoted to the accidental, as opposed to the essential? U

The bearing of a child takes nine months, no matter how many women are assigned. Many software tasks have this characteristic because of the sequential nature of debugging.

The most pernicious and subtle bugs are system bugs arising from mismatched assumptions made by the authors of various components.

In the lower right-hand corner of Fig. 1.1 stands the programming systems product. This differs from the simple program in all of the above ways. It costs nine times as much. But it is the truly useful object, the intended product of most system programming efforts.

Turski and I both insist that pipe-dreaming inhibits forward progress and wastes effort.

The preparation of a PERT chart is the most valuable part of its use. Laying out the network, identifying the dependencies, and estimating the legs all force a great deal of very specific planning very early in a project. The first chart is always terrible, and one invents and invents in making the second one.

Programming managers have long recognized wide productivity variations between good programmers and poor ones. But the actual measured magnitudes have astounded all of us. In one of their studies, Sackman, Erikson, and Grant were measuring performances of a group of experienced programmers. Within just this group the ratios between best and worst p

How does one control a big project on a tight schedule? The first step is to have a schedule. Each of a list of events, called milestones, has a date. Picking the dates is an estimating problem, discussed already and crucially dependent on experience. For picking the milestones there is only one relevant rule. Milestones must be concrete, specific,

We centralized all our machines and tape library and set up a professional and experienced machine-room team to run them. To maximize scarce S/360 time, we ran all debugging runs in batch on whichever system was free and appropriate. We tried for four shots per day (two-and-one-half-hour turnaround) and demanded four-hour turnaround. An auxiliary 1