Data for Overall Development of the VADS Product Line

all_lines: 1925523 1883751 117964 604078 4531316
SLOC: 1508695 1272771 117964 604078 3503508
files: 6057 9385 2815 3653 21910
updates: 47775 34516 12963 12189 107443
new_features: 26483 23031 5594 6145 61253
Fixes: 13890 5841 4603 1058 25392
Fixes/feature: 0.52 0.25 0.82 0.17 0.41
Fixes/KSLOC: 9.21 4.59 39.02 1.75 7.25
devel_cost: $15,873,508 $8,446,812 $1,814,610 $2,254,982 $28,389,856
cost/SLOC: $10.52 $6.62 $15.38 $3.72 $8.10
defects: 1020 122 (A) (B) 1242
defects/KSLOC: 0.676 0.096 (A) (B) 0.355

C_FILE - Files of C-based source
ADA_FILE - Files of Ada-based source

The C and Ada areas are worked by about the same people (with a slight advantage to C) and using the same tools under approximately the same conditions.

Source: Stephen Zeigler,
“Comparing Development costs of C and Ada”, 1995

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From the Script: SLIDE 36 - Data for Overall Development of the VADS Product Line

The VADS product line is a set of programming tools sold by Rational Software Corporation. It was originally developed by Verdix, which later merged with Rational. An analysis was performed on the historical software development records as part of the merger. The results were used to determine the value of the companies and also to discover the best practices to continue in the new merged company.

The study was conducted in 1993 through 1994. The results are shown in this table. They provide us with an objective comparison of C and Ada. These statistics were derived from data generated automatically by the software configuration control system. The C and Ada areas are worked by about the same people, using the same tools, under approximately the same conditions. The C programmers enjoyed a slight advantage because they tended to be more experienced.

The conclusion was that C development was more costly than Ada. You will note that the cost per thousand lines-of-code for C is $10.52. For Ada it is $6.62! The defect rate per thousand lines-of-code for C was over seven times the rate for Ada.

Ada code was found to be better organized, because the language encourages better programming. Errors are easier to locate. The programming tools are superior. The increased power of the Ada language was found to make complex programming tasks easier.

From a business and technical standpoint, this study proved that Ada makes more sense than C, and early reports are that C++ is showing even higher error rates. [Zeigler]