Constructive COTS Model
(COCOTS) Status
Chris Abts
cabts@sunset.usc.edu
USC Center for Software Engineering
Annual Research Review
Feb. 6, 2001
Copyright 2001
University of Southern California
Briefing Outline
• COCOTS Overview
• Research Highlights Since ARR 2000
• Data Highlights
• New Glue Code Submodel Results
• Next Steps
• Benefits
CA 2/06/01
2
COCOTS Overview
LCA
(preliminary
design review )
Staffing
LCO
(requirements
review)
1. COTS
Assessment
2. COTS
Tailoring
IOC
(system
delivery)
3. Glue Code
Development
New System Development
Not Involving COTS Components
4. System Effort due to COTS Volatility
Time
CA 2/06/01
LCO – Lifecycle Objectives
LCA – Lifecycle Architecture
IOC – Initial Operational Capability
COCOTS Effort Estimate
COCOMO II Effort Estimate
3
Research Highlights Since ARR 2000
• Data collected for four sources of effort
• Reasonably robust calibration of Glue
Code submodel
• Spreadsheet Tool
CA 2/06/01
4
Data Highlights
Mean % of Total COTS Effort by Activity (+/- 1 SD)
70.00%
61.25%
60.00%
% Person-months
50.00%
49.07%
50.99%
40.00%
31.06%
30.00%
20.00%
20.75%
21.76%
20.27%
11.31%
10.00%
0.88%
0.00%
-10.00%
-7.57%
assessment
-7.48%
tailoring
glue code
2.35%
system volatility
-20.00%
CA 2/06/01
5
Data Highlights
Median Initial Filtering Effort by COTS Class
generic
0.63
2.00
telemetry processing
operating systems
network managers
0.50
0.27
GUIs/GUI builders
0.10
emulators
0.08
databases
1.91
data conversion packages
0.00
0.75
0.50
1.00
1.50
2.00
2.50
Person-months
CA 2/06/01
6
Data Highlights
Median Detailed Assessment Effort by COTS Class
generic
1.33
telemetry processing
operating systems
2.37
0.50
network managers
GUIs/GUI builders
emulators
7.17
0.67
0.00
databases
data conversion packages
5.75
0.00
0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00
Person-months
CA 2/06/01
7
Data Highlights
Median Tailoring Effort by COTS Class
report generator
6.00
OS
2.00
network management
12.67
14.00
GUI
emulator
3.00
disk array
4.00
device drivers
3.00
DBMS
communications protocol
38.29
1.00
back office retail
0.00
3.00
10.00
20.00
30.00
40.00
50.00
Person-months
CA 2/06/01
8
New Glue Code Submodel Results
• Current calibration looking reasonably good
– Excluding projects with very large,
very small amounts of glue code (Effort Pred):
• [0.5 - 100 KLOC]: Pred (.30) = 9/17 = 53%
• [2 - 100 KLOC]: Pred (.30) = 8/13 = 62%
– For comparison, calibration results shown at ARR 2000:
• [0.1 - 390 KLOC]: Pred (.30) = 4/13 = 31%
• Propose to revisit large, small, anomalous projects
– A few follow-up questions on categories of code & effort
• Glue code vs. application code
• Glue code effort vs. other sources
CA 2/06/01
9
New Glue Code Submodel Results (Detailed)
Overly large and small glue code projects set aside.
A=2.13
1.16.2001
PM
PROJECT
B
C
N3
S
P2
Q
P5
G3
J
P1
E6
P3
M1
OO4
K
A
L
HH1
D
P4
CA 2/06/01
eff size (ksloc)
468
25
20
4.2
3
50
5
50
1.2
10
66
30
5
156.25
1.5
8.05
1.3
1
6.2115
0.2
B
1.04
1.04
1.04
1.04
1.04
1
1.04
1.04
1.04
1.04
1.04
1.04
1.05
1
1.04
1.06
1
1.07
1
1.04
Pred (.30) = 8/13 = 62%
xEAF
0.510453806
1.852572737
0.322405591
2.390191594
0.963253616
0.673812512
1.006681407
0.529078185
0.293750042
0.380170097
1.080272605
0.417769338
3.069851933
1.634415034
0.444883317
0.204635155
0.586150455
0.337287985
0.341574591
0.455368578
(est)
650.7163767
112.20507
15.48293759
22.64600403
6.431708548
71.76103253
11.4340597
65.89132839
0.756320788
8.878867139
179.5720163
30.58597083
35.4336211
543.9537534
1.444643319
3.976522848
1.62305061
0.718423407
4.519200912
0.181892109
(rpt'd)
60
75
12
18
6
72
12
84
1
12
250
60
81
1411
4
12
7
6
74
6
Pred (.30) = 9/17 = 53%
%Rerr
984.53%
49.61%
29.02%
25.81%
7.20%
-0.33%
-4.72%
-21.56%
-24.37%
-26.01%
-28.17%
-49.02%
-56.25%
-61.45%
-63.88%
-66.86%
-76.81%
-88.03%
-93.89%
-96.97%
10
Next Steps
• Data conditioning
– Follow-up questions on categories of code & effort
• Further data collection
– Accelerating collection of 10 additional data points over next
8 weeks (including a first pass at COTS maintenance data)
– As always, can you help?
• COCOTS total lifecycle model
– Two FAA-sponsored workshops, Int’l COCOMO forum
breakout session held in 2000; USC-SEI-CeBASE workshop
on COTS-based systems this week
– COCOTS data survey being expanded to address total
lifecycle issues based on insights gained from above meetings
CA 2/06/01
11
Benefits
• Existing
– Independent source of estimates
– Checklist for effort sources
– (Fairly) easy-to-use development phase tool
• On the Horizon
– Empirically supported, tightly calibrated, total
lifecycle COTS estimation tool
CA 2/06/01
12