Availability
a1. ping/echo
a2. heartbeat
a3. exception
a4. voting
a5. active redundancy
a6. passive redundancy
a7. spare
a8. shadow
a9. state resynchronization
a10. rollback
a11. removal from service
a12. transactions
a13. process monitor

Performance
p1. increase efficiency
        of computation
p2. reduce overhead
        of computation
p3. manage event rate
p4. control frequency
        of sampling
p5. introduce concurrency
p6. maintain multiple copies
p7. increase available resource
p8. scheduling policy

Usability
u1. separate user interface
u2. cancel
u3. undo
u4. aggregate
u5. user model
u6. system model
u7. task model

Modifiability
m1. semantic coherence
m2. anticipate expected changes
m3. generalize module
m4. limit possible options
m5. abstract common services
m6. hide information
m7. maintain existing interface
m8. restrict communication paths
m9. use an intermediary
m10. runtime registration
m11. configuration files
m12. polymorphism
m13. component replacement
m14. adherence to defined protocols

Security
s1. authenticate users
s2. authorize users
s3. maintain data confidentiality
s4. maintain integrity
s5. limit exposure
s6. limit access
s7. intrusion detection
s8. restoration (see availability)
s9. identification
s10. audit trail

Testability
t1. record/playback
t2. separate interface
        from implementation
t3. specialized access routes
        and interfaces
t4. built-in monitors