10101000. 01010100 0201010 About This Course 101010- The topics discussed include 0102101000 10101000. Concepts and relationships, 00:10100 10103000: analytical models and supporting tools 0000 1010001 techniques for software reliability improvement, 01010 1000.including 1010:000 0101010001.. fault avoidance fault elimination, fault tolerance 10101000L0 0101010003. error detection and repair 0.0.10000. failure detection and retraction 010101000 10:101000.0. risk management 03010100 SZ CALGARY SENG521 (Fall 2002) far@enel. calgary. ca 11
SENG521 (Fall 2002) far@enel.ucalgary.ca 11 About This Course … ◼ The topics discussed include: ◼ Concepts and relationships; ◼ analytical models and supporting tools; ◼ techniques for software reliability improvement, including: ◼ fault avoidance, fault elimination, fault tolerance ◼ error detection and repair, ◼ failure detection and retraction; ◼ risk management
10101000. 01010100 10201000 010201000 1010100022 010102000 01 10 UNIVERSITY OF caLgary Section 2 0:101010u0 10:0:000 Reliability 0102010002 10101000L0 0201010002 10.101000 010101000 10:101000 030101000 02010002 01010.1sENG521(a|200 far @enel. calgary. ca
SENG521 (Fall 2002) far@enel.ucalgary.ca 12 Section 2 Reliability
10101000. 01010100 1020 Reliability: Natural System 101010 Natural system 0:1020100 life cycle 10:101000 Wear out 0..0.0-- Aging effect: Life g 010101o0 span of a natural 10101000 0:101010u system is limited 10:101000: by the maximum 01010100 010000 reproduction rate 010100 of the cells 10101000 010101000 10:101000 03010100 SZ CALGARY SENG521 (Fall 2002) far@enel. calgary. ca
SENG521 (Fall 2002) far@enel.ucalgary.ca 13 Reliability: Natural System ◼ Natural system life cycle. ◼ Aging effect: Life span of a natural system is limited by the maximum reproduction rate of the cells
10101000. 01010100 1020 Reliability: Hardware 101010- Hardware life 010210100 cycle 10:101000 Wear out 0.00- Useful life span 10210100 01010o0 of a hardware 10101000 0:101010u system is limited 0.01.01000: by the age(wear 01010100 10101000- out)of the system 0201020002 10101000 010101000 10:101000 03010100 SZ CALGARY SENG521 (Fall 2002) far@enel. calgary. ca
SENG521 (Fall 2002) far@enel.ucalgary.ca 14 Reliability: Hardware ◼ Hardware life cycle. ◼ Useful life span of a hardware system is limited by the age (wear out) of the system
10101000. 01010100 1020 Reliability: Software 01010 Software life cycle Increased failure 01010-- Software systems rate due to side effects 10:101000 00:1010 are change 10101000(updated ) many 0.0.0.times during their 101010 0:101010u cycle Actual curve 101010. Each update adds to 01020100 10102000 he structural Idealized curve 010100s deterioration of the Tir 10101000 software system 01010100 10:101000 03010100 SZ CALGARY SENG521 (Fall 2002) far@enel. calgary. ca 15
SENG521 (Fall 2002) far@enel.ucalgary.ca 15 Reliability: Software ◼ Software life cycle. ◼ Software systems are changed (updated) many times during their life cycle. ◼ Each update adds to the structural deterioration of the software system