3 research outputs found
ΠΠ½Π°Π»ΠΈΠ· ΠΈ ΡΠΈΠ½ΡΠ΅Π· ΠΌΠ°ΡΡΠ΅Π²ΡΡ ΡΠ΅ΡΡΠΎΠ² Π·Π°ΠΏΠΎΠΌΠΈΠ½Π°ΡΡΠΈΡ ΡΡΡΡΠΎΠΉΡΡΠ²
The paper shows the relevance of testing storage devices in modern computing systems. Mathematical models of memory device faults and the efficiency of their detection, in particular, complex pattern sensitive faults of the PNPSFk type, based on classical march memory tests are presented. Limit estimates are given for the completeness of coverage of such faults depending on the number of memory cells involved in the fault. The necessity of synthesis of memory march tests characterized by high efficiency of PNPSFk failure detection is substantiated. The concept of a primitive providing conditions for activation and detection of various types of PNPSFk is defined. Examples of analysis and synthesis of memory march tests with different coverage of PNPSFk faults are given. The March OP memory test is synthesized, which is characterized by the maximum completeness of PNPSFk fault coverage and has the lowest time complexity compared to the known memory march tests, which provide the same comprehensiveness of coverage of complex memory device faults.Π ΡΡΠ°ΡΡΠ΅ ΠΏΠΎΠΊΠ°Π·ΡΠ²Π°Π΅ΡΡΡ Π°ΠΊΡΡΠ°Π»ΡΠ½ΠΎΡΡΡ ΡΠ΅ΡΡΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π·Π°ΠΏΠΎΠΌΠΈΠ½Π°ΡΡΠΈΡ
ΡΡΡΡΠΎΠΉΡΡΠ² ΡΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΡΡ
Π²ΡΡΠΈΡΠ»ΠΈΡΠ΅Π»ΡΠ½ΡΡ
ΡΠΈΡΡΠ΅ΠΌ. ΠΡΠ΅Π΄ΡΡΠ°Π²Π»ΡΡΡΡΡ ΠΌΠ°ΡΠ΅ΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΌΠΎΠ΄Π΅Π»ΠΈ Π½Π΅ΠΈΡΠΏΡΠ°Π²Π½ΠΎΡΡΠ΅ΠΉ Π·Π°ΠΏΠΎΠΌΠΈΠ½Π°ΡΡΠΈΡ
ΡΡΡΡΠΎΠΉΡΡΠ² ΠΈ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΡ ΠΈΡ
ΠΎΠ±Π½Π°ΡΡΠΆΠ΅Π½ΠΈΡ, Π² ΡΠ°ΡΡΠ½ΠΎΡΡΠΈ, ΡΠ»ΠΎΠΆΠ½ΡΡ
ΠΊΠΎΠ΄ΠΎΡΡΠ²ΡΡΠ²ΠΈΡΠ΅Π»ΡΠ½ΡΡ
Π½Π΅ΠΈΡΠΏΡΠ°Π²Π½ΠΎΡΡΠ΅ΠΉ ΡΠΈΠΏΠ° PNPSFk, Π½Π° Π±Π°Π·Π΅ ΠΊΠ»Π°ΡΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΌΠ°ΡΡΠ΅Π²ΡΡ
ΡΠ΅ΡΡΠΎΠ². ΠΡΠΈΠ²ΠΎΠ΄ΡΡΡΡ ΠΏΡΠ΅Π΄Π΅Π»ΡΠ½ΡΠ΅ ΠΎΡΠ΅Π½ΠΊΠΈ ΠΏΠΎΠ»Π½ΠΎΡΡ ΠΏΠΎΠΊΡΡΡΠΈΡ ΠΏΠΎΠ΄ΠΎΠ±Π½ΡΡ
Π½Π΅ΠΈΡΠΏΡΠ°Π²Π½ΠΎΡΡΠ΅ΠΉ Π² Π·Π°Π²ΠΈΡΠΈΠΌΠΎΡΡΠΈ ΠΎΡ ΠΊΠΎΠ»ΠΈΡΠ΅ΡΡΠ²Π° Π·Π°ΠΏΠΎΠΌΠΈΠ½Π°ΡΡΠΈΡ
ΡΡΠ΅Π΅ΠΊ, ΡΡΠ°ΡΡΠ²ΡΡΡΠΈΡ
Π² Π½Π΅ΠΈΡΠΏΡΠ°Π²Π½ΠΎΡΡΠΈ. ΠΠ±ΠΎΡΠ½ΠΎΠ²ΡΠ²Π°Π΅ΡΡΡ Π½Π΅ΠΎΠ±Ρ
ΠΎΠ΄ΠΈΠΌΠΎΡΡΡ ΡΠΈΠ½ΡΠ΅Π·Π° ΠΌΠ°ΡΡΠ΅Π²ΡΡ
ΡΠ΅ΡΡΠΎΠ², Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΠ·ΡΡΡΠΈΡ
ΡΡ Π²ΡΡΠΎΠΊΠΎΠΉ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΡΡ ΠΎΠ±Π½Π°ΡΡΠΆΠ΅Π½ΠΈΡ PNPSFk Π½Π΅ΠΈΡΠΏΡΠ°Π²Π½ΠΎΡΡΠ΅ΠΉ. ΠΠΏΡΠ΅Π΄Π΅Π»ΡΠ΅ΡΡΡ ΠΏΠΎΠ½ΡΡΠΈΠ΅ ΠΏΡΠΈΠΌΠΈΡΠΈΠ²Π°, ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠΈΠ²Π°ΡΡΠ΅Π³ΠΎ ΡΡΠ»ΠΎΠ²ΠΈΡ Π°ΠΊΡΠΈΠ²ΠΈΠ·Π°ΡΠΈΠΈ ΠΈ ΠΎΠ±Π½Π°ΡΡΠΆΠ΅Π½ΠΈΡ ΡΠ°Π·Π»ΠΈΡΠ½ΡΡ
Π²ΠΈΠ΄ΠΎΠ² PNPSFk. ΠΡΠΈΠ²ΠΎΠ΄ΡΡΡΡ ΠΏΡΠΈΠΌΠ΅ΡΡ Π°Π½Π°Π»ΠΈΠ·Π° ΠΈ ΡΠΈΠ½ΡΠ΅Π·Π° ΠΌΠ°ΡΡΠ΅Π²ΡΡ
ΡΠ΅ΡΡΠΎΠ², ΠΈΠΌΠ΅ΡΡΠΈΡ
ΡΠ°Π·Π»ΠΈΡΠ½ΡΡ ΠΏΠΎΠ»Π½ΠΎΡΡ ΠΏΠΎΠΊΡΡΡΠΈΡ PNPSFk Π½Π΅ΠΈΡΠΏΡΠ°Π²Π½ΠΎΡΡΠ΅ΠΉ. Π‘ΠΈΠ½ΡΠ΅Π·ΠΈΡΡΠ΅ΡΡΡ ΠΌΠ°ΡΡΠ΅Π²ΡΠΉ ΡΠ΅ΡΡ March OP, Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΠ·ΡΡΡΠΈΠΉΡΡ ΠΌΠ°ΠΊΡΠΈΠΌΠ°Π»ΡΠ½ΠΎΠΉ ΠΏΠΎΠ»Π½ΠΎΡΠΎΠΉ ΠΏΠΎΠΊΡΡΡΠΈΡ Π½Π΅ΠΈΡΠΏΡΠ°Π²Π½ΠΎΡΡΠ΅ΠΉ PNPSFk ΠΈ ΠΈΠΌΠ΅ΡΡΠΈΠΉ ΠΌΠΈΠ½ΠΈΠΌΠ°Π»ΡΠ½ΡΡ Π²ΡΠ΅ΠΌΠ΅Π½Π½ΡΡ ΡΠ»ΠΎΠΆΠ½ΠΎΡΡΡ ΠΏΠΎ ΡΡΠ°Π²Π½Π΅Π½ΠΈΡ Ρ ΠΈΠ·Π²Π΅ΡΡΠ½ΡΠΌΠΈ ΠΌΠ°ΡΡΠ΅Π²ΡΠΌΠΈ ΡΠ΅ΡΡΠ°ΠΌΠΈ, ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠΈΠ²Π°ΡΡΠΈΠΌΠΈ ΡΠ°ΠΊΡΡ ΠΆΠ΅ ΠΏΠΎΠ»Π½ΠΎΡΡ ΠΏΠΎΠΊΡΡΡΠΈΡ ΡΠ»ΠΎΠΆΠ½ΡΡ
Π½Π΅ΠΈΡΠΏΡΠ°Π²Π½ΠΎΡΡΠ΅ΠΉ Π·Π°ΠΏΠΎΠΌΠΈΠ½Π°ΡΡΠΈΡ
ΡΡΡΡΠΎΠΉΡΡΠ².
ΠΠΎΡΡΡΠΎΠ΅Π½ΠΈΠ΅ ΠΈ ΠΏΡΠΈΠΌΠ΅Π½Π΅Π½ΠΈΠ΅ ΠΌΠ°ΡΡΠ΅Π²ΡΡ ΡΠ΅ΡΡΠΎΠ² Π΄Π»Ρ ΠΎΠ±Π½Π°ΡΡΠΆΠ΅Π½ΠΈΡ ΠΊΠΎΠ΄ΠΎΡΡΠ²ΡΡΠ²ΠΈΡΠ΅Π»ΡΠ½ΡΡ Π½Π΅ΠΈΡΠΏΡΠ°Π²Π½ΠΎΡΡΠ΅ΠΉ Π·Π°ΠΏΠΎΠΌΠΈΠ½Π°ΡΡΠΈΡ ΡΡΡΡΠΎΠΉΡΡΠ²
The urgency of the problem of testing storage devices of modern computer systems is shown. The mathematical models of their faults and the methods used for testing the most complex cases by classical march tests are investigated. Passive pattern sensitive faults (PNPSFk) are allocated, in which arbitrary k from N memory cells participate, where k << N, and N is the memory capacity in bits. For these faults, analytical expressions are given for the minimum and maximum fault coverage that is achievable within the march tests. The concept of a primitive is defined, which describes in terms of march test elements the conditions for activation and fault detection of PNPSFk of storage devices. Examples of march tests with maximum fault coverage, as well as march tests with a minimum time complexity equal to 18N are given. The efficiency of a single application of tests such as MATS ++, March Cβ and March PS is investigated for different number of k β€ 9 memory cells involved in PNPSFk fault. The applicability of multiple testing with variable address sequences is substantiated, when the use of random sequences of addresses is proposed. Analytical expressions are given for the fault coverage of complex PNPSFk faults depending on the multiplicity of the test. In addition, the estimates of the mean value of the multiplicity of the MATS++, March Cβ and March PS tests, obtained on the basis of a mathematical model describing the problem of the coupon collector, and ensuring the detection of all k2k PNPSFk faults are given. The validity of analytical estimates is experimentally shown and the high efficiency of PNPSFk fault detection is confirmed by tests of the March PS type.ΠΠΎΠΊΠ°Π·ΡΠ²Π°Π΅ΡΡΡ Π°ΠΊΡΡΠ°Π»ΡΠ½ΠΎΡΡΡ Π·Π°Π΄Π°ΡΠΈ ΡΠ΅ΡΡΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π·Π°ΠΏΠΎΠΌΠΈΠ½Π°ΡΡΠΈΡ
ΡΡΡΡΠΎΠΉΡΡΠ² ΡΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΡΡ
Π²ΡΡΠΈΡΠ»ΠΈΡΠ΅Π»ΡΠ½ΡΡ
ΡΠΈΡΡΠ΅ΠΌ. ΠΡΡΠ»Π΅Π΄ΡΡΡΡΡ ΠΌΠ°ΡΠ΅ΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΌΠΎΠ΄Π΅Π»ΠΈ Π½Π΅ΠΈΡΠΏΡΠ°Π²Π½ΠΎΡΡΠ΅ΠΉ Π·Π°ΠΏΠΎΠΌΠΈΠ½Π°ΡΡΠΈΡ
ΡΡΡΡΠΎΠΉΡΡΠ² ΠΈ ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΠ΅ΠΌΡΠ΅ ΠΌΠ΅ΡΠΎΠ΄Ρ ΡΠ΅ΡΡΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π½Π°ΠΈΠ±ΠΎΠ»Π΅Π΅ ΡΠ»ΠΎΠΆΠ½ΡΡ
ΠΈΠ· Π½ΠΈΡ
Π½Π° Π±Π°Π·Π΅ ΠΊΠ»Π°ΡΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΌΠ°ΡΡΠ΅Π²ΡΡ
ΡΠ΅ΡΡΠΎΠ². ΠΡΠ΄Π΅Π»ΡΡΡΡΡ ΠΏΠ°ΡΡΠΈΠ²Π½ΡΠ΅ ΠΊΠΎΠ΄ΠΎΡΡΠ²ΡΡΠ²ΠΈΡΠ΅Π»ΡΠ½ΡΠ΅ Π½Π΅ΠΈΡΠΏΡΠ°Π²Π½ΠΎΡΡΠΈ (PNPSFk), Π² ΠΊΠΎΡΠΎΡΡΡ
ΡΡΠ°ΡΡΠ²ΡΡΡ ΠΏΡΠΎΠΈΠ·Π²ΠΎΠ»ΡΠ½ΡΠ΅ k ΠΈΠ· N ΡΡΠ΅Π΅ΠΊ ΠΏΠ°ΠΌΡΡΠΈ, Π³Π΄Π΅ k << N, Π° N ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»ΡΠ΅Ρ ΡΠΎΠ±ΠΎΠΉ Π΅ΠΌΠΊΠΎΡΡΡ ΠΏΠ°ΠΌΡΡΠΈ Π² Π±ΠΈΡΠ°Ρ
. ΠΠ»Ρ ΡΡΠΈΡ
Π½Π΅ΠΈΡΠΏΡΠ°Π²Π½ΠΎΡΡΠ΅ΠΉ ΠΏΡΠΈΠ²ΠΎΠ΄ΡΡΡΡ Π°Π½Π°Π»ΠΈΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ Π²ΡΡΠ°ΠΆΠ΅Π½ΠΈΡ ΠΌΠΈΠ½ΠΈΠΌΠ°Π»ΡΠ½ΠΎΠΉ ΠΈ ΠΌΠ°ΠΊΡΠΈΠΌΠ°Π»ΡΠ½ΠΎΠΉ ΠΏΠΎΠ»Π½ΠΎΡΡ ΠΏΠΎΠΊΡΡΡΠΈΡ, ΠΊΠΎΡΠΎΡΡΠ΅ Π΄ΠΎΡΡΠΈΠΆΠΈΠΌΡ Π² ΡΠ°ΠΌΠΊΠ°Ρ
ΠΌΠ°ΡΡΠ΅Π²ΡΡ
ΡΠ΅ΡΡΠΎΠ². ΠΠΏΡΠ΅Π΄Π΅Π»ΡΠ΅ΡΡΡ ΠΏΠΎΠ½ΡΡΠΈΠ΅ ΠΏΡΠΈΠΌΠΈΡΠΈΠ²Π°, ΠΎΠΏΠΈΡΡΠ²Π°ΡΡΠ΅Π³ΠΎ Π² ΡΠ΅ΡΠΌΠΈΠ½Π°Ρ
ΡΠ»Π΅ΠΌΠ΅Π½ΡΠΎΠ² ΠΌΠ°ΡΡΠ΅Π²ΠΎΠ³ΠΎ ΡΠ΅ΡΡΠ° ΡΡΠ»ΠΎΠ²ΠΈΡ Π°ΠΊΡΠΈΠ²ΠΈΠ·Π°ΡΠΈΠΈ ΠΈ ΠΎΠ±Π½Π°ΡΡΠΆΠ΅Π½ΠΈΡ Π½Π΅ΠΈΡΠΏΡΠ°Π²Π½ΠΎΡΡΠ΅ΠΉ PNPSFk Π·Π°ΠΏΠΎΠΌΠΈΠ½Π°ΡΡΠΈΡ
ΡΡΡΡΠΎΠΉΡΡΠ². ΠΡΠΈΠ²ΠΎΠ΄ΡΡΡΡ ΠΏΡΠΈΠΌΠ΅ΡΡ ΠΏΠΎΡΡΡΠΎΠ΅Π½ΠΈΡ ΠΌΠ°ΡΡΠ΅Π²ΡΡ
ΡΠ΅ΡΡΠΎΠ², ΠΈΠΌΠ΅ΡΡΠΈΡ
ΠΌΠ°ΠΊΡΠΈΠΌΠ°Π»ΡΠ½ΡΡ ΠΏΠΎΠ»Π½ΠΎΡΡ ΠΏΠΎΠΊΡΡΡΠΈΡ, Π° ΡΠ°ΠΊΠΆΠ΅ ΠΌΠ°ΡΡΠ΅Π²ΡΡ
ΡΠ΅ΡΡΠΎΠ² Ρ ΠΌΠΈΠ½ΠΈΠΌΠ°Π»ΡΠ½ΠΎΠΉ Π²ΡΠ΅ΠΌΠ΅Π½Π½ΠΎΠΉ ΡΠ»ΠΎΠΆΠ½ΠΎΡΡΡΡ, ΡΠ°Π²Π½ΠΎΠΉ 18N. ΠΡΡΠ»Π΅Π΄ΡΠ΅ΡΡΡ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΡ ΠΎΠ΄Π½ΠΎΠΊΡΠ°ΡΠ½ΠΎΠ³ΠΎ ΠΏΡΠΈΠΌΠ΅Π½Π΅Π½ΠΈΡ ΡΠ΅ΡΡΠΎΠ² ΡΠΈΠΏΠ° MATS++, March Cβ ΠΈ March PS Π΄Π»Ρ ΡΠ°Π·Π»ΠΈΡΠ½ΠΎΠ³ΠΎ ΠΊΠΎΠ»ΠΈΡΠ΅ΡΡΠ²Π° k β€ 9 ΡΡΠ΅Π΅ΠΊ ΠΏΠ°ΠΌΡΡΠΈ, ΡΡΠ°ΡΡΠ²ΡΡΡΠΈΡ
Π² Π½Π΅ΠΈΡΠΏΡΠ°Π²Π½ΠΎΡΡΠΈ PNPSFk. ΠΠ±ΠΎΡΠ½ΠΎΠ²ΡΠ²Π°Π΅ΡΡΡ ΠΏΡΠΈΠΌΠ΅Π½ΠΈΠΌΠΎΡΡΡ ΠΌΠ½ΠΎΠ³ΠΎΠΊΡΠ°ΡΠ½ΠΎΠ³ΠΎ ΡΠ΅ΡΡΠΈΡΠΎΠ²Π°Π½ΠΈΡ Ρ ΠΈΠ·ΠΌΠ΅Π½ΡΠ΅ΠΌΡΠΌΠΈ Π°Π΄ΡΠ΅ΡΠ½ΡΠΌΠΈ ΠΏΠΎΡΠ»Π΅Π΄ΠΎΠ²Π°ΡΠ΅Π»ΡΠ½ΠΎΡΡΡΠΌΠΈ, Π² ΠΊΠ°ΡΠ΅ΡΡΠ²Π΅ ΠΊΠΎΡΠΎΡΡΡ
ΠΏΡΠ΅Π΄Π»Π°Π³Π°Π΅ΡΡΡ ΠΏΡΠΈΠΌΠ΅Π½ΡΡΡ ΡΠ»ΡΡΠ°ΠΉΠ½ΡΠ΅ ΠΏΠΎΡΠ»Π΅Π΄ΠΎΠ²Π°ΡΠ΅Π»ΡΠ½ΠΎΡΡΠΈ Π°Π΄ΡΠ΅ΡΠΎΠ². ΠΡΠΈΠ²ΠΎΠ΄ΡΡΡΡ Π°Π½Π°Π»ΠΈΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ Π²ΡΡΠ°ΠΆΠ΅Π½ΠΈΡ Π΄Π»Ρ ΠΏΠΎΠ»Π½ΠΎΡΡ ΠΏΠΎΠΊΡΡΡΠΈΡ ΡΠ»ΠΎΠΆΠ½ΡΡ
Π½Π΅ΠΈΡΠΏΡΠ°Π²Π½ΠΎΡΡΠ΅ΠΉ PNPSFk Π² Π·Π°Π²ΠΈΡΠΈΠΌΠΎΡΡΠΈ ΠΎΡ ΠΊΡΠ°ΡΠ½ΠΎΡΡΠΈ ΡΠ΅ΡΡΠ°. ΠΡΠΎΠΌΠ΅ ΡΠΎΠ³ΠΎ, Π΄Π°ΡΡΡΡ ΠΎΡΠ΅Π½ΠΊΠΈ ΡΡΠ΅Π΄Π½Π΅Π³ΠΎ Π·Π½Π°ΡΠ΅Π½ΠΈΡ ΠΊΡΠ°ΡΠ½ΠΎΡΡΠΈ ΡΠ΅ΡΡΠΎΠ² MATS++, March Cβ ΠΈ March PS, ΠΏΠΎΠ»ΡΡΠ΅Π½Π½ΡΠ΅ Π½Π° ΠΎΡΠ½ΠΎΠ²Π°Π½ΠΈΠΈ ΠΌΠ°ΡΠ΅ΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΌΠΎΠ΄Π΅Π»ΠΈ, ΠΊΠΎΡΠΎΡΠ°Ρ ΠΎΠΏΠΈΡΡΠ²Π°Π΅Ρ Π·Π°Π΄Π°ΡΡ ΡΠΎΠ±ΠΈΡΠ°ΡΠ΅Π»Ρ ΠΊΡΠΏΠΎΠ½ΠΎΠ², ΠΈ ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠΈΠ²Π°ΡΡΠΈΠ΅ ΠΎΠ±Π½Π°ΡΡΠΆΠ΅Π½ΠΈΠ΅ Π²ΡΠ΅Ρ
k2k Π½Π΅ΠΈΡΠΏΡΠ°Π²Π½ΠΎΡΡΠ΅ΠΉ PNPSFk. ΠΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ°Π»ΡΠ½ΠΎ ΠΏΠΎΠΊΠ°Π·ΡΠ²Π°Π΅ΡΡΡ ΡΠΏΡΠ°Π²Π΅Π΄Π»ΠΈΠ²ΠΎΡΡΡ Π°Π½Π°Π»ΠΈΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΎΡΠ΅Π½ΠΎΠΊ ΠΈ ΠΏΠΎΠ΄ΡΠ²Π΅ΡΠΆΠ΄Π°Π΅ΡΡΡ Π²ΡΡΠΎΠΊΠ°Ρ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΡ ΠΎΠ±Π½Π°ΡΡΠΆΠ΅Π½ΠΈΡ Π½Π΅ΠΈΡΠΏΡΠ°Π²Π½ΠΎΡΡΠ΅ΠΉ PNPSFk ΡΠ΅ΡΡΠ°ΠΌΠΈ ΡΠΈΠΏΠ° March PS
Designing Fault-Injection Experiments for the Reliability of Embedded Systems
This paper considers the long-standing problem of conducting fault-injections experiments to establish the ultra-reliability of embedded systems. There have been extensive efforts in fault injection, and this paper offers a partial summary of the efforts, but these previous efforts have focused on realism and efficiency. Fault injections have been used to examine diagnostics and to test algorithms, but the literature does not contain any framework that says how to conduct fault-injection experiments to establish ultra-reliability. A solution to this problem integrates field-data, arguments-from-design, and fault-injection into a seamless whole. The solution in this paper is to derive a model reduction theorem for a class of semi-Markov models suitable for describing ultra-reliable embedded systems. The derivation shows that a tight upper bound on the probability of system failure can be obtained using only the means of system-recovery times, thus reducing the experimental effort to estimating a reasonable number of easily-observed parameters. The paper includes an example of a system subject to both permanent and transient faults. There is a discussion of integrating fault-injection with field-data and arguments-from-design