Timestamp Ordering Protocol MCQs For Gate Exam -

Timestamp Ordering Protocol MCQs

Q1

T1 has timestamp TS(T1) = 5, T2 has TS(T2) = 8.
T1 requests W(A), R(A) was last read by T2. Which occurs?
A. T1 proceeds
B. T1 is aborted
C. T2 is aborted
D. Deadlock

✅ Answer: B
Solution:

Timestamp ordering: TS(T1) < TS(T2), T1 wants to write on A → violates TO rules (write-after-read conflict) → T1 aborted.

Q2

T1: TS = 10, wants to R(B). Last write of B by T2: TS = 12.
What happens?
A. T1 reads successfully
B. T1 is aborted
C. T2 is aborted
D. Both wait

✅ Answer: B
Solution:

T1 older than last write → read-after-write conflict → T1 aborted (Thomas Write Rule may ignore if allowed, else abort).

Q3

Which of the following ensures conflict-serializable schedules using timestamps?
A. Basic 2PL
B. Strict 2PL
C. Timestamp Ordering (TO)
D. Rigorous 2PL

✅ Answer: C
Solution:

TO schedules operations based on timestamps → ensures conflict serializability without locks.

Q4

T1: TS=6, requests W(A); last write of A by T2: TS=5.
Can T1 proceed?
A. Yes
B. No, abort T1
C. T2 abort
D. Wait

✅ Answer: A
Solution:

TS(T1)=6 > last write TS(T2)=5 → no conflict → T1 proceeds.

Q5

T1: TS=4, requests R(A); last write TS(A) = 6.
Which occurs?
A. T1 reads A
B. T1 aborts
C. T2 aborts
D. Deadlock

✅ Answer: B
Solution:

Read-after-write conflict: T1 older than last write → violates TO rules → T1 aborted.

Q6

T1: TS=7, wants W(B); last read of B by T2: TS=8.
Action?
A. T1 writes successfully
B. T1 aborts
C. T2 aborts
D. Both wait

✅ Answer: B
Solution:

Write-after-read conflict: T1 older than last read → violates TO → T1 aborted.

Q7

Which property is guaranteed by Timestamp Ordering?
A. Deadlock-free
B. Conflict-serializable
C. Cascading abort-free
D. All of the above

✅ Answer: D
Solution:

TO protocol: no waits → deadlock-free
Enforces conflict serializability
Cascading aborts avoided by aborting conflicting transactions

Q8

T1: TS=10, requests R(A); last write of A TS=8.
Can T1 read?
A. Yes
B. No
C. T2 abort
D. Deadlock

✅ Answer: A
Solution:

T1 newer than last write → read allowed → T1 reads successfully.

Q9

T1: TS=3, wants W(A); last read by T2: TS=4.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 aborted
D. Wait

✅ Answer: B
Solution:

Write-after-read conflict: T1 older than last read → violates TO → T1 aborted.

Q10

T1: TS=9, requests R(B); last write of B TS=5.
Can T1 read?
A. Yes
B. No
C. T2 abort
D. Deadlock

✅ Answer: A
Solution:

Read-after-write allowed since T1 newer than last write → T1 reads successfully.

Q11

T1: TS=6, wants W(A); last write of A TS=6.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 aborted
D. Deadlock

✅ Answer: B
Solution:

T1 timestamp equals last write → conflict → T1 aborted.

Q12

Which is not true about Timestamp Ordering Protocol?
A. Deadlock-free
B. Uses timestamps to order operations
C. Guarantees recoverable schedules
D. May require waits

✅ Answer: D
Solution:

TO is non-blocking → transactions never wait → deadlock-free, no waits required.

Q13

T1: TS=5, wants R(A); last write TS(A)=7.
Action?
A. T1 reads successfully
B. T1 aborts
C. T2 abort
D. Wait

✅ Answer: B
Solution:

Read-after-write conflict: T1 older than last write → T1 aborted.

Q14

T1: TS=8, wants W(B); last read TS(B)=6.
Can T1 proceed?
A. Yes
B. No, abort T1
C. T2 abort
D. Wait

✅ Answer: A
Solution:

T1 newer than last read → no conflict → T1 writes successfully.

Q15

Which rule applies for Write-after-Read conflicts in TO?
A. Abort older transaction
B. Abort newer transaction
C. Delay transaction
D. Ignore

✅ Answer: A
Solution:

Older transaction attempting write after newer read → violates TO → older transaction aborted.

Q16

T1: TS=12, requests R(A); last write TS(A)=10.
Action?
A. T1 reads successfully
B. T1 aborted
C. T2 aborted
D. Deadlock

✅ Answer: A
Solution:

T1 newer than last write → read allowed → T1 reads successfully.

Q17

T1: TS=4, wants W(A); last read TS(A)=7.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 aborted
D. Wait

✅ Answer: B
Solution:

Write-after-read conflict: T1 older than last read → T1 aborted.

Q18

Which property is inherent in Timestamp Ordering Protocol?
A. Deadlock-free
B. Cascading aborts free
C. Serializability
D. All of the above

✅ Answer: D
Solution:

TO protocol → deadlock-free, avoids cascading aborts by aborting conflicting transactions, ensures serializability.

Q19

T1: TS=9, wants W(A); last write TS(A)=7.
Can T1 write?
A. Yes
B. No, abort
C. T2 abort
D. Wait

✅ Answer: A
Solution:

T1 newer than last write → write allowed.

Q20

T1: TS=3, requests R(A); last write TS(A)=5.
Action?
A. T1 reads successfully
B. T1 aborted
C. T2 aborted
D. Deadlock

✅ Answer: B
Solution:

T1 older than last write → violates read-after-write rule → T1 aborted.

Q21

T1: TS=6, requests W(A); last read TS(A)=8.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 aborted
D. Wait

✅ Answer: B
Solution:

Write-after-read conflict: T1 older than last read → violates TO → T1 aborted.

Q22

T1: TS=12, requests R(B); last write TS(B)=10.
Can T1 read?
A. Yes
B. No, abort
C. T2 abort
D. Wait

✅ Answer: A
Solution:

T1 newer than last write → read allowed.

Q23

T1: TS=4, requests W(C); last write TS(C)=5.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 aborted
D. Wait

✅ Answer: B
Solution:

T1 older than last write → violates write-after-write TO rule → T1 aborted.

Q24

Which type of conflict is resolved by aborting the older transaction in TO?
A. Read-after-write
B. Write-after-read
C. Write-after-write
D. Both B and C

✅ Answer: B
Solution:

In write-after-read, older transaction trying to write after newer read → older aborted.

Q25

T1: TS=8, requests R(A); last write TS(A)=10.
Action?
A. T1 reads successfully
B. T1 aborted
C. T2 aborted
D. Wait

✅ Answer: B
Solution:

T1 older than last write → read-after-write conflict → T1 aborted.

Q26

T1: TS=15, requests W(B); last read TS(B)=12.
Can T1 write?
A. Yes
B. No, abort
C. T2 abort
D. Wait

✅ Answer: A
Solution:

T1 newer than last read → write allowed.

Q27

Which property is ensured inherently by Timestamp Ordering?
A. Deadlock-free
B. Conflict-serializable
C. Cascading-abort-free
D. All of the above

✅ Answer: D
Solution:

TO protocol → no waits → deadlock-free
Ensures serializability
Avoids cascading aborts by aborting conflicting transactions.

Q28

T1: TS=9, requests R(C); last write TS(C)=7.
Can T1 read?
A. Yes
B. No, abort
C. T2 abort
D. Deadlock

✅ Answer: A
Solution:

T1 newer than last write → read allowed → T1 reads successfully.

Q29

T1: TS=5, wants W(D); last read TS(D)=6.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 aborted
D. Wait

✅ Answer: B
Solution:

Write-after-read conflict: T1 older than last read → T1 aborted.

Q30

T1: TS=11, requests R(B); last write TS(B)=10.
Can T1 read?
A. Yes
B. No
C. T2 abort
D. Wait

✅ Answer: A
Solution:

T1 newer than last write → read allowed.

Q31

T1: TS=7, requests W(A); last write TS(A)=7.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 aborted
D. Deadlock

✅ Answer: B
Solution:

Timestamp equal → violates TO → T1 aborted.

Q32

Which type of operation never waits in TO protocol?
A. Read
B. Write
C. Both read & write
D. None

✅ Answer: C
Solution:

TO protocol → non-blocking → conflicts resolved via abort → transactions never wait → deadlock-free.

Q33

T1: TS=8, requests R(A); last write TS(A)=12.
Action?
A. T1 reads successfully
B. T1 aborted
C. T2 aborted
D. Wait

✅ Answer: B
Solution:

T1 older than last write → read-after-write conflict → T1 aborted.

Q34

T1: TS=10, wants W(B); last read TS(B)=9.
Can T1 write?
A. Yes
B. No, abort
C. T2 abort
D. Wait

✅ Answer: A
Solution:

T1 newer than last read → write allowed.

Q35

Which rule handles write-after-write conflicts in TO?
A. Abort older transaction
B. Abort newer transaction
C. Delay transaction
D. Ignore conflict

✅ Answer: B
Solution:

Newer transaction trying to write → older/newer comparison → if timestamp newer, may proceed or older aborted → ensures serializability.

Q36

T1: TS=6, requests R(C); last write TS(C)=8.
Action?
A. T1 reads successfully
B. T1 aborted
C. T2 abort
D. Deadlock

✅ Answer: B
Solution:

T1 older than last write → violates TO → T1 aborted.

Q37

T1: TS=13, requests W(D); last read TS(D)=11.
Can T1 write?
A. Yes
B. No, abort
C. T2 abort
D. Wait

✅ Answer: A
Solution:

T1 newer than last read → write allowed.

Q38

Which property is unique to Timestamp Ordering Protocol compared to 2PL?
A. Deadlock-free
B. Serializability
C. Cascading-abort-free
D. Lock-based

✅ Answer: A
Solution:

TO is non-locking → deadlock-free by design → unlike 2PL, which may deadlock.

Q39

T1: TS=5, wants W(E); last read TS(E)=7.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 aborted
D. Wait

✅ Answer: B
Solution:

Write-after-read conflict: older transaction → T1 aborted.

Q40

T1: TS=9, requests R(E); last write TS(E)=6.
Can T1 read?
A. Yes
B. No, abort
C. T2 abort
D. Wait

✅ Answer: A
Solution:

T1 newer than last write → read allowed.

Q41

T1: TS=7, requests W(A); last read TS(A)=10.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 aborted
D. Wait

✅ Answer: B
Solution:

Write-after-read conflict: older transaction trying to write after newer read → violates TO → T1 aborted.

Q42

T1: TS=12, requests R(B); last write TS(B)=9.
Can T1 read?
A. Yes
B. No, abort
C. T2 abort
D. Deadlock

✅ Answer: A
Solution:

T1 newer than last write → read allowed → T1 reads successfully.

Q43

T1: TS=6, requests W(C); last write TS(C)=7.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 aborted
D. Wait

✅ Answer: B
Solution:

Older transaction trying to write after newer write → violates TO → T1 aborted.

Q44

T1: TS=8, requests R(A); last write TS(A)=10.
Action?
A. T1 reads successfully
B. T1 aborted
C. T2 aborted
D. Wait

✅ Answer: B
Solution:

Read-after-write conflict → T1 older than last write → T1 aborted.

Q45

T1: TS=14, requests W(B); last read TS(B)=12.
Can T1 write?
A. Yes
B. No, abort
C. T2 abort
D. Wait

✅ Answer: A
Solution:

T1 newer than last read → write allowed → T1 writes successfully.

Q46

Which property is guaranteed by Timestamp Ordering Protocol?
A. Deadlock-free
B. Conflict-serializable
C. Cascading-abort-free
D. All of the above

✅ Answer: D
Solution:

TO protocol → non-blocking (deadlock-free), aborts conflicting transactions (cascading-abort-free), ensures serializability.

Q47

T1: TS=5, requests R(D); last write TS(D)=8.
Action?
A. T1 reads successfully
B. T1 aborted
C. T2 abort
D. Wait

✅ Answer: B
Solution:

T1 older than last write → read-after-write conflict → T1 aborted.

Q48

T1: TS=11, requests W(C); last read TS(C)=10.
Can T1 write?
A. Yes
B. No, abort
C. T2 abort
D. Wait

✅ Answer: A
Solution:

T1 newer than last read → write allowed.

Q49

T1: TS=7, requests R(E); last write TS(E)=5.
Action?
A. T1 reads successfully
B. T1 aborted
C. T2 abort
D. Wait

✅ Answer: A
Solution:

T1 newer than last write → read allowed.

Q50

T1: TS=6, requests W(A); last read TS(A)=9.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 abort
D. Wait

✅ Answer: B
Solution:

Write-after-read conflict → older transaction → T1 aborted.

Q51

T1: TS=13, requests R(B); last write TS(B)=10.
Can T1 read?
A. Yes
B. No
C. T2 abort
D. Deadlock

✅ Answer: A
Solution:

T1 newer than last write → read allowed → T1 reads successfully.

Q52

T1: TS=8, requests W(C); last write TS(C)=8.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 abort
D. Deadlock

✅ Answer: B
Solution:

Timestamp equal → violates TO rule → T1 aborted.

Q53

T1: TS=5, requests R(A); last write TS(A)=7.
Action?
A. T1 reads successfully
B. T1 aborted
C. T2 abort
D. Wait

✅ Answer: B
Solution:

Read-after-write conflict → T1 older than last write → T1 aborted.

Q54

T1: TS=10, requests W(B); last read TS(B)=8.
Can T1 write?
A. Yes
B. No, abort
C. T2 abort
D. Wait

✅ Answer: A
Solution:

T1 newer than last read → write allowed → T1 writes successfully.

Q55

Which operation never waits in Timestamp Ordering?
A. Read
B. Write
C. Both read & write
D. None

✅ Answer: C
Solution:

TO is non-blocking → transactions abort conflicts instead of waiting → deadlock-free.

Q56

T1: TS=7, requests R(D); last write TS(D)=9.
Action?
A. T1 reads successfully
B. T1 aborted
C. T2 abort
D. Deadlock

✅ Answer: B
Solution:

Older read after newer write → T1 aborted.

Q57

T1: TS=14, requests W(E); last read TS(E)=11.
Can T1 write?
A. Yes
B. No, abort
C. T2 abort
D. Wait

✅ Answer: A
Solution:

T1 newer than last read → write allowed → T1 writes successfully.

Q58

T1: TS=6, requests R(C); last write TS(C)=8.
Action?
A. T1 reads successfully
B. T1 aborted
C. T2 abort
D. Deadlock

✅ Answer: B
Solution:

Read-after-write conflict → T1 older → aborted.

Q59

T1: TS=12, requests R(D); last write TS(D)=10.
Can T1 read?
A. Yes
B. No, abort
C. T2 abort
D. Deadlock

✅ Answer: A
Solution:

T1 newer than last write → read allowed.

Q60

T1: TS=5, requests W(A); last read TS(A)=7.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 abort
D. Wait

✅ Answer: B
Solution:

Write-after-read conflict → older transaction → T1 aborted.

Q61

T1: TS=9, requests W(A); last read TS(A)=12.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 aborted
D. Wait

✅ Answer: B
Solution:

Write-after-read conflict: T1 older than last read → violates TO → T1 aborted.

Q62

T1: TS=13, requests R(B); last write TS(B)=10.
Can T1 read?
A. Yes
B. No, abort
C. T2 abort
D. Deadlock

✅ Answer: A
Solution:

T1 newer than last write → read allowed → T1 reads successfully.

Q63

T1: TS=7, requests W(C); last write TS(C)=9.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 aborted
D. Wait

✅ Answer: B
Solution:

Older write after newer write → violates TO → T1 aborted.

Q64

T1: TS=8, requests R(D); last write TS(D)=10.
Action?
A. T1 reads successfully
B. T1 aborted
C. T2 aborted
D. Wait

✅ Answer: B
Solution:

Read-after-write conflict → T1 older than last write → T1 aborted.

Q65

T1: TS=15, requests W(E); last read TS(E)=12.
Can T1 write?
A. Yes
B. No, abort
C. T2 abort
D. Wait

✅ Answer: A
Solution:

T1 newer than last read → write allowed → T1 writes successfully.

Q66

T1: TS=5, requests R(A); last write TS(A)=8.
Action?
A. T1 reads successfully
B. T1 aborted
C. T2 abort
D. Deadlock

✅ Answer: B
Solution:

Older read after newer write → T1 aborted.

Q67

T1: TS=12, requests W(B); last read TS(B)=10.
Can T1 write?
A. Yes
B. No, abort
C. T2 abort
D. Wait

✅ Answer: A
Solution:

T1 newer than last read → write allowed → T1 writes successfully.

Q68

T1: TS=6, requests R(C); last write TS(C)=9.
Action?
A. T1 reads successfully
B. T1 aborted
C. T2 abort
D. Deadlock

✅ Answer: B
Solution:

Read-after-write conflict → older transaction → T1 aborted.

Q69

T1: TS=14, requests R(D); last write TS(D)=11.
Can T1 read?
A. Yes
B. No, abort
C. T2 abort
D. Deadlock

✅ Answer: A
Solution:

T1 newer than last write → read allowed.

Q70

T1: TS=5, requests W(A); last read TS(A)=7.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 abort
D. Wait

✅ Answer: B
Solution:

Write-after-read conflict → older transaction → T1 aborted.

Q71

T1: TS=9, requests R(B); last write TS(B)=6.
Can T1 read?
A. Yes
B. No, abort
C. T2 abort
D. Deadlock

✅ Answer: A
Solution:

T1 newer than last write → T1 reads successfully.

Q72

T1: TS=8, requests W(C); last write TS(C)=8.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 abort
D. Deadlock

✅ Answer: B
Solution:

Timestamp equal → violates TO → T1 aborted.

Q73

T1: TS=6, requests R(D); last write TS(D)=9.
Action?
A. T1 reads successfully
B. T1 aborted
C. T2 abort
D. Deadlock

✅ Answer: B
Solution:

Older read after newer write → T1 aborted.

Q74

T1: TS=13, requests W(E); last read TS(E)=11.
Can T1 write?
A. Yes
B. No, abort
C. T2 abort
D. Wait

✅ Answer: A
Solution:

T1 newer than last read → write allowed.

Q75

T1: TS=7, requests R(A); last write TS(A)=10.
Action?
A. T1 reads successfully
B. T1 aborted
C. T2 abort
D. Deadlock

✅ Answer: B
Solution:

Read-after-write conflict → older → T1 aborted.

Q76

T1: TS=10, requests W(B); last read TS(B)=8.
Can T1 write?
A. Yes
B. No, abort
C. T2 abort
D. Wait

✅ Answer: A
Solution:

T1 newer than last read → write allowed → T1 writes successfully.

Q77

Which property is unique to TO compared to 2PL?
A. Deadlock-free
B. Serializability
C. Cascading-abort-free
D. Lock-based

✅ Answer: A
Solution:

TO is non-locking → deadlock-free by design.

Q78

T1: TS=5, requests W(C); last read TS(C)=7.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 abort
D. Wait

✅ Answer: B
Solution:

Write-after-read conflict → T1 aborted.

Q79

T1: TS=12, requests R(D); last write TS(D)=10.
Can T1 read?
A. Yes
B. No, abort
C. T2 abort
D. Deadlock

✅ Answer: A
Solution:

T1 newer than last write → read allowed.

Q80

T1: TS=6, requests W(E); last write TS(E)=9.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 abort
D. Wait

✅ Answer: B
Solution:

Older write after newer write → T1 aborted.

Q81

T1: TS=8, requests R(A); last write TS(A)=7.
Can T1 read?
A. Yes
B. No
C. T2 abort
D. Deadlock

✅ Answer: A
Solution:

T1 newer than last write → read allowed.

Q82

T1: TS=5, requests W(B); last read TS(B)=8.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 abort
D. Wait

✅ Answer: B
Solution:

Write-after-read conflict → older → T1 aborted.

Q83

T1: TS=14, requests R(C); last write TS(C)=10.
Action?
A. T1 reads successfully
B. T1 aborted
C. T2 abort
D. Deadlock

✅ Answer: A
Solution:

T1 newer than last write → read allowed.

Q84

T1: TS=7, requests W(D); last read TS(D)=9.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 abort
D. Wait

✅ Answer: B
Solution:

Write-after-read conflict → T1 older → T1 aborted.

Q85

T1: TS=11, requests R(E); last write TS(E)=10.
Can T1 read?
A. Yes
B. No
C. T2 abort
D. Deadlock

✅ Answer: A
Solution:

T1 newer than last write → read allowed.

Q86

T1: TS=6, requests W(A); last write TS(A)=9.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 abort
D. Wait

✅ Answer: B
Solution:

Older write after newer write → T1 aborted.

Q87

T1: TS=13, requests R(B); last write TS(B)=11.
Can T1 read?
A. Yes
B. No
C

. T2 abort
D. Deadlock

✅ Answer: A
Solution:

T1 newer than last write → read allowed.

Q88

T1: TS=5, requests W(C); last read TS(C)=7.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 abort
D. Wait

✅ Answer: B
Solution:

Write-after-read conflict → T1 aborted.

Q89

T1: TS=12, requests R(D); last write TS(D)=10.
Can T1 read?
A. Yes
B. No
C. T2 abort
D. Deadlock

✅ Answer: A
Solution:

T1 newer than last write → read allowed.

Q90

T1: TS=6, requests W(E); last write TS(E)=9.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 abort
D. Wait

✅ Answer: B
Solution:

Older write after newer write → T1 aborted.

Q91

T1: TS=8, requests R(A); last write TS(A)=7.
Can T1 read?
A. Yes
B. No
C. T2 abort
D. Deadlock

✅ Answer: A
Solution:

T1 newer than last write → read allowed.

Q92

T1: TS=5, requests W(B); last read TS(B)=8.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 abort
D. Wait

✅ Answer: B
Solution:

Write-after-read conflict → T1 aborted.

Q93

T1: TS=14, requests R(C); last write TS(C)=10.
Action?
A. T1 reads successfully
B. T1 aborted
C. T2 abort
D. Deadlock

✅ Answer: A
Solution:

T1 newer than last write → read allowed.

Q94

T1: TS=7, requests W(D); last read TS(D)=9.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 abort
D. Wait

✅ Answer: B
Solution:

Write-after-read conflict → T1 older → T1 aborted.

Q95

T1: TS=11, requests R(E); last write TS(E)=10.
Can T1 read?
A. Yes
B. No
C. T2 abort
D. Deadlock

✅ Answer: A
Solution:

T1 newer than last write → read allowed.

Q96

T1: TS=6, requests W(A); last write TS(A)=9.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 abort
D. Wait

✅ Answer: B
Solution:

Older write after newer write → T1 aborted.

Q97

T1: TS=13, requests R(B); last write TS(B)=11.
Can T1 read?
A. Yes
B. No
C. T2 abort
D. Deadlock

✅ Answer: A
Solution:

T1 newer than last write → read allowed.

Q98

T1: TS=5, requests W(C); last read TS(C)=7.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 abort
D. Wait

✅ Answer: B
Solution:

Write-after-read conflict → T1 aborted.

Q99

T1: TS=12, requests R(D); last write TS(D)=10.
Can T1 read?
A. Yes
B. No
C. T2 abort
D. Deadlock

✅ Answer: A
Solution:

T1 newer than last write → read allowed.

Q100

T1: TS=6, requests W(E); last write TS(E)=9.
Action?
A. T1 writes successfully
B. T1 aborted
C. T2 abort
D. Wait

✅ Answer: B
Solution:

Older write after newer write → T1 aborted.