#Made_Easy_Workbook

Question

T₁:R₁(A)R₁(B)W₁(B)

T₁:R₂(A)R₂(B)W₂(B)

(a)number of serializable schedule.

(b) number of non-serializable schedule.

(c) number of non serial schedules which are serializable.

 

Comments

a. 8

b. 12

c. 6

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yes ..correct answer.Please write solution for this

Answer 1

T₁:R₁(A)R₁(B)W₁(B) 

T₁:R₂(A)R₂(B)W₂(B)

total schedules(concurrent)= (6!)/3!*3! = 20

now serializable schedules are:

T1-->T2 = 4 schedules as R2 can be kept at 4 different places. similarly for  T2-->T1 =4 schedules as only R1 can be moved. .

so total 8 serializable schedules.. answer A.

non serializable schedule = total schedule - serializable schedule

  =20-8 =12 non serializable schedule answer B

now from 8 serializable schedule : 2 are serial as T1-->T1 and T2->T1`

so total number of non serial serializable schedule = 8 -2 =6 answer c.

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Comments

if you can upload an image showing possibilities then it will be a great help

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@anil ji see now :)

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which item of R1 And R2 u r talking about?

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transaction is T1->T2 and we can only move R2(A) to four different positions in transactions T1.