A computer has 1000 K of main memory. The jobs arrive and finish in the…

2018

A computer has 1000 K of main memory. The jobs arrive and finish in the sequence Job 1 requiring 200 K arrives Job 2 requiring 350 K arrives Job 3 requiring 300 K arrives Job 1 finishes Job 4 requiring 120 K arrives Job 5 requiring 150 K arrives Job 6 requiring 80 K arrives Among best fit and first fit, which performs better for this sequence?

  1. A.

    First fit

  2. B.

    Best fit

  3. C.

    Both perform the same

  4. D.

    None of the above

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Correct answer: A

First Fit successfully allocates all jobs in the sequence, whereas Best Fit fails to allocate Job 6. With First Fit, Job 4 occupies the hole left by Job 1 (200K), leaving an 80K fragment that accommodates Job 6. Best Fit places Job 4 in the smallest sufficient hole (150K), fragmenting memory into unusable pieces for Job 6. Thus, First Fit performs better for this specific sequence of arrivals and finishes.

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