1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Nonamiya [84]
3 years ago
9

Disk requests come in to the disk driver for cylinders 10, 22, 20, 2, 40, 6, and 38, in that order. A seek takes 6 msec per cyli

nder. How much seek time is needed for: (a) First-come, first served (b) Closest cylinder next (c) Elevator algorithm (initially moving upward) In all cases, the arm is initially at cylinder 20.
Mathematics
1 answer:
m_a_m_a [10]3 years ago
3 0

Answer:

a) 876 ms

b) 360 ms

c) 348 ms

Step-by-step explanation:

a) When using the  First-come, first serve order, the starts at the initial cylinder  and is served in the same order as it arrives.

For  First-come, first serve, the order is served from (20), 10, 22, 20, 2, 40, 6, and 38.

Seek time = 10 + 12 + 2+ 18 + 38 + 34 + 32 = 146 cylinder

The request uses 146 cylinders, therefore the seek time = 146 cylinder * 6 ms/cylinder = 876 ms

b) When using the Closest cylinder next the  request starts at the initial cylinder  and is served using the shortest movement from current position.

For Elevator algorithm, the order is served from (20), 20, 22, 10, 6, 2, 38, 40

Seek time = 0 + 2 + 12+ 4 + 4 + 36 + 2 = 60 cylinder

The request uses 146 cylinders, therefore the seek time = 60 cylinder * 6 ms/cylinder = 360 ms

c) When using the Elevator algorithm the  request starts at the initial cylinder and moves upwards, then reverses direction.

For  Closest cylinder next, the order is served from (20), 20, 22, 38, 40, 10, 6, 2

Seek time = 0 + 2 + 16+ 2 + 30 + 4 + 4 = 58 cylinder

The request uses 146 cylinders, therefore the seek time = 58 cylinder * 6 ms/cylinder = 348 msa) When using the  First-come, first serve order, the starts at the initial cylinder  and is served in the same order as it arrives.

For  First-come, first serve, the order is served from (20), 10, 22, 20, 2, 40, 6, and 38.

Seek time = 10 + 12 + 2+ 18 + 38 + 34 + 32 = 146 cylinder

The request uses 146 cylinders, therefore the seek time = 146 cylinder * 6 ms/cylinder = 876 ms

b) When using the Closest cylinder next the  request starts at the initial cylinder  and is served using the shortest movement from current position.

For Elevator algorithm, the order is served from (20), 20, 22, 10, 6, 2, 38, 40

Seek time = 0 + 2 + 12+ 4 + 4 + 36 + 2 = 60 cylinder

The request uses 146 cylinders, therefore the seek time = 60 cylinder * 6 ms/cylinder = 360 ms

c) When using the Elevator algorithm the  request starts at the initial cylinder and moves upwards, then reverses direction.

For  Closest cylinder next, the order is served from (20), 20, 22, 38, 40, 10, 6, 2

Seek time = 0 + 2 + 16+ 2 + 30 + 4 + 4 = 58 cylinder

The request uses 146 cylinders, therefore the seek time = 58 cylinder * 6 ms/cylinder = 348 ms

You might be interested in
Help me on 4. Please, I will be answering questions while I wait :)
FinnZ [79.3K]
8:4 
8 to 4
8/4

:D :D :D
4 0
3 years ago
Read 2 more answers
The sides of a triangle are 30, 18, and 24. Use the Pythagorean Theorem to determine if the triangle is right, acute, or obtuse.
Shtirlitz [24]

Answer:

a right triangle

is equal to

Step-by-step explanation:

Pythagorean's theorem is a²+b²=c² with c being the longest sides. If it is true then it is a right triangle.

<u>18²</u> + <u>24²</u> = <u>30²</u>

324+576=900

This is true so the triangle is a right triangle

5 0
2 years ago
The city of Yorkton, Saskatchewan, has an area of 24.0 km^2. If this city were a perfect square, what would it’s exact perimeter
Elis [28]

Answer:

8\sqrt{6}  inches

Step-by-step explanation:

Let l represent the length of the square

The area of a square = l^2

That means,

l^2 = 24 km^2

Take the square root of both sides

l = \sqrt{24}

l = \sqrt{4*6

l = \sqrt{4} *\sqrt{6}

l = 2\sqrt{6}

Now lets find the perimeter

Perimeter of a square, P = 4l

P = 4* 2\sqrt{6}

P = 8\sqrt{6} inches

3 0
3 years ago
A bag of 8 apples cost $2.88. What is the cost of one apple
k0ka [10]
You have to use the formula cost over quantity Divide 8 and $2.88 The answer is. 0.36
6 0
3 years ago
9. What is the difference between an isometric transformation and one that is not isometric? Provide examples to illustrate at l
Sveta_85 [38]
An isometric transformation is a transformation of the objects position, without changing the object itself. There are three types of isometric transformation; translation, reflection, and rotation. Nonisometric transformations change and alter the dimension or shape of an object, like enlargement.
6 0
2 years ago
Other questions:
  • What is the range the 3rd side of the triangle can be with sides 15 cm and 14 cm?
    13·1 answer
  • Factorise completely 4y^2-z^2
    7·1 answer
  • How do you find the probability of the sum of 6 when rolling a die?
    10·1 answer
  • Solve 3x-7=4+6+4x and show your work.<br> Is there one solution, infinite solutions, or no solution?
    14·2 answers
  • Which of the following are used to prove that triangles are congruent? 1. ASA 2. SSS 3. AAA 4. AAS 5. SAS select all that apply.
    11·1 answer
  • Twice a number plus 8 is equal to 22​
    12·2 answers
  • What is the value of u?
    8·1 answer
  • To sacrifice my own life for pakistan
    13·2 answers
  • Find the area of the shaded region. Round to the nearest hundredth where necessary.
    10·1 answer
  • EASY QUESTION??? HELP
    6·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!