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slega [8]
3 years ago
7

Consider a magnetic disk consisting of 16 heads and 400 cylinders. This disk has four 100-cylinder zones with the cylinders in d

ifferent zones containing 160, 200, 240. and 280 sectors, respectively. Assume that each sector contains 512 bytes, average seek time between adjacent cylinders is 1 msec, and the disk rotates at 7200 RPM. Calculate the (a) disk capacity, (b) optimal track skew, and (c) maximum data transfer rate.
Engineering
1 answer:
e-lub [12.9K]3 years ago
3 0

Answer:

Disk Capacity  = 45056000 bytes

Optimal skew = 26.455 ≈ 27

Maximum Data transfer rate =  262.5 GB per second

Explanation:

given data

heads = 16

cylinders = 400

cylinder zones = 100

each sector contains = 512 bytes

average seek time = 1 msec

disk rotates = 7200 RPM

to find out

disk capacity, optimal track skew, and maximum data transfer rate

solution

first we get total number of sectors that is  

total number of sector = number of zones × (number of sectors in different zones

total number of sector = 100 × (160+200+240+280)

total number of sector = 88000

so

Disk Capacity = total number of sectors  ×  size of each sector

Disk Capacity =  88000 × 512

Disk Capacity  = 45056000 bytes

and

Rotation time = \frac{60}{7200}

Rotation time = 8.33 milli seconds

so Optimal number of sectors in a track = average of ( 160,200,240,280 )

Optimal number of sectors in a track  = 220

now New sector is read every  \frac{8.33}{220} i.e = 0.0378 ms

here Optimal skew = seek time ÷ new sector read time

Optimal skew = \frac{1}{0.0378}

Optimal skew = 26.455 ≈ 27

and

here we know that for maximum transfer rate we will select cylinder with maximum number of sectors i.e here  280 sectors

so

capacity of one track with maximum = 280 × 512

capacity of one track with maximum =  = 143360 bytes

and Number of rotations in 1 second is = \frac{7200}{60}

Number of rotations in 1 second is = 120

so Data transfer rate = Number of heads × Capacity of one track × Number of rotations in one second

Data transfer rate =  16 × 143360 × 120

Data transfer rate = 275251200 bytes per second

Data transfer rate =  262.5 GB per second

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Air with a mass flow rate of 2.3 kg/s enters a horizontal nozzle operating at steady state at 450 K, 350 kPa, and velocity of 3
viktelen [127]

Answer:

Given that

Mass flow rate ,m=2.3 kg/s

T₁=450 K

P₁=350 KPa

C₁=3 m/s

T₂=300 K

C₂=460 m/s

Cp=1.011 KJ/kg.k

For ideal gas

P V = m R T

P = ρ RT

\rho_1=\dfrac{P_1}{RT_1}

\rho_1=\dfrac{350}{0.287\times 450}

ρ₁=2.71 kg/m³

mass flow rate

m= ρ₁A₁C₁

2.3 = 2.71 x A₁ x 3

A₁=0.28 m²

Now from first law for open system

h_1+\dfrac{C_1^2}{200}+Q=h_2+\dfrac{C_2^2}{2000}

For ideal gas

Δh = CpΔT

by putting the values

1.011\times 450+\dfrac{3^2}{200}+Q=1.011\times 300+\dfrac{460^2}{2000}

Q=1.011\times 300+\dfrac{460^2}{2000}-\dfrac{3^2}{200}-1.011\times 450

Q= - 45.49 KJ/kg

Q =- m x 45.49 KW

Q= - 104.67 KW

Negative sign indicates that heat transfer from air to surrounding

4 0
3 years ago
A solid round bar with a diameter of 2.32 in has a groove cut to a diameter of 2.09 in, with a radius of 0.117 in. The bar is no
Alenkinab [10]

Answer:

nf=1.11 (Goodman criterion)

ny=2.41 (factor of safety for fatigue)

Explanation:

From the table A-20 Deterministic ASTM minimum tensile and yield strengths for HR and CD steels, we have approximately:

Sut=120 kpsi

Sy=66 kpsi

Due Sut<1400 Mpa, the endurance limit is:

Se=0.5Sut=0.5*120=60 kpsi

The surface condition modification factor is:

ka=a(Sut)^{b}=2.7(120)^{-0.265} =0.759

The effective diameter is:

de=0.37d=0.37*2.09=0.7733 in

The size factor is:

kb=0.879de^{-0.107} =0.879(0.7733)^{-0.107} =0.9

The endurance limit at critical location is:

See=ka*kb*kc*kd*kd*ke*kf*Se=0.759*0.9*1*60=40.986 kpsi

\frac{D}{d}=\frac{2.32}{2.09}  =1.11\\\frac{r}{d}=\frac{0.117}{2.09}  =0.056

From Figure A-15-15 chart, the Kf = 2.1

The notch sensitivity is:

\sqrt{a}=0.246-3.08(10^{-3})Sut+1.51(10^{-5})Sut^{2}-2.67(10^{-8})Sut^{3}

\sqrt{a}=0.246-3.08(10^{-3})(120)+1.51(10^{-5})(120^{2})-2.67(10^{-8})(120^{3})=0.048

q=\frac{1}{1+\frac{\sqrt{a} }{\sqrt{r} } }=\frac{1}{1+\frac{0.048}{\sqrt{0.117} } }=0.877

The fatigue stress is:

Kf=1+q(Kt-1)=1+0.877(2.1-1)=1.96

The moment of inertia is:

I=\frac{\pi }{64} d^{4}=\frac{\pi }{64}  (2.09^{4})=0.936 in^{4}

The maximum stress is:

omax=\frac{M*c}{I}=\frac{25000*\frac{2.09}{2} }{0.936}  =27911.32 psi=27.911 kpsi

The mean stress is:

om=Kf\frac{omax+omin}{2} =1.96\frac{27.911+0}{2}=27.35 kpsi

The alternate stress is:

oa=Kf|\frac{omax-omin}{2}|=27.35 kpsi

The fatigue factor using Goodman is:

\frac{1}{nf}=\frac{oa}{See}+\frac{om}{Sut}\\\frac{1}{nf}=\frac{27.35}{40.986}+\frac{27.35}{120}

nf=1.11

the factor of safety is:

ny=\frac{Sy}{omax}=\frac{66}{27.35}  =2.41

4 0
4 years ago
Create a program named IntegerFacts whose Main() method declares an array of 10 integers.Call a method named FillArray to intera
musickatia [10]

Answer:

C# codee

using System;

class IntegerFacts

{

static void Main()

{

int[] x = new int[10];

int sum = 0;

int siz = 0, high = 0, low = 0, avg = 0;

siz = FillArray(x);

Statistics(x, ref high, ref low, ref sum, ref avg, siz);

Console.Write("The highest value is " + high);

Console.Write("\nThe lowest value is " + low);

Console.Write("\nThe sum of the values is " + sum);

Console.Write("\nThe average is " + avg);

}

static void Statistics (int [] b, ref int h, ref int l, ref int s, ref int a, int size)

{

if (size == 0)

h = l = s = a = 0;

else

{

int i =0;

l = 999;

h = 0;

s = 0;

for (; i < size;++i)

{

if(b[i] > h)

h = b[i];

if(b[i] < l)

l = b[i];

s += b[i];

}

a = s / size;

}

}

static int FillArray (int[] a)

{

int i = 0, count = 0;

int intTemp =0 ;

string temp;

for(i = 0 ; i < 10 ; i++)

{

Console.Write("Enter element number"+(i+1) +" : ");

temp = Console.ReadLine();

if (int.TryParse(temp, out intTemp)) {

if (intTemp != 999)

{

a[i] = intTemp;

count++;

}

else

break;

}

else

{

Console.Write("\n\nOops.. You entered a wrong number. Try again \n\n");

i--;

}

}

return count;

}

}

Explanation:

The output of the above program is given in the attached file.

8 0
4 years ago
A 0.5 m^3 container is filled with a mixture of 10% by volume ethanol and 90% by volume water at 25 °C. Find the weight of the l
svp [43]

Answer:

total weight of liquid = 4788.25 N or 488.09 kg

Explanation:

given data

total volume = 0.5 m³

volume of ethanol = 10 %  of volume = 0.10 × 0.5 = 0.05 m³

volume of water = 90 % at 25 °C of volume = 0.90 × 0.5 = 0.45 m³

to find out

weight of the liquid

solution

we know that density of water at 25  is 997 kg/m³

and density of ethanol is 789 kg/m³

so weight of water is = density × volume × g

put here value and we take g = 9.81

weight of water is = 997 × 0.45 × 9.81

weight of water = 4401.25 N     ......................1

weight of ethanol is = density × volume × g

put here value and we take g = 9.81

weight of ethanol is = 789 × 0.05 × 9.81

weight of ethanol = 387.00 N       ...............2

so total weight of liquid = sum of equation 1 add 2

total weight of liquid =  4401.25 + 387

total weight of liquid = 4788.25 N or 488.09 kg

7 0
3 years ago
Fill in the tables and find the equivalent resistance for the following circuits:
Dafna11 [192]

Answer:

12 32

Explanation:

3 0
2 years ago
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