Computers and Technology, 15.02.2020 02:55 anonymous176

It takes 2 seconds to read or write one block from/to disk and it also takes 1 second of CPU time to merge one block of records. Assume that all input, output, and CPU processing is sequential and there is no waiting time. The block size is 100 records. a) (7) Give an optimal 4-way merging scheme to merge the 6 runs into 1. b) (7) What is the total time taken by the optimal scheme

Answers: 2

Show answers

Answers

Answer from: yoyo6710

Part a: For optimal 4-way merging, initiate with one dummy run of size 0 and merge this with the 3 smallest runs. Than merge the result to the remaining 3 runs to get a merged run of length 6000 records.

Part b: The optimal 4-way merging takes about 249 seconds.

Explanation:

The complete question is missing while searching for the question online, a similar question is found which is solved as below:

Part a

For optimal 4-way merging, we need one dummy run with size 0.

Merge 4 runs with size 0, 500, 800, and 1000 to produce a run with a run length of 2300. The new run length is calculated as follows $L_{mrg}=L_0+L_1+L_2+L_3=0+500+800+1000=2300$ Merge the run as made in step 1 with the remaining 3 runs bearing length 1000, 1200, 1500. The merged run length is 6000 and is calculated as follows

$L_{merged}=L_{mrg}+L_4+L_5+L_6=2300+1000+1200+1500=6000$

The resulting run has length 6000 records.

Part b

For step 1

Input Output Time

Input Output Time is given as

$T_{I.O}=\frac{L_{run}}{Size_{block}} \times Time_{I/O \, per\, block}$

Here

L_run is 2300 for step 01Size_block is 100 as givenTime_{I/O per block} is 2 sec

$T_{I.O}=\frac{L_{run}}{Size_{block}} \times Time_{I/O \, per\, block}\\T_{I.O}=\frac{2300}{100} \times 2 sec\\T_{I.O}=46 sec$

So the input/output time is 46 seconds for step 01.

CPU Time

CPU Time is given as

$T_{CPU}=\frac{L_{run}}{Size_{block}} \times Time_{CPU \, per\, block}$

Here

L_run is 2300 for step 01Size_block is 100 as givenTime_{CPU per block} is 1 sec

$T_{CPU}=\frac{L_{run}}{Size_{block}} \times Time_{CPU \, per\, block}\\T_{CPU}=\frac{2300}{100} \times 1 sec\\T_{CPU}=23 sec$

So the CPU time is 23 seconds for step 01.

Total time in step 01

$T_{step-01}=T_{I.O}+T_{CPU}\\T_{step-01}=46+23\\T_{step-01}=69 sec\\$

Total time in step 01 is 69 seconds.

For step 2

Input Output Time

Input Output Time is given as

$T_{I.O}=\frac{L_{run}}{Size_{block}} \times Time_{I/O \, per\, block}$

Here

L_run is 6000 for step 02Size_block is 100 as givenTime_{I/O per block} is 2 sec

$T_{I.O}=\frac{L_{run}}{Size_{block}} \times Time_{I/O \, per\, block}\\T_{I.O}=\frac{6000}{100} \times 2 sec\\T_{I.O}=120 sec$

So the input/output time is 120 seconds for step 02.

CPU Time

CPU Time is given as

$T_{CPU}=\frac{L_{run}}{Size_{block}} \times Time_{CPU \, per\, block}$

Here

L_run is 6000 for step 02Size_block is 100 as givenTime_{CPU per block} is 1 sec

$T_{CPU}=\frac{L_{run}}{Size_{block}} \times Time_{CPU \, per\, block}\\T_{CPU}=\frac{6000}{100} \times 1 sec\\T_{CPU}=60 sec$

So the CPU time is 60 seconds for step 02.

Total time in step 02

$T_{step-02}=T_{I.O}+T_{CPU}\\T_{step-02}=120+60\\T_{step-02}=180 sec\\$

Total time in step 02 is 180 seconds

Merging Time (Total)

Now the total time for merging is given as

$T_{merge}=T_{step-01}+T_{step-02}\\T_{merge}=69+180\\T_{merge}=249 sec\\$

Total time in merging is 249 seconds seconds

It takes 2 seconds to read or write one block from/to disk and it also takes 1 second of CPU time to

Answer from: Quest

solution:

this situation is called an ip conflict.

data from a server is sent in small bits called packets. in an ip conflict, some packets will end up in one computer while some other packets will end up in another computer.

so…overall none of the computers get the data as the original message or picture being sent by the server cannot be retrieved with only half the packets. so it will show up as an error.

thus the final answer is d.

Answer from: Quest

By checking for voltage with a neon tester;

Another question on Computers and Technology

Computers and Technology, 22.06.2019 09:40

In the lab, which of the following displayed a list of all installed services and included a description of the service, the current state, and whether the service started automatically or manually? a. the services manager b. the applications summary c. the recommended services d. list the safe services list

Answers: 2

Answer

Computers and Technology, 22.06.2019 17:40

Consider the simple 3-station assembly line illustrated below, where the 2 machines at station 1 are parallel, i.e., the product only needs to go through one of the 2 machines before proceeding to station 2.what is the throughput time of this process?

Answers: 2

Answer

Computers and Technology, 23.06.2019 16:30

20 points archie wants to use a reflector as he photographs a newlywed couple. what would he consider in his choice? a. shadow and sunny b. homemade and professional c. lamps and boards d. incident and reflected e. neutral density and enhancement

Answers: 3

Answer

Computers and Technology, 23.06.2019 19:30

What are loans to a company or government for a set amount of time

Answers: 1

Answer

You know the right answer?

It takes 2 seconds to read or write one block from/to disk and it also takes 1 second of CPU time to...

Questions