Question

.Consider the 1000000-record mailing-list file discussed in the text.The file is to be backed up on2400-foot reels of6250-bpi tape with 0.3-inch interblock gaps. Tape sped is200inches per second,

a. Show that only one tape would be required to backup the fleifblocking factor of 50 is used.

6. If a blocking factor of 50is used, how manyextra records couldbe

:accommodated on a2400-foot tapel

c. What is the efective recording density when a blo(king facto50is used?

d. Howlarge does the blocking factor have to be to achieve the maxbmum effective recording density What negative results can result from increasing the blocking factor∶(Note An I/O buffer largeenough to holda block must be allocaed.）

veirradorbne

pae. What would be the minimum blocking factor required to ft the



sf. Ifa blocking factor of 50 is used, howlong would it take to readbone block,including the gap? What would the effectivetransmison

ion rate be?How long would it take to read the entire fle 只.How long would it take to perform a binary search for one records: in the fle, assuming that i is not possible to read backwards on the

tape?(Asume that it takes 60 seconds to rewind the tape.c-Compare this with the expected average time it would take for a

sequential search for one record.



h. Weimplicitly assume in our discusions of tape performance thal the tape drive is always reading or writing at full sped, so notine is lost by starting and stopping. This is not necessarily the case. ForCexample, some drives automaticall stop after writing each block. Suppose that the extra time it takes to start before reading aablock and to stop after reading the block totals I msec and that theydrive must start before and stop ater reading each block. How much will the effctive transmission rate be decreased due to start-ing and stopping if the blocking factor is1?What ifit is 50?​

Answer 1

Step-by-step explanation:

on2400-foot reels of6250-bpi tape with 0.3-inch interblock gaps. Tape sped is200inches per second,

a. Show that only one tape would be required to backup the fleifblocking factor of 50 is used.

6. If a blocking factor of 50is used, how manyextra records couldbe

:accommodated on a2400-foot tapel

c. What is the efective recording density when a blo(king facto50is used?

d. Howlarge does the blocking factor have to be to achieve the maxbmum effective recording density What negative results can result from increasing the blocking factor∶(Note An I/O buffer largeenough to holda block must be allocaed.）

veirradorbne

pae. What would be the minimum blocking factor required to ft the

sf. Ifa blocking factor of 50 is used, howlong would it take to readbone block,including the gap? What would the effectivetransmison

ion rate be?How long would it take to read the entire fle 只.How long would it take to perform a binary search for one records: in the fle, assuming that i is not possible to read backwards on the

tape?(Asume that it takes 60 seconds to rewind the tape.c-Compare this with the expected average time it would take for a

sequential search for one record.

h. Weimplicitly assume in our discusions of tape performance thal the tape drive is always reading or writing at full sped, so notine is lost by starting and stopping. This is not necessarily the case. ForCexample, some drives automaticall stop after writing each block. Suppose that the extra time it takes to start before reading aablock and to stop after reading the block totals I msec and that theydrive must start before and stop ater reading each block. How much will the effctive transmission rate be decreased due to start-ing and stopping if the blocking factor is1?What ifit is 50?