# Recent questions tagged disks

1
Suppose you have a Linux file system where the block size is $2K$ bytes, a disk address is $32$ bits, and an $i-$node contains the disk addresses of the first $12$ direct blocks of file, a single indirect block and a double indirect block. Approximately, what is the largest file that can be represented by an $i-$node? $513$ Kbytes $513$ MBytes $537$ Mbytes $537$ KBytes
2
Comprehension: For the question given below: concern a disk with a sector size of $512$ bytes, $2000$ tracks per surface, $50$ sectors per track, five double-sided platters, and average seek time of $10$ milliseconds. If $T$ is the capacity of a track in bytes, and $S$ is the capacity of each surface in ... $(T,S)=$ _______ $(50 K, 50000 K)$ $(25 K, 25000 K)$ $(25 K, 50000 K)$ $(40 K, 36000 K)$
3
Comprehension: For the question given below: concern a disk with a sector size of $512$ bytes, $2000$ tracks per surface, $50$ sectors per track, five double-sided platters, and average seek time of $10$ milliseconds. What is the capacity of the disk, in bytes? $25,000 K$ $500,000 K$ $250,000 K$ $50,000 K$
4
Comprehension: For the question given below: concern a disk with a sector size of $512$ bytes, $2000$ tracks per surface, $50$ sectors per track, five double-sided platters, and average seek time of $10$ milliseconds. Given below are two statements: Statement $I$: The ... $II$ are false Statement $I$ is correct but Statement $II$ is false Statement $I$ is incorrect but Statement $II$ is true
5
Comprehension: For the question given below, concern a disk with a sector size of $512$ bytes, $2000$ tracks per surface, $50$ sectors per track, five double-sided platters, and average seek time of $10$ milliseconds. If the disk platters rotate at $5400$ rpm ( ... minute), then approximately what is the maximum rotational delay? $0.011$ seconds $0.11$ seconds $0.0011$ seconds $1.1$ seconds
6
For the question given below, concern a disk with a sector size of $512$ bytes, $2000$ tracks per surface, $50$ sectors per track, five double-sided platters, and average seek time of $10$ milliseconds. If one track of data can be transferred per revolution, then what is the data transfer rate? $2,850$ KBytes/second $4,500$ KBytes/second $5,700$ KBytes/second $2,250$ KBytes/second
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1 vote
9
The seek time of a disk is $30$ ms. It rotates at the rate of $30$ rotations/second. The capacity of each track is $300$ words. The access time is (approximately) $62$ ms $60$ ms $50$ ms $47$ ms
10
Which level of RAID refers to disk mirroring with block striping? RAID level $1$ RAID level $2$ RAID level $0$ RAID level $3$
11
Which level of RAID refers to disk mirroring with block striping? RAID level $1$ RAID level $2$ RAID level $0$ RAID level $3$
1 vote
12
A $3.5$ inch micro floppy high density disk contains the data _________ . $720 \: MB$ $1.44 \: MB$ $720 \: KB$ $1.44 \: KB$
1 vote
13
When we move from the outermost track to the innermost track in a magnetic disk, then density(bits per linear inch) increases. decreases. remains the same. either remains constant or decreases.
14
What is the elapsed time of $P$ if records of $F$ are organized using a blocking factor of $2$(i.e. each block on $D$ contains two records of $F$) and $P$ uses one buffer? $12$ sec. $14$ sec. $17$ sec. $21$ sec.
15
Where does the swap reside? RAM ROM DISK On-chip cache
16
What is the average Access Time for a drum rotating at $4000$ revolutions per minute? $2.5$ milliseconds $5.0$ milliseconds $7.5$ milliseconds $4.0$ milliseconds
1 vote
17
Which access method is used for obtaining a record from cassette tape? Direct Sequential Random Parallel
18
A magnetic disk has $100$ cylinders, each with $10$ tracks of $10$ sectors. If each sector contains $128$ bytes, what is the maximum capacity of the disk in kilobytes? $1,280,000$ $1280$ $1250$ $128,000$
19
A bitmap terminal contains $1600$ by $1200$ pixels. To scroll a window, the CPU (or controller) must move all the lines of text upward by copying their bits from one part of the video RAM to another. If a particular window is $80$ lines high by $80$ characters ... baud rate of the terminal? Putting a character on the screen takes $5\: \mu sec.$ How many lines per second can be displayed?
20
Many versions of UNIX use an unsigned $32$-bit integer to keep track of the time as the number of seconds since the origin of time. When will these systems wrap around (year and month)? Do you expect this to actually happen?
21
A system simulates multiple clocks by chaining all pending clock requests together as shown in Fig. 5-30. Suppose the current time is $5000$ and there are pending clock requests for time $5008, 5012, 5015, 5029,4$ and $5037.$ Show the values of Clock header, Current ... pending) signal arrives at time $5017$ for $5033.$ Show the values of Clock header, Current time and Next signal at time $5023.$
22
A computer uses a programmable clock in square-wave mode. If a $500\:MHz$ crystal is used, what should be the value of the holding register to achieve a clock resolution of a millisecond (a clock tick once every millisecond)? $100$ microseconds?
23
In the discussion on stable storage, a key assumption is that a CPU crash that corrupts a sector leads to an incorrect ECC. What problems might arise in the five crash-recovery scenarios shown in Figure 5-27 if this assumption does not hold?
24
In the discussion on stable storage, it was shown that the disk can be recovered to a consistent state (a write either completes or does not take place at all) if a CPU crash occurs during a write. Does this property hold if the CPU crashes again during a recovery procedure. Explain your answer.
25
In the discussion of stable storage using nonvolatile RAM, the following point was glossed over. What happens if the stable write completes but a crash occurs before the operating system can write an invalid block number in the nonvolatile RAM? Does this race condition ruin the abstraction of stable storage? Explain your answer.
26
A personal computer salesman visiting a university in South-West Amsterdam remarked during his sales pitch that his company had devoted substantial effort to making their version of UNIX very fast. As an example, he noted that their disk driver used the elevator ... the performance that he measured was identical to what would be expected from first-come, first-served. Was the salesman lying?
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 cylinder. How much seek time is needed for First-come, first served. Closest cylinder next. Elevator algorithm (initially moving upward). In all cases, the arm is initially at cylinder 20.
A disk manufacturer has two $5.25$-inch disks that each have $10,000$ cylinders. The newer one has double the linear recording density of the older one. Which disk properties are better on the newer drive and which are the same? Are any worse on the newer one?