unit 16

How many bytes are wasted for a file of 2500 bytes assuming blocks are 512 bytes?

60

One advantage of HDDs over SSDs is

HDDs are cheaper per megabyte than SSDs.

The length of a logical record is fixed for a given operating system.

false

When the exclusive lock is applied to a file then _____________

only one process can use this file

A Flash Translation Layer

tracks which physical block contains only invalid pages.

13.Systems that do not permit access to the files of another user do not need protection

true

All file systems suffer from internal fragmentation.

true

In general, SCAN disk head scheduling will involve less movement of the disk heads than C-SCAN disk head scheduling.

true

In most RAID implementations, a hot spare disk is not used for data, but is configured for replacement should any other disk fail.

true

Indexed sequential-access method allows to locate any record with no more than two direct-access reads:

true

Is an extension a part of a file name?

true

Solid state disks (SSDs) commonly use the FCFS disk scheduling algorithm.

true

An I/O system call does not include

---------------CPU speed. ---------------storage device address. memory address.

If a current directory is /home/user/jane and then the propose path to file /home/user/mike/prog.c is_____________________

../mike/prog.c

A hard disk drive has 16 platters, 8192 cylinders, and 256 4KB sectors per track. The storage capacity of this disk drive is at most

128 TB. ----------------- 128 GB. ----------------- 32 TB

A two-level directory can be thought as a tree of height _________

2 and its root is MFD

The following information is presented for the prog.c [-rwxr-xr-- 1 Jim staff 130 May 25 22:13 prog.c] Users Jim, Sara and Mike are the members of the group staff

Alan can read prog.c

Why is a directory structure needed?

All of the other answers

Read or write performance of a hard disk drive depends on

All the other answers

Which of the following is TRUE about NAS and Cloud storage?

In an event of temporary network disconnection, an application using NAS will typically hang while an application using cloud storage will typically pause.

Which of these RAID levels is best for storing large volumes of data?

RAID level 5

Is an extension a part of a file name?

True

Host-attached storage is ____.

accessed via local I/O ports

The file protection can be provided by:

all of the other answers

Number of sectors per track increases as we move from inner zone to outer zone, because

angular velocity of disk rotation can remain constant.

In the case of UNIX, where sharing is implemented by symbolic link________________________

both of the above

In a swap map in Linux

counter value 5 indicates that the page slot is occupied and the page is shared by five processes.

close() operation _____ an open count associated with a given file.

decreases

Which access type should be used when there is a need for a fast access to massive amount of data:

direct access

Low-level formatting ____.

divides a disk into sections that the disk controller can read and write

12.UNIX rm command can delete non-empty directory

false

A track is the smallest unit of data transfer in a hard disk drive.

false

Data striping provides reliability for RAID systems.

false

Disk controllers do not usually have a built-in cache.

false

In asynchronous replication, each block is written locally and remotely before the write is considered complete.

false

In tree-structured directory the search path always contains "the current directory"

false

It is crucial to the file system to understand the type of a file?

false

SCAN disk head scheduling offers no practical benefit over FCFS disk head scheduling.

false

Sequential access to a file is based on a disk model of a file.

false

Sharing of memory-mapped sections of memory among multiple processes can be efficiently realized without the usage of virtual memory:

false

create() system call uses open-file table.

false

Memory-mapped I/O works well with devices that are characterized by:

fast response times

File's _______ is a unique tag identifies the file within the file system.

identifier

The garbage collection is necessary _____

in general graph directory structure only

A RAID structure ____.

is primarily used to ensure higher data reliability

The current directory is

may be included in the search path

A full bootstrap program

may be infected by viruses.

To further optimize I/O performance, some SSD schedulers

merge adjacent write requests but not adjacent read requests.

Disk scheduling algorithms in operating systems consider only seek distances, because

modern disks do not disclose the physical location of logical blocks.

If a few bits in an HDD sector or NVM page are corrupted, the controller can recover the correct values using ECC only if

number of bits corrupted is low irrespective of where the corruption occurs in the sector/page.

In the two-level directory, if a user refers to a particular file then__________________

only his/her own UFD (user file directory) is searched

Which classifications of users are typically used in access-control list to condense its length:

owner, group, universe

DRAMs are now commonly used for mass data storage, because

programs can share data easily when using RAMs.

Difference between sector sparing and sector slipping is

sector sparing results in copying of a single sector while sector slipping may result in copying of multiple sectors.

What are the two components of positioning time?

seek time + rotational latency

The SCAN scheduling algorithm ____.

services the request next to the current head position in the direction of the head movement

When the shared lock is applied to a file then ____________

several processes can acquire the lock concurrently

Manipulating files through memory rather than using the read() and write() system calls_________________

simplifies and speeds up file access and usage

ACL (access-control list) is associated with each file and directory. It

specifies user names and types of access allowed for each of them

For our purposes the MBR specifies _________.

the information needed to define that volume (as partitioned by the partition record)

Because all file systems suffer from internal fragmentation, the following relation is true:

the larger block size, the greater the internal fragmentation

The surface of a magnetic disk platter is divided into ____.

tracks