Device Management / File Management Flashcards
1
Q
- Monitoring the status of each device (storage drives, printers, etc.)
A
Device Management
2
Q
- assigned to only one job at a time
- serve that job for the entire time it’s active or until it
releases them
A
Dedicated Devices
3
Q
Examples of Dedicated Devices
A
- Tape drives
- Printer
- Scanner
- Plotters
4
Q
- can be assigned to several processes
A
Shared Devices
5
Q
- can be shared by several processes at the same time by interleaving
their requests.
A
Direct Access Storage Device (DASD)
6
Q
- a combination of dedicated and shared devices.
- they’re dedicated devices that have been transformed into
shared devices.
A
- Virtual Devices
7
Q
a printer converted into sharable devices through a
A
spooling program
8
Q
One USB host can accommodate up to
A
127 different devices
9
Q
- acts as an interface between the OS, device drivers, and applications
attached via USB host.
A
Universal Serial Bus (USB) Controller
10
Q
A physical device that receives, stores, and allows users and programs
to access electronic data.
A
Storage Media
11
Q
Examples of Storage Media
A
- CD ROM, DVD ROM, DAT tape, DLT tape, disk drives, SSD,
Flash Drive, etc.
12
Q
Storage media are divided into two groups:
A
Sequential Access Storage Media
Direct Access Storage Devices (DASD)
13
Q
- store records sequentially, one after the other
A
Sequential Access Storage Media
14
Q
- store either sequential or direct access files
A
Direct Access Storage Devices (DASD)
15
Q
- Developed for routine secondary storage in early computer
systems and features records that are stored serially, one after
other.
A
Magnetic tape
16
Q
- Determined by the number of characters that can be
recorded per inch, such as (1600 bpi).
A
Density of the Tape
17
Q
- Records can be stored individually or grouped into blocks:
A
Sequential Access Storage Media
18
Q
- Way of grouping the record into blocks before recording them on
tape.
A
Blocking
19
Q
- The rate at which data is transferred from sequential
access media
A
Transfer Rate
20
Q
Transfer Rate formula
A
- Transfer Rate (ips) = density * transport speed.
21
Q
Direct Access Storage Devices (DASD)
Grouped into 3 categories:
A
- Magnetic disks (Fixed-Head, Movable-Head)
- Optical discs
- Flash memory
22
Q
- Looks like CD or DVD covered with magnetic film that has been
formatted. - Each circle is called track.
- Data is recorded serially on each track by the fixed read/write
head position over it.
A
Fixed-Head Magnetic Disk Storage
23
Q
- Like a computer hard drives.
- Have one read/write head that floats over each surface of each
disk.
A
Movable-Head Magnetic Disk Storage
24
Q
- Was made possible by developments in laser technology.
- Single spiraling track of same-sized sectors.
- Running from the center to the rim of the disc.
A
Optical Disc Storage
25
Optical disc consists of a
single spiraling track of
same-sized sectors running
from the center to the rim of
the disc.
Optical Disc Storage
26
To put data on an optical disc, a high-intensity laser beam burns indentations
on the disc that are called
pits.
27
These pits, which represent 0s, contrast with the unburned flat areas, called
____, which represent _s.
lands, 1s
28
A magnetic disk, which consists of concentric tracks of sectors, spins
at a constant speed—this is called
constant angular velocity (CAV).
29
The disc drive adjusts the speed of the disc’s spin to compensate for
the sector’s location on the disc—this is called
constant linear
velocity (CLV).
30
* A type of electrically erasable programmable read-only memory (EEPROM).
* A nonvolatile removable medium that emulates random access memory, but,
unlike RAM, stores data securely even when it’s removed from its power
source.
Flash Memory Storage
31
(EEPROM).
electrically erasable programmable read-only memory
32
* The bits can be erased only by applying
the flash to a large block of memory with
each flash erasure, the block becomes
less stable.
Flash Memory Storage
33
Examples of Flash Memory
- USB flash drives
- SSDs
- Memory cards,
- Smartphones, tablets, etc.
34
File Manager is also called the
File Management System
35
is the software responsible for:
- Creating, deleting, modifying, controlling access to files
File Management System
36
are the building blocks of any operation system.
Permanent storage of information & data.
Files
37
The output of program is called
executable file.
38
There are several ways to access files:
* Sequential File Access
* Direct File Access
* Indexed File Access
39
* Is a method of accessing data
sequentially/one record at a time
by starting from the beginning of
the file to its end.
* This access method is the most
primitive and straightforward
method of accessing files.
Sequential File Access
40
* Also known as Random file access.
* Allows users to access data directly
from any location within the file without
the need to read/write all the records
that come before it.
Direct File Access
41
* Is a method that incorporates the benefits
of both sequential and direct file access.
* Creating an index file that maps logical
keys or data elements to their
corresponding physical addresses within
the file.
* Index is searched sequentially and its
pointer is used to access the file directly.
Indexed File Access
42
refers to the ability of the operating system to distinguish
different types of file such as text files, source files, and binary files etc.
File type
43
Operating system like MS-DOS and UNIX have the following types of
files:
* Ordinary files
* Directory files
* Special files
44
* These are the files that contains user information.
* These may have text, databases or executable program.
* The user can apply various operations on such files like
- add, modify, delete or even remove the entire file.
Ordinary files
45
contains list of file and other related information to
those files.
Directory files
46
Also known as “folders” in other operating systems.
Directory files
47
Special Files are files are also known as
device files.
48
data is handled character by character as in case of terminals or printers.
Character special files
49
− data is handled in blocks as in the case of disks and tapes.
Block special files
50
The file is created with no data.
Create:
51
: File must has to be deleted when it is no longer needed just to
free up the disk space.
Delete
52
The process must open the file before using it.
Open:
53
The file must be closed to free up the internal table space,
when all the accesses are finished and the attributes and the disk
addresses are no longer needed.
Close:
54
The file read operation is performed just to read the data that
are stored in the required file.
Read:
55
The file write operation is used to write the data to the file,
again, generally at the current position.
Write:
56
The file append operation is same as the file write operation
except that the file append operation only add the data at the end of
the file.
Append:
57
: For random access files, a method is needed just to specify
from where to take the data. Therefore, the file seek operation
performs this task.
Seek
58
The file rename operation is used to change the name of the
existing file.
Rename:
59
FILE OPERATIONS
Create
Close
Open
Delete
Read
Rename
Write
Append
Seek
60
is a list of files that stores all the related information about the file it
hold with the contents.
Directory
61
Types of Directory Structure
1. Single-level directory structure
2. Two-level directory structure
3. Tree-structured directory structure
62
- in a _____ directory system, all the files are placed in one
directory
Single-level directory structure
63
- in the _____ directory system, the system maintains a master
block that has one entry for each user.
Two-level directory structure
64
- in the _______ directory, the directory themselves are files. This files
to the possibility of having sub-directories that can contain files and sub-
subdirectories
Tree-structured directory structure
65
Layered File System layers
Application Program Layer:
Logical File System Layer:
File Organization Module Layer:
Basic File System Layer:
I/O Control Interface Layer:
Physical Hardware Device Layer:
66
- user creates application program
Application Program Layer:
67
- manages the meta data information
Logical File System Layer:
68
- maintain information about file
File Organization Module Layer:
69
- generate command for device driver
- also manage buffer memory and
cache
Basic File System Layer:
70
- it consists of device driver & interrupt
handler
- transfer data: between main memory to disk
system.
I/O Control Interface Layer:
71
- contain actual hardware device
Physical Hardware Device Layer:
72
A reduction in the amount of bits required to represent data is
known as
data compression.
73
is performed by a program that uses a formula or algorithm to
determine how to shrink the size of the data.
Compression
