Categorize, describe, and give examples of
the major functions of operating systems.
According to Operating
System Concepts Essentials (2014), operating systems' primary
functions include CPU scheduling, memory management,
communication management,
synchronization, error detection, resource allocation,
accounting, and protection and security.
Also, the explanation of algorithms, structures, and
threads. The functionalities are interface (UI)
is what the user sees and interacts with to natural
processes on the computer. The UI can be a
command line, batch interface, or a graphical user
interface (GUI) (Silberschatz, Galvin,
Gagne, 2014). Program execution refers to the ability
to start and stop a program. A program
first needs to be loaded to the main memory to execute and
can then be terminated normally or
through an error. I/O operations are managed through
the operating system so as not to introduce
user error when a program calls for input or output
from/to a device. In addition, the operating
system provides file management capabilities to the
user(s) so that they can create or delete files
or rename them. In some cases, the operating system
also controls access to the files so that only
a specific group of users has permissions
(Silberschatz, Galvin, & Gagne, 2014). The basic
functions of the O.S. are managing machine resources,
coordinate the hardware and organize
files and directories on storage devices. Multi-user,
Single-User, Multiprocessor, Multitasking,
Single-tasking, and real-time.
The three main purposes are:
• To provide an environment for a computer user to
execute programs
on computer hardware in a convenient and efficient
manner.
• To allocate the separate resources of the computer
as needed to
solve the problem given. The allocation process should
be as fair
and efficient as possible.
• As a control program it serves two major functions:
(1) supervision
of the execution of user programs to prevent errors
and improper use
of the computer, and (2) management of the operation
and control of I/O devices.
Protection refers to the
controlled access to a system by users, while security refers to
the authentication of users, defending I/O devices,
and recording breach attempts (Silberschatz,
Galvin, & Gagne, 2014).
Illustrate the hierarchy of subsystems, components,
or subcomponents of operating systems
and explain how they interact with one
another.
According to
Silberschatz, Galvin, & Gagne, the hierarchy of system has multiple
functions. To name a few: GUI, user interface, program
execution, I/O operations, filesystem
management, etc. GUI: the GUI allows the user the
ability to control the system. Another method
is called monolithic and refers to the fact that all
the operating system's functionalities are
bundled into one space instead of being stored in
multiple sections. The GUI gives all authorized
users the ability to add or delete files, share
information via synchronization and program
execution. Also, the data can be retrieved at any
later date by users. Memory hierarchy has
several levels starting from inexpensive and slow disk
technology to DRAM main memory and
SRAM CPU caches all the way to the registers
(Silberschatz, Galvin & Gagne, 2014).
Describe the process, process state, and process control block. Compare single- and multi-
threaded motivations and models. Describe
the critical-section problem and explain a
software solution that resolves this
problem.
The process assigns a
process identification number (PID) to each process as the system
processes one at a time. Each process is only
permitted to enter crucial variables when granted
permission and all others are completed with their
task at hand. The process control block is the
datum, the process is as sounds, "the state the
process is currently running (Silberschatz, Galvin,
& Gagne para 3.5)" A
Process Control Block for each process is a data structure in the operating
system kernel containing the information needed to manage
a particular process. A PCB is
created in the kernel whenever a new approach
progresses and completes. The OS maintains a
queue of PCBs, one for each process, which encloses
all the information about the process. It is a
data structure. (Studytonight Technologies, 2021),
(Shenoy, P., 2013) A thread is “a flow of
control within a process.” (Silberschatz, Galvin,
& Gagne, 2014). Multiple thread source code,
data, files, memory, registers, a program counter, and
a “stack which contains the execution
history” (Tutorials Point, 2018) "Threads
represent a software approach to improving
performance of operating system by reducing the
overhead thread is equivalent to a classical
process" (Tutorials Point, para. 1) Process
is the unit of work in a modern time-sharing system
(Silberschatz, Galvin, & Gagne, 2014) This is in
place to make sure that the processes are
executed one at a time.
The solution to fix the problem: The algorithms must be
true to work and correct the problem.
OS Theory Concept Map – Section 2
Outline the objectives and functions of
memory management in operating systems.
(Resource: Leverage Figures 7.1, 7.2, 7.3,
and 7.4 from the textbook.)
Compare and contrast the physical address
space with the virtual address space as they
relate to different memory mapping
techniques in operating systems.
Memory management in
operating systems has five main purposes: Its function is to
allocate memory for action or program. It is used
to create virtual addressing space while also
sharing resources. It is meant to swap between memory
management resources for datum and is
used for the static or dynamic memory location (Silberschatz,
Galvin & Gagne, 2014).
Static
Relocation must be relocated before or during the loading of a process into
memory. The
the program must always be loaded into the same address
space in memory or the relocator must be
rerun.
Dynamic Relocation
- can be freely moved around in memory—virtual-to-physical address space
mapping completed at run-time.
Protection-
write protection to prevent data and instructions from being over-written. Read
security to ensure the privacy of data and
instructions.
Sharing, Logical
Organization of Memory: Logical organization - processes are composed of
modules of varying sizes, modules independently
compiled, modules with different protection
needs even to the degree of sharing. Physical
organization - typically a two-level organization:
main memory and secondary memory. (Silberschatz,
Galvin & Gagne, 2014).
Virtual Memory,
Dynamic Address Translation Mechanism - transforms virtual addresses into
physical addresses. Virtual address space can be
smaller or the same size as PM.
Address Translation
Mechanism: physical, real, or binary address is a memory address
represented in the form of a binary number on the
address bus circuitry to enable the data bus to
access a particular storage cell of main memory or a
register of (Wikipedia) memory mapped I/O
device.
Virtual address space is
the maximum amount of address space available to an
application, (People) depending on the architecture,
e.g., CPU register size. Virtual memory
enables each process to have its (Wikipedia) unique
view of a computer's memory. "Virtual
address space (VAS) or address space is the set of
ranges of virtual addresses that an operating
system makes available to a process." (Wikipedia)
The content of virtual addresses usually starts
at a low address. It can extend to the highest address
allowed by the computer's instruction set
architecture and is "supported by the operating
system's pointer size implementation, which can
be 4 bytes for 32-bit or 8 bytes for 64-bit OS
versions. This provides several benefits, one of
which is security through process isolation assuming
each process is given"(Wikipedia) separate
address space.
In computer architecture,
the memory hierarchy separates computer storage into an order
based on response time. Since response time,
complexity, and capacity are related, (Wikipedia)
their performance and control technologies may also
distinguish the levels. (Wikipedia)
Outline the objectives and functions of
file systems management and the supported
operations, including their reliability
and performance.
Outline the objectives and functions of
file systems management and the supported
operations, including their reliability
and performance.
Multi-level structure
directory stops the issues of overlap of "name collision problems."
Consider two programmers are working on a joint
contract, they each have their own file and can
share their files with one another. An acyclic graph
is a graph with no cycles which prohibits the
sharing of files or directories. With a copy of a
file, there is an original, and the programmers
have access to two different copies, one programmer
can make a change, the change will not
show up on the other programmer's file. But with a
shared file the changes are made and visible
for the other programmer. (Silberschatz, Galvin, Gagne
2014, 10.3.6) There is an absolute and
relative pathname this gives defines a path from the
current directory. It is important to write the
file exactly as to not have looping occur so that the
system keeps looking for the file if it cannot
be found.
Describe different types of input/output devices, distinguishing between the
hardware and software layers and summarizing the integration across I/O and memory
components.
I/O devices are used to
help information be utilized by the outside world. By doing so
this is by moving data into and out of the system.
Some input devices are
Keyboard (The most common and very popular input device is
the keyboard), Mouse, Touchpad, TrackPoint, Scanner,
Microphone, Digital Cameras, pointing
device (which is used to move cursor position on a
monitor screen), Barcode reader, Joystick,
Webcam, Optical Character Reader (OCR)) OCR is an the input device used to read a printed text),
Touch screen, Digitize. Etc. Devices that are
considered output devices are Character Printers,
Drum Printer, Laser Printers. Projector, Plotters,
Monitor, Speakers, Headphone. The external
device will send information that is stored in a
memory unit this information is transferred.
Programmed I/O,
Interrupt- initiated I/O, and Direct memory access DMA. The
Programmed I/O, Interrupt- initiated I/O need
intervention between the processor and memory
any data in this scenario will need to go thru the
processor therefore the transfer rate is affected
by the speed of the processor. The causes the
processor to have to manage instructions that need
to be executed for each I/O transfer. Allowing
peripherals to directly communicate with each
other removes the intervention of the CPU. CPU remains
Idle and has no control over the
memory bus. There is a direct transfer between the I/O
devices and the memory unit.
(Silberschatz, A., Galvin, P. B., & Gagne, G. para 8)
OS Theory Concept Map WEEK 4
Outline the goals and principles of the domain- and language-based protection in a modern
computer system and describe how an access
matrix is used to protect specific resources a
process can access. (Consider using a
matrix representation to illustrate concepts.)
Describe how security is
used to protect programs, systems, and networks from threats.
The most obvious to prevent the goal and principle of
a domain is to stop malicious misuse of the
system by users or programs. It is also to ensure that
all shared resources are used only following
the system policies. This may be set by either the
system designers or administrators. Doing so
will ensure that the errant programs will cause the
minimal amount of damage as possible.
One way to secure the system is a Cloud-agnostic the system is available to staff and individuals.
Another way is the matrix representation to illustrate concepts; this will divide the matrix into rows to
secure them to be more
effective.
According to Silberschatz, A., Galvin, P. B., &
Gagne, G., this is the protection that we have
been discussing can be viewed as an access matrix, in
which columns represent different system
resources and rows represent different protection
domains. Entries within the matrix indicate
what access that domain has to that resource? The
owner right adds the privilege of adding new
rights or removing existing ones
It is best to give only certain individuals access to
the information they need to complete their
jobs, not all files. This should stop corruption and
individuals having access to necessary files
that they have no use for. Or to be able to breach any
company files that should be kept secret,
such as financial or other high-security files.
OS Theory Concept Map - Section 5
Single-Level File Directory Diagram
Two-Level File Directory Diagram
Tree-Structured File Directory Diagram
To protect against these
threats, systems are protected at four different levels:
physical (sites, workstations, and rooms containing
systems are made secure and allow limited
access), human (the authorization of users attempting
access to the system), operating system
(protected against accidental and malicious security
breaches), and at the network level
(connections over private lines or private wireless
networks) (Silberschatz, Galvin, & Gagne,
2014). One can also add a password to ensure security
of your personal files and information.
Cloud computing is very popular to protect information
and be able to share information. I utilize
my Arizona University Cloud often, which also makes
file share much easier.
In this class, I have learned about threads, which I knew nothing about until this
class. The Maps making helped me see the order of
processing and how sharing works for the
order of procedure. I have also learned fundamental
concepts that underlie operating systems,
including multiprogramming, concurrent processes, CPU
scheduling, synchronization, memory
management, file systems, protection, and security.
Many examples from natural systems are
given to illustrate the application of concepts. At the end of this course, a student will understand
the principles and techniques required for understanding
and designing operating systems.
Final Concept Map Week 5
References:
Ahlawat, A. (2021) Studytonight, Technologies,
2021, https://www.studytonight.com/
Columbia University.
(n.d.) Unit 4: Application and System Software. Retrieved October
4, 2018 from, http://www.columbia.edu
Franklin, C., & Coustan, D. (2000). Process
Control Block in Operating System. Retrieved
September 20, 2018, from https://www.includehelp.com/operating-systems/processcontrol-block-in-operating-system.aspx
Geeks for Geeks. (n.d.). File Systems: Operating
Systems. Retrieved October 4, 2018 from
https://www.geeksforgeeks.org/file-system-operating-systems/
Hand, S. (2010). Operating Systems. Retrieved
September 27, 2018 from
https://www.cl.cam.ac.uk/teaching/1011/OpSystems/os1a-slides.pdf.
Shukla, A. (2017). Process Control Block in Operating
System. Retrieved September 20, 2018,
from https://www.includehelp.com/operating-systems/process-control-block-inoperating-system.aspx
Silberschatz, A., Galvin, P. B., & Gagne, G.
(2014). Operating system concepts essentials (2nd
ed.). Retrieved from https://www.vitalsource.com
Staff, C. (n.d.). Introduction to Operating Systems.
Retrieved September 27, 2018 from
http://staff.um.edu.mt/csta1/courses/lectures/csm202/os10.html
The Critical Section Problem. Retrieved September 20,
2018, from
http://crystal.uta.edu/~ylei/cse6324/data/critical-section.pdf
TutorialsPoint. (n.d.). Operating System – Memory
Management. Retrieved September 27,
2018 from
https://www.tutorialspoint.com/operating_system/os_memory_management.htm
Tutorials Point. (2018). Operating System -
Multi-Threading. Retrieved September 20, 2018,
from https://www.tutorialspoint.com/operating_system/os_multi_threading.htm
Tutorials Point. (n.d.). Operating System- Security.
Retrieved on October 11, 2018 from
https://www.tutorialspoint.com/operating_system/os_security.htm
University of North Carolina, Chapel Hill, Department
of Computer Science. (n.d.). COMP
730/242 Class Notes:
Section 8: Protection. Retrieved on October 10, 2018 from
http://www.cs.unc.edu/~dewan/242/s07/notes/prot.PDF
https://people.cs.pitt.edu/~xianeizhang/notes/vm.html
https://en.wikipedia.org/wiki/Binary_address
https://en.wikipedia.org/wiki/Memory_hierarchy
https://en.wikipedia.org/wiki/Virtual_address_space
Some Maps are from Internet
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