This document discusses various aspects of file systems including:
1. It defines what a file is and lists some common file attributes like name, size, and timestamps.
2. It describes different file operations like create, read, write, delete and different methods to access and store files like sequential, random, and index access.
3. It discusses file system implementation techniques like contiguous allocation, linked lists, and i-nodes and how free space is managed through approaches like bitmaps and linked lists.
This Presentation is for Memory Management in Operating System (OS). This Presentation describes the basic need for the Memory Management in our OS and its various Techniques like Swapping, Fragmentation, Paging and Segmentation.
This section of the memory is also referred to as backup storage.
The storage capacity of primary storage is not sufficient to store the large volume so secondary storage.
Secondary storage also know as external memory or auxiliary storage not directly accessible by the CPU.
This Presentation is for Memory Management in Operating System (OS). This Presentation describes the basic need for the Memory Management in our OS and its various Techniques like Swapping, Fragmentation, Paging and Segmentation.
This section of the memory is also referred to as backup storage.
The storage capacity of primary storage is not sufficient to store the large volume so secondary storage.
Secondary storage also know as external memory or auxiliary storage not directly accessible by the CPU.
Memory management is the act of managing computer memory. The essential requirement of memory management is to provide ways to dynamically allocate portions of memory to programs at their request, and free it for reuse when no longer needed. This is critical to any advanced computer system where more than a single process might be underway at any time
This Slides covers:
Introduction to world of Computers, Basic Structure of Computer System, Computers in Home (Reference, Education & Communications, Entertainment an Digital Media Delivery, Smart Appliances, Home Computers), Computers in Education, Computers in workplace (productivity and decision making, customer services, communications), Computers on the move (Portable and Hand held computers, Self-Service kiosks, GPS Applications), Generation of Computer, Types of Computer (Size and Technology wise), Support Systems - Hardware and Software, Computer Peripherals, Memory Management.
Secondary memory is where programs and data are kept on a long-term basis. Common secondary storage devices are the hard disk and optical disks. The hard disk has enormous storage capacity compared to main memory. The hard disk is usually contained inside the case of a computer.
Operating System
Topic Memory Management
for Btech/Bsc (C.S)/BCA...
Memory management is the functionality of an operating system which handles or manages primary memory. Memory management keeps track of each and every memory location either it is allocated to some process or it is free. It checks how much memory is to be allocated to processes. It decides which process will get memory at what time. It tracks whenever some memory gets freed or unallocated and correspondingly it updates the status.
Memory management is the act of managing computer memory. The essential requirement of memory management is to provide ways to dynamically allocate portions of memory to programs at their request, and free it for reuse when no longer needed. This is critical to any advanced computer system where more than a single process might be underway at any time
This Slides covers:
Introduction to world of Computers, Basic Structure of Computer System, Computers in Home (Reference, Education & Communications, Entertainment an Digital Media Delivery, Smart Appliances, Home Computers), Computers in Education, Computers in workplace (productivity and decision making, customer services, communications), Computers on the move (Portable and Hand held computers, Self-Service kiosks, GPS Applications), Generation of Computer, Types of Computer (Size and Technology wise), Support Systems - Hardware and Software, Computer Peripherals, Memory Management.
Secondary memory is where programs and data are kept on a long-term basis. Common secondary storage devices are the hard disk and optical disks. The hard disk has enormous storage capacity compared to main memory. The hard disk is usually contained inside the case of a computer.
Operating System
Topic Memory Management
for Btech/Bsc (C.S)/BCA...
Memory management is the functionality of an operating system which handles or manages primary memory. Memory management keeps track of each and every memory location either it is allocated to some process or it is free. It checks how much memory is to be allocated to processes. It decides which process will get memory at what time. It tracks whenever some memory gets freed or unallocated and correspondingly it updates the status.
CompTIA exam study guide presentations by instructor Brian Ferrill, PACE-IT (Progressive, Accelerated Certifications for Employment in Information Technology)
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Useful documents for engineering students of CSE, and specially for students of aryabhatta knowledge university, Bihar (A.K.U. Bihar). It covers following topics, File concept, access methods, directory structure
Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
Personal development courses are widely available today, with each one promising life-changing outcomes. Tim Han’s Life Mastery Achievers (LMA) Course has drawn a lot of interest. In addition to offering my frank assessment of Success Insider’s LMA Course, this piece examines the course’s effects via a variety of Tim Han LMA course reviews and Success Insider comments.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
Safalta Digital marketing institute in Noida, provide complete applications that encompass a huge range of virtual advertising and marketing additives, which includes search engine optimization, virtual communication advertising, pay-per-click on marketing, content material advertising, internet analytics, and greater. These university courses are designed for students who possess a comprehensive understanding of virtual marketing strategies and attributes.Safalta Digital Marketing Institute in Noida is a first choice for young individuals or students who are looking to start their careers in the field of digital advertising. The institute gives specialized courses designed and certification.
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The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
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Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
1. 1. It becomes essential to store information for long-
term so that it can be accessed at any time.
2. it is also essential to make data sharable among
various processes.
3. This information can be huge in size and therefore,
must be accommodated on the appropriate storage
devices.
1
2. What is File?
A file is sequence of logical records i.e. a
sequence of bits and bytes.
File Attributes:
A file has various attributes like name, type,
location, size, protection, time and data of
creation, user information etc.
2
3. File naming
File naming=File name + File
extension
Eg. Student.doc
In this example the Student is
the file name and doc is the file
extension
3
5. File Attributes
A file has a name and data. Other than
this, it contains information like date
and time of file creation, file’s current
size etc. with a file. These are known as
attributes of a file.
5
6. Operations that can be performed on files
are:
1. CREATE: A blank file is created.
2. DELETE: The purpose of this system call is to delete
this file
3. OPEN: Open a file either for reading or writing.
4. CLOSE: When a file is no longer accessed.
6
7. READ: When a file is only to be read.
Write: To write some data on file.
Append: To add some data to the end
of the file.
Rename: To rename the file.
Note: A file can be made read-only, hidden,
system-file, and so-on by setting its read only flag
to 1, its hidden flag to 1, its system flag to 1 and so
on.
7
8. File Access Methods
Sequential Access: in this access method, data
records are retrieved in the same order in which
they have been stored on the disk. E.g data stored
on magnetic disk.
Random Access: In case of random access the
record is searched from the disk based on its direct
address information. The technique used is
Hashing. In hashing every record is associated
with a key number to preprocess the address
calculation. Hash function is used to obtain
absolute address of a particular record.
8
10. Index Access method: Indexed file
approach is helpful with multiple
attribute fields like in database files. In
these files, every field is associated with
an index key. While querying data the
index key is kept in the memory and
related records are fetched from the
disk.
10
14. Access paths
Two possible methods for access path are:
1. Absolute path name: It is a listing of the directories
and files from the root directory to the intended file.
For example, the path ‘c:/windows/programs/spss.exe’
means that the root directory contains a subdirectory
‘windows’, which further contains a subdirectory
‘programs’, that contains an executable “spss.exe”.
14
15. 2. Relative path name: This uses the concept of current
directory (also known as working directory). A user
can specify a particular directory as his current
working directory and all the path names instead of
being specified from the root directory are specified
relative to the working directory. For example, if the
current working directory is ‘usercurr’, then the file
whose absolute path is ‘usercurrstudent’ can be
referred simply as ‘student’.
15
16. Directory Operations
CREATE: A directory is created.
DELETE: A directory is deleted.
OPENDIR: Directories can be opened for reading
it.
CLOSEDIR: When a directory has been read, it
should be closed to free up internal table space in
main memory.
RENAME: Directories can be renamed just like
files.
16
17. File Protection
File systems often contain information that is highly
valuable to their users.
Protecting this information against unauthorized
usage is therefore, a major concern of all the file
systems.
17
18. 1. File protection through Access Control
Following are the few file operations that can be
controlled:
Read - Read a file
Write - Write the file
Append - Append a file
Delete - Delete a file
List - List the name and attributes of a file
Rename - Rename a file
Edit - Changing the contents of a file
Copy - Make a copy of a file.
18
19. Access control list
This list may contain the user name and the types of
access allowed for each user. The operating system
checks this access control list (associated with a file)
whenever a user requests an access to a particular file.
But one limitation of Access control list is
their length, so we create groups.
19
20. Classify the users of a file into three types:
1. Owner - The user who created the file.
2.Group - A set of users who are sharing the file and
need similar access.
3.Universe - All remaining users in the system
constitute universe
20
21. 2. File protection through password
Files can be protected by a password. The owner of a
file can control its access by assigning a password.
Thus, only those users who know the password, can
access a particular file.
21
22. File System Implementation
There are 4 ways of File system
implementation. They are the following:
1. Contiguous allocation
2. Linked list allocation
3. Linked list allocation using an index
4. I-nodes
22
23. 1. Contiguous allocation
The simplest allocation scheme is to store each file as a
contiguous block of data on the disk. Thus, on a disk
having blocks size 1k, a 25k file would be allocated 25
consecutive blocks.
23
24. 2. Linked list allocation
The second method for storing files is to keep each one as
a linked list of disk blocks, as shown in Figure below. The
first word of each block is used as a pointer to the next
one. The rest of the block is used for storing data.
24
25. 3. Linked list allocation using an index
In this technique instead of having a pointer, an index is
maintained.
25
26. 4. I-nodes
This method is used by UNIX operating system. In
this scheme, each file is associated with a little table
called an
i-node (index node).
26
27. Free Space Management
Free space management is used to reuse the disk
space created after deleting the files.
We have 4 techniques for Free space
management, Which are the following:
1. Bit map
2. Linked list
3. Grouping
4. Counting
27
28. 1. Bit map
The free space list is implemented as a bit map. Every
bit represents a block on the disk. The bit for a block is
1 if it is free and it is 0 if the block is allocated.
28
29. 2. Linked list
This approach maintains a linked list of all the free
disk blocks. The first free block in the list can be
pointed out by a head pointer, which is kept in a
special location on the disk.
29
30. 3. Grouping
Another approach is to store the addresses of n free
blocks in the first free block. The last block contains
the addresses of other n free blocks and so on.
30
31. 4. Counting
In this technique, instead of keeping a list of addresses
of n free blocks, it is more convenient to keep the
address of the first free blocks and the number n of
free contiguous blocks that follow the first block.
31
32. Security
Security violations (misuse) of the system can be either
accidental or intentional. It is easier to protect against
the accidental misuse than to protect against the
intentional misuse.
Security means Security from:
Theft of information
Unauthorized modification of data
Unauthorized destruction of data
32
33. System can be protected from
such threats at two levels:
1. Physical
2. Human
33
34. Authentication
Authentication of a user is based on:
1. User identifier and password (Passwords)
2.Artifact-based Authentication: Badge card
possessed by a user (Artifacts)
3.Finger prints, retina pattern (Biometrics techniques)
34
35. Encryption
Encryption is one such mechanism, which allows such data
to be scrambled so that even if some one intercepts it on
the network, it is not readable to him/her.
35
36. Encryption Schemes
These are two kinds of encryption:
1. ‘Symmetrical Encryption’ or secret key which uses a
single key to encrypt and decrypt the transmitted data.
2.‘Asymmetrical Encryption’ which uses ‘Private Key’, in
which one key is used to encrypt and another to
decrypt the transmitted data.
36
37. Viruses, Worms and Trojans
A computer virus is a small program written to alter
the way a computer operates and it executes without
the permission or knowledge of the user.
Worms are basically the programs that replicate
themselves from system to system without the use of a
host file.
Trojan horses are impostors - files that claim to be
something desirable, but in fact, are malicious.
37
38. Threat Monitoring
The security of a system can be done by a
technique called Threat-monitoring.
The techniques that can be used for threat
monitoring are:
1. A time sharing system can keep the count of
the number of incorrect passwords given,
when a user is trying to log in. More than a few
incorrect attempts may signal an attempt to
guess a password.
38
39. 2. Audit log is another common technique used for
threat monitoring. An audit log records the time of
use, the details of users etc.
3. The system can be scanned periodically for
security holes. Scanning can be done when the
system has less traffic.
4. In case we are using Internet use firewall and
antivirus programs.
39
41. Methods for Enforcement of Protection
Mechanisms
There are 2 methods for Enforcement of
Protection Mechanisms, which are the
Following:
1. Access rights
2. Access matrix
41
42. 1. Access rights
Access rights consists of domain. Thus, a
domain known as protection domain can be
defined for a process. Such a domain will
contain the set of objects and the types of
operations that can be invoked on each
object. This means that domain is a set of
<object, rights> pair.
For e.g. D = < data file F, {read, write} >; it
can perform only read and write operations
on the data file named ‘F’.
42
43. 2. Access Matrix
It is used to describe which users have access to
what objects (resources). Thus, basically it checks
the access rights of users on system resources.
43