Operating System Assignment: Comparison Between Windows and Unix

Question

Requirements

• Demonstrate an understanding of Operating System concepts; processes, shared memory, concurrency file systems or performance processing
• Demonstrate you are able to conduct scientific research
• Demonstrate you are able to critically analyse several sources of information on a topic

Available research topics : You should focus on the topic that has the same number as the last number of your FAN;

• Operating systems kernels: - Compare the organisational differences between Micro Kernels and Monolithic Kernels
• File systems:- Compare the permissions models between UNIX file systems and Windows file systems
• Processes: Compare the differences in process management algorithms for single CPU systems and SMP or multi-CPU systems
• Memory management: Compare differences in memory allocation algorithms for single CPU systems and SMP or multi-CPU systems
• Real time systems: Compare real time operating systems and discuss how they support real time processing.
• Microprocessors: Discuss how voltage scaling and operating systems work together to function in low power scenarios such as in wearable devices.
• Security: Compare the security available in mobile operating systems and identify which is most secure.
• Performance: Explain why understanding worst case execution time is important and how is it calculated?
• Efficiency: Explain how embedded operating systems are different from standard operating systems and how they help to improve performance in embedded systems.
• Architecture: Compare 32 vs 64 bit operating systems. What are the advantages and disadvantages of each and what applications are each most suited for?

Answer

Introduction
The operating systems Assignment critically analyzes the basic differences between the permissions and models of Windows and UNIX file systems. A file system typically refers to the mechanism of storing and retrieving data on a computer disk. UNIX and Windows operating systems implement their file systems in different ways. The aim of this operating systems Assignment is to discover the innate differences between these two operating systems in terms of the file systems management. For this purpose, the operating systems Assignment compares and contrasts the permissions of Windows and UNIX file systems in order to yield an in depth idea about their working procedures. Both the operating systems can conceptually handle a same set of files. However, significance difference lies in the file permission structure, models and management.

Windows File System Permission Model
In Windows operating system, the FAT32 (File Allocation Table 32) file system stores data in chunks of 32 bits. The naming convention supported by FAT32 file system requires ASCII character set. The file name must start with a number or letter and does not support any special characters (. " / \ [ ] : ; | = ,). However, there are certain disadvantages in FAT32 file system such as fragmentation, lack of storage efficiency for larger disk partitions, and lack of fault tolerance.

In 1990s, Microsoft built a more reliable, secure and high performance file system called NTFS (New Technology File System). The common permissions in NTFS file system are, read, modify, change owner and delete. Setting the permission requires specifying the level of access for groups and users. NTFS permissions are same for local and network users and granted at the Windows log on (Perrin, 2011). Windows administrators provide access control for the files, folders, containers, and objects using the NTFS utility on the network. The ‘Security Descriptor’ is responsible for deciding what kind of access (read/ modify/ delete/ change owner) is allowed for individual users and group of users.

The standard permissions in NTFS include ‘full control’, ‘modify’, ‘read & execute’, ‘read’ and ‘write’. ‘Deny’ can be used to deny access to a folder or deny full control permission. However, in the later versions of NTFS, Microsoft has included certain advanced permissions that include the following:

Traverse folder/ Execute file: Allows navigating through folders to reach files even if there is no permission to access the traversed files.

List folder/ Read data: Allows viewing a list of contents and data files in a folder.

Read attributes: Allows viewing read-only and hidden attributes of a file or folder.

Read extended attributes: Allows viewing extended attributes

Create files/ Write data: Allows creating files within a folder, make changes, and overwrite existing content.

Create folders/ Append data: This permission allows creating folders within folders, make changes to the end of file. However, it does not allow overwriting or deleting data in a file.

Apart from these, the other advanced permissions are write attributes, write extended, delete, change permissions, read permissions, and take ownership (Morgan, 2017).

UNIX File System Permission Model
UNIX file system deals with three core aspects such as user, groups, and ownership. UNIX operating system has files and directories in tree structure where the basic permissions are, read, write and execute. UNIX OS uses nine bits for specifying the access permission for a file, where each bit is marked by r (read), w (write) and x (execute). The UNIX file permissions depend on a simplified and abbreviated form of ACL (Access Control List) (Reynolds, 2014). The DAC (Discretionary Access Control) enables users to configure the level of access for the resources that they ‘own’.

Table 1: 9-bit permission model

In the 9-bit permission model, the permissions of files can be changed using the command ‘chmod’. Apart from that, the ‘setuid’ allows running executables with the permission of a file owner. The ‘setgid’ command is used as an equivalent of ‘setuid’ property of groups. The ‘Sticky bit’, when assigned to files and directories, prevents users from deleting (Doyle, 2011). For instance, ‘/tmp’ folder allows any user to store files. However, only the file owner has the access rights to delete or modify the file stored in ‘/tmp’. The ‘umask’ command defines the permissions to be masked when a file is created.

One example of the major limitation of the 9-bit permission model can be the command ‘setuid-root’. This command allows any ordinary users to perform administrative tasks. Moreover, the 9-bit permission model used by UNIX operating system has no fine-grained access control measures for the non-class users.

Comparison
The initial design of UNIX operating system by AT&T included disk space at a premium and each file had three sets of permissions such as the access permissions for ‘everyone’, ‘the owning group’, and the ‘owning user’. The three types of permissions are typically read, write, and execute. The execute permission allows a user to run a binary program or a script.

There is a challenge in this scenario. If a second user needs write access to a particular file, then it is essential to create a new group allowing both the first and second users. This new group needs to replace ‘the owning group’. Hence, there is a high chance of these permissions to become messy in large organizations.

However, in the Windows file system, the file permissions model goes to the extreme by defining permissions to every file for any number of users, groups or everyone. Moreover, the category for ‘everyone’ encompasses system users, guests, authenticated users, network users and so on. These fine-grained permissions can be set for inheritance by subfolders, which enforces any change in parent folder to replicate automatically to the subfolders.

On the other hand, UNIX enforces application-level and network-level permissions, in which certain applications are allowed to access specific folders (McDermott, 2017). However, even if this additional feature adds adequate flexibility in operating system security, the job of debugging permission-based errors is significantly difficult. It requires many days of fine-tuning in order to implement a UNIX server and get it ready for production, due to the fine-grained application-level permissions.

Therefore, Windows OS offers fine-grained user-level control whereas UNIX involves application-level control. It can be said that Windows file system permissions are ideal for file storage and management. On the other hand, UNIX offers effective permission model for web and application servers.

The octal 777 permission in UNIX is equivalent to ‘full control’ permission in Windows file system. UNIX allows setting permission through graphical shell or using ‘chmod’ command. Many modern UNIX distributors support ACLs (Access Control Lists) based security for directories and files. However, the sysadmins mostly use the UNIX owner-group-world permission model (Rafacz, 2011). In order to delegate authority, UNIX users often use the ‘su’ and ‘sudo’ for administrator privileges. On the other hand, the Windows UAC (User Access Control) can be compared with ‘sudo’ in UNIX. Windows users use ACLSs in file-level while UNIX users rely upon the outdated model of owner-group-world permission model.

Conclusion
It can be seen in this operating systems Assignment that UNIX operating system has three specific permissions that can be applied to each class (user, group, other), which are, read, write, and execute. It is possible to change permission behavior in UNIX with the setuid, setgid and sticky bits. The sticky mode or text mode encourages the kernel to retain the image of an object beyond termination. In Windows, if an object or a file has a null ACL, then it has no restriction. On the other hand, if the file has an empty ACL then no one can access the file.

Appendix - Annotated Bibliography
1. McDermott, J. (2017). Introduction to UNIX-family File Permissions | Learning Tree Blog. [online] Learning Tree Blog. Available at: https://blog.learningtree.com/introduction-unix-family-file-permissions/ [Accessed 12 Sep. 2018].

In this article, the author has discussed the authorization specifics in the UNIX file permission model. McDermott (2017) has reflected on the basic permission types (read, write, and execute) supported by UNIX operating system along with a brief overview of changing permissions with the chmod command. The paper also discussed some common file modes in UNIX.

2. Doyle, M. (2011). Understanding File Permissions. [online] Elated.com. Available at: https://www.elated.com/articles/understanding-permissions/ [Accessed 12 Sep. 2018].

In this article, Doyle (2011) has discussed about the basic purpose and importance of file system permissions. In this context, the author has focused on defining permissions from the UNIX operating system perspective. The paper explains the 9-bit permission model in UNIX that defines permission for each class including the users (u), groups (g) and other (o). The author also discussed setting permissions with FTP and SSH.

3. Mfillpot. (2010). Understanding Linux File Permissions. [online] Linux.com | The source for Linux information. Available at: https://www.linux.com/learn/understanding-linux-file-permissions [Accessed 12 Sep. 2018].

In this article, the author has researched the the Linux file permissions along with the three basic permission groups and permission types. The author further defines the ways to view, understand, and modify the permissions. The paper also discusses about the methods for explicitly defining permissions as well as using binary references to set permissions.

4. White, K. (2012). Understanding File System Permissions | Mac OS X Support Essentials: File Systems | Peachpit. [online] Peachpit.com. Available at: http://www.peachpit.com/articles/article.aspx?p=1403238&seqNum=5 [Accessed 12 Sep. 2018].

In this article, White (2012) discusses the ownerships for permissions along with the traditional UNIX permissions. In addition to that, the research also encompasses the ACLs (Access Control Lists), permission to hierarchical context, permissions for sharing, home folder sharing and securing new files or objects.

5. Perrin, C. (2011). Understand the setuid and setgid permissions to improve security. [online] TechRepublic. Available at: https://www.techrepublic.com/blog/it-security/understand-the-setuid-and-setgid-permissions-to-improve-security/ [Accessed 12 Sep. 2018].

In this article, Perrin (2011) discussed how the basic UNIX permissions in the operating system file management work and why it is important for security reasons. More precisely, the significance of the two commands such as setuid and setgid are discussed in terms of enhancing the security of UNIX file systems. The author also compared and contrasted between good and bas security in this context.

6. Morgan, M. (2017). Windows Share Permissions Best Practices (Server 2016) | Global Knowledge Blog. [online] Global Knowledge Blog. Available at: https://www.globalknowledge.com/blog/2017/09/19/best-practices-for-share-permissions-in-windows-server-2016/ [Accessed 12 Sep. 2018].

In this article, Morgan (2017) has discussed about the best practices for share permissions in Windows Server 2016. For this purpose, the author has also discussed about the certain limitations and drawbacks pertaining to the share permissions in Windows. The paper also considers how NTFS solves the identified issues.

7. Reynolds, R. (2014). Managing Permissions on Windows with Access Control Lists. [online] Puppet. Available at: https://puppet.com/blog/managing-permissions-on-windows-access-control-lists [Accessed 12 Sep. 2018].

In this article, the author Rob (2014) has reflected on the role of ACLs along with its most fundamental features and functions. The author has discussed the ACL type structure and permission properties along with examples, granular permission and website setup with ACL.

8. Rafacz, R. (2011). Linux File Permissions. [online] Pluralsight.com. Available at: https://www.pluralsight.com/blog/it-ops/linux-file-permissions [Accessed 12 Sep. 2018].

The article discusses about the Linux file permissions. The author Rafacz (2011) has explained how to identify file and directory permissions in UNIX OS as well as how to change the permissions. The author also discussed about how to change ownership, groups etc. with appropriate commands. The operating systems assignments are being prepared by our IT assignment help experts from top universities which let us to provide you a reliable online assignment help service.