...programs and intermediate between the computer’s user and its hardware. There are many different types of Operating serves that are available to use. There are four main Operating systems that are used in today’s Technological world: UNIX, Linux, Mac, and Windows. Each one of these systems has its own unique aspects to offer users, while still sharing the same basics that an operating system needs. Memory Management UNIX/Linux In comparison to other operating systems, UNIX is quite different when it comes to managing its memory. It uses extremely sophisticated memory management algorithms to make the best use of memory resources. Though UNIX and Linux are extremely similar when it comes to how things work internally, there are slight differences that make UNIX distinct. One process that UNIX uses is Swapping; this is done by moving chunks of the Virtual Memory, known as pages, out of the main memory and moving others in. In order for this process to work at its best, those pages that are needed must be accessible in the Main Memory at the demand of the CPU. When a page is expected to be needed in the very near future it is called a resident set. This can lead to errors due to memory allocation issues. If the CPU attempts to access a page that is no longer available in the Main Memory, a page fault will occur, and the needed page will then have to be located, as the CPU...
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...File Management: File Access in UNIX POS/355 July 7, 2014 File Management: File Access in UNIX The Problem Company X is an organization that utilizes a UNIX operating system supporting approximately 5,000 users. Recently, the IT Department has received a request from the CEO of the company; 4,990 out of its 5,000 users on the network need to be able to access one file. How would the IT Department specify the protection scheme in UNIX where the other ten users would not be able to gain access to that one file? Traditional UNIX File Access Control According to Stallings (2012), “Most UNIX systems depend on, or at least are based on, the file access control scheme introduced with the early versions of UNIX.” Because the 4,990 users only need access to one file versus many different files, the traditional file access control UNIX provides is sufficient. The premise of UNIX file access control is based on file permissions that can assign ownership to three categories of users. The first is the user, who is the file or directory owner, usually the user who created the file. The owner of a file assigns the permissions to the file, such as the right to read the file, to write to the file (make changes to it), or, to execute the file if the file is a command (Oracle, 2012). The second category is a group. A group is “members of a group of users” (Oracle, 2012). In this case the owner of the file would create a group, assign the permissions to the group, and then add...
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...UNIX Protection Scheme Cedric Lee POS/355 Scott Stewart March 25, 2013 UNIX Protection Scheme There is an operation system that supports 5,000 users, and the company only wants to allow 4,990 users permission to access one file. In order to have a protection scheme in UNIX, a number of operations need to be performed first in order for this to work. UNIX file management hierarchy is very essential to know in order to understand and devise a plan that will allow this protection scheme to protect the files. Without knowledge of the hierarchy of the file management system within the UNIX operating system, there is no way that the 4,990 will have access to only one file. A file access control scheme will be the design of UNIX operating system. Therefore, user ids and passwords are needed in order to gain access to the system. All users of the UNIX operating system will each be given a user id and a user password. These user ids and passwords will be kept by the assigned users only. The protection of these ids and passwords depend on how well the user protects them. Encryptions and decryptions can also be used when the users are attempting to login. The administrator can put each user into different groups that allow access or deny access to certain files within the operating system. By doing this, there can be control on who can access what file due to the permission given to them by the administrator. The administrator is referred to as the super user because...
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...UNIX operating system and its features UNIX is a certified brand of The Open Group that belongs to a family of computer operating systems. UNIX stands among some initial operating systems which has to be written in a high level programming language that is C. Further Bell labs circulated it in a way that anyone could customize it according to his own wishes. As a result in late 70’s, number of versions of this operating systems were running at several places [Vangie Beal(2015)]. File permissions features of UNIX The most important feature of UNIX Operating system is that it procures a safe and sound method for storing data and information. Each file stored in UNIX has some characteristics and attributes like “owner permissions” in which it specifies that what actions and tasks the owner of the information or file can execute or perform. The second permission is “group permissions” which allows the user who is a part of group can perform different functions on a particular file of the same group but for this one must have to be a part of the group. The third is “other permissions”. It is a permission which determines what type of actions and functions, rest of the users can perform on particular file [Tutorialspoint(2014)]. Security feature of UNIX The security of the systems can be increased by some specific settings which controls the access of different users. This feature includes read, write and execute access options. The read access option allows users to view and...
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...UNIX File Management POS 355 Oct-29-2012 UNIX File Management UNIX file systems consist of six types of files. Normal, directory, special, named pipes, links, and symbolic links. Today’s UNIX Operating Systems support multiple file systems in which the files map into the same underlying system for supporting file systems and allocating disk space. The information for each file resides in an index node (inode). Before a user can access a UNIX file the user must be granted the correct permissions (Stallings, 2012). UNIX Files A normal UNIX file is nothing more than data the user or a program has entered into the file. An ordinary UNIX file does not contain any internal structure from the file system; instead it consists of random data in zero or more data blocks. The next UNIX file is called a directory, which are hierarchically organized that contain files as well as other directories. Directories are normal that are setup with special privileges allowing only the file system to write to them. The third UNIX file is called special, these files contain no data, but they provide a method to map physical devices to file names. The next UNIX files are called named pipes. A named pipe is an interprocess communications tool that buffers the data received so a process that reads from the pipe can receive the data on a first-in-first-out basis. The fifth UNIX file is an alternate file name for an existing file. The sixth UNIX file is called a symbolic link. The symbolic link is...
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...Explain how the UNIX permission system implements access control. Describe an extension of this system that permits finer control. Access Control in Unix UNIX has an implementation of access control lists for providing the features of security to its users. Every user has a right to log into the system with his/her credentials (username and password) and initiate a process which can further make system requests. Every process is assigned a unique identifying number called the process “uid”. This number can be obtained from the /etc/password file. A sample record from this file looks like below: “uid” essentially is the user id of the user who started the process. Every process may also carry an “effective uid”, which may or may not be different from its uid. Access control lists are also categorized with the use of group ids or group names. Every process has a list of groups, it is associated with. This is the basic level of authentication implemented in Unix. Since Unix understands everything as a file, it is important to see how security is ensured for files in Unix. There are 12 mode bits which are used to encode the privileges related to protection. Out of these 12 bits, first 9 bits are divided into 3 groups. Each group contains 3 bits describing the permissions related to user (u), group (g) and others (o). If a bit is set to “ON”, the corresponding privilege is enabled (r – read, w – write, x – execute). Extension of Unix security system A finer security...
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...File Management POS355 May 30, 2012 File Management When implementing a networked information system that will support thousands of users, it is important to consider which files will need restricted access, and which will be open to all users. The purpose of this essay will explore how a Unix system configured to support five thousand users is able to allow only four thousand nine hundred ninety of those users access to a single file. Unix File Access Control Although Unix has evolved over the years, even the most up to date system relies quite heavily upon the originally introduced file access scheme found in the very early versions of Unix. The core of this functionality essentially states that there are three possible permissions any user can have with a single file: read, write, and execute. Permissions for each of these actions are stored with the file’s inode and granted for three groups: the file owner, member’s of the file’s group; and everyone else. All of these permissions are identified in the first nine bits of the file’s twelve protection bits. The last three bits of the file’s protection bits indicate special behavior. The first two bits tell Unix whether to duplicate the permissions granted for the file owner, or file group, upon execution, respectively. The third bit represents a sticky bit that was originally used in early versions of Unix, but has since been decommissioned. This permission essentially told the operating system whether to keep...
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...UNIX /Linux versus MAC versus Windows Paper POS/355 March 11, 2013 Bhupinder Singh UNIX/Linux versus MAC versus Windows Paper Introduction Today we live in a world where technology is the way to go. Even in this century there are people that are still clueless on the operating system. It is different, exciting when a new and advance system comes out. But some of us are so confused when it comes to the basics of new technology. Operating systems are programs which manages the computer’s hardware. The systems provide a basic for the applications programs between the computer user and its hardware. When looking, there are so many different types of operating systems that are available. The four main operating systems that are used are Windows, Mac, UNIX, and Linux. For every computer there are many different items that make the system a whole. When it comes to the different operating systems there are different features available, even though when you think of computers a person might think security will all be the same but there are difference between each one. As you read more you will understand the security and the difference between a MAC, UNIX/LINUX and Windows systems and how each one works. Access control goal is to protect a resource from unauthorized access while facilitating seamless and legitimate use of such resources. Presently, each day users hold the need to access to those resources through a broad line of devices...
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...File Management POS/355 05/13/2013 John Buono File Management The file managers function is to regulate all of the files on a system that is stored on the storage mediums. There are several tasks that the file manager must perform in order to manage these files. The file manager must be able to identify the unique naming conventions of the files in order to complete its tasks. The file manager must also be able to determine the location of the files, the sectors that make up the file on the storage medium, and the order of those sector that make up the file. It is important that the file manager work with the device manager and use effective algorithms for the read and write of files. The file manager also gives or denies access to files by users or programs. The file manager also is in cooperation with the process manager to allocate or de-allocate files to the processor. The last task is that the file manager provides easy commands that assist users and/or programs in file handling (Gallert, 2000) . Unix/Linux File Management UNIX/Linux uses the distinction of inodes to refer to files or segments of files on the system and uses pointers to indicate where the files are on the storage media. There are some slight differences between each version of Unix/Linux but we will not go into those differences in this paper and will only cover the basics of file management. No matter what version of Unix/Linux is being used the file structure and permissions do seem to be...
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...UNIX for DBA`s Author: Sandeep Akkasani 1. INTODUCTION TO UNIX 1.1 Single-User Systems The personal computer (PC) is a small General-purpose system that can execute programs to perform a wide variety of tasks. The PC, however, was designed for use by one person at a time, that is, it is Single-User oriented with MS-DOS as the de facto standard operating system for this range of machines. Single user systems became very popular due to the low cost hardware and wide range of software available for these machines. 1.2 Multi-User Systems As opposed to single-user systems there are also larger systems, which more than one person can use at any time. Such systems are referred to as multi-user systems. Multi-user systems would be required when a number of applications have to be run simultaneously, or common resources, like printers and disks, are to be shared by a number of users. 1.3 Hardware – Multi-User Systems While the hardware components of a multi-user system are similar to that of a singleuser system, the following differences should be noted. The CPU of a multi-user system is more powerful and has capabilities to support multi-programming and multi-tasking, two features essential for multi-user systems. The Hard disk of a multi-user system is bigger in capacity. Most multi-user systems use magnetic tape as external storage for backup of software. Single-user systems use floppies as the backup device. This is because multi-user ...
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...File Management Paper {Your Name} {Your Class} {Date} {Instructor} File Management Paper Before we discuss how I would specify a protection scheme in UNIX® for 4990 users out of 5000 to access one file I think we need to first discuss what file management is in UNIX® and how security is implemented for this type of request. File management is a lot like file management in the DOS days of computers operating systems. Even with the early days of Windows up to Windows 3.11 file management and security were perfumed much the same way UNIX® still does it. Why? Because it works. In DOS and still in the most current version of Windows, Windows 8.1, security to files and directories is performed the same way. You have an attributed command with switches for specific action: R- Read Only, A- Archive, S- System Files, H- Hidden Using the + and – symbols before each instructs the system whether to add or remove the attribute. Example: Attrib –R Text.doc. This command will allow the file text.doc to be editable. Where in DOS and Windows upper and lowercase mean the same thing. I file called. TEXT.DOC is the same as a file named text.doc. Not so in UNIX®. A file with uppercase, DOCUMENT.TXT, or lowercase, document.txt, are two totally different files. UNIX® already provides a way for a system administrator to grant access to files and directories for other users. There are three classes of users who may have access to files and directories...
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...File Management Nina N. Rountree POS 355 Terrence Carlson June 10, 2013 Operating systems that have numerous users with various security level clearances will require file protection. A UNIX operating system with 5,000 users could implement conventional UNIX file access controls if 4,990 of those users share the same level of security clearance. By means of a file access control structure on the UNIX operating system, each individual user is given a user ID (special user identification number). Users on a UNIX operating system will be allocated to a main class and possibly a variety of classes that will be associated with a unique class ID. Whenever a user creates a file, it is indicated by the individual’s unique user ID along with the user’s main class ID. Each individual user's accessibility is managed by the administrator with a file access control security type structure. The administrator can manage the permissions of all three main classes; read, write, and execute. Access is permitted to three types of users: the creator or owner of the file, the class the file belongs to, and various users with access to the system despite their class. The access control policy affects the level of access that is permitted by whom and under what conditions. Discretionary Access Control (DAC) manages permissions based on the requester’s identity and the regulations linked to access and permissions. Mandatory Access Control (MAC) manages permissions based on assessing protection...
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...UNIX®/Linux® versus Mac® versus Windows® POS/355 October 29, 2012 Carol S. Eichling UNIX®/Linux® versus Mac® versus Windows® There are several computer operating systems available on the market, and it is sometimes difficult to choose. Therefore, it is important to compare the system capabilities to make the decision easier. The three biggest players in the operating systems market are UNIX®/Linux®, Mac®, and Microsoft® Windows® with Windows® holding the largest market share (Boitor & Brătucu, 2011). These three operating systems are capable of multi-processing and have similar capabilities; however, and it is important to compare and contrast how they handle memory management, process management, file management, and security, which are critical system functions. Discussing memory management, which is a vital component in operating systems, is first. Memory Management Memory management refers to the way a system makes use of the computer’s RAM (Random Access Memory). Many of the operating systems in use on computer systems have positives and negatives in their use of memory attributes. “Memory management is usually divided into three areas: hardware, operating system, and application…although the distinctions are a little fuzzy. In most computer systems, all three are present to some extent, forming layers between the user's program and the actual memory hardware” (Ravenbrook Limited, 2001, p. 1). There are several types of memory, including main memory, file system...
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...UNIX, Linux, Mac, and Windows OS Comparison Paper B. James Bryant UNIX, Linux, Mac, and Windows OS Comparison In 1956, General Motors produced the first OS for its IBM 704 series mainframe. Since then companies around the world, both big and small, have been tirelessly researched, testing, and releasing newer and faster operating systems for the world to use. Among these are systems developed by/for UNIX, Linux, Microsoft, and Apple. In fact, it’s safe to say that these four companies have a monopoly on all current technology used in both the military, corporate, and private sectors all around the world. UNIX Operating System Unix operating systems have the ability to be multi-user, multi-tasking and portable. Multi-user capabilities are accomplished through time sharing which means the processor allocates slices of time to first one process and then the next, sharing the available time in sequence with waiting processes (Nagpal, 2009). Unix can run in either command line interface, CLI, or graphic user interface or GUI mode. A key and unique feature of Unix is that it has a modular design which allows parts of the system to be added or removed without affecting performance of the other parts making Unix systems highly customizable. Unix operating systems have four core components, (1) the kernel, (2) the shell, (3) the file system, and (4) the utilities or tools and applications (Love et al, 2005). The kernel is the lowest layer of the operating system that...
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...ngA Basic UNIX Overview Asriel UNIX FOR DOS ADDICTED WaReZ PuPPieZ AND THEIR PETS Introduction ------------ One of the most common operating systems in existance is Unix. Unix exists in many different flavors, from Berkeley BSD to AT&T System V to SunOs. Basic working knowledge of Unix is almost essential to a hacker, as it is the system a hacker is most likely to come across. If you intend to use the internet at all, or to do any serious exploration of Telenet, the ability to navigate through Unix is a necessity. (Unix is also the single most interesting system in existance: it's just fun to fuck with). Unix Logins ----------- Most Unix logins look essentially the same. A general Unix login prompt looks something like this: connected to five.finger.com login: That first line is the system identifier. Although it's not at all essential to what you are doing, it's good to know what system you are attempting to log on to. The second line is what typically identifies the system you are on as Unix. Almost all Unix systems greet a user with the same prompt: login:. Well, there's not much to do in Unix from the outside, and Unix systems are typically fairly secure at this point. You may be able to obtain a list of users, or current users, by logging in as 'who', but other than that there are few functions available here. Unless you are on the internet, or have accounts specifically...
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