UNIX - An Inroduction
What is an operating system? · Kernel - provides a well-defined interface between programs and the hardware. It is a resource manager where the resources include memory, CPU access, input/output ports, etc. · Shell - interacts with the user, accepting commands and starting user programs. · Utilities - include programs required to make the system useful, such as programs to copy files, or simple text editors. · Windowing system - a collection of programs that implement a graphical user interface. Although the traditional definition of an operating system includes just the kernel, it is now more commonly known as a collection of most or all of these components. How A Kernel Defines the Operating System How a kernel defines the interface between programs and the underlying hardware greatly affects the programs designed for that operating system. Some features that define the kernel are: · Single or Multi-Tasking · A single-tasking operating system allows only one program to run at a time. This program must complete before a second program may begin. · A multi-tasking operating system allows multiple programs to run on the same system. In order to do this, it must define a means of communicating between programs, protecting running programs from errors encountered in other programs, and for scheduling when programs will run. · Single or Multi-User · A single-user operating system has only one user at a time. This user is granted exclusive access to all system resources. · A multi-user operating system can have more than one user at the same time. Most multi-user operating systems are also multi-tasking. · Memory Management · This defines how memory is allocated to specific tasks, and how memory is protected from other processes. · Device Interface · Device interfaces define the nature of the peripherals which may be connected to a system, the ease with which new devices are added, the extent to which the full power of a device may be used, and how knowledgeable user programs have to be to work with that device. · File System · The design of the file system is often so closely linked to the kernel design that is often the first indicator of differences between similar operating systems. This can include such simple clues as how files are named, or how directories or folders are named. · Degree of Integration · While some systems attem...
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...iles (password, group files) /tmp area for temporary storage, usually cleaned up after reboots, never store important files here Hard Drives, Partitions, CDROM, Network Drives, … · In other operating systems (DOS, Windows, Mac, OS/2) second hard drives, partitions, CDROMS, and network drives are displayed as a separate folder at the same level as the main drive (i.e. C:, D:, E:). · In Unix there is nothing before the root /. All other drives are contained within the root, transparent to the user. The root user sets up the additional drives using the mount command. · /dev/sda1 on / is the main hard drive mounted at the root · /dev/sdb2 on /home2 is a second hard drive mounted at /home2. That is if you look at the contents of /home2 you will be looking at the contents of the second hard drive. · /dev/scd0 on /cdrom is a SCSI cdrom mounted at /cdrom. · fox:/home on /tmp/home is the home directory of the machine fox mounted at /tmp/home.
Bibliography
1. Learning the UNIX Operating System, 4th Edition By Jerry Peek, Grace Todino, and John Strang O’Reilly & Associates, Inc. 2. UNIX For Dummies, 2nd Edition By John R. Levine and Margaret Levine Young IDG Books Worldwide, Inc.
I was very interested in computers and technology as a child, both playing games and building fake parts for them. Still in elementary school, I was fascinated by these computing machines, spending hours on end working with DOS to satisfy my curiosity. Around my middle school years, Windows became graphical, and I found interest in even more computer games with even greater experiences and capabilities. Windows was the dominant operating system at the time, but I was soon to find there was a whole different world out there of operating systems. While out on vacation in Washington, DC, my Dad and I were able to meet with the local Tech Fanatics group, HackDC. It was here where I discovered Linux. Linux, an alternative to Windows, immediately grabbed my attention when I saw it in use. It appeared to me as something that only the extreme computer users even heard of. Upon my return home,
The Linux operating system is the catchall term for the dozens of software stacks built around the free and open source Linux kernel. Clumped into distribution...
Nick Carraway, the narrator for The Great Gatsby, has his narration structured in a diary like manner so to simulate a personal inner-voice from Nick. This structure creates a different perspective for the reader, instead of being told from an on-looker such as the author the story is read through the eyes of a character. This technique uses the first person, and is commonly from just one character’s perspective. This structure can also be seen in The Great Gatsby, where Tom’s narration is recalled in a sequence of recollections as the play is depicted from memory. However, both characters in these texts become entrapped in responsibility through their narration. Because Nick uses his narration as means to express his suppressed opinions about Gatsby, since Nick cannot bring himself to the idea of letting go Gatsby down “"They're a rotten crowd," I shouted across the lawn. "You're worth the whole damn bunch put together."” I've always been glad I said that. It was the only compliment I ever gave him, because I disapproved of him from beginning to end.” Although Nick disapproves of Gatsby, he cannot help but become caught up in Gatsby’s dream. Nick feels responsible for Gatsby, he feels that he must give Gatsby support and encouragement. Because Nick and Gatsby are friends, and Nick understands that he must do all that he can to help
...k down upon. In other words, the idea of what Harlem was and what it could have been “exploded” in nearly everyone’s mind. However, as Harlem began to spiral downward, Hughes looked to pick Harlem back up. In 1951, in the midst of chaos in Harlem, Hughes published his poem “A Dream Deferred” in hopes to call people’s attention to the devastating effects Harlem was experiencing. Although issues regarding racism began to be addressed in the 1960’s, Harlem continued to fall apart. It wasn’t until the 1980’s that Harlem would begin to get back up off its feet. Patrols began increasing to deter crimes and retail stores began to gradually open up as seen with 65 East 125th Street. However, even though Harlem had begun undergoing a process of gentrification, for every step forward time had gone for the previous fifty years, it seemed as if Harlem took two steps back.
“What happens to a dream deferred?” Is the question posed by the infamous Poet, activists, novelist, and playwright Langston Hughes in his 1951 poem by the name of Harlem or Dream deferred. In the poem, Hughes straightforwardly flings us a question, in which at first seem pretty simple in meaning but as you continue to read the concept becomes more and more complex and profound. The telling reader to pursue after their dream or the dream will soon disappear, an inspirational theme in which Hughes display in several of his works. Harlem uses clear-cut use of literary elements such as Metaphor, Speakers, Imagery, and Rhythm to describe just how 1950’s Harlem community perceived and valued their dream through the eye of Hughes. His approach was very straight forward and infuses in the concept in the most rudimentary way yet there’s nothing plain about the poem.
Not long ago computers were non-existent in many homes. When computers were first introduced to the world, they were for the sole purpose of performing business functions. The only people who owned computers were large organizations. Eventually, computers were introduced into the homes of those who could afford to buy them. Today, just about everyone owns some form of system that they use daily to help manage their day-to-day operations. What many once survived without now seems impossible to do without. As technology continues to grow, it has a greater effect on families and the education system. Some companies such as Microsoft and Apple made it possible to reinvent a new form of technology that would change the world. Each company had some form of struggle and overtime had to keep up with the changes of time and the way people communicated. From the first day of its invention, organizations have had to steadily implement new operating systems to keep up with the demands of the people while staying afloat with competitors. The ways of life for many have changed as well as the way people communicate. It is evident that the history and uses of computers have changed the world but these computers could not perform without the operating systems. Various operating systems will be discussed, how they began and how they each changed since they were first introduced. Although, they all had a purpose each varied in how they performed and changed the lives of many and will continue in the near future.
Information systems are a vital necessity to healthcare institutions in the United States and other nations with the ominous need to keep up with technology, research, and science in the 21st. Century. Most of healthcare institutions in Africa still depend on physical documentation, written by hand and afterword’s stored in binders locked away in storing facilities. With the growing populace in Africa, gathering information concerning patients health documents is costly, hard to maintain, and unethical. Therefore, in this case scenario I’m going to target my research, in developing countries in Africa in general, who are striving to improve ideal management information system. The goal is to aim efforts to improve public health through enhanced supervision through healthcare information, such the ability to collect, store and analyze accurate health data, service transfer proficiency, improve data accuracy, value of involvement, increase accountability and to learn about trends. The objective of this information system is to record information on health events and check the quality of services at different stages of health care. The data collected will also help to notify forthcoming healthcare policy determinations.
As the internet is becoming faster and faster, an operating system (OS) is needed to manage the data in computers. An Operating system can be considered to be a set of programed codes that are created to control hardware such as computers. In 1985 Windows was established as an operating system and a year earlier Mac OS was established, and they have dominated the market of the computer programs since that time. Although, many companies have provided other operating systems, most users still prefer Mac as the most secured system and windows as it provides more multiple functions. This essay will demonstrate the differences between windows
It all began in 1991, during the time of monumental computing development. DOS had been bought from a Seattle hacker by Bill Gates, for a sum of $50,000 – a small price for an operating system that had managed sneak its way across the globe due to a clever marketing strategy. Apple’s OS and UNIX were both available, though the cost of running either was far greater than that of running DOS. Enter MINIX, an operating system developed from the ground up by Andrew S. Tanenbaum, a college professor. MINIX was part of a lesson plan used to teach students the inner-workings of an operating system. Tanenbaum had written a book on MINIX called “Operating System” and anyone who had picked up a copy would find the 12,000 lines of code that comprised MINIX itself. This was a big issue; due to the fact that all know (well published) operating systems to that point had been well guarded by software developers, thus making it difficult for people to truly expand on operating system mechanics.
Watson, J. (2008). A history of computer operating systems (pp. 14-17). Ann Arbor, MI: Nimble Books.
Operating system design goals and requirements are divided into two groups. What are these two groups?
When an executable file is loaded into memory, it is called a process. A process is an instance of a program in executing. It contains its current activity, such as its program code and also the contents of the processor’s register. It generally includes the process stack, which contain temporary data, and a data section, which global variables. During runtime, it may include a heap, or dynamically allocated memory. In contrast with a program, a process is “an active entity, with a program counter specifying the next instruction to execute and a set of associated resources” (Operating System Concept 106). A process is a program that executes a single instance of a thread. Multiple threads can exist which allows more than one task to perform at a time. Multithreaded processes may share resources such as code, data, and file section. They do not share resources such as registers and stack.
An Operating system is system software that controls the system’s hardware that interacts with users and the application software. As we all may know, Windows Microsoft has always been a commercial high-level sale in the retail industry and an in domain operating system used today. But there are more operating systems than just Windows Microsoft than the general population may assume. Linux is another well-known operating systems, which is free and open-source software. Linux is also used in companies we would have never thought of like Google, NASA, USPS, Amazon and many more companies. Linux and Microsoft operating systems have been in competition to see which one is the best operating system in the market. There are so many resemblances
The central unit is the basic part of the computer and includes all the main computer parts. It is the heart of the computer system. It is responsible for executing, or running the software. The software programs are translated into a series of codes made up of 1s to 0s that the CPU can understand. Every code means a certain operation should take place.
computer architecture Computer architecture covers the design of system software, such as the operating system (the program that controls the computer), as well as referring to the combination of hardware and basic software that links the machines on a computer network. Computer architecture refers to an entire structure and to the details needed to make it functional. Thus, computer architecture covers computer systems, microprocessors, circuits, and system programs. Typically the term does not refer to application programs, such as spreadsheets or word processing, which are required to perform a task but not to make the system run.