Identify and fully describe the main developments Essay Example for Free

Identify and fully describe the main developments Essay 1. Identify and fully describe the main developments of Operating Systems, giving examples of their origins and use. Batch Operating Systems were an early operating system available, and were first introduced in the mid 50s. They were designed to make human manual work easier; humans were replicating identical jobs over and over again, hence in batch. A batch operating system keeps itself eventful; it does this by taking jobs from a batch queue, instead of waiting for people to submit jobs. The jobs are then processed one or more at a time under control of the operating system, however most jobs undertaken in this operating system would be single-task. These type of operating system were often left to work overnight, mainly because the jobs were batched the next job in the queue would be commenced as soon as the previous job had been completed, this way of processing would allow for a large work load to be automatically completed without the requirement to wait and tell the computer to do the next job. Real Time Operating Systems (RTOS) are often embedded, meaning a integral part of a system inside another device. They have very little user interface capability. Real time operating systems like their name implies, respond to an input immediately. Real time operating systems are capable of processing data so quickly that the results are available to influence the activity currently taking place. [Computer Science 5th Edition, CS French, Ashford Press Gosport, 1996] Real time operating systems guarantee a certain capability within a specified time constraint; these time constraints are usually very rigid. If the system does not conform to this time limit, the system ultimately fails. They are used for various purposes; a few of these are medical equipment, industrial control systems and car computers. Parallel Systems have more than one processor to carry out a single job. The systems often carry out one single job using the resources of both processors of the machine; however some systems will have a processor dedicated to a single task. These operations work in parallel (side by side) of one another. Distributed Systems act as an illusion to a user. A multiple number of nodes are set up on a network, to allow data access or device sharing. This allows for other users of different machines to access data on another machine on the network. For example at college a student logs on to the machine, the machine seems local to the user, the user observes the system as using its own local drives and devices. However these Drives and devices are setup on a client-server machine but appear to be local to the user. Time Sharing Operating Systems allow multi-tasking, the operating system shares a slice of the processor resources to designated programs and users logged on to the system. For example, it is not unusual for a home user to have a word processing package, internet browser and a multimedia package to be open at the same time. Microsoft Windows is a great example for allowing this. Personal Computer Operating Systems were brought about in the early 70s. However it wasnt until the 1980s that they became popular, and the focus of the operating system changed from the hardware aspect, to that of the user interface (how the user observes the operating system). Personal Computer Systems are simply operating systems that share the processors resources for single users tasks. The main concept behind personal computer operating systems is the user interface. The workings are important; however the main principal is that the user is entirely interactive with the system. These are perhaps the most difficult for designers to produce, as a very high level knowledge of user interface design is required. This is to allow users of any level to use the system comfortably. It allows for considerable power for a single user to run high-tech graphics and multimedia packages. These operating systems evolved in to very capable systems, allowing for heavy multi-tasking usage. Examples of Personal Computer operating systems are as follows: Microsoft Windows Linux Apple Macintosh MAC OS 2. Identify and fully describe the main purposes of an operating system. All components of the operating system are required to be covered, to clearly show an understanding of what each component does and how they fit into the overall system design. Process Management Process management is a way of tracking processes and managing them in such a way that there is enough processor resources to correctly function. Process is another word for a task that is to be performed by the computer. Along with a process is a set of information about the particular process. The information required to track these processes are stored in a data package called a Process Control Block (PCB). The process control block contains the following information about a process:   An identification number that uniquely identifies the process Owner ID An identification of the user/device who the process belongs to   Priority A number to represent its priority to the system   Status What its current state is. This is 1 of 3 states (Ready, Waiting, Running). Units of Processor Time Used   Resources waiting for for example paper for the printer.   Link to Another PCB   Registers the registers the process has contents in. Process ID 239845 Owner ID Chris. Oliver Priority 25 Status Waiting Units of Processor Time Used 264 Resource waiting for Disks [printer] Link to another PCB Next PCB in wait Queue Registers Contents of registers when process last stopped running An example of a PCB is shown below: this is for a print job A Processes state is diagrammatically shown below, this shows state transition and how it works. A process can be in one of five states; these five states are as follows: State Definition HOLD A processs state at the beginning, this is when the devices and memory allocation size is decided. READY this state is when the process has been allocated all the resources required and is ready for being operated on by the computer RUNNING This state is when the process is in the CPU WAITING This is when the process stops because of an input or output waiting to be completed. The process is removed from the processor and is allocated this state. It is given this state until the input or output is given the all clear. FINISHED This is when the process has been finished, and all the devices used by the process have been released ready for the next process. Deadlocks Deadlocks occur when a multiple number of processes fight for very little resources available from the processor. For example one process has been granted the allocation of the modem, however is waiting for a text file, but process two has the text file and is waiting for the modem. In this instance each process will not gather the resources required because they have been allocated to another process, this is where a deadlock occurs. Process Management in an operating system has the job to destroy one of the processes to allow for one of the processes to be put in the ready queue. Scheduling Scheduling is a method in the operating system that allows processes to enter the ready queue allowing them to then take execution. The strategies used to take these processes and allow them to be ready for execution are as follows:   Process the maximum amount of jobs.   Sharing out processing time equally to users   Providing acceptable response times, this is in the form of not running intensive programs while users are logged on to the system. Keeping devices as busy as possible.   Attempting to gradually freeing up of processes, instead of crashing.   Avoid Deadlocking Scheduling is comprised of three sections: 1 Long Term Scheduling this is where processes are batched together, when the resources and space are free the process is then executed. This type of scheduling is used for jobs like heavy overnight print jobs. 2 Mid-Term Scheduling this is where a decision is made as to whether the processor is to busy for the amount of processes attempting to use it, the decision can be then fixed by terminating processes. When the system is free again the process can be re-executed. 3 Short Term Scheduling is a where the next process is selected from the ready queue; it uses algorithms to do this. Shortest burst time being the time spent running before the process will have to wait before an input or output operation. Shortest remaining time is the processes that have very little time left; this inevitably allows space for another process to execute. Priority scheduling a control that allow special circumstance processes to execute through the system quickly. Round robin limits the time a process is allowed to run before it is removed, it is then placed back in the ready queue. Memory Management Memory is an area in which data and instructions are stored. These operations must be managed by an operating system in order for the system to be stable and to run fluently. Memory management within an operating system must ensure that a process has enough memory to run, ensuring it does not go in to another processes slot as this causes corruption. This management is a way of protecting memory from becoming unstable. Memory management is also responsible for using the computers other memory sources effectively, to ensure programs run smoothly and effectively. This is handled by using virtual memory; using the hard disc drive as a temporary memory source for processes and data. This can benefit the user in various ways: The user is not rigidly restricted to space available. Using a large virtual memory space provides convenience for instances where large programs etc. are required to be stored in memory. Users are using less physical memory; therefore the system can handle more users on the system. High Speed Cache is a fast memory storage; cache predicts the data that the CPU may need next, it then retrieves it from RAM and places it in to the high speed cache, this speeds up system performance, as cache is a lot faster than RAM is in providing for the processor. The operating systems task is to control an even flow of the processes and decide where they should go practically, moving processes to the best location as the scheduler asks it to do so. This scheduler knows what process is next in line therefore can tell memory it is next and to move it to a suitable location for it to be quickly accessed. Paging Paging is a method used in operating systems to make a programs memory non-contiguous, in simple terms; allowing a program to be allocated to any memory location available. This is used when a bulk of data is bigger than the memory allocation it has been given; it firstly fills the memory allocation provided, and then stores the rest of the data in any space available in memory. This method of splitting the data is known as Fragmentation. This decreases system performance. Defragmentation To enhance the performance of the memory of a secondary storage medium, the operating system runs an operation called Defragmentation. Defragmentation is a process that sorts data in to a contiguous sequence. If a non-contiguous set of data is found, it will be relocated and stored as a whole. The image above is an illustration to show pictorially how a storage device could look in a data structure. As you can see fragmented files are scattered. If this data was attempted to be retrieved it would be slower feedback to the user as the data has been fragmented and would have to be found first. If data is to be found quickly and retrieved without a problem, the diagram below shows how a data structure should pictorially look. The image shows a contiguous data structure, with no fragmented files. This is the idea state for a system to be operated under. File and Disk Management TALK ABOUT HOW MEMORY IS STORED i. e. CONTIGIOUS Blocks of data are assigned in a complete row, using this method the files are simple to access. The space must be large enough to store all the data Files may become larger, therefore the space may be too small in the future, then it will need relocating (moved) This then causes fragmentation of the storage device. , NON CONTIGIOUS Files are recognised by operating systems and worked upon by using file extensions. A file consist of two parts, one being the unique name to the user, second being the file extension related to the program that runs that type of file. The operating system recognises exactly which program to open when the file is run. The way that files and data are managed, is critical to the performance of the computer and the security of the data. File management within an operating system provides a logical way for the user to observe there data, instead of having the complication of the physical implementation. Operating systems main job in this area is to ensure that data is stored and relocated correctly, as well as having the responsibility to process files, find space to store them, and to retrieve this data at any time. For example a . PDF file when run will be recognised by the operating system to be open in Adobe Acrobat Reader, providing the program is installed on the computer. An operating system can perform several different tasks towards files, they are as follows: Operation/Task Function Create finding space for it on storage medium, a new record made in directory Write Finds the file from directory and adds data to it. Read Finds the file then puts it in to memory and a read pointer is used to track where the next read place is to take place. In most operating systems however, a write pointer is held at this point, in-case the user intends to write to the file while reading Delete finds the file, then frees all space given to it, this is then erased from the computer Files are a collection of saved information that is stored on a type of storage medium for later retrieval. File attributes are the information related to the file, just like we have information related to ourselves, i. e. telephone number and home address. A files attributes are vital in order for the operating system to create a file structure system, it does this by using the attributes to sort the files in to some kind of order. For computer data files there are a set of minimum attributes related to them, they are as follows: Attribute Name Role Name an identifier to the user, in the form of a string of characters Type the type of file it is, this is important as different operating systems handle different types of files differently. Location Information held about where the file is stored, usually in the form of a path to it. e. g. C:\Documents and Settings\Chris\Assignment. doc. Size The size of the file (in bytes) e. g. 270kb. Protection Permissions to who can access the file. I. e. Read Only Date when the file was created, modified or accessed. Author the person the file was created and saved by. Directories Directories are a hierarchical way of separating these files; directories simply make it simpler for users to relocate the file at another time. The root is the top directory of a file system; the root is determined by the operating system. The root directory is usually the bootable device on a home computer system. Commonly C: Paths are a list of directories that the operating system goes through to find a run able file. For example: C:\windows\cdplayer. exe The operating system will go in to the root and then in to the directory Windows the file named cdplayer. exe will then be located and executed. Tree Structure are of a hierarchical nature, therefore the top level is the root of the directory and every other sub directory from which all other directories stem off. A Backslash is used to separate and indicate directories within directories (sub directories) Directories allow a method for the operating system to easy locate files. Volumes are a fixed amount of storage space allocated on a device. If a hard disc drive has two partitions set up, then it is said to have two volumes because it has two separate fixed storage spaces. Formatting a device in turn means to prepare it for read and write access. It does this by wiping all drive information that has been pre-set, it then tests each sector of the disc to ensure they are reliable enough for read and writing in and out of. File Allocation Techniques FAT (File Allocation Table) 32. Located on the storage device, basically holds the relevant information in a table, to find the data on the disk. its security does not measure up to that of NTFS and its filename size constraint is poor to that of NTFS. Searches from top to bottom when looking for a file. Contains the first block of each file on the disk, Requires a tremendous amount of space NTFS (New Technology File System) Used in Windows NT based operating systems Uses a similar table to that of FAT32 to keep track of file locations Looks at directory structure from the side to help speed up the location of files Uses Link Listed Allocation. Linked allocation creates inked lists using disk sectors as nodes. For example, if the sector size is 512 bytes, and it takes a 32 bit number to represent the next block address, then only 508 bytes can be used to store data (the other 4 bytes are used to locate the next file sector). This approach eliminates external fragmentation (since even the smallest block can now be used). Some problems with this approach are that seeking within a file is now difficult. For example, if were interested in the last 100 bytes of a 100mb file, we need to traverse all the sectors of the file (follow links) to get to the last 100 bytes. Another major issue is that we need to do a disk seek with every disk sector (unless disk sectors are contiguous). And yet another issue with this is that storing pointers on every disk sector uses up a lot of disk space. UNIX Used I-Nodes an indexed file allocation method. Its fast for small blocks of data and can accommodate extremely large volumes of data RAM Disk RAM disks are a temporary storage solution, data cannot be permanently saved, and data is lost on any type of system shut off. I. e. system reboots. A Random Access Memory disk is a segment of the main memory that is left for extra storage if required. This is otherwise known as a Virtual Drive. The main use for this area is that of performing operations to files, this is a better way of performing operations as the rate at which they can be performed on are that much higher than that of a physical drive. Size constraints are a major problem with RAM disks, as they are limited to that only of the RAM contained in the machine. For example in modern home computer systems 256mb of RAM is contained, therefore only 256megabyte of RAM disc can be used. 256mb in todays computing is very little in comparison to what users require. OS Services files, copy, delete, rename, view, find, backup Directories create, rename, list, delete Programming, Open, close, read, write, seek File allocation methods, FAT 32, NTFS, UNIX, Disk caching RAM disk Defragmentation I/O System Management DMA DMA takes control of the system by imitating the processor; it does this to enable itself to transfer data to and from the memory using the system bus. Buffering is required primarily because of the slow nature of I/O Device function. It is a way of smoothing out an I/O operation, Virtual Segmentation each process is divided in to slices (segments) non-resident Caching and Spooling of Input and output devices Drivers System Components ( CPU, RAM, System Bus, Local Buses, Device Controllers, Control Registers, Devices). IO response System (polling, interrupts, I/O, DMA Kernal Layers, Purpose, Device, Drivers, System calls Device Management Device management controls hardware resources; this includes the control over selection and operation of the devices used for input, output or storage. 2. Select an appropriate type of operating system for the following ICT needs, giving the choice of current operating systems [trade names]: a) Local council office department in charge of the collection, and distribution of council tax. b) A national car-rental agency, whose main computing centre is located in Sheffield, through which all of the daily transactions for the business are conducted. c) An electro-plating circuit board manufactures. d) A travelling company representative, who uses technology to keep in touch with his office. 3. Research and identify the different operating systems currently available for desktop computers. From your research and investigations of these operating systems you must critically evaluate them. This evaluation should clearly demonstrate your understanding of the differences found including and potential disadvantages. Bibliography http://www. cse. lehigh. edu/~glennb/um/book/c10os. htm http://dragon. acadiau. ca/~dbenoit/3713/slides/pdf/Week2. 1_History. pdf http://cne. gmu. edu/itcore/processes/Time. html http://www. netnam. vn/unescocourse/os/35. htm#3. 5. 3%20Virtual%20memory%20concept http://www. cs. aue. auc. dk/~akbar/ospdfiles/wschap7. PDF Books [Computer Science 5th Edition, CS French, Ashford Press Gosport, 1996].

Progression of Photography Essay -- History of Photography

Photography is an affection, a craving and an addiction. It is impossible to explain why people love taking photos, but once people are engaged in photography professionally, nothing will stop them. It has always been a great magic and momentous secret which opens the world to the people, which makes us look at the things used to be taken for granted with special attitude, which makes us ponder over the existing problems. Photography can truly be considered a magical act – here is a little black box that can capture the images of people and wild animals, strange places, and loved ones on a rectangular piece of paper that can be viewed days and years later. This is a visual trick that never ceases to delight the members of the audience, the magician most of all (Watson 78). Photography not only depicts life but also reveals things which are usually hidden behind our indifference, business, and pursuit for money. The word photography comes from two ancient Greek words: photo, for "light," and graph, for "drawing"(The History of Photography). "Drawing with light" is an apt way of describing the artistic field of photography. According to a world-renowned photographer, Ansel Adams, â€Å"You don’t take a photograph, you create it.† Each time a photograph is made, light or some other form of radiant energy, such as x-rays, is used to record an image of an object or scene on a light-sensitive surface at a specific time point (Watson 79). In the infancy of photography these recorded images were called sun pictures or heliograph. This was because sunlight was used to create the image. Mankind has been recording images at since the cave paintings of some 20,000 years ago. With the invention of photography, a realistic image that would have ta... ...ain — thereby giving you the ability to experiment with your photos in a way which was never possible with the film camera. So now most of the processing is electronic in the form of 0s and 1s as opposed to the mechanical and chemical operation in the traditional cameras. The cameras that operate based on this principle are known as digital cameras and the art of making digital images is called digital photography. Works Cited "Digital Photography." Digital - Photography - Tips. Web. 18 Feb. 2011. http://www.digital-photography-tips.net/history-of-digital-phtography-early-days.html. "History of Photography." About Inventors. About.com, Web. 17 Feb. 2011. http://inventors.about.com/od/pstartinventionsa/stillphotography.html. "What is Digital Photography." Make Use Of. Web. 16 Feb. 2011. www.makeuseof.com/tag/technology-explained-digital-photography/.

Country Music vs Rap Music Essay

Today there are many different genres of music. There are many types of music for anyone. Country and Rap music may be two most popular types of music. Many people who like country dislike rap music and the other way around. Many people who listen to rap would never listen to country or ever admit to it. On the other hand people who listen to country may enjoy some rap music. In each type of music, they have many sub-genres. There also are many stereotypes that are associated with these different genres of music. Many people think that country music and rap are completely different but they do have some similarities. Country music originates from the southern states. Country music has been around longer than rap music. Country music started to get popular in the 1920’s whereas rap was started in the 1970s. Many people who dislike this kind of music think it’s a bunch of hicks singing about how they lost their girlfriend, dog or truck. Most country songs tell stories, beginning, middle and end. Unlike rap music, many country songs do not include cuss words or very few of them. Rap music contains many cuss words and sexually explicit lyrics. Also where Rappers sing about drugs, country singers sing about drinking beer. Some believe country singers are only white; in contrast there are some Black Country singers. Rap music was first started in New York City. Rap music consists of rhyming and relies on technological tricks to sound good. Most rap singers sing about money and all the luxuries it brings. However, on the other hand, country music is mostly about hard working Americans. When people think of rap singers they think of gangsters wearing tons of jewelry. When people think of country singers they think of rednecks wearing cowboy hats and boots. These are stereotypes that people refer to when thinking of these two genres of music. Today there are more similarities between rap and country. Now there is a new genre of music that combines country and rap. Singers like Cowboy Troy rap during singing a country song. Even some Toby Keith songs have some relation to rap. Tim McGraw, a country singer, and Nelly, a rap singer, combined to sing a song together. Rap, supports criminality and unjust behaviors while country is generally more appreciative of the little things in life that doesn’t cause any harm. Country is exceptionally the overall most formal and most decent pick of the two categories, as compared to rap which is labeled by most, terrible music. In my opinion I would listen to country music over rap any day. Many people wouldn’t agree with me and may think the complete opposite. Many people think that there are absolutely no similarities between rap and country. Well these people are wrong, country and rap are coming more similar, with the new genre of country, country-rap. This genre may bring fans of rap to the country side of music. With different stereotypes that come with listening to these types of music, may lessen there willing to listen to a completely different type of music. Both genres of music have been criticized. Country music and rap music may be different but they do have some similarities.

What is Religion Essay

Curious to man is his origin. Man’s genesis has baffled philosophers and intellectuals for centuries upon centuries.   No definitive answer has been given but several theories have been put forward.   Among the theories postulated, is the Creation Theory. This theory forms the basis of most religions. The theory states that a supernatural being created everything out of nothing and governs the universe. The world, through it’s diverse in cultures and beliefs, has led to the genesis of several religions most of which have a constant factor, a supernatural being; a Creator. What the Creator is referred to differs from place to place. Christians call him God, Muslims refer to him as Allah and Buddhists say Buddha. The main goal of most religions based on this theory is the veneration of the Creator and the ideal that we are all created to live up to his standards. Religion: is this a way of life? The term religion comes from the Latin verb ‘Religare’ which means binding. According to onlinedictionary.com, religion is a set of beliefs concerning the cause, nature, and purpose of the universe, especially when considered as the creation of a superhuman agency or agencies, usually involving devotional and ritual observances, and often containing a moral code governing the conduct of human affairs. There are 3 major religions with at least 1 billion followers which are: Christianity, Islam, and Hinduism (of which Buddhism may or may not be considered an offshoot). It is however impossible to accurately predict the number of religions. This is because there are many small, isolated religions in certain parts of the world. Some claim that there are as many religions as there are people, a rough estimation would put it at approximately 6.7 billion believers in the world today. However, this figure can only be factored in tentatively, as there are new religions that are made almost every day. So what is religion really? What does it entail to be religious? Are there any perks associated with this moral high ground? And if so, what are they? These are some of the many questions that have continuously plagued my mind and the search for their answers has not been comforting. As a child, I was brought up in a Christian home. I was taught to believe in God, to live according to the Christian doctrines and uphold Christian morals and values, to know that there is a place of eternal joy (heaven) for those who follow the Christian doctrine and a place of eternal suffering (hell) for those who shun the teachings. Scriptures often quoted on a daily basis and most like Romans 3:23(for the wages of sin are death) would serve to haunt my conscience should I contemplate any mischief. This has lead to the metamorphosis of my four point approach to Christianity: the major belief, the doctrine, the promise and the consequence. I had always taken religion and Christianity as synonyms. I would use them interchangeably as they meant one and the same thing. Going to church; obeying parents; reading the bible; being good to others and striving to do good at all times; religion to me meant that there was someone high above watching my every action and ready to punish me for any misdemeanors. This meant not associating to the people of other religions and sects. Cults and occults have always been an abomination. There was nothing that I could do in hiding, which meant living in fear. Then I grew up. I became older; I began having a deeper comprehension of things and started to question and challenge authority. Questions were not left to be questions anymore but now involved a deeper sense of satisfaction derived from seeking the answers. The question that most are still asking to date is: which religion is the ordained one? Which will lead to heaven? Is there even a heaven? Is it the Catholics or is it the Buddhists? As I understand it now, religion is like someone’s personality. One cannot ‘confine it to a box’ or try to seek one generalization to serve for all. Religion is dynamic, it means different things to different people and different people practice it differently. There are also some controversial aspects of religion such as the ever present association of the ever Islam culture with an affinity for terrorism. Albeit not true, many accentuate this misinformed notion and consequently many fail to interact with people of different cultures. Do the actions of fellow believers define who you are? Do the doctrines of your faith necessarily confine you to them? I would suggest that they do not. Ones faith is versatile and choice will forever be the determining factor of free will. Thus one should be defined by their actions and no by the deeds of their kind. Many religions are based on faith as many have not yet seen their supreme being and thus rely on their faith to continue in this ‘way of life’. But what is faith? Faith is simply the belief in the unseen. This is, in essence what drives religion. If we were to be guided by traditional definitions and ways of handling religion, it would mean that very few people are correct about this matter. What would then happen to the rest of the populations? Because of the nature of the subject and lack of credible answers to support theses, another group of individuals has been on the rise: atheists. What do we make of atheists? Atheism has been in existence since time immemorial and the number of people who choose this path is ever increasing. These are people who’ve chosen to not believe in the whole aspect of religion and are not attached or follow any particular one. They choose to find a neutral ground but as popularly asserted: I would rather live as if there was a God and find out that there is none, than to live as if there is none and find out that there is. In conclusion, regardless of the affiliation to a particular religious group, they all point out towards and accept or recognize a supreme being. The question of whether which one is more correct than the other, is however not my call to make. I have always been a Christian. I always will be. However, there is a big difference between the Christian that I was and the Christian that I am now. I am now more informed in decisions and there is a reason for my decisions and my accepted way of doing things and also how I perceive them. This however, does not mean that I consign my religion to a pedestal and consider the others as rubbish. No! I believe that it is important to fully understand what you believe in and with equal measure stand up for it. More importantly, is the ability to develop a relationship between you and your God. The different sects might and could be misleading, so developing a more close relationship will be able to justify your actions should you be held accountabl e.