The AT T Breakup free essay sample

Causes of divestiture effects on firm public. Background, competition, five segments after breakup, merger activity, advertising promotion, economics services. ATT (formerly American Telephone and Telegraph) is the worlds largest telecommunications company providing services, products and systems to consumers, businesses, governments and other telecommunication companies. At one time, AT had the broadest, most advanced communications network in the world, and created Bell Labs, a premier manufacturer of telecommunications equipment. In 1984, AT was forced to divest into separate businesses; the company rebuilt its business to include long distance, computers and manufacturing. In late 1995, the company announced that it would divest into three separate companies along its business unit lines. This research examines the conditions which led to the 1984 breakup, and whether that divestiture benefited the American public.

Operating systems Essay Example

Operating systems Essay Example Operating systems Essay Operating systems Essay Operating systems can be compared on the basis of their various features. In this article, we are going to make a comparison between Mac and the Windows operating systems. First, lets us see that how a common user can differentiate these two operating systems. What Windows has and Mac doesnt have: à ¯Ã‚ ¿Ã‚ ½ Larger software directory à ¯Ã‚ ¿Ã‚ ½ Best for custom built computers à ¯Ã‚ ¿Ã‚ ½ Lower cost when used with customized pc Shortfalls of Windows over Mac à ¯Ã‚ ¿Ã‚ ½ More prone to viruses, bugs, malwares, spywares and spam wares with low stability as compared to Mac à ¯Ã‚ ¿Ã‚ ½ Costs more in the long run as certain hardware updates cost more money à ¯Ã‚ ¿Ã‚ ½ Poor GUI and productivity. Mac can perform twice or thrice faster than Windows as it does not require you to wait for a process to end for an infinite period of time What Mac has and Windows does not have: à ¯Ã‚ ¿Ã‚ ½ Better GUI à ¯Ã‚ ¿Ã‚ ½ It costs just $129 to upgrade Leopard with all features available for use. No business edition, no premium edition. à ¯Ã‚ ¿Ã‚ ½ Costs less in the long run. Most of Mac upgrades cost less than those of Windows OS Disadvantages of Mac over Windows: à ¯Ã‚ ¿Ã‚ ½ Smaller software library à ¯Ã‚ ¿Ã‚ ½ Low user familiarity with the interface à ¯Ã‚ ¿Ã‚ ½ Cost can rise if not used for a larger amount of time. Now let us peep into the technical details about these operating systems. Describing MAC Operating System: Mac uses an open-source kernel called XNU. This XNU kernel is in fact a conglomeration of the BSD and Mach Kernels that use POSIX system calls. POSIX is the same set of system calls that is used in UNIX builds. Mac manages the memory using the priority-hierarchy of preemptive multitasking system. Through this system, the kernel can assign a priority to each running process and whenever a program needs some system resources, it checks the priority level of the program. If a program with highest priority requests for a resource, the kernel assigns it the requested resource with an allocated time. Whenever a program attempts to use a resource that is not assigned to it, it generates an event called system interrupt. Kernels attention is flagged, taking the complete control of the hardware; it lets the operating system to decide to cope with this malfunctioning program. A course of events reports error and shuts the program. XNU kernel is a standard powerful and simple kernel for running an operating system. Mac makes use of a Hierarchal File System PLUS or HFS+. A file system performs several jobs. They manages the hard drive for file type support, file storage, assignment of blocks of disk space and organization of these blocks, and insuring the integrity of the data stored on the disk. For instance, when a hard drive is formatted by a file system, every part of drive is assigned with sections of hard drive and at least one block is allowed for a file to be used i.e. every block is one of 2^32nd power block, and the file system supports up to 8 exabytes of file volume of the file. HFS+ is also known as jounraled FS. Before making changes to any file or part of file, it writes those changes to a special file called journel. This makes the recovery of lost file easier e.g. if a file is lost due to a sudden change such as power failure, the system just returns to the journel and reads the previous status to recover the file. This system has a flaw as well. Creation of journel requires a large disk space and hence reducing the size of usable space on the disk. As far as the system calls are concerned, Mac uses POSIX which is a standard set of system calls for UNIX. A system call is just a message created by a program to use resources or take some other action sent to the kernel. A system call can be one out of the five main operations: write, read, close, open and pipe.Mac makes better use of POSIX system and uses it to avoid the deadlocks where all processes suspend and the operating system hangs. Describing Microsoft Windows Operating System Windows uses the kernel named ntoskrnl.exe (NT Operating System Kernel) this is a hybrid of microkernel and monolithic system kernels. We can better say that it attempts to encompass all possible kernel jobs into one larger kernel but renders some parts of kernel to work with them and lets the kernel to run them aside as independent processes which kernel just conveys messages back and forth. Both systems have their own drawbacks so a hybrid kernel is better rather a single extreme. A good trait of ntoskrnl.exe is that it executes the complicated jobs as separate processes and bundles the simple jobs and hardware management into a central kernel. This approach creates difficulty when an attempt is made to change the functions of the operating system. Windows has many programs and processes to offset this complication, designed to enable the user to change to the system settings to some extent and is often can help an average user to cope with. Windows uses the NTFS file system which is a security-oriented and journaled file system. This file system has many specialized features like Disk Quotas (the administrator can allocate limited disk space to individual users), Alternate Data Streams (in which a file can be associated with other files without mentioning in the original file) and file shadowing (in which a file is copied whenever new replacement is saved). Windows also makes use of the POSIX file system calls. This system of system calls helps the operating system to manage the threads under processing. But as there are other mechanisms for application management working side by side, Windows become more prone to system h ands due to the deadlocks among the threads under processing. To facilitate the user and make its use easier, Windows provides the user with a greater degree of control over the processes and applications running on the computer. For that reason, user find this operating system more convenient to use and learn and this is also the main reason of its popularity particularly in the countries where English is not a native language.