This report is about the need to upgrade the new computer systems for our company. It also discusses the advantages and the disadvantages of both the old system which is currently used by our company and the new system available at present. The aim is to bring substantial benefits to the company by using a new computer system which supports multiprogramming and virtual memory. This is because quality of our products and services are very poor when compare to other companies which are using new computer systems such as Multiprogramming and Virtual Memory. There are several disadvantages and constraints appear in our current system. And also the current system is now nearly out of date and may fail to work properly. The maintenance cost is increasing and the quality of service which the system provides are decreasing. For these reasons it is time to analyze the current system and to introduce the new system very soon.
The current system (Single User Batch System)
The current system is using old technology called the batch system. It is used by several years all over the industrial countries and was very famous. Its growth brought many changes in the industrial world and human’s working style. However this technology and its development continued and still carried out by the scientists and the engineers. And also they invented more powerful efficient systems than the batch system. Furthermore the batch system is now considered as very old inefficient system. The increased performances of the new systems are very higher than the batch system and they outweigh the batch system from its position. When analyze the current system it is worth to see how the system works and its technological features.
In the batch system, the monitor program is resident in memory and occupied in some memory spaces. Therefore the memory space for user program is limited and cannot run very large programs. If the user program is very large and tries to extend in monitor programs space, abort and get the next job. And also the monitor program uses some valuable processor time as well.
The current system takes considerable time between jobs more than execution time. This is to say it required setup time during which the operating system was loaded, tapes and disk packs were mounted, appropriate forms were placed in the printer etc. After completion of one job it needs teardown time as tapes and disk packs were removed, forms were removed, time cards were punched out etc. During these periods the computer sits idle and the valuable time is wasted.
Furthermore these single user systems waste a considerable amount of the computing resource. The program consumes the CPU resource until an input or output is needed. When the input/output request is issued, the job often cannot continue until the requested data is either sent or received. Input and output speeds are extremely slow compared with CPU speeds. For these reasons the machines are poorly utilized and the processor is processing for only a fraction of the available time and, in fact, the entire system sat idle until finishes a program.
When use the current system our company faces several problems and constraints from it. The employees finding very difficult when use this system and it is not very user-friendly built. The management team also struggling to organize and finish the tasks properly within the deadlines because of the current system’s constraints. The following main problems are identified during the system analyze.
* In this system the operator need to batch the card packs for each job and a program called monitor which controls the execution of each job.
* The major constraint is only one job can process at a time. Therefore the users have to wait for long time to finish their tasks and it wastes most of employer’s lot of time.
* The sales catalogue of products and services used to price customer orders is often out of date. In particular, new items and services are not catalogued immediately and items which are now no longer stocked still appear. The problem is located in the time-consuming nature of the batch system used to prepare the catalogue from the inventory records.
* Customer requirements are sometimes difficult to deal with as records of orders are unable to access immediately on time.
* Orders that cannot be immediately satisfied from current stock and production that is, back orders are not processed consistently.
* Due to the large number of documents flowing through the system the time taken to process an order may be days, even if all the goods are held in the warehouse.
* For some kind of huge jobs it takes time in hourly rate or days. Consequently large number of employers could not able to finish their job within one day as a result they can not carried out other jobs and unable to meet their deadlines.
* Data within the system is generally stored in a way which makes it difficult for management to retrieve useful information. For instance, regular reports are time-consuming to produce and are often late, rendering them ineffective for control purposes or to aid medium-term strategies.
* As a result company’s all the processes are carried out in very slow rate and unable to provide quality service for our customers.
* The company’s market’s falling rate is increasing every year and the number of our customer are decreasing very rapid rate. The problem is located in the time-consuming batch system.
However it is important to analyze other new systems which currently available such as with multiprogramming and virtual memory techniques. Actually the multiprogramming system and the virtual memory systems were built by computer designers to over come these problems.
A system with Multiprogramming
To overcome these problems there is an alternative available technology called multiprogramming which runs several programs at a time. This is done in rapid sequence, and reduces the idle time of the processor. Normally, input and the output is much slower than the processor, therefore when a program require input/output, processor can run another process at that time. Similarly, when a program uses the processor other program can use various input/output devices. To achieve this some form of memory management and scheduling algorithms are used according to solve the problems several programs may resident in a memory and deciding which program to run.
* It reduces the CPU idle time and increase the throughput. Therefore the efficiency and utilization of a system are increased.
* And also this system developed to service multiple interactive users at once. Therefore the system will respond quickly to user requests and increase the through put as a result it increases the productivity.
* Many users can do the same job at once even they use the same program. It is not a problem because current operating systems are designed to manage those problems and even they are designed to share those program parts in primary memory as well. Therefore primary storage also will not be wasted.
* In addition some new features of the operating systems such as multi tasking etc, they makes very easy to use and increase the efficiency as well. For example users can switch between applications. A new application may be started with the START command. Then each application can use all the resources and peripherals.
On the other hand this multiprogramming requires considerably more storage than a single user system. However, the improved resource use for the CPU and the peripheral devices more than justifies the expense of additional storage. And also virtual memory system frequently solves this problem. If the system has both multiprogramming and virtual memory technique, the efficiency will be increased more.
A System with Virtual Memory
Above described multiprogramming system require large size of memory to keep several programs at once in memory as mentioned above. However it is not necessary to have needed large size of memory, because the virtual memory technique uses the memory efficiency by using small size of memory and swapping the programs between memory and hard disk. When the programs like this user or programmer run, they will feel there is a large size of memory in the system. This is to say it creates virtual memory. Most computers including desktops have virtual memory system nowadays.
* This has been done by using limited resources and provides great benefits for users for low cost
* Helps to run several programs at once in limited resources and facilitates the operation of shared multi-user systems.
* It allows creating user programs independently
* This storage allocation allows running the programs larger than available storage
* The virtual memory implemented by using two common advanced methods paging and segmentation. These methods are help to use idle hard disk as well.
Those two methods are very complex and handled by operating system. However when use the system user does not need to care about available storage space and how the virtual memory works but user will feel there is a large size of memory in the system. It does not mean it makes to feel virtually that many process run on the system. This is to say the processes are running on the virtual memory system is larger than the processes can run on real storage which has not got virtual memory system. As a result it makes user to feel there is a large storage available for the use but the actual memory size is small. I.e. by using different kind of techniques the small amount of memory is used much efficiently.
It is very clear now the multiprogramming and the virtual memory techniques are provides high quality for the computer system and they provides substantial benefits for low cost. And also the multiprogramming and the virtual memory technologies are very popular and used by several companies. Furthermore they have many advantages and could not find any disadvantages when compare to our old batch system. Batch system is now uncommon and if we continued with the current system our company may face massive lost in our market. The new system with multiprogramming and the virtual memory will increase the quality of our service and productivity. These developments sought not only to increase the number of tasks completed per unit of time but also to increase the efficiency of hardware usage on single tasks. Furthermore by using new system our market can be extended across the world and can maintain the steadiness. I believe that it will be a forwarded and reasonable movement of our company’s history and necessary to do now.
H.M DIETEL, Operating Systems, second edition
IDA. M. FLYNN, ANN McLVER McHOES, Understanding Operating Systems, second edition
ANDREW S. TANENBAUM, Structured Computer Organization, fourth edition