RESEARCH TOPICS:
A.Research the size of operating system software by finding the amount of secondary storage(disk)space required by different versions of the same operating system or different operating systems.If their size substantially different.Explain why that may be the case, such as platforms issues,features,etc.Cite your sources.
ANSWER:
File systems organize storage on disk drives, and can be viewed as a layered design:
At the lowest layer are the physical devices, consisting of the magnetic media, motors & controls, and the electronics connected to them and controlling them. Modern disk put more and more of the electronic controls directly on the disk drive itself, leaving relatively little work for the disk controller card to perform.
I/O Control consists of device drivers, special software programs ( often written in assembly ) which communicate with the devices by reading and writing special codes directly to and from memory addresses corresponding to the controller card's registers. Each controller card ( device ) on a system has a different set of addresses ( registers, a.k.a. ports ) that it listens to, and a unique set of command codes and results codes that it understands.
The basic file system level works directly with the device drivers in terms of retrieving and storing raw blocks of data, without any consideration for what is in each block. Depending on the system, blocks may be referred to with a single block number, ( e.g. block # 234234 ), or with head-sector-cylinder combinations.
The file organization module knows about files and their logical blocks, and how they map to physical blocks on the disk. In addition to translating from logical to physical blocks, the file organization module also maintains the list of free blocks, and allocates free blocks to files as needed.
The logical file system deals with all of the meta data associated with a file ( UID, GID, mode, dates, etc ), i.e. everything about the file except the data itself. This level manages the directory structure and the mapping of file names to file control blocks, FCBs, which contain all of the meta data as well as block number information for finding the data on the disk.
B.Consult current literature to research file-naming for four different operating systems.(not including UNIX,MS-DOS,Windows,or Linux).Note the acceptable range of characters,maximum length,case sensitivity,etc.Give examples of both acceptable and unacceptable file names.For extra credit,explain how extra File Managers for those operating system shorten long file names(if they do so)in their internal lists to make them easier to manipulate.Cite your sources.
EXERCISES:
1.) Explain in you own words why file deallocation is important and what would happen if it did not occur on a regular basis.
ANSWER:
A dellocation is the process performed by the computer that releases the block of information from memory and allows that information to be used by a different program.
Although you might get an excellent answer in this category (History), there are scores of experts in the category: Computers & Internet, sub-category: Programming & Design who are just itching to answer your questions in detail.- Why not give them a crack at it (and the others like it) ?
1. Explain in your own words why file dealloction is important and what would happen if it did not occur on regular basis.
ANSWER:
Deallocation is important because it frees up resources for other processes, files, etc. and If ,it is did not occur on a regular basis then there would be limited services and a computer can perform at one time or over a period of time.
2. Describe how file manager allocates a file to a single user.List steps that you think would be followed and explain your reasoning.
ANSWER:
file manager is allocates a file first through finding the secondary storage devices and after that ,it loads the files to memory while they updates the records of the running file at the time.
3. Is device independence important to the File Manager?Why o why not?Describe the consequences if that were not the case.
ANSWER:
yes,because the property of a computer program whose successful execution (without recompilation) does not depend on the type of physical unit associated with a given logical unit employed by the program.
4. Do you think that file retrieval is different on a menu-driven system and command driven-system? Explain your answer and describe any differences between the two. Give an example of when each would be preferred over the other.
ANSWER:
the difference is in the interface which where they work together.
5. Imagine one real life example of each: a multi-file volume and a multi-volume file. Include a description of the media used for storage and a general description of the data in the file.
ANSWER :
In real life the multi-file volume is just like our life that is only one which only god can manage and knows our life will end.
As multi-volumes files is just like the Gods love which he share in his people and his people
share their love back at him.
6. As described in this chapter, files can be formatted with fixed-lenght fields or variable-length fields. In your opinion, would it be feasible to combine both formats in a single disk? Explain the reasons for your answer.
ANSWER:
No,its not feasible to combine both formats in a single disk because the two fields are in different areas.
7. Explain why it's difficult to support direct access to files with variable-length records. Suggest a method for handling this type of file if direct access is recquired.
ANSWER:
It is difficult to direct access because it is hard to find the exact location of records ,such as we suggest the variable-length record because it is the easy to access file directly at the period of time.
8. Give an example of the names of three files from your own PC that do not reside at the root or master directory. For each file, list both the relative filename and it's complete filename.
