CS609 Current Final Term Fall 2013 File 10

1. calculate the sector # for following cluster 44H. we have following information block per cluster=8 first user block no is =20.................... 2 marks

Sector # = Cluster # * Sector Per Cluster

2. ntfs store file name in ___225_________ and fat store file name in _______31___ characters? .... 2 marks not sure

3. what is paging in context of non contiguous memory system? ...... 2 marks

1.      A process is subdivided into segment of variable size and each segment or few segments of the process can be placed anywhere in memory

80386 and higher processors also support Paging, i.e. a Process may be divided into fixed size Pages and then only few pages may be loaded any where in memory for Process Execution.

4. what type of operations performed by system software ? ........... 2 marks

5. what is usage of cd. and cd..      3 marks pg281

6. three different types of computer virus?.......... 3 marks

There are various types of viruses but we will discuss those which embed themselves within the program or executable code which are

Executable file viruses
Partition Table or boot sector viruses

7. what is difference in physical and logical view of file ? .......... 3 marks

File

• Is logically viewed as an organization of Data.
• Physically it can be a collection of clusters or blocks.
• O.S. needs to maintain information about the cluster numbers of which a file may be comprised of.

8. discuss all the step performed by following c statement 

unsigned int far *lpt= (unsigned int far *)0x00400008;

outport((*lpt+2), inport (*lpt+2)|0x10;

outport (0x21, inport(0x21)|0x80).................... 3 marks

9. how communication of modem can be improved in term of data transfer?.......... 5 marks 

Run regular anti-virus and anti-malware scans on all computers using the DSL modem.

Contact your ISP. Ask them to run a speed test. This test can help you determine the source of any

faults in your connection, and whether they originate at your ISP at at your location.

Reset network equipment like the modem and any routers in use if you notice any slowdown in speed. If your networking hardware is experiencing any difficulties, this reset may resolve them.

Install DSL line filters on any other telephone jacks in your house or office that use the same line as the DSL modem. Plug the line filter in the phone jack, and then plug your devices into the line filter. These get rid of any interference from these other devices that may be robbing your modem of its top speeds.

10. how can a certain volume with moderate space and another volume with large space can be managed by same fat system ?................. 5 marks

how can a certain volume with moderate space and another volume with large space can be managed by the same FAT system. The answer is that the number of entries might be same but the size of cluster may be different. The cluster size can vary from 512 bytes to 32K in powers of 2 depending upon the volume size. The above slide shows how the cluster size and the exact number of required FAT entries can be determined.

11. how disk partitioning software works? ............. 5 marks

Write the code part of partition table to appropriately load the Boot Block of active partition in primary partition table.
• Places data in the partition table regarding primary and extended partitions.

• As per specification of the user assigns a appropriate size to primary and extended partition by modifying their data part.

12. how can we recover the deleted content of file ? explain each step of recovery ....... 5 marks 

0xE5 at the start of file entry is used to mark the file as deleted. • The contents of file still remain on disk.

• The contents can be recovered by placing a valid file name, character in place of E5 and then recovering the chain of file in FAT.

• If somehow the clusters used by deleted file has been overwritten by some other file, it cannot be recovered.