CS609 Current Final Term Fall 2013 File 11

1:Disadvantages of using undocumented service of Itnterrupt?(2)

This may not be available in all versions of DOS.

(2)Purpose of this block statement (2)

char hi,char lo;

hi=hi-0x30;

lo=lo-0x30;

hi=hi4;

hi=hi|li;

3: How much space is reserverd for root directory in FAT 32? (2)

No fixed space reserved for root directory.

4:What is contiguous memory management system?(2)

Earlier Operating System like DOS has contiguous memory management system i.e. a program cannot be loaded in memory if a

contiguous block of memory is not available to accommodate it

6:Translate the cluster#into LSN in FAT 32(3)

After calculating the sector number for the cluster the contents of the file can be accessed by reading all the blocks within the cluster. In this way only the starting cluster will be read. If the file contains a number of cluster the subsequent clusters numbers within the file chain can be accessed from the FAT.

For NTFS simply the following formula will be used to translate the sector number into cluster number. Sector # = Cluster # * Sector Per Cluster

8:Meaning of this C ststement . (3)

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

If ((inport((*lpt)+1)&0x80)==80)

Check the status of the printer if it is idle or not

9:Why we need to convert a cluster number into sector number?(5)

All the system calls use the LSN address. If the cluster number is known it should be converted into LSN to access the blocks within the cluster. Moreover all the information about file management uses the cluster number rather than the LSN for simplicity and for the purpose of managing large disk space.

10:Using port 61h write the C language statement that should connect interval timer to the speaker and in next ststement it should turn off the speaker.(5)-

page74