Sardar Patel University 2007 B.E Computer Science Computer peripherals (CP313)(Internal ) - Question Paper

[B]Justify your answer:
Unformatted hard-disk capacity is always greater than formatted disk.
? hard disk drive can have formatted and unformatted storage capacity during the formatting process a large part of the disk surface is used for writing track and sector info this decreases the area available for data storage on the hard disk drive.


[C]What do you mean by RLL (1, 7) and RLL (2, 7)? Justify FM is RLL (0, 1) and MFM is RLL (1, 3).

? RLL (1, 7): -in this scheme in a series or in a run length the minimum number of 0s next to every other is one, and maximum number of 0s together can not be more then seven.
? RLL (2, 7): -in this scheme in a series or in a run length the minimum number of 0s next to every other is two, and maximum number of 0s together can not be more then seven.
? RLL (0, 1): - in FM scheme in a series or in a run length the minimum number of 0s next to every other is zero, and maximum number of 0s together can not be more then one

? RLL (1,3): in MFM recording there will always be at lowest one” no pulse” signal i.e. 2 pulse will never come together, and the maximum number of position without any pulse never be more then three.
















[D]Explain subsequent terms: (Any Three)
1) Key De-bouncing.
Answer: on keyboard scanning once value is received on the keyboard on the keyboard interface the interface must wait for very sort duration and then again recheck if the signal is still
There. That is done for the debouncing purpose.
2) Typematic Delay.
The delay ranging from your keeping the key pressed and the key starting to repeat itself and to change typematic rate
3) Typematic Rate.
The speed number of times per 2nd at which the key repeats itself when the key is kept pressed.
4) Encoding of Scan code.
Keyboard sends a scan code to the processor to inform about the pressing of the key on the keyboard. About it is make or break scans code.

OR
[D] discuss process of software interfacing in Keyboard

? When key is pressed, then microprocessor on the key board (i.e. Intel 8048) generates the scan code for that particular key. This processor generates various code for Key closer and key release of the key.
? A small program on within this processor takes care of the debouncing of the common keyboard.
? Once a key closure or release is obtained and the proper scan code is generated by the keyboard microprocessor, the scan code is stored into the keyboard buffer memory available inside the keyboard and is made available at the proper port so that the BIOS can learn it.

Earning:   Approval pending.