Chapter 27

Question 1

What is PIT

Answer 1

Programmable Interval Timer (PIT) is a very important peripheral device.

Question 2

What is the number of chip of PIT

Answer 2

8254

Question 3

How system time maintains

Answer 3

Through timer interrupt

Question 4

Which is highest priority interrupt

Answer 4

timer interrupt

Question 5

How computers can control external hardware

Answer 5

Computers can control external hardware through various external ports like the parallel port, the serial port, and the new additions USB and FireWire.

Question 6

What are 2 views of parallel port

Answer 6

The parallel port has two views, the connector that the external world sees and the parallel port controller ports through which the processor communicates with the device connected to the parallel port.

Question 7

What is DB-25

Answer 7

The parallel port connector is a 25pin connector called DB-25

Question 8

Is parallel port a bidirectional port

Answer 8

Yes

Question 9

What is ACK pin in parallel port

Answer 9

Pin 10, the ACK pin, is normally used by the printer to acknowledge the receipt of data and show the willingness to receive more data.

Question 10

What is port number of data port

Answer 10

378

Question 11

What is port number of control port

Answer 11

37A

Question 12

What is the example usage of parallel port

Answer 12

printer

Question 13

What is the command of terminate program

Answer 13

mov ax, 0x4c00

Question 14

We should disable interrupts while we are changing the stack (SS or SP). True of false

Answer 14

True

Question 15

Is HH:MM:SS.DD What is DD

Answer 15

hundredth of second

Question 16

How IBM track time when computer is switched on

Answer 16

IBM PC uses a Real Time Clock (RTC) chip to keep track of time while switched off. It provides clock and calendar functions through its two I/O ports 70h and 71h