CS609 Quiz #1 Solution and Discussion

What is output of the following program;

union REGS regs;
void main (void )
regs.h.al = 0x99;
regs.h.ah = 0x00;
printf ("%x",regs.x.ax);


The circular keyboard buffer starts at the address 40:1EH and contains 32 bytes. The
address 40:1AH stores the head of this circular buffer while the address 40:1CH stores the
tail of this buffer. If the buffer is empty the head and tail points at the same location as
shown in the diagram above.



Ref: Page 55 Handout

32 bytes can be stored in Keyboard Buffer

Total No. of bytes that can be stored in Keyboard Buffer is____.

If we want to produce the shrill voice from the speaker phone then we have to load the ___ divisor value at Port ___.

if the following function,
keep(1, 1000);
is called in the TSR program, it means that ________ No. of bytes are reserved in the memory.


In counter register bit no. 3 changes its value between 0 and 1 with in ____clock cycles

Parameters in interrupts are passed through _________ .

Getting interrupt vector refers to the operation which is used to read the _________ address stored with in vector.


Int86() has ________ parameters.


If we want to send printing on the printer then we have to perform following steps.

The address of partition block on hard disk is ___________________________.