Arrange the following services in the ascending order of their interrupt number in ‘C’ : (a) Keyboard service (b) Print screen service (c) Video display service (d) Memory size service The correct order of sequence is :
(b), (c), (d), (a)
These are the PC BIOS interrupt services, invoked from C through library calls such as int86() or in-line INT n instructions. Each service has a fixed vector number:
| Service | Interrupt | Hex | Decimal |
|---|---|---|---|
| Print screen | INT 05H | 05 | 5 |
| Video display | INT 10H | 10 | 16 |
| Memory size | INT 12H | 12 | 18 |
| Keyboard | INT 16H | 16 | 22 |
Sort ascending. 05H < 10H < 12H < 16H, so the order is print screen, video, memory size, keyboard — that is (b), (c), (d), (a), which is option 2.
Why print screen is the outlier. Interrupts 00H–1FH are the low vectors, and the first eight are reserved for processor exceptions (divide by zero, single step, breakpoint, overflow) and hardware IRQs. Print screen at 05H sits inside that low block because it was originally triggered directly by a keyboard scan code, before the BIOS service block proper begins at 10H. That is the single fact that decides this question: everything else is above 10H, so print screen must come first, which immediately eliminates options 1, 3 and 4.
The BIOS block from 10H upward is worth carrying as a group, since the numbering is close and easily confused:
| INT | Service |
|---|---|
| 10H | Video display |
| 11H | Equipment list |
| 12H | Memory size |
| 13H | Disk I/O |
| 14H | Serial communications |
| 16H | Keyboard |
| 17H | Printer |
| 1AH | Time of day |
The trap to avoid. INT 21H is the DOS function-call interrupt, not a BIOS service, and INT 09H is the keyboard hardware interrupt (IRQ1) that fills the buffer — distinct from INT 16H, the BIOS service a program calls to read from that buffer.
Hence, the ascending order is (b), (c), (d), (a).
Similar Questions
The function "isalnum( )" returns a non-zero value if the character is alphanumeric and zero otherwise. What is header file to be used in the main program ?
To read a integer variable, find the correct format given below :
Int m;
Find the correct list, which is the reverse (at all levels) of the given list :
[[4, 7, 8], 2, 9, [19, 6], 20, 3]
(i) 3, 20
(ii) 9, 2
(iii) [6, 19]
(iv) [8, 7, 4]Which of the following is not an infinite loop ?
(A) int i = 1;
while (1)
{
i++ ;
}
(B) for ( ; ; ) ;
(C) int t = 0, f ;while (t)
{
f = 1;
}
(D) int y, x = 0 ;
do
{
y = x;
}
while (x == 0);
The three types of loops available in C language are
i. for
ii. while
iii. do-whileWhich loops do not operate without testing the condition even once ?
Match the following :
List – I List – II a. associativity i. memory storage b. # define ii. if-then-else c. auto iii. operators with equal precedence d. conditional operator iv. define operator Codes :
Assertion (A) : 'C' uses many data types such as integers (short and long) and float etc.
Reason (R) : Conversion specifier used for short unsigned integer is % lu.
Which bitwise operator is suitable for turning off a particular bit in a number ?
Which storage class is used for the variables that are often required in a program ?
Which is not a proper way of array declaration ?
Important Questions from Miscellaneous
The magazine in which Mahatma Gandhi mentioned what he wanted the Constitution to do is:
Which gas shields the surface of the earth from ultraviolet radiation from the sun?
Which event is marked as an Intangible Cultural Heritage of Humanity by UNESCO?
Who has been conferred with the rank of the Commander of the Order of the British Empire in 2018?
Who directead the film ‘Bhuvan Shome’?
