31. Write the advantages of loosely coupled system over tightly coupled systems?
Ans:
1. More number of CPUs can be added in a loosely coupled system to improve the system performance
2. The system structure is modular and hence easy to maintain and troubleshoot.
3. A fault in a single module does not lead to a complete system breakdown.
32. What is the different clock frequencies used in 80286?
Ans: Various versions of 80286 are available that run on 12.5MHz, 10MHz and 8MHz clock frequencies.
33. Define swapping in?
Ans: The portion of a program is required for execution by the CPU, it is fetched from the secondary memory and placed in the physical memory. This is called ‘swapping in’ of the program.
34. What are the different operating modes used in 80286?
Ans: The 80286 works in two operating modes
1. Real addressing mode
2. Protected virtual address mode.
35. What are the CPU contents used in 80286?
Ans: The 80286 CPU contains almost the same set of registers, as in 8086
- Eight 16-bit general purpose register
- Four 16-bit segment registers
- Status and control register
- Instruction pointer.
36. What is status flag bit?
Ans: The flag register reflects the results of logical and arithmetic instructions. The flag register digits D0, D2, D4, D6, D7 and D11 are modified according to the result of the execution of logical and arithmetic instruction. These are called as status flag bits.
37. What is a control flag?
Ans: The bits D8 and D9 namely, trap flag (TF) and interrupt flag (IF) bits, are used for controlling machine operation and thus they are called control flags.
38. What is instruction pipelining?
Ans: Major function of the bus unit is to fetch instruction bytes from the memory. In fact, the instructions are fetched in advance and stored in a queue to enable faster execution of the instructions. This concept is known as instruction pipelining.
39. What is swapping?
Ans: The procedure of fetching the chosen program segments or data from the secondary storage into the physical memory is called ‘swapping’.
40. What is mean by microcontroller?
Ans: A device which contains the microprocessor with integrated peripherals like memory, serial ports, parallel ports, timer/counter, interrupt controller, data acquisition interfaces like ADC,DAC is called microcontroller.
41. Explain about MODEL
Ans: This directive provides short cuts in defining segments. It initializes memory model before defining any segment. The memory model can be SMALL, MEDIUM, COMPACT or LARGE.
- Model Code segments Data segments
- Small One One
- Medium Multiple One
- Compact One Multiple
- Large Multiple Multiple
42. Explain PROC & ENDP
Ans: PROC directive defines the procedures in the program. The procedure name must be unique. After PROC the term NEAR or FAR are used to specify the type of procedure. Example FACT PROC FAR. ENDP is used along with PROC and defines the end of the procedure.
43. Explain SEGMENT & ENDS
Ans: An assembly program in .EXE format consists of one or more segments. The starts of these segments are defined by SEGMENT and the end of the segment is indicated by ENDS directive.
- Format Name SEGMENT
- Name ENDS
44. Explain TITLE & TYPE
Ans: The TITLE directive helps to control the format of a listing of an assembled program. It causes a title for the program to print on line 2 of each page of the program listing. Maximum 60 characters are allowed. Format TITLE text. TYPE operator tells the assembler to determine the type of specified variable in bytes. For bytes the assembler gives a value 1, for word 2 & double word 4.
45. Define SOP
Ans: The segment override prefix allows the programmer to deviate from the default segment
Eg : MOV CS : [BX] , AL
1 2 3 4 5