Frequently Asked Questions - X86 Microprocessor

These interview questions test the knowledge of x86 Intel architecture and 8086 microprocessor specifically.

1. What is a Microprocessor? - Microprocessor is a program-controlled device, which fetches the instructions from memory, decodes and executes the instructions. Most Micro Processor are single- chip devices.
2. Give examples for 8 / 16 / 32 bit Microprocessor? - 8-bit Processor - 8085 / Z80 / 6800; 16-bit Processor - 8086 / 68000 / Z8000; 32-bit Processor - 80386 / 80486.
3. Why 8085 processor is called an 8 bit processor? - Because 8085 processor has 8 bit ALU (Arithmetic Logic Review). Similarly 8086 processor has 16 bit ALU. 
4. What is 1st / 2nd / 3rd / 4th generation processor? - The processor made of PMOS / NMOS / HMOS / HCMOS technology is called 1st / 2nd / 3rd / 4th generation processor, and it is made up of 4 / 8 / 16 / 32 bits.
5. Define HCMOS? - High-density n- type Complimentary Metal Oxide Silicon field effect transistor.
6. What does microprocessor speed depend on? - The processing speed depends on DATA BUS WIDTH.
7. Is the address bus unidirectional? - The address bus is unidirectional because the address information is always given by the Micro Processor to address a memory location of an input / output devices.
8. Is the data bus is Bi-directional? - The data bus is Bi-directional because the same bus is used for transfer of data between Micro Processor and memory or input / output devices in both the direction.
9. What is the disadvantage of microprocessor? - It has limitations on the size of data. Most Microprocessor does not support floating-point operations.
10. What is the difference between microprocessor and microcontroller? - In Microprocessor more op-codes, few bit handling instructions. But in Microcontroller: fewer op-codes, more bit handling Instructions, and also it is defined as a device that includes micro processor, memory, & input / output signal lines on a single chip.
11. What is meant by LATCH? - Latch is a D- type flip-flop used as a temporary storage device controlled by a timing signal, which can store 0 or 1. The primary function of a Latch is data storage. It is used in output devices such as LED, to hold the data for display.
12. Why does microprocessor contain ROM chips? - Microprocessor contain ROM chip because it contain instructions to execute data.
13. What is the difference between primary & secondary storage device? - In primary storage device the storage capacity is limited. It has a volatile memory. In secondary storage device the storage capacity is larger. It is a nonvolatile memory. Primary devices are: RAM / ROM. Secondary devices are: Floppy disc / Hard disk.
14. Difference between static and dynamic RAM? - Static RAM: No refreshing, 6 to 8 MOS transistors are required to form one memory cell, Information stored as voltage level in a flip flop. Dynamic RAM: Refreshed periodically, 3 to 4 transistors are required to form one memory cell, Information is stored as a charge in the gate to substrate capacitance.
15. What is interrupt? - Interrupt is a signal send by external device to the processor so as to request the processor to perform a particular work.
16. What is cache memory? - Cache memory is a small high-speed memory. It is used for temporary storage of data & information between the main memory and the CPU (center processing unit). The cache memory is only in RAM.
17. What is called “Scratch pad of computer”? - Cache Memory is scratch pad of computer.
18. Which transistor is used in each cell of EPROM? - Floating –gate Avalanche Injection MOS (FAMOS) transistor is used in each cell of EPROM.
19. Differentiate between RAM and ROM? - RAM: Read / Write memory, High Speed, Volatile Memory. ROM: Read only memory, Low Speed, Non Voliate Memory.
20. What is a compiler? - Compiler is used to translate the high-level language program into machine code at a time. It doesn’t require special instruction to store in a memory, it stores automatically. The Execution time is less compared to Interpreter.
21. Which processor structure is pipelined? - All x86 processors have pipelined structure.
22. What is flag? - Flag is a flip-flop used to store the information about the status of a processor and the status of the instruction executed most recently
23. What is stack? - Stack is a portion of RAM used for saving the content of Program Counter and general purpose registers.
24. Can ROM be used as stack? - ROM cannot be used as stack because it is not possible to write to ROM.
25. What is NV-RAM? - Nonvolatile Read Write Memory, also called Flash memory. It is also know as shadow RAM.

Check Out Assembly Language Tutorials : 8085 & 8086