UNIT 1
INFORMATION TECHNOLOGY
CHAPTER -3
THE MEMORY
1. What is the main function of memory unit in a computer?
The function of a memory unit is to store instructions and data for processing and intermediate and final result after processing.
2. Why cache memory included in computers?
To minimize the idle time of CPU ,a special high speed memory element called cache memory and placed in between CPU registers and Primary memory. The speed of cache memory is 10 times faster than primary memory.by making active programs and data available in fast cache memory , it is possible to increase the performance rate of the CPU.
3. Write a short note on Registers.
A register is a temporary storage area built into a CPU. Some registers are used internally and cannot be accessed outside the processor, while others are user-accessible. Registers vary in both number and size, depending on the CPU architecture. Some processors have 8 registers while others have 16, 32, or more. For many years, registers were 32-bit, but now many are 64-bit in size. A 64-bit register is necessary for a 64-bit processor, since it enables the CPU to access 64-bit memory addresses.
Internal registers include the instruction register (IR), memory buffer register (MBR), memory data register (MDR), and memory address register (MAR). The instruction register fetches instructions from the program counter (PC) and holds each instruction as it is executed by the processor. The memory registers are used to pass data from memory to the processor.
4. What are the advantages of primary memory over secondary memory.
Primary memory is the main memory of the computer system. Accessing data from primary memory is faster because it is an internal memory of the computer. Primary memory is expensive and is available in limited in size in a computer. It has an operating speed is higher than that of secondary memory.
5. What are the advantages of secondary memory over primary memory?
Secondary memory device are low cost, large storage capacity and data stored are permanent in nature.
6. Distinguish between RAM and ROM.
RAM ROM
1. Temporary storage 1. Permanent storage
2. Store data in Mega bits per second 2. Store data in Gigabits per second
3. Volatile 3. non volatile
4. Random access memory 4. Read only memory
5. Writing data is faster 5. Writing data is slower.
6. Used in normal operations 6. Used for start up process of computer
7. what is Firmware?
Firmware is a software program or set of instructions programmed on a hardware device. It provides the necessary instructions for how the device communicates with the other computer hardware. Firmware is typically stored in the flash ROM of a hardware device. While ROM is "read-only memory," flash ROM can be erased and rewritten because it is actually a type of Flash memory.
Example BIOS chip, TV Remote etc
8. What is an optical disc?
An optical disc is an electronic data storage medium that can be written to and read from using a low-powered laser beam. Various types of optical discs are available. The various types optical discs available now are CD ROM,CD Rewritable, DVD etc.
9. Differentiate between CD ROM and Rewritable CD.
A Compact Disc Read Only Memory (CD ROM) is read the data at any number of times but can not delete or rewrite. Here the data is recorded on a highly reflective coating of the disc along a spiral track.
Re-Writable (CD-RW) is an erasable disc that can be reused. The data on a CD-RW disc can be erased and recorded over numerous times.
10. What are the main differences between DVD and Blue Ray disc?
DVD can store large volume of data. It is same as compact discs. Storage capacity from 4.7GB TO 17 GB. The DVD technology use more tiny pits ,closer tracks and red laser for data reading .
Blue Ray disc is an optical disc format designed high definition video and store large amounts of data. Blue laser reads from and write to the disc rather than the red laser of DVD.Storage capacity 50GB.
11. Explain the term pit and land?
The lands represent 1 and the pits represent 0 in binary computing. The bits are read by the disc drive that uses a laser beam to distinguish between the lands and pits based on the amount of scattering or deflection that occurs when the beam of light hits the surface of the disc.
Objective type questions and answers
1. --------------------- is the fastest memory element in hierarchy
Ans. Cache memory
2. Pick the odd one out
a. Hard disk
b. Floppy disc
c. Bioschip
d. Magnetic disc
Ans. Bioschip
3. Storage capacity of a 3.5 inch floppy disc is -------------
Ans. 1.44 MB
4. DVD stands for ----------------------
Ans. Digital versatile disc
5. Name some popular secondary storage devices
Ans. Floppy disc, Hard disc, CD, DVD, Blue Ray
Essay type questions
1. Memory hierarchy in a computer system (refer text)
2. Differentiate between random access direct access and sequential access memory devices. Give example for each
Ans. ( explain Primary and Secondary storage devices )
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