Test: Cache Memory- 2 - Computer Science Engineering (CSE) MCQ

PROM is not a part of auxiliary memories in a Computer system.

• Secondary Memory/ Auxiliary memory:
  • An Auxiliary memory is the lowest-cost, highest-capacity and slowest-access storage in a computer system. 
  • It is permanent in nature, so it is also called non-volatile.
  • In these memories, programs and data are kept for long-term storage or when not in immediate use.
  • Examples of auxiliary memories are magnetic tapes, Floppy, CD-ROM and magnetic disks.
  • The PROM (Programmable Read-Only Memory) has the option of being programmed.
  • It is not a part of auxiliary memory.

The correct answer is a - ii, b - iii, c - iv, d - i.

Magnetic Tape

• It is a medium for magnetic storage.
• It is made of a thin, magnetizable coating on a long, narrow strip of plastic film.
• It is Auxiliary Storage Device, which means it is an external storage device.
• In the magnetic tape, only one side of the ribbon is used for storing data.
• It is sequential memory which contains a thin plastic ribbon to store data and is coated by magnetic oxide.

• The memory unit is the amount of data that can be stored in the storage unit.
• This storage capacity is expressed in terms of Bytes.
  • Bit (Binary Digit): A binary digit is logical 0 and 1 representing a passive or an active state of a component in an electric circuit.
  • Nibble: A group of 4 bits is called a nibble.
  • Byte: A group of 8 bits is called byte. A byte is the smallest unit, which can represent a data item or a character.
  • Word: A computer word, like a byte, is a group of a fixed number of bits processed as a unit, which varies from computer to computer but is fixed for each computer.

• Yotta Byte (PB) is considered the largest.
• 1 Yotta Byte (YB) = 1024 Zettabytes

• SRAM memory devices are very much similar, mainly in terms of speed, to the cache memory.
• SRAM stands for Static random-access memory.
• Static random-access memory is a type of random-access memory that uses latching circuitry to store each bit.
• SRAM is volatile memory; data is lost when power is removed.
• The term static differentiates SRAM from DRAM which must be periodically refreshed.

• The permanent memory of a computer is known as ROM(Read-only memory).
• In computers and other electronic devices, read-only memory (ROM) is a form of non-volatile memory.
• After the memory unit is manufactured, data contained in ROM cannot be electronically changed. Read-only memory, also known as firmware, is useful for storing software that is rarely updated during the life of the device.
• Plug-in cartridges containing ROM can be used to distribute software applications (such as video games) for programmable computers.
• Read-only memory refers to memory that is hard-wired and cannot be modified electronically after manufactures, such as a diode matrix or a mask ROM integrated circuit (IC).

• Cache memory is a special very high-speed memory.
  • It is used to speed up and synchronize with the high-speed CPU. Cache memory is more expensive than main memory or disk memory but economical as compared to CPU registers.
  • Cache memory is an extremely fast memory type that acts as a buffer between the RAM and the CPU.
  • It holds frequently requested data and instructions so that they are immediately available to the CPU when needed.
  • Cache memory is used to reduce the average time to access data from the main memory.

• Digital Camera
  • It is a camera that captures photographs in flash memory.
  • The basis for digital camera image sensors is metal-oxide-semiconductor technology.
  • Steven Sasson invented the world's first digital camera in 1975.
• Flash Memory
  • It is a type of nonvolatile memory that erases data in units called blocks and rewrites data at the byte level.
  • It is widely used for storage and data transfers in consumer devices, industrial applications.
  • Flash memory is a non-volatile computer storage chip,
  • It is made up of EEPROM.
  • EEPROM is the acronym of electrically erasable programmable read-only memory,
  • EEPROM is a Programmable ROM that can be erased and reprogrammed using an electrical charge.
  • It was first was developed by George Perlegos.
  • It allows the user to update the computer BIOS without having to open the computer or remove any chips.
  • It is organized as arrays of floating-gate transistors.
  • USB flash drives, Memory cards are examples of flash memory storage.
  • BIOS is stored in a Flash memory chip.

• ROM(Read-only Memory) is permanent memory in the computer system.
• The computer system cannot write any data on ROM.

• DRAM:
  • It is dynamic random access memory and is widely used as a computer's main memory. Hence, Option 2 is correct.
  • Each DRAM memory cell is made up of a transistor and a capacitor within an integrated circuit, and a data bit is stored in the capacitor.
• DDR-RAM:
  • It stands for Double Data Rate Synchronous Dynamic Random-Access Memory.
  • These are the computer memory that transfers the data twice as fast as regular chips like SDRAM chips because DDR memory can send and receive signals twice per clock cycle as a comparison.
• SRAM:
  • It stands for Static Random Access Memory.
  • It is a form of a semiconductor.
  • It is widely used in microprocessors, general computing applications, and electronic devices.
  • The SRAM is volatile in nature which means the data stored in it gets all wiped out once the power supply is cut.
  • SRAM is comprised of flip-flops. 
• PRAM:
  • In computer science, a parallel random-access machine is a shared-memory abstract machine.
  • As its name indicates, the PRAM is intended as the parallel-computing analogy to the random-access machine.

• Registers are tiny memory spaces that are physically situated on the CPU chip. The CPU has direct access to the data contained in them, and it may be accessed very quickly.
• Memory, often known as primary storage, is a general term for storage that the CPU of a computer may access directly.
• RAM is a quick-access storage media that operates at a fast speed. The CPU can access RAM data relatively quickly because the RAM is directly connected to the CPU through the memory bus.
• The CPU can immediately access data stored in primary memory, whereas secondary memory cannot.
• The data kept in the ROM can't be accessed directly by the processor. Information is sent into the RAM before it can be performed by the processor in order to access ROM data first.
• Random access memory that is also cache memory does not require refreshing. Because it is integrated into the CPU, the processor has the quickest possible access to memory locations and can access commonly used data and instructions in nanoseconds.

• Hard disc platters are separated into a number of concentric tracks. Each track has a number of sectors that can individually hold the same amount of data.
• The smallest physical storage unit on a disc is called a sector, and on most file systems, it has a fixed size of 512 bytes.
• Data is kept on hard drives in tiny, concentrically spaced bands. A drive head can read or write data on a track, which is a circular band or ring, while it is in one position. A 3.5-inch hard drive has a maximum track count of over a thousand. Each track's sectors are its sections.
• A track on a magnetic disc or optical disc is divided into sectors for computer disc storage. Hard disc drives (HDDs) and CD-ROMs and DVD-ROMs typically store 512 bytes and 2048 bytes of user-accessible data, respectively, in each sector.

The actual timing signals that govern the transfer of data between input unit, processor, memory and output units are generated by the Control Unit (CU) and the Memory Unit stores the processed data.

Control Unit (CU):

• This component of a computer's central processing unit (CPU) directs the operation of the computer.
• It manages and coordinates the hardware of the computer.
• The control unit directs the flow of data between the CPU and other devices, it fetches, decodes, and executes instructions from memory, and employs timing signals to control the other units.

Memory Unit:

• This is where the computer stores data.
• After the data has been processed by the CPU, the Control Unit will guide the storage of this processed data back into memory units, such as RAM, or if the data needs to be stored long term, into secondary storage like a hard-drive or SSD.

• One gigabyte in the memory context of data storage comprises 1024 MB (megabyte) or 1 million bytes.
• In SI units, it is written as 109. This is the most commonly used unit of storage in modern times.

• RAM (Random Access Memory)
  • It is the hardware in a computing device where the operating system (OS), application programs, and data in current use are kept so they can be quickly reached by the device's processor.
• RAM
• It is the main memory in a computer.
• It is much faster to read from and write to than other kinds of storage, such as a hard disk drive (HDD), solid-state drive (SSD) or optical drive.
• Synchronous dynamic random-access memory (synchronous dynamic RAM or SDRAM) is any DRAM where the operation of its external pin interface is coordinated by an externally supplied clock signal.
• SDRAM has a synchronous interface, whereby changes on control inputs are recognised after a rising edge of its clock input.

Computer memory is divided into a large number of small parts called cells. Each cell (location) has a unique address, which varies from 0 to memory size – 1.

ROM stores the program instructions required to initially boot the computer. It only allows reading.

ROM chip is non-volatile, meaning its data is retained even when the device is powered off.

Cache memory is a small, very high-speed semiconductor memory, which helps to speed up CPU. It is placed as a buffer between the CPU and RAM.

Segmentation is a process or method in which memory is divided into groups of variable length called segments.

RAM is a volatile chip memory that performs both read and write operations. That’s why, it is also called read-write memory (called RWM).

In Programmable Read-Only Memory (PROM), If there is an error in writing instructions or data, the error cannot be erased. PROM chip becomes unusable.

there are two types of Random Access Memory or RAM. They are SRAM (Static RAM) and DRAM (Dynamic RAM).

RAM is volatile which means its data are lost when the device is powered off.