Which of the following statements with regard to the solid state drive (SSD) is/are correct ? 1. Spinning speed of SSD is zero. 2. SSD consumes more energy compared to hard disk drive (HDD). 3. SSD could be used as virtual memory when RAM is insufficient. 4. SSD can replace the processor. Select the answer using the codes given below :
- (a)1 only
- (b)1 and 3
- (c)3 and 4
- (d)2 and 4
Answer
Why
Correct — B, (b) 1 and 3. Take the four statements one at a time.
Statement 1 — CORRECT. A solid state drive stores data in flash memory cells and has NO moving parts at all: no platters, no spindle motor, no read-write head on an arm. Its spinning speed is therefore zero in the literal sense, which is the whole contrast with a hard disk drive, where platters turn at a rated speed — commonly 5,400 or 7,200 revolutions per minute — and the head must wait for the right sector to come round. Removing that mechanical delay is why an SSD's access time is measured in microseconds against milliseconds, and why it is also silent and far more tolerant of being knocked about.
Statement 2 — INCORRECT. An SSD consumes LESS energy than a hard disk drive, not more. The largest single consumer of power in a hard disk is the motor that keeps the platters spinning and the actuator that moves the head; an SSD has neither, which is why laptops gained battery life when the industry moved to flash storage. There is a small qualification worth knowing rather than hiding — a high-performance drive under sustained heavy writing can draw appreciable power in bursts — but on any ordinary comparison the flash drive is the more economical.
Statement 3 — CORRECT. Virtual memory is the arrangement by which the operating system treats part of the DRIVE as an extension of main memory: when physical RAM runs short, pages that are not being used are written out to a swap area or page file on storage and read back when needed. That swap area can perfectly well sit on an SSD, and doing so is common, because the drive's low latency makes swapping far less painful than it was on a spinning disk. It does not make the SSD into RAM — it is orders of magnitude slower, and heavy swapping wears flash cells — but the statement claims only that it CAN be used this way, and it can.
Statement 4 — INCORRECT, and it is a category error rather than a fine judgement. A drive stores data; a processor executes instructions. No amount of storage performs computation, and nothing about flash memory changes that.
Statements 1 and 3 stand, so the answer is 1 and 3.
Why the others are wrong
- (a)1 only — Right about statement 1 and too cautious about statement 3. A candidate lands here by reading 'virtual memory' as though it meant RAM and rejecting the statement because an SSD is not RAM. Virtual memory is precisely the technique of using drive space as an overflow for main memory, and it is a standard part of every modern operating system.
- (c)3 and 4 — Keeps a correct statement and adds an impossible one. Statement 4 confuses the two halves of a computer — storage and processing — and no reading of it can be rescued. An option containing statement 4 can be eliminated before any of the finer judgements are made, which is how this item should be attacked.
- (d)2 and 4 — Both of its statements are wrong. It pairs the energy claim, which has the comparison backwards, with the processor claim, which is a category error. It is the option for a candidate who has heard that solid state drives run hot under load and has generalised from that to overall consumption.
Concept
A solid state drive stores data as charge trapped in floating-gate or charge-trap flash cells, arranged in pages and blocks, with a controller managing where data physically goes. Because it has no mechanics, access time does not depend on where data sits, so random reads are almost as fast as sequential ones — the opposite of a hard disk, where seek and rotational delay dominate. Flash cells wear out after a finite number of write-erase cycles, so controllers spread writes across the device by wear levelling and keep spare capacity in reserve. A hard disk drive remains cheaper per unit of capacity, which is why bulk storage still uses it. Both are SECONDARY, non-volatile storage: their contents survive power being switched off, unlike RAM.
Statement items in the computing block are usually a mix of one obvious truth, one comparison with its direction reversed, one that tests a definition, and one category error. Sorting them in that order is efficient: eliminate the category error first, settle the definitional one next, and leave the comparison for last. Here, striking out every option containing statement 4 leaves only (a), (b) and (d), and settling statement 3 finishes the item.
This is the only statement-list item in its part of the paper, and its four statements are of four different kinds: a physical fact, a comparison, a definition, and a category error. Attack them in that order of cost. The category error — a drive replacing a processor — is settled instantly and removes two options. The physical fact is settled next. Only then is the definitional judgement about virtual memory needed, and by that point it decides between two options rather than four. Sorting statements by how expensive they are to settle is a general technique for this paper's forty-three statement items.
Key facts
- A solid state drive has no moving parts; a hard disk drive has platters spinning typically at 5,400 or 7,200 revolutions per minute.
- SSD access times are in microseconds against milliseconds for a hard disk, and random access costs little more than sequential.
- SSDs consume less power than hard disks, having no spindle motor or actuator, and are silent and shock-resistant.
- Virtual memory extends main memory by using a swap area or page file on secondary storage.
- Using an SSD for that swap area is common and effective, though it is far slower than RAM and adds write wear.
- Flash cells have a finite number of write-erase cycles; controllers use wear levelling to spread writes.
- Both SSDs and hard disks are non-volatile secondary storage, unlike volatile RAM.
- Hard disks remain cheaper per unit of capacity, which keeps them in use for bulk storage.
Study next
Common traps
- Reading 'virtual memory' as a synonym for RAM.
- Reversing the direction of an energy or speed comparison; check which side the claim favours.
- Missing that one statement in the set belongs to a different category altogether.
- Assuming a statement is false because it is loosely worded; statement 1's 'spinning speed is zero' is odd phrasing for a true fact.
Storage and memory questions occur in every EPFO paper, generally as a single-fact item or a four-statement set like this one. Prepare the components as a table — what it does, whether it is volatile, how fast, how much it costs per unit — because every one of these items is a row of that table read out.
Related PYQs
EPFO_EOAO_2020_Q28Which one of the following memories is extremely fast and acts as a high-speed buffer between the CPU and the main memory ?
- (a) RAM
- (b) ROM
- (c) Flash Memory
- (d) Cache Memory
Answer(d) Cache Memory
The same hierarchy tested one level up — which memory acts as a high-speed buffer between the processor and main memory, the level at which speed is bought at the cost of capacity.
Practice
- practice — not a real PYQ
Virtual memory in a computer system is best described as which one among the following ?
- (a)An additional bank of RAM chips installed on the motherboard
- (b)Space on secondary storage used by the operating system as an extension of main memory
- (c)Memory built into the processor for frequently used instructions
- (d)Read-only memory containing the start-up program
Answer(b) Space on secondary storage used by the operating system as an extension of main memory
- practice — not a real PYQ
Which one among the following is a reason why a solid state drive gives faster random access than a hard disk drive ?
- (a)It stores data in compressed form
- (b)It has no seek or rotational delay, having no moving parts
- (c)It is connected directly to the processor instead of to memory
- (d)It keeps all data permanently in cache
Answer(b) It has no seek or rotational delay, having no moving parts