The content of computer memory which is non-volatile, even when the power goes off is :

Question

UnlockIAS · Accepted Answer

Correct — C, ROM, Read-Only Memory. 'Volatile' in computing means the stored contents survive only as long as the power supply does. ROM is non-volatile: whatever is written into it stays written when the machine is switched off, which is exactly why it is the memory chosen to hold the instructions a computer needs before it has loaded anything from disk. In an ordinary personal computer the ROM (or its modern flash-based equivalent) holds the firmware — the BIOS or UEFI and the bootstrap loader — the small program that runs the moment power arrives, tests the hardware and then loads the operating system into RAM. If that program lived in volatile memory it would vanish every time the machine was switched off and the computer could never start itself, so the boot firmware must be non-volatile by design. ROM is also the reason a washing machine, a calculator or a microwave remembers what to do without any disk at all: the whole program sits permanently in ROM. That is the property the question is naming, so (c) is the marked answer.

Why the other options are wrong — (a) There is no computer memory called REM. The letters are put there as a near-miss for ROM and RAM, and they are recognisable from elsewhere — REM is Rapid Eye Movement, a stage of sleep, and 'roentgen equivalent man', an old unit of radiation dose. In programming, REM is the keyword that begins a comment line in BASIC and in MS-DOS batch files, which is doubtless where the examiner found it, but a comment keyword is not a kind of memory. Rejecting a plausible-looking three-letter abbreviation that does not actually exist is a standard prelims skill.  (b) RAM, Random Access Memory, is the opposite of what the question asks for: it is volatile. It is the computer's working memory, holding the operating system, the running programs and the data being worked on, and its contents are lost the instant power is removed — which is precisely why unsaved work disappears in a power cut. Dynamic RAM, the type used for main memory, must in fact be electrically refreshed thousands of times a second merely to hold its contents while the machine is on. RAM is the most tempting wrong answer because it is the memory people actually shop for and talk about, but the question is asking which memory survives the power going off, and RAM does not.  (d) Wrong because one of the listed options is correct. ROM is a genuine and precisely defined category of non-volatile computer memory, so there is no need to fall back on 'none of the above'. This option only becomes attractive to a candidate who has talked themselves out of ROM by over-thinking the fact that modern ROM chips can be rewritten — an interesting nuance, but not one that changes the classification.

Concept: Computer memory is divided first into primary memory, which the processor can address directly, and secondary storage such as hard disks, solid-state drives, optical discs and flash drives. Primary memory itself splits into two families defined by volatility. RAM is volatile read-write memory and forms the working space where running programs and their data live. ROM is non-volatile memory whose contents are fixed at or near the time of manufacture and are read during normal operation; it carries the firmware, the bootstrap loader and, in embedded appliances, the whole control program. Cache memory and the processor's registers are small, extremely fast and also volatile. The distinction the question tests — volatile against non-volatile — is the single most examined idea in this part of the syllabus.

State PCS 2024 Q105 — Science & Technology PYQ with Answer

State PCS 2024 Q105 — Science & Technology PYQ with Answer