The devices that work with computer systems as soon as they are connected are described as
- (a)Hot Swapping
- (b)Bay Swap
- (c)Plug-N-Play
- (d)USB Swapping
Answer
Why
Correct — C, (c) Plug-N-Play.
PLUG AND PLAY IS THE CAPABILITY THAT LETS A COMPUTER DETECT, IDENTIFY AND CONFIGURE A DEVICE BY ITSELF THE MOMENT IT IS ATTACHED, so that the device is usable without the person attaching it having to set anything up. The stem's own words — 'work with computer systems as soon as they are connected' — are a plain-language definition of it.
WHAT ACTUALLY HAPPENS WHEN A PLUG-AND-PLAY DEVICE IS CONNECTED, in four steps:
1. DETECTION. The bus signals that something new is present, and the operating system is told. 2. IDENTIFICATION. The device reports an identifier of its own — a vendor code and a product code held in the device itself — and often a class saying what KIND of thing it is: a keyboard, a mass-storage device, a printer. 3. RESOURCE ALLOCATION. The system assigns whatever the device needs to talk to the processor, and does so without clashing with anything already installed. 4. DRIVER BINDING. The system matches the reported identifier to a DEVICE DRIVER — the small program that translates between the operating system and that particular piece of hardware — loads it, and the device starts working.
WHY IT WAS A LANDMARK. Before plug and play, fitting an expansion card meant setting small switches or jumpers on the card by hand to choose its interrupt line and memory addresses, consulting a manual to find a combination not already in use, and installing driver software from a disk. Two cards set to the same resources simply refused to work, and finding out which two was the user's problem. Plug and play moved all of that into the firmware and the operating system, and it is the reason a keyboard, a mouse, a pen drive or a printer attached today is usable in seconds.
THE BOOKLET PRINTS IT AS 'Plug-N-Play', with a capital N standing in for 'and' between two hyphens — one of several ways the name is written, alongside 'Plug and Play' and the abbreviation PnP. It is the same thing.
Why the others are wrong
- (a)Hot Swapping — A real capability, and the closest of the three to the answer, so the distinction is worth holding precisely. HOT SWAPPING means removing or attaching a component WHILE THE SYSTEM IS RUNNING AND POWERED — replacing a failed disk in a server's drive array, changing a redundant power supply, pulling out a pen drive — without shutting the machine down. Its opposite is a cold swap, where the machine must be powered off first. So hot swapping is about POWER AND CONTINUITY OF SERVICE, while plug and play is about AUTOMATIC CONFIGURATION. The two are independent ideas that often travel together: a USB device is both hot-swappable and plug-and-play, but an old expansion card could be plug-and-play while still requiring the machine to be opened and switched off, and a hot-swappable component in a purpose-built server may still need to be configured by an administrator. The stem asks about devices that WORK as soon as they are connected, which is the configuration half, not the power half.
- (b)Bay Swap — Not a standard term for this capability at all. A BAY is a physical slot in a computer's chassis into which a drive or module is fitted — the openings that hold hard disks and optical drives in a desktop, or the modular bay of some laptops into which an optical drive, a second battery or an extra disk could be fitted in turn. Swapping what sits in a bay is a description of a MECHANICAL act: sliding one module out and another in. It says nothing about whether the machine recognises the new module, allocates resources to it, or finds a driver for it, which is the entire content of the question. The option is on the page as a plausible-sounding assembly of two real computing words, and it is a good example of why an acronym or a phrase should be learned with its definition attached rather than by the feel of the words.
- (d)USB Swapping — Another phrase that sounds technical and names nothing. USB is the UNIVERSAL SERIAL BUS, the standard interface by which most peripherals are attached to a computer, and it is itself an example of a bus designed around the two capabilities in this question: a USB device may be attached and removed while the machine runs, and it is configured automatically when attached. But 'USB swapping' is not the name of that behaviour; it is at best a description of exchanging one USB device for another. Naming the connector instead of the capability is a category error of exactly the kind these definitional items are built to catch — the question asks what the BEHAVIOUR is called, and the answer must be the name of a behaviour, not of a port. The same paper asks separately what USB stands for, which is worth pairing with this item.
Concept
PLUG AND PLAY (PnP) is the combination of hardware, firmware and operating-system support that makes a newly attached device usable without manual configuration. Three parties have to co-operate: the DEVICE must be able to identify itself, the BUS and firmware must be able to enumerate what is attached and allocate resources, and the OPERATING SYSTEM must be able to match the device to a driver and load it.
THE DEVICE DRIVER is the piece that makes the whole thing work and is the concept most worth taking away. It is a small program that sits between the operating system and one specific kind of hardware, translating general instructions — 'print this page', 'read this block' — into the exact signals that model of device understands. Without the right driver the hardware is present but unusable, which is why an unrecognised device shows up as an unknown device rather than as a printer. Modern systems ship with large libraries of drivers and can fetch missing ones over a network, which is why attaching common hardware now appears to need nothing at all.
WHAT CAME BEFORE, and why the term exists. On the older ISA expansion bus a card had to be told by hand which interrupt request line, which direct-memory-access channel and which range of input-output addresses to use, by moving jumpers or setting switches on the card itself. Conflicts were common and diagnosing them was tedious. The PCI bus, and later USB and PCI Express, were designed so that devices announce themselves and the system allocates resources, and operating systems from the mid-1990s onward were built around that.
HOT SWAPPING AND HOT PLUGGING are the neighbouring ideas, and the distinction is the one this question is built on:
PLUG AND PLAY — the device is CONFIGURED automatically when attached. HOT SWAPPING — the device may be attached or removed while the system is POWERED AND RUNNING. COLD SWAP — the machine must be shut down before the component is changed.
USB, PCI Express, SATA in its hot-plug mode, and the drive bays and power supplies of enterprise servers all support hot swapping; the internal memory modules and the processor of an ordinary desktop do not.
WHERE ELSE THIS SHOWS UP. Two conventions worth knowing: safely removing a storage device before unplugging it, which lets the operating system finish writing anything still held in memory, and the device manager or equivalent listing of attached hardware, which is where an unrecognised device or a driver problem is diagnosed.
Computers, networks and information technology make up about eleven questions on this APFC paper, and they are asked as office-level vocabulary: define a term, expand an acronym, name the software or capability that does a stated job. Nothing on this strand requires specialist knowledge, and nothing rewards breadth without precision.
The recurring shape of the option set is the one used here: three of the four choices are either real terms from the same area or plausible constructions from real words, and the discrimination rests entirely on knowing what the term actually names. Recognition is worthless. Preparation therefore means one exact sentence per term — what category of thing it is, and what its defining property is — rather than a general familiarity with computing words.
Two of the wrong options here, 'Bay Swap' and 'USB Swapping', are not standard terms in the industry at all; they are assembled from real vocabulary to sound right. That is a pattern worth expecting on this paper: if a phrase feels technical but you cannot say what it means, that is evidence rather than a reason to guess.
The one genuinely near miss, hot swapping, teaches the more useful lesson. Two capabilities that usually arrive together — attaching a device while the machine runs, and having it configure itself — are separate ideas with separate names, and the stem's wording points at one of them. Reading the stem for WHICH property is being described, rather than for the general topic, is the whole skill.
Key facts
- Plug and Play is the automatic detection, identification, resource allocation and driver loading that makes a newly attached device usable with no manual configuration.
- The device supplies an identifier of its own — a vendor and product code, and often a device class — which the operating system uses to find the matching driver.
- A DEVICE DRIVER is a program that translates between the operating system and one specific piece of hardware; without it the device is present but unusable.
- Before plug and play, expansion cards had to be assigned interrupt lines and address ranges by hand, using jumpers or switches, and resource clashes were common.
- HOT SWAPPING is a different capability: attaching or removing a component while the system is powered and running. Its opposite is a cold swap.
- USB devices are both plug-and-play and hot-swappable, which is why the two ideas are so easily confused.
- Buses designed for automatic configuration include PCI, PCI Express and USB; the older ISA bus was not.
- 'Safely remove' before unplugging a storage device exists so that data still held in memory is written out before power is cut.
- The booklet prints the term as 'Plug-N-Play'; it is also written 'Plug and Play' and abbreviated PnP.
Study next
Common traps
- Confusing plug and play with hot swapping. One is about automatic configuration, the other about doing it while powered on.
- Naming the port instead of the capability — the error the 'USB Swapping' option is built on.
- Assuming a device that is recognised is fully working. Without the correct driver it may be detected and still unusable.
- Treating a plausible-sounding phrase as a real term. 'Bay Swap' is assembled from real words and names nothing.
- Forgetting that plug and play needs support from the device, the bus and the operating system together, not from any one of them.
- Removing a storage device without letting the system finish writing, which risks losing data still held in memory.
Information technology on EPFO papers is asked as vocabulary an office user is expected to have: what a term means, what an acronym stands for, which piece of software or hardware performs a named job. The options are drawn from the same corner of the subject, and at least one of them is usually a phrase invented to sound plausible. Because every choice looks like it belongs, the item cannot be answered by recognition — only by having a definition attached to the word. The productive method is to ask what CATEGORY the answer must belong to, given the stem: here a capability, so a name for a physical act or for a connector cannot be right. Learn the small family of terms around each concept together — plug and play with hot swapping and device drivers, USB with the buses and ports — because the option sets are built out of exactly those neighbours.
Related PYQs
EPFO_APFC_2016_Q89USB is the acronym for
- (a) Uniform Service Broadcasting
- (b) Unique Solution Bus
- (c) Universal Serial Bus
- (d) Universal Service Broadcasting
Answer(c) Universal Serial Bus
What USB stands for, asked on this same paper — the companion item to the 'USB Swapping' option here, and the bus on which plug and play is most familiar.
EPFO_APFC_2016_Q87A collection of programs that controls how the computer system runs and processes information is called
- (a) Compiler
- (b) Operating System
- (c) Linker
- (d) Assembler
Answer(b) Operating System
Which of four named programs controls how a computer system runs — the operating system is the party that performs the detection and driver loading described in this item.
EPFO_EOAO_2017_Q105Which one of the following is hardware?
- (a) Power point
- (b) Control unit
- (c) Printer driver
- (d) Operating system
Answer(b) Control unit
Which of four listed items is hardware — the same categorial discipline of asking what KIND of thing a term names before choosing between plausible options.
Practice
- practice — not a real PYQ
The program that enables an operating system to communicate with a specific piece of hardware is called a
- (a)Compiler
- (b)Device driver
- (c)Linker
- (d)Spooler
Answer(b) Device driver — it translates the operating system's general instructions into the exact signals one model of hardware understands. A compiler converts high-level source code into machine code, a linker joins compiled modules into an executable program, and a spooler queues jobs such as printing so a slow device does not hold up the processor.
- practice — not a real PYQ
Replacing a failed hard disk in a running server without switching the machine off is an example of
- (a)Hot swapping
- (b)Defragmentation
- (c)Booting
- (d)Formatting
Answer(a) Hot swapping — attaching or removing a component while the system stays powered and in service. Defragmentation reorganises files already on a disk so they occupy contiguous space, booting is the start-up sequence that loads the operating system, and formatting prepares a storage medium to hold a file system.