What does the acronym PaaS stand for in cloud computing?
- (a)Platform as a Service
- (b)Program as a Service
- (c)Product as a Service
- (d)None of the above
Correct — A, Platform as a Service.
PaaS expands to Platform as a Service, the middle rung of the cloud service stack set out in NIST Special Publication 800-145. In NIST's terms the consumer does not manage or control the underlying network, servers, operating systems or storage; the application and its data are yours.
Patching and automatic scaling usually come with a PaaS product as well, but they are provider practice rather than part of the NIST definition.
Below it sits Infrastructure as a Service, where you rent processing, storage and network and administer the operating system yourself. Above it sits Software as a Service, where you simply use a finished application.
Carry away that the three models are named for what the provider hands over — infrastructure, platform or software. Fix that ladder and the expansion of any one of the three follows.
- (b)Program as a Service — One word has been swapped: 'Program' for 'Platform'. It reads plausibly, because pushing your own program onto a managed runtime is exactly what a PaaS is for — you hand over code and the provider runs it.
But the P in the acronym names the platform the provider supplies, not the program you put on it. An acronym item asks you to recall a fixed expansion, not to reconstruct a sensible phrase from the letters.
- (c)Product as a Service — This phrase does have currency, but in a different literature. It is used in business writing on servitisation and the circular economy for the model in which a firm sells the use of a product rather than the product itself — leasing, pay-per-use, take-back arrangements.
The stem fixes the domain with the words 'in cloud computing'. In that domain the P is Platform, and the layer sits between Infrastructure as a Service and Software as a Service.
- (d)None of the above — A catch-all option earns the mark only when the fact the stem asks for is absent from every named option. Here option (a) states the expansion exactly, so the catch-all is false.
The hazard is treating 'None of the above' as insurance against uncertainty. It is not a hedge — it is a positive assertion that the list is deficient, and it collapses the moment one listed option is right. Test each named option against the fact first.
Cloud computing is sold in layers, and each layer is named for how much of the stack the provider takes over. NIST Special Publication 800-145 fixes three service models: Software as a Service, Platform as a Service and Infrastructure as a Service.
IaaS supplies fundamental resources — processing, storage, networks. You deploy and run arbitrary software on them, including the operating system, and you keep it patched.
PaaS supplies a managed environment: operating system, language runtime, supporting services, scaling. You deploy applications built with the languages, libraries and tools the provider supports, and control your application plus some hosting-environment settings.
SaaS supplies the finished application, reached through a browser or an interface. Your control is limited to your data and user-specific configuration.
As-a-Service procurement is now common in both private and government IT. Knowing which layer a term names is what lets you read a tender document, a policy note or a migration announcement correctly.
An item like this sits where general science-and-technology awareness meets everyday administrative vocabulary. The terms travel well outside IT departments, into budget lines, e-governance projects and data-security debate.
- NIST Special Publication 800-145 defines the three cloud service models as Software as a Service, Platform as a Service and Infrastructure as a Service.
- In PaaS the consumer deploys applications created with languages, libraries and tools the provider supports, without managing the underlying servers, operating systems, storage or network.
- In IaaS the consumer provisions processing, storage and networks, and can run arbitrary software on them, including operating systems.
- In SaaS the consumer uses the provider's application and controls little beyond user-specific configuration settings.
- Google App Engine, Microsoft Azure App Service and Red Hat OpenShift are commonly cited PaaS offerings; Amazon EC2 is a standard IaaS example.
- The same NIST document lists five essential characteristics: on-demand self-service, broad network access, resource pooling, rapid elasticity and measured service.
- It also names four deployment models: private cloud, community cloud, public cloud and hybrid cloud.
- India's GI Cloud initiative, branded MeghRaj, is run under the Ministry of Electronics and Information Technology.
Reading downwards, the provider takes over more of the stack. PaaS is the rung where the platform is supplied and the program is yours.
- Rebuilding an acronym from a plausible English word instead of recalling the fixed expansion — 'Program' and 'Product' both fit the letter P.
- The phrase 'Product as a Service' exists in circular-economy writing; the words 'in cloud computing' in the stem settle which sense is wanted.
- Treating 'None of the above' as a hedge against uncertainty rather than as a claim that the list is deficient.
- Blurring PaaS into SaaS: if you are building and deploying the application it is PaaS; if you are only using a finished one it is SaaS.
- Blurring PaaS into IaaS: responsibility for the operating system is the dividing line between the two.
- Memorising vendor names without the layer definition, which fails the moment an unfamiliar product is named in the options.
The service-model stack appears as a direct expansion item like this one, and as an odd-one-out — which listed term is not a cloud service layer, or which does not belong to the 'as a Service' family.
It also appears as a scenario: a description of who manages the operating system, the runtime and the application, with the model left to be named. Descriptive papers ask for cloud computing to be defined, its services listed and its advantages argued.
The durable preparation is to hold the three NIST models with one sentence each on what the provider manages and what the consumer keeps.
UKPSC_2016_PRE_PaperI_Q1102016Same commission, same vocabulary: its options are the service layers of cloud computing, with Platform as a Service among them. What differs is the direction of the test — 2016 asks which listed item is not an independent service layer, an odd-one-out across the whole set, while 2025 asks for the expansion of one acronym. Both are answered from the same three-model ladder.
ESE_GS_2021_Q272021Same 'as a Service' family, with PaaS spelled out as Platform as a Service inside the options. What differs is the demand: this one asks which listed service falls outside the cloud category, so it needs a judgement about the boundary of the family, whereas the UKPSC item needs recall of a single fixed expansion.
UPPSC_2019_MAINS_PaperIII_Q192019Same subject at the far end of the format range — a descriptive Mains question asking what cloud computing is and what services it renders, which is answered by laying out the service models. What differs is the output: a keyed letter suffices here, while the Mains item needs the models explained and the advantages argued in prose.
UPSC_2011_GS1_Q992011Adjacent rather than identical. It defines a Virtual Private Network, and one of its options describes access to a shared pool of computing resources through a service provider — wording that belongs to the cloud definition. What differs is the concept being keyed; the value of reading them together is the discipline of separating a secure-tunnelling idea from a resource-pooling one.
- practice — not a real PYQ
Under the NIST definition of cloud computing, which service model lets the consumer deploy applications built with the provider's supported languages and tools, while the provider manages the operating system, servers, storage and network?
- (a)Infrastructure as a Service
- (b)Platform as a Service
- (c)Software as a Service
- (d)Hardware as a Service
Answerb — Platform as a Service is defined by exactly this split: the application and its configuration belong to the consumer, everything beneath belongs to the provider.(a) fails because an IaaS consumer provisions raw processing, storage and network and installs the operating system. (c) fails because a SaaS consumer uses a finished application rather than deploying one.
(d) fails because the three service models named in NIST SP 800-145 are SaaS, PaaS and IaaS.
- practice — not a real PYQ
A team writes a web application, pushes the source code to a provider that builds it, patches the operating system and adds instances as traffic rises. The team never logs into a server. This arrangement is best described as:
- (a)Infrastructure as a Service
- (b)Software as a Service
- (c)Platform as a Service
- (d)Colocation hosting
Answerc — the provider supplies the runtime, the patching and the scaling, while the team supplies only the application. That is the platform layer.(a) fails because administering the operating system is the IaaS consumer's job, and this team never logs into a server. (b) fails because the team is building the application, not consuming a finished one.
(d) fails because colocation means housing your own physical hardware in someone else's data centre.
- practice — not a real PYQ
Which one of the following is a standard example of a Platform as a Service offering?
- (a)Amazon EC2 virtual machine instances
- (b)Gmail
- (c)Google App Engine
- (d)A leased physical server that the customer administers end to end
Answerc — Google App Engine accepts application code and runs it on a managed platform, with the operating system, runtime and scaling handled by the provider.(a) fails because EC2 rents virtual machines whose operating system the customer administers — the infrastructure layer. (b) fails because Gmail is a finished application used through a browser — the software layer.
(d) fails because a server the customer administers end to end is dedicated hosting rather than one of the cloud service models.