Cloud Computing Glossary


Infrastructure as a Service (IaaS) is the offering of compute, storage and networking resources in a hosted environment. IaaS traditionally sits at the base of a cloud computing pyramid that may also comprise PaaS (Platform as a Service) and SaaS (Software as a Service), with the amount of customer control over the virtualized IT resources decreasing as the pyramid is ascended. In a typical IaaS deployment, the service provider manages everything below the hypervisor layer (the server, storage and networking hardware and its virtualization), leaving the customer to handle operating system, middleware and application deployment on self-service virtual machines that can be ‘spun up’ on demand, usually via a web-based dashboard or API.

Neat definitions rarely fit the real world and the lines between SaaS, IaaS and PaaS are becoming increasingly blurred. Choosing the right IaaS provider is the most critical decision a business makes when deciding to move to the cloud.


Public Cloud

Public cloud offers a multi-tenant environment with third-party cloud services for servers, data storage and applications whose primary means of access is via a public network such as the internet. This type of cloud environment typically offers subscribers a pay-as-you-go or monthly fee option to pay for only the services they need, making it a great option for quick deployment that is easily scalable and accessible rather than on-premise infrastructure changes. The downside to public cloud is that it is public and shared space. It can be less secure and not easily customizable for organizations that need to ensure specific performance SLAs or compliance standards such as HIPAA, PCI, and SSAE-16


Private Cloud

Private Cloud offers the same flexibility and breadth of services available in a few clicks from a public provider, but with dedicated equipment and customized for the enterprise.  Private clouds are generally custom designed infrastructure to fit exacting standards whether it is in the company’s data center or hosted by a provider.

Private clouds deliver performance in a completely customizable model that can be built to suit nearly any requirement.  With the flexibility and services of a public cloud, but the security, performance, and peace of mind of a private data center deployment. Private clouds bring the best of both worlds. Private clouds are a great solution for companies that rely on proven methods and need control of their environment, but would benefit from hosted virtual machines rather than managing a data center.


Hybrid Cloud

Hybrid Cloud is the integration of on and off-premise systems enabling workloads to move between public and private environments. This solution offers more flexibility and enhanced security options for sensitive or critical workloads. This option is best for companies that experience demand spikes which require additional resources due to seasonal changes, or running analytics on accumulated data.



KeyCloud™ delivers compute, storage, and network through Infrastructure-as-a-Service (IaaS). KeyCloud offers highly secure virtual and dedicated machines in an environment that enables an organization to run apps on KeyInfo’s carrier grade data center for 99.999% uptime. Engineered on a pool of highly redundant servers and storage, KeyCloud is available in custom configurations to rapidly respond to each Client’s IT needs. KeyCloud services will quickly and dynamically scale as business needs grow without ever having to worry about hardware infrastructure again.


Platform as a Service (PaaS)

Instead of installing in-house hardware, software, and servers, an enterprise can develop, test, and run applications more rapidly using a cloud hosted platform solution where the provider hosts networks, servers and storage with control overy software deployment and configuration settings. PaaS is a layer of abstraction on top of the infrastructure which removes the operating system and supporting core services (web, caching, database, etc.) and focuses primarily on using IaaS as a vehicle to deploy software.


Database as a service (DBaaS)

Database-as-a-Service (DBaaS) is a service that is managed by a cloud operator (public or private) that supports applications, without the application team assuming responsibility for database administration. Application developers should not need to be database experts. The database would seamlessly scale and be maintained, upgraded, backed-up and handle server failure, all without impacting the developer in any way. Similar to PaaS, but more focused, DBaaS delivers a database (or database cluster) with a layer of abstraction  separating the infrastructure and underlying database software from the developer.


Software as a Service (SaaS)

Saas is a software licensing and delivery model in which software is licensed on a subscription basis and is centrally hosted by a provider. It is sometimes referred to as “on-demand software”. and is typically accessed by users using a thin client via a web browser. One of the biggest selling points is the potential to reduce IT support costs by outsourcing hardware and software maintenance and support to the SaaS provider.

SaaS has become a common model for many business applications, including office and messaging software, payroll processing software, DBMS software, management software, CAD software, development software, gamification, virtualization, accounting, collaboration, customer relationship management (CRM), management information systems (MIS), enterprise resource planning (ERP), invoicing, human resource management (HRM), talent acquisition, content management (CM) and service desk management. SaaS has been incorporated into the strategy of all leading enterprise software companies.


Disaster Recover as a Service (DRaaS)

DRaaS is a service that ensures small to mid-size businesses are “Always On,” even in the event of disaster, with replication and hosting of physical or virtual servers by a third party. Unlike managing a secondary site, DRaaS eliminates the cost of an off-premise location, infrastructure, and personnel by offering replication solutions on either a contractual or pay-per-use basis. DRaaS virtually eliminates downtime and data loss through replication between physical, virtual, and cloud environments, empowering infrastructure choice and flexibility with a complete disaster recovery plan. With failover and fail-back, non-disruptive production environment DR tests can happen in minutes.



(Advanced Interactive eXecutive) is a series of proprietary UNIX operating systems developed and sold by IBM for several of its computer platforms. Originally released for the IBM 6150 RISC workstation, AIX now supports or has supported a wide variety of hardware platforms, including the IBM RS/6000 series and later POWER and PowerPC-based systems, IBM System i, System/370 mainframes, PS/2 personal computers, and the Apple Network Server. AIX was the first operating system to utilize journaling file systems, and IBM has continuously enhanced the software with features like processor, disk and network virtualization, dynamic hardware resource allocation and reliability engineering ported from its mainframe designs.



The AS/400 – formally renamed the ‘eServer iSeries/400,’ but still commonly known as AS/400, is a mid-size server designed for small businesses and departments in large enterprises and now redesigned so that it will work well in distributed networks. The AS/400 uses the PowerPC microprocessor with its reduced instruction set computing (RISC) technology. Its operating system is called the OS/400. With multi-terabytes of disk storage and a Java virtual memory closely tied into the operating system, IBM hopes to make the AS/400 a kind of versatile all-purpose server that can replace PC servers and Web servers in the world’s businesses, competing with both Wintel and UNIX servers, while giving its present enormous customer base an immediate leap into the Internet.



The IBM i Operating System (IBM i) is unique in the IT industry for its level of integration and for the underlying architecture of the operating system itself. Evolving, as it has, from the forward-thinking System/38 and AS/400 architectures, IBM i offers tremendous value in low total cost of ownership. It provides IT professionals a platform to implement and run business solutions while protecting the significant investments they have made over the years in mission-critical software. IBM System i™ is IBM’s previous generation of systems designed for IBM i clients. Subsequently replaced by the new IBM Power™ Systems, System i models and resources remain available for IBM i clients. The new IBM eServer i5 servers are the first servers in the industry based on the IBM POWER5 64-bit microprocessor. They give the flexibility to move from one generation of technology to another without disrupting a company’s business. IBM i5/OS Version 5 Release 3, the next generation of OS/400, features support for multiple operating systems and application environments on a single, simplified platform.



Built with open technologies and designed for mission-critical applications, IBM Power Systems offer servers designed for big data that are optimized, secure, and adapt to changing business demands. They deliver superior cloud economics with secure and open choices and incorporate innovation from a growing ecosystem that broadens application choice and enhances optimization.


IBM Power

IBM has a series of high performance microprocessors called POWER followed by a number designating generation, i.e. POWER1, POWER2, POWER3 and so forth up to the latest POWER8. These processor have been used by IBM in their RS/6000, AS/400, pSeries, iSeries, System p, System i and Power Systems line of servers and supercomputers. They have also been used in data storage devices by IBM and by other server manufactures like Bull and Hitachi.



PowerLinux is the result of uniting high-performing Power Architecture with the open-source Linux OS. The combination produces a customizable system capable of handling large quantities of data more efficiently without the need for additional hardware. IBM POWER processor-based systems offer reliability, availability and serviceability characteristics that are not commonly found in server families running the Linux OS and provide mission-critical applications a higher level of support than other 32- or 64-bit Linux environments. PowerLinux systems include PowerVM virtualization built into the system. PowerVM is designed to pool resources and optimize their use across multiple application environments and operating system instances. This virtualization increases server efficiency by creating higher utilization per core and more throughput per server.


Systems P

IBM System p™ servers are IBM’s previous generation of products for AIX® and Linux® clients. Subsequently replaced by the new IBM Power™ Systems, System p models and resources remain available for AIX and Linux clients.



RS/6000 is a family of RISC-based UNIX servers, workstations and supercomputers made by IBM in the 1990s. The RS/6000 family replaced the IBM RT computer platform in February 1990 and was the first computer line to see the use of IBM’s POWER and PowerPC based microprocessors. RS/6000 was renamed eServer pSeries in October 2000.