computer science

Open Virtualization Format

Open Virtualization Format is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Open Virtualization Format rather than just read about it. In short: Open Virtualization Format (OVF) is an open standard for packaging and distributing virtual appliances or, more generally, software to be run in virtual machines. The standard describes an "open, secure, portable, efficient and extensible format for the packaging and distribution of software to be run in virtual machines".

Key takeaways

Open Virtualization Format belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Open Virtualization Format to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Open Virtualization Format from memory before moving on to harder problems.

Reference excerpt

Open Virtualization Format (OVF) is an open standard for packaging and distributing virtual appliances or, more generally, software to be run in virtual machines. The standard describes an "open, secure, portable, efficient and extensible format for the packaging and distribution of software to be run in virtual machines". The OVF standard is not tied to any particular hypervisor or instruction set architecture. The unit of packaging and distribution is a so-called OVF Package which may contain one or more virtual systems each of which can be deployed to a virtual machine.

History In September 2007 VMware, Dell, HP, IBM, Microsoft and XenSource submitted to the Distributed Management Task Force (DMTF) a proposal for OVF, then named "Open Virtual Machine Format". The DMTF subsequently released the OVF Specification V1.0.0 as a preliminary standard in September, 2008, and V1.1.0 in January, 2010. In January 2013, DMTF released the second version of the standard, OVF 2.0 which applies to emerging cloud use cases and provides important developments from OVF 1.0 including improved network configuration support and package encryption capabilities for safe delivery. ANSI has ratified OVF 1.1.0 as ANSI standard INCITS 469-2010. OVF 1.1 was adopted in August 2011 by ISO/IEC JTC 1/SC 38 of the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) as an International Standard ISO/IEC 17203. OVF 2.0 brings an enhanced set of capabilities to the packaging of virtual machines, making the standard applicable to a broader range of cloud use cases that are emerging as the industry enters the cloud era. The most significant improvements include support for network configuration along with the ability to encrypt the package to ensure safe delivery.

Design An OVF package consists of several files placed in one directory. An OVF package always contains exactly one OVF descriptor (a file with extension .ovf). The OVF descriptor is an XML file which describes the packaged virtual machine; it contains the metadata for the OVF package, such as name, hardware requirements, references to the other files in the OVF package and human-readable descriptions. In addition to the OVF descriptor, the OVF package will typically contain one or more disk images, and optionally certificate files and other auxiliary files. The entire directory can be distributed as an Open Virtual Appliance (OVA) package, which is a tar archive file with the OVF directory inside.

Industry support OVF has generally been broadly accepted. Several virtualization players in the industry have announced support for OVF.

Worked examples

Example 1 — a first encounter with Open Virtualization Format

Start with the simplest possible case. Write down what Open Virtualization Format claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Open Virtualization Format before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Open Virtualization Format ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Open Virtualization Format

In research: Open Virtualization Format appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Open Virtualization Format in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Open Virtualization Format is common in secondary-school and first-year university syllabi. It links to neighbouring topics Computer standards, DMTF standards, ISO/IEC standards, so understanding it makes those chapters shorter.
In everyday life: Look for Open Virtualization Format outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Open Virtualization Format in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Open Virtualization Format means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Open Virtualization Format out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Open Virtualization Format in simple terms?

Why does Open Virtualization Format matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Open Virtualization Format?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Open Virtualization Format.