computer science

NetBoot

NetBoot 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 NetBoot rather than just read about it. In short: NetBoot was a technology from Apple which enabled Macs with capable firmware (i.e. New World ROM) to boot from a network, rather than a local hard disk or optical disc drive.

Key takeaways

NetBoot 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 NetBoot to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NetBoot from memory before moving on to harder problems.

Reference excerpt

NetBoot was a technology from Apple which enabled Macs with capable firmware (i.e. New World ROM) to boot from a network, rather than a local hard disk or optical disc drive. NetBoot is a derived work from the Bootstrap Protocol (BOOTP), and is similar in concept to the Preboot Execution Environment. The technology was announced as a part of the original version of Mac OS X Server at Macworld Expo on 5 January 1999. NetBoot has continued to be a core systems management technology for Apple, and has been adapted to support modern Mac Intel machines. NetBoot, USB, and FireWire are some of the external volume options for operating system re-install. NetBoot is not supported on newer Macs with the T2 security chip or Apple silicon.

Process A disk image with a copy of macOS, macOS Server, Mac OS 9, or Mac OS 8 is created using System Image Utility and is stored on a server, typically macOS Server. Clients receive this image across a network using many popular protocols including: HTTPS, AFP, TFTP, NFS, and multicast Apple Software Restore (ASR). Server-side NetBoot image can boot entire machines, although NetBoot is more commonly used for operating system and software deployment, somewhat similar to Norton Ghost. Client machines first request network configuration information through DHCP, then a list of boot images and servers with BSDP and then proceed to download images with protocols mentioned above. Both Intel and PowerPC-based servers can serve images for Intel and PowerPC-based clients.

NetInstall NetInstall is a similar feature of macOS Server which utilizes NetBoot and ASR to deliver installation images to network clients (typically on first boot). Like NetBoot, NetInstall images can be created using the System Image Utility. NetInstall performs a function for macOS similar to Windows Deployment Services for Microsoft clients, which depend on the Preboot Execution Environment.

Legacy Mac OS 8.5 and Mac OS 9 use only BOOTP/DHCP to get IP information, followed by a TFTP transfer of the Mac OS ROM file. Next, two volumes are mounted via AppleTalk over TCP on which the client disk images reside. All in all, the Classic Mac OS uses three images; a System image which contains the operating system and may contain applications. Next a private image (or scratch disk) is mounted in an overlay over the read-only System image. Finally, an applications image is mounted. This image, however, may be empty.

Worked examples

Example 1 — a first encounter with NetBoot

Start with the simplest possible case. Write down what NetBoot 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 NetBoot 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 NetBoot 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 NetBoot

In research: NetBoot 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 NetBoot 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: NetBoot is common in secondary-school and first-year university syllabi. It links to neighbouring topics MacOS, Network booting, so understanding it makes those chapters shorter.
In everyday life: Look for NetBoot 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 NetBoot in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NetBoot 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 NetBoot out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NetBoot in simple terms?

NetBoot was a technology from Apple which enabled Macs with capable firmware (i.e. New World ROM) to boot from a network, rather than a local hard disk or optical disc drive.

Why does NetBoot 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 NetBoot?

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 NetBoot.