Capability-based computer systems
by Henry M. Levy · first published 1984
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9HN commenters
2014–2026first – last mentioned
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…what the parent is talking about, and does in this case. It's an older morph of capability based security than the newer crypto enforced name concept, but equally valid. You can read more about it in Capability Based Computer Systems by Henry M Levy. The Hydra MMP, GE-645, and iAPX 432 are older implementions of this concept in hardware. In both cases (TCB table enforced and crypto one way function enforced) the name is the capability,…
on “A Kernel Hacker Meets Fuchsia OS” ↗System/38, later AS/400, was one of the most brilliantly designed systems of the time that I've seen: https://homes.cs.washington.edu/~levy/capabook/Chapter8.pdf Designed for business apps, future-proofing, integrated database, largely self-managing, capability-security, continuing on solid (POWER) hardware... did about everything right. That's why we regularly fix crashed Windows and 'NIX machi
on “IBM launches Linux-only mainframe system” ↗Here is a book of case studies of object-capability projects in the 1960s 70s and 80s, including several products from big computer companies: http://homes.cs.washington.edu/~levy/capabook/
on “Ask HN: What projects are 20 years ahead of their time?” ↗Henry M Levy's relevant 1984 book, Capability-Based Computer Systems, is available free in PDF form on the author's web site: http://homes.cs.washington.edu/~levy/capabook/
on “Single Address Space Operating System” ↗> It implemented support for objects at the hardware level, > with access protection for on a per-object basis. Periodic reminder that Henry Levy's Capability-Based Computer Systems is available in PDF form for free¹. The 432 was slow, but the i960² was a clean RISC that could have had a future. ¹ http://homes.cs.washington.edu/~levy/capabook/ ² https://en.wikipedia.org/wiki/Intel_i960
on “Six works of Computer Science-Fiction” ↗We were thinking on the same lines. IBM System/38 was truly a brilliant, integrated design in so many ways. Even had capability-security built into the hardware. Check it out at the reference below. Intel made a monster of a system too. Would love to have either on a SOC or an inexpensive server. http://homes.cs.washington.edu/~levy/capabook/index.html
on “Apple’s Bitcode Telegraphs Future CPU Plans” ↗Smart thinking. It was already done in a dozen different ways. Two cited in my comment: https://news.ycombinator.com/item?id=10125348 Also see capability-based computer systems by levy. Free book. Pointer protection by itself can give all kinds of benefits. Modern version of that is Cambridge's CHERI processor which is open-source and already runs FreeBSD. :) https://www.cl.cam.ac.uk/research/security/ctsrd/cheri/
on “How security flaws work: the buffer overflow” ↗Applied to whole systems to make them more secure from hardware up: http://homes.cs.washington.edu/~levy/capabook/ Modern project already running FreeBSD with capability security: http://www.cl.cam.ac.uk/research/security/ctsrd/cheri/ Also look up CapDesk and DARPAbrowser.
on “Capability Based Security” ↗Im at work but these two should be a nice start: https://www.smecc.org/The%20Architecture%20%20of%20the%20Bur... http://homes.cs.washington.edu/~levy/capabook/ Bitsavers and Wikipedia are good resources. The summaries of most on Wikipedia are accurate enough with references to get more authorative information on. I found a lot of it that way.
on “Let’s Stop Bashing C” ↗And they've been such since the 70s: http://homes.cs.washington.edu/~levy/capabook/ (This book is well worth reading...)
on “Fuchsia: a new operating system” ↗I can't comment on the "never been infected" claim, but the AS/400 does have an unusual architecture based on something called "capabilities" that provide support for objects and protection in the hardware (actually, the microcode). Then the OS is built on that. There is a detailed explanation of how this works in the AS/400 ancestor System/38 in chapter 8 in this book: http://homes.cs.washingt
on “The Only Operating System That Has Never Been Infected” ↗Whether an IBM hater or UNIX lover, I still recommend you check out the AS/400 or IBM i architecture. It was a very, forward-looking design from very, long ago. I found some slides to make it more accessible to busy or lazy folks. :) It was also resilient to attack in first form as a capability-based, computer system. This book has many examples with AS/400 predecessor being “System/38” if yall w
on “IBM iSeries (AS/400) Architecture [pdf] [slides]” ↗There is also Levy's book https://homes.cs.washington.edu/~levy/capabook/
on “Linear Address Spaces: Unsafe at any speed” ↗This book has many of them: https://homes.cs.washington.edu/~levy/capabook/
…untrusted code safely, because in such a system, all objects – from whole programs to an object as small as the number 4 – would be safe and sealed off from each other on a hardware level. I'm reading Capability-Based Computer Systems [0] by Henry M. Levy (1984), motivated by wanting to learn about the Burroughs B5000 that Alan Kay has praised multiple times. I've only started to learn about these things and I don't understand the…
on “WebAssembly 101: A developer’s first steps” ↗