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The Xinu Page

xinu.cs.purdue.edu

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Re: The Xinu Page

#11

Post by artlogic »

I own volumes 1, 2 and the PC version. I can vouch for the quality and understandability of the code. I've read a number of operating systems books, and I've found volume 1 to be one of the most straightforward - if you can get past the fact it's written with the PDP-11 in mind. I bought the PC version on a whim after reading volume 1, and found it to be lacking in a number of ways, using BIOS for many system services and glossing over memory protection (not surprising as it targeted the 8086).

One of the more interesting things about Xinu is that its security model is ring based, and if I remember right, it takes advantage of rings 0-3, unlike many modern operating systems. I can't actually remember if the PDP-11's hardware supported this, or if it was emulated by the kernel.

One of my rainy day projects has always been to get Xinu up and running on a PDP-11 emulator - too many operating systems, too little time.

Re: The Xinu Page

#12

Post by Erwin »

artlogic wrote: post #11

I own volumes 1, 2 and the PC version. I can vouch for the quality and understandability of the code. I've read a number of operating systems books, and I've found volume 1 to be one of the most straightforward - if you can get past the fact it's written with the PDP-11 in mind. I bought the PC version on a whim after reading volume 1, and found it to be lacking in a number of ways, using BIOS for many system service…

OS/2 was another one using multiple rings.

Interestingly VirtualBox takes advantage of x86's multiple rings: http://www.virtualbox.org/manual/ch10.html#idp12629776 (which contains other interessting details about VirtualBox, like the disassembles and patches code running in the VM in certain cases)

Re: The Xinu Page

#13

Post by primitur »

Sweet ram o' the rod, a name from the mists emerges.. It has been a long time since I played with Xinu, at least before Linux came to rule the roost .. someone remind me, though, doesn't Xinu have its own compiler onboard, i.e. why do we need two machines, just to bootstrap? Once booted, does a Xinu machine have all it needs to build an image for another Xinu machine?

I guess its a matter of taste, but this dusty beard reckons its not Unix if you're not building another Unix with it. ;P]

Re: The Xinu Page

#14

Post by mapleoin »

andybak wrote: post #9

Just to point out another title edit by the mods. The original title was 'Xinu is not Unix'. Considering that's the first line of the body copy it was hardly excessive editorialising in need of fixing and actually did a better job of setting expectations than the pedestrian replacement title.

These mods seem too much like bots lately. Maybe they are?

Re: The Xinu Page

#17

Post by JulianMorrison »

mapleoin wrote: post #14
andybak wrote: post #9

Just to point out another title edit by the mods. The original title was 'Xinu is not Unix'. Considering that's the first line of the body copy it was hardly excessive editorialising in need of fixing and actually did a better job of setting expectations than the pedestrian replacement title.

These mods seem too much like bots lately. Maybe they are?

If HN wants to force use of the element as the post title, why not just auto fill it from the URL and disable editing? it seems silly to offer an editable field whose contents are auto-discarded.
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