Re: mmaping on plan9? (was Re: [9fans] venti /plan9port mmapped

["Bakul Shah via 9fans" <9fans@9fans.net>]

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Exactly. And the same failure modes exist (if your swap device or exec file access suddenly fails). In general Unix-type OSes only handle the "happy path" well and do not expend heroic efforts to deal with errors.

Here by mmap  Ron and I mean memory mapping and not linux/BSD specific mmap API. If any mmap API is added to plan9, it need not follow the example of linux/BSD but it should be well integrated.

> On Feb 9, 2026, at 7:23 AM, ron minnich <rminnich@gmail.com> wrote:
> 
> as for mmap, there's already a defacto mmap happening for executables. They are not read into memory. In fact, the first instruction you run in a binary results in a page fault. 
> 
> Consider a binary larger than your physical memory (this can happen). Without the defacto mmap, you could not run it.
> 
> Similarly, in HPC, there are data sets far larger than physical memory. mmap makes use of these data sets manageable. Nothing else has been proposed which comes close. 
> 
> ron
> 
> On Sun, Feb 8, 2026 at 5:35 PM ron minnich <rminnich@gmail.com <mailto:rminnich@gmail.com>> wrote:
>> suns would survive server outages. At least in the 90s. Linux NFS had its own ideas for failure. 
>> 
>> Statelessness, like everything, has its good and bad points. Note that NFS was never truly stateless for v2 and later; servers had to have a dup cache, for practical reasons. 
>> 
>> Stateless is not cheap. NFS does not even have a mount rpc, for example, so every packet carries with it authentication information and user identity. Every. Single. One.
>> 
>> But you could reboot a server, and you'd see the infamous "nfs server not responding still trying" on the client for hard mounts. For soft mounts, you'd see data loss. For spongy mounts, well, some combination of the two :-)
>> 
>> When all is said and done, like it or not, NFS has had greater success than 9p, for all kinds of reasons, some of which make sense, others which don't.
>> 
>> 
>> 
>> On Sun, Feb 8, 2026 at 1:01 PM Ethan Azariah <eekee57@fastmail.fm <mailto:eekee57@fastmail.fm>> wrote:
>>> On Sun, Feb 8, 2026, at 3:10 PM, Alyssa M wrote:
>>> > I seem to recall NFS will even 
>>> > survive a server reboot by being stateless (not that I've actually 
>>> > tried that...)
>>> 
>>> I forget exactly which NFS version I was using back in 2004, but programs with open files didn't survive me tripping over an ethernet cable despite the disconnect not lasting 10 seconds. Server & client were Linux. I remember wondering what NFS's statelessness was for, exactly, though I guess the failure to 'come back' might have been an implementation issue. Newer NFS versions aren't stateless.
>>> 
>>> Surviving a server reboot would be nice though. :)
> 
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