Subject: Re: Pseudo-disk driver
To: None <>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: tech-kern
Date: 10/31/2001 12:04:04
I wrote

>> I've built a pseudo-disk driver.  With suitable userland code, it
>> could in principle replace ccd, raid, vnd, encrypting vnd, just
>> about any software disk layer.

Perry responded

> Why don't you put the code up somewhere so others could bang it into
> shape for NetBSD?

and I've also gotten private response expressing interest.

I've got my entire private patch tree up on; see  (I don't yet have
anything in place giving the original rev of patched files; I recognize
the need for that in many cases, though since this is new, rather than
patches to existing files, it's not relevant here.)  My pseudo drivers
are in src/sys/dev/pseudo/ under the directory given above; as you
might expect from the names, the pseudo-disk driver is in pdisk*.

Doubtless some will shudder at it for one reason or another, and there
are probably functional problems left as well as performance and
stylistic problems; it is only a day old. :-)  There also is nearly no
documentation; pdisk.doc and the patches to the SPARC and Alpha MAKEDEV
scripts (see src/etc/etc.sparc/MAKEDEV and src/etc/etc.alpha/MAKEDEV -
look for "pdisk") are about it at the moment.  There also are no
userland programs save what I've hacked together here at home.  Those
will follow; as I say, it's only a day old yet.

The pseudo-tape driver, which I'd also seen some interest in, is in
ptape* alongside the pseudo-disk driver.  The tape version is
significantly older and better documented; see
src/share/man/man4/ptape.4 for a driver manpage, and
src/usr.sbin/ptaped/ for a sample userland program (that ptaped is the
program I used with it at the site where I mentioned I used it for
production backups, not just a useless-as-is skeleton program.)

Of course, the rest of what I've got there is available for anyone
interested.  I'll be happy to correspond further about any of it with
anyone interested, including "what the heck is _this_?" type stuff. :-)

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