Subject: Re: how to concatenate disks
To: None <>
From: der Mouse <mouse@Collatz.McRCIM.McGill.EDU>
List: current-users
Date: 08/03/1994 15:32:39
>> [the following should probably be in some sort of FAQ, so people
>>  don't have to go to the 'source', as i did.]

>> How To Concatenate Disks
>> --- -- ----------- -----

> No, it should be a man page.

Preferably, but I'd take a doc file over nothing.

However, I'm curious.  What's machine-dependent about this sort of disk
trickery?  More specifically, why is the ccd stuff everyone is talking
about in the hp300 port, rather than over in some machine-independent
part of the kernel?  I can't see anything conceptually difficult about
a disk driver that just parcels out I/O requests to other drivers (set
via ioctls, perhaps), and while it may not be easy, I don't see any
reason why a machine-specific version of it would be any easier.  (I
tried to do something very similar once under pre-Reno 4.3, and never
got it to work reliably.)

Ideally, I'd like to see a disk driver that turns around and reflects
I/O requests back to a user process, which can stripe or interleave or
whatever else it feels like.  (Efficient?  Who said anything about it
being efficient?  I suspect it would be at least usably fast....)  I'd
even write it myself, but if the concatenated disk driver is
machine-dependent, there is clearly magic I don't understand going on

					der Mouse