Path: utzoo!attcan!uunet!uport!jmsully
From: jmsully@uport.UUCP (John M. Sully)
Newsgroups: comp.unix.microport
Subject: Re: 2 ESDI drives, and misc. flames
Message-ID: <390@uport.UUCP>
Date: 1 Aug 88 17:04:09 GMT
References: <138500039@cdp>
Reply-To: jmsully@uport.UUCP (John M. Sully)
Organization: Microport Systems, Scotts Valley, CA
Lines: 33

In article <138500039@cdp> steve@cdp.UUCP writes:
|Can anyone sumarize the issues surrounding running two ESDI
|drives on Microport V/386 2.2 ?  

The problem you are wondering about is the infamous "2-drive" problem.
To summarize: it appears that some samples of a given controller will
cause problems when switching between drives with the current version
of the hard disk driver.  This problem has been, to the best of our
knowledge, resolved in the driver being incorporated into the next release
of both the 286 and 386 product.

|Another interesting note.  In a fit of frustration, I tried to
|link the 386/ix hd.o driver into the uPort kernel.  The link
|failed, with undefined (global) symbols 'dpt1' and 'dpt2'.  I
|find it outrageous that Microport decided to break the SVR3
|driver interface.  After all, isn't the success of UNIX based
|on the standard interfaces it provides ?

My guess is that these are global symbols in the Interactive driver which
are referenced by some other driver in Interactive's distribution.  The
core (not the device drivers) of both our kernels is based on the same
code from AT&T.  Microport did *not* decide to break the kernel interface
and neither did Interactive.

|As another experiment, I tried to link Microport's Everex tape
|driver (ev.o), into a 386/ix kernel.  But this also failed --
|and you can guess who's software introduced undefined symbols !
|ev.o references 'dmainitted' and 'initdma'.  Incredible.

As in the above case, these symbols are located in our floppy driver and
are used to indicate whether or not the DMA controller has been initialized.

John M. Sully