[TUHS] Re: 4.3 BSD version in the Unix Archive

Markus Weber jmbw at nather.com
Thu Oct 2 01:33:15 AEST 2003

I found out a bit more.

For any non-OpenVMS OS I tried on simh/vax (read: different flavors of BSD),
disk initialization is a common problem area. NetBSD glitches on mounting
the installation CD/disk, Quasijarus has a hard time deciding which disks
are online and which are not, and finally OpenBSD installs without problem,
but fails when mounting the root filesystem when it boots off ra0a. I can
however boot off the install-time kernel on the floppy disk and access the
partitions on ra0 just fine.

It became apparent that OpenBSD's in-core disk label defaulted to data
matching the c partition where the a partition should have been. After more
digging, it seemed that ra_putonline was called, but rx_putonline must have
failed somehow. To add insult to injury, after adding a few printf
statements to rx_putonline the OpenBSD sort-of-GENERIC kernel now boots.

Here's the relevant block of code:

        struct rx_softc *rx;
        struct  mscp *mp;
        struct  mscp_softc *mi = (struct mscp_softc *)rx->ra_dev.dv_parent;
        volatile int i;

printf("entered rx_putonline\n");
        rx->ra_state = DK_CLOSED;
        mp = mscp_getcp(mi, MSCP_WAIT);
        mp->mscp_opcode = M_OP_ONLINE;
        mp->mscp_unit = rx->ra_hwunit;
        mp->mscp_cmdref = 1;
        *mp->mscp_addr |= MSCP_OWN | MSCP_INT;

        /* Poll away */
        i = bus_space_read_2(mi->mi_iot, mi->mi_iph, 0);
        if (tsleep(&rx->ra_dev.dv_unit, PRIBIO, "rxonline", 100*100))
                rx->ra_state = DK_CLOSED;
printf("rx->ra_state = %d\n",rx->ra_state);
        if (rx->ra_state == DK_CLOSED)
                return MSCP_FAILED;
printf("rx_putonline returns DONE\n");
        return MSCP_DONE;

My guess is that the very first printf upsets the emulation timing just
enough to make things work. I'd have to read more code and RQDX3
documentation to take this further, but maybe this is enough to go on to
make it obvious to somebody else why Quasijarus on simh exhibits these
awfully long disk probe timeouts. I hope that once this problem has been
narrowed down a bit more, a fix to simh/vax will make all BSDs happy.

-----Original Message-----
From: Michael Sokolov [mailto:msokolov at ivan.Harhan.ORG]
Sent: Friday, September 26, 2003 3:48 PM
To: jmbw at nather.com; tuhs at tuhs.org
Subject: RE: [TUHS] Re: 4.3 BSD version in the Unix Archive

[...] If so, SIMH's MSCP emulation must be lacking in quality.

[...]But I will grant the possibility that the kernel is not w/o fault
either in that
perhaps it's going south (dereferencing a garbage pointer and crashing) when
MSCP controller (in this case SIMH's poor emulation) is doing something it
doesn't expect.
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