vd.4

早期freebsd实现

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.\"     @(#)vd.4	8.1 (Berkeley) 6/5/93
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.Dd June 5, 1993
.Dt VD 4 tahoe
.Os
.Sh NAME
.Nm vd
.Nd
.Tn VERSAbus
storage module controller/drives
.Sh SYNOPSIS
.Cd "controller vd0 at vba? csr 0xffff2000 vector vdintr"
.Cd "disk dk0 at vd0 drive 0"
.Sh DESCRIPTION
This is a generic
.Tn VERSAbus
storage module disk driver for the
Computer Consoles
.Tn SMD
.Pq Tn VDDC
and
.Tn SMD-E
disk controllers.
.Pp
The
.Nm vd
driver is a fairly typical block
.Tn I/O
device, except
raw block
.Tn I/O
counts must be a multiple of 1024 bytes,
whether the actual sector size is 512 or 1024 bytes.
Likewise,
.Xr seek
calls should specify a multiple of 1024 bytes.
See
.Xr physio 4 .
.Pp
The first sector of each disk contains a disk label
containing geometry information and partition layouts (see
.Xr disklabel 5 ) .
This sector is normally write-protected, and disk-to-disk copies should
avoid copying this sector.
The label may be updated with
.Xr disklabel 8 ,
which can also be used to write-enable and write-disable the sector.
.Sh DISK SUPPORT
During autoconfiguration,
as well as when a drive is opened after all partitions are closed,
the first sector of the drive is examined for a disk label.
If a label is found, the geometry of the drive and the partition tables
are taken from it.
If no label is found,
The driver checks for a disk label on sector 0 of each drive
during autoconfiguration.
If no label is found,
the driver tries to access the last track on each drive
to determine the type of drive attached.
The driver has default partition tables for
seven different drives:
.Tn CDC FSD
(160
.Tn MB ) ,
.Tn CDC
9766 (300
.Tn MB ) ,
.Tn CDC XFSD
(340
.Tn MB ) ,
.Tn CDC
515
.Tn MB ,
Fujitsu 360
.Tn MB ,
Fujitsu Eagle (440
.Tn MB ) ,
and Maxtor 340
.Tn MB .
If the drive is not recognized, a single small partition is created
to allow a label to be written.
.Pp
The partition tables in the disk label and the
.Pa disktab
file specify partition offsets and sizes in sectors, which are 512 bytes
on
.Tn SMD
drives and 1024 bytes on 5 1/4"
.Tn ESDI
drives.
By convention,
the ?a partition is normally used for the root file system or other small
file system,
and the ?b partition is used as a paging area.
The ?c partition maps the rest of the pack,
except the last 5 cylinders which are reserved for bad sector forwarding,
and diagnostic use.
.Sh FILES
.Bl -tag -width /dev/dk[0-7][a-f]xx -compact
.It Pa /dev/dk[0-7][a-f]
dk block files
.It Pa /dev/rdk[0-7][a-f]
dk raw files
.El
.Sh DIAGNOSTICS
.Bl -diag
.It vd%d: %s controller.
This message is printed during autoconfiguration to identify
the type of controller, either
.Tn VDDC
or
.Tn SMDE .
.Pp
.It vd%d: init error.
During autoconfiguration the controller failed to respond to
an initialize command.
.Pp
.It vd%d: diagnostic error.
During autoconfiguration the controller failed  to respond to
a diagnostic command.
.Pp
.It dk%d: unknown drive type.
The system was unable to identify the specified drive as
one of the drives described above; the drive will not be
configured.
.Pp
.It vd%d: drive %d: config error.
The system encountered a hard error when it tried to configure
a drive during autoconfiguration.
.Pp
.It vd%d: starting drives, wait ... .
This message indicates the system is about to tell the
controller to ``start'' the drives attached to  it.
.Pp
.It dk%d: %s <ntrak %d, ncyl %d, nsec %d>.
For each drive recognized during autoconfiguration the system
prints a message of this form.  The drive type is displayed
as well as the geometry: tracks/cylinder, cylinders, and sectors/track.
.Pp
.It vd%d: lost interrupt.
The system failed to receive an interrupt from the controller after
submitting a request.
The system attempts to abort the current request and simulate an
interrupt to unwedge the controller.
During processing of the simulated interrupt, a controller error
will be reported as described below.
.Pp
.It vd%d: stray interrupt.
The system received an unexpected interrupt; it is ignored.
.Pp
.It dk%d%c: write locked.
An attempt was made to write to a drive that is physically write-protected.
.Pp
.It "dk%d%c: controller err %sing fsbn %d [of %d-%d] (dk%d bn %d cn %d tn %d sn %d) status %b ecode %x; resetting controller... retrying."
.br
.It "dk%d%c: drive err %sing fsbn %d [of %d-%d] (dk%d bn %d cn %d tn %d sn %d) status %b ecode %x; resetting drive... retrying."
An attempted transfer resulted in a controller or drive error.
The controller or drive is reset, and the transfer is attempted
a second time.
.Pp
.It "dk%d%c: hard error %sing fsbn %d [of %d-%d] (dk%d bn %d cn %d tn %d sn %d) status %b ecode %x."
An unrecoverable error was encountered.  The filesystem block number reported
is a logical sector number on the indicated partition;
it is expressed using 1024-byte sectors.
If the transfer involved multiple blocks, the block range is printed as well.
The parenthesized fields list the actual disk sector number
relative to the beginning of the drive
(in 512- or 1024-byte blocks, as appropriate),
as well as the cylinder, track and sector number of the block.
The error status field of the device control
block is printed in hexadecimal followed by a symbolic description.
If this is an
.Tn SMDE
controller, the error code is also displayed.
.Pp
.It "dk%d%c: soft error %sing fsbn %d [of %d-%d] (dk%d bn %d cn %d tn %d sn %d) status %b ecode %x."
A recoverable error was detected by the controller.
The fields are interpreted in the same way as those for hard errors.
.Pp
.It "dk%d%c: soft ecc %sing fsbn %d [of %d-%d] (dk%d bn %d cn %d tn %d sn %d)."
A recoverable
.Tn ECC
error was detected and corrected by the controller
during the indicated transfer.
.Pp
.It vd%d: drive %d: couldn't reset.
The system was unable to reconfigure a drive during a controller reset.
.Pp
.It vd%d: controller timeout.
The controller failed to complete an operation within a reasonable
time.  This message is usually followed by another message indicating
what operation timed out; e.g. ``during config'' for a configuration
command.
.El
.Sh SEE ALSO
.Xr disklabel 5 ,
.Xr disklabel 8
.Sh HISTORY
The
.Nm
driver appeared in
.Bx 4.3 tahoe .
.Sh BUGS
Writes
scribble on the tail of incomplete blocks.
.Pp
The system should use real disk sector numbers internally,
instead of assuming 1024-byte sectors;
errors should report filesystem block numbers using the actual sector size.
Raw
.Tn I/O
should be permitted on any sector boundary.