dgsc(7) DG/UX R4.11MU05 dgsc(7)
NAME
dgsc - VME SCSI-2 bus adapter (88k only)
SYNOPSIS
dgsc(parent-bus[,controller-num[,adapter-id]]) or
dgsc([controller-num[,adapter-id]])
DESCRIPTION
The dgsc adapter allows an AViiON server to access Small Computer
System Interface (SCSI) devices. The adapter links a host's VME bus
to a SCSI bus. The adapter is available with either a single-ended
or a differential SCSI bus interface, and supports some SCSI-2
features, including command queueing/tagging and "fast" SCSI.
To access a SCSI device via the interface, you must specify the
appropriate dgsc adapter as the parent bus device within the name of
a SCSI device to be configured (e.g., st or sd). See the scsi_bus(7)
man page for a list of the supported child SCSI devices.
To configure dgsc devices, you must add to the DG/UX system
configuration file one or more device name entries that contain one
of the forms described in the synopsis above. The parameters in a
device name have the following meanings:
· The parent-bus parameter is itself a device name, representing
the VME bus device to which the controller is attached (vme(0) or
vme(1), for example). In the second form of the device name,
this parameter is omitted, a parent bus of vme(0) is assumed, and
all subsequent parameters move up one position. Thus, dgsc(3) is
equivalent to dgsc(vme(0),3). Note that only the second device
name form is accepted when specifying a boot command string to
the AViiON SCM.
· The controller-num parameter is a hexadecimal number in the range
0 through F which distinguishes the various standard addressing
values to which the controller may be jumpered. Consult the
table below for details on these address settings. The default
value for controller-num is 0.
· The adapter-id parameter is a hexadecimal number in the range 0
through F which specifies the SCSI ID that will be used to
address the adapter itself on its SCSI bus. If any of the
devices on the bus do not support wide SCSI addressing (see your
hardware documentation to determine this), then adapter-id is
limited to the range 0 through 7. The default value for adapter-
id is 7.
Each dgsc controller board contains two jumperable VME board address
settings: the interrupt vector number used by the board, and the A16
address of the board's 16-bit control register space. The following
hexadecimal address values are used for the 16 standard controller-
num instances supported by the device driver on each parent VME bus:
Controller Interrupt A16 Address
Number Vector
Number
0 30 FFFFC000
1 30 FFFFC080
2 32 FFFFC100
3 33 FFFFC180
4 34 FFFFC200
5 35 FFFFC280
6 36 FFFFC300
7 37 FFFFC380
8 38 FFFFC400
9 39 FFFFC480
A 3A FFFFC500
B 3B FFFFC580
C 3C FFFFC600
D 3D FFFFC680
E 3E FFFFC700
F 3F FFFFC780
A dgsc device can still be used even if it is not jumpered to one of
the standard address settings. However, such a device is referred to
as a non-standard instance, and it requires a different device name
format:
dgsc@intr-vec-num(parent-bus,a16-addr[,adapter-id]) or
dgsc@intr-vec-num(a16-addr[,adapter-id])
The parameters in a non-standard device name have the following
meanings:
· The intr-vec-num value is the hexadecimal VME interrupt vector
number used by the board. There is no default value for this
parameter; it must always be specified explicitly.
· The parent-bus parameter has exactly the same meaning here as it
does in the standard device name format.
· The a16-addr parameter is the hexadecimal value of the VME A16
address of the board's 16-bit control register space. There is
no default value for this parameter; it must always be specified
explicitly.
· The adapter-id parameter has exactly the same meaning here as it
does in the standard device name format.
A dgsc adapter attempts to use the SCSI synchronous data transfer
protocol, by negotiating a synchronous offset with each device on the
the SCSI bus. If this negotiation fails, the asynchronous mode is
used.
EXAMPLES
The following entry in a DG/UX configuration file configures all SCSI
disk units on all SCSI IDs on the third standard dgsc controller on
the first VME bus:
sd(dgsc(vme(0),2),*)
The following entry is a synonym for the example above:
sd(dgsc(2),*)
The following entry is identical to the example above, except that
the SCSI adapter ID is 6 instead of 7:
sd(dgsc(2,6),*)
For more information about DG/UX device configuration, refer to
"Writing a Device Driver" in Programming in the DG/UX Kernel
Environment.
SEE ALSO
scsi_bus(7), vme(7).
Licensed material--property of copyright holder(s)