Page of GC20-1801-10 As Updated March 3, 1980 by TNL GN25-0776 RCTLUNIT Macro
Even though some devices attach directly to the channel without a
separate control unit, a RCTLUNIT macro instruction must be
included for them. For example, if you want to define a 3215, you
must code an RDEVICE and RCTLUNIT macro for the 3215; even though
the 3215 does not require a control unit, it requires a RCTLUNIT macro. If several different devices have addresses that are within
the same control unit address, only one RCTLUNIT can be
specified. Which control unit you specify is not relevant. ALTCH= (n, n,n)
specifies the alternate channel(s) to be used with the control unit
address if the primary channel path is unavailable or offline. n
represents the one-digit channel addresses for the alternate
channel paths. Up to three alternate channels can be specified.
There can be nc splitting of control units when using alternate
channels. All devices on one physical control unit must be defined
as having alternate channel(s) or no alternate channel(s). FEATURE=xxx-DEVICE is the optional control unit feature. The feature, xxx-DEVICE, indicates that the control unit is controlling more than eight
devices. The prefix, xxx, can be 16,32,48,64,80,96,112,. 128,
144, 160, 176, 192, 208, 224, 240, or 256. "Appendix B: Configuration Aid" lists the maximum number of devices that may be
specified for each control unit. This feature may be specified for
a 2403, 2702, 2703, 2803, 2835, 3272, 3345, 3704, 3705, 3803, 3830, ICA, IFA, or ISC. For any unsupported control unit, FEATURE=16-DEVICE is valid and is
the maximum you can specify. Unsupported control units are any
tha t do not a ppear in the "Configurations" section of Part 1. The starter system does not provide support for device
configurations over 16 when you are defining the devices needed to
do the system generation. Therefore, if your installation includes
control units that share more than 16 devices and are also
switchable to another processor, the channel interface enable
switch from the other processor should be in the disable position
while you perform the system generation.
The following examples illustrate the use
instruction to describe the control units
printer-keyboard with address 01F, a 2314, and
through 04B. RCTLUNIT ADDRESS=018,CUTYPE=3215 RCTLUNIT ADDRESS=230,CUTYPE=2314 of the RCTLUNIT macro
for: a 3215 console
a 3705 with lines 040 RCTLUNIT ADDRESS=040,CUTYPE=3705,FEATURE=16-DEVICE Part 2. Defininq Your VM/370 System 153
Page of GC20-1801-10 As Updated March 3, 1980 by TNL GN25-0776 RCTLUNIT Kacro The RCHBLOK contains an index to each of thirty-two possible RCUBLOKS. When the ALTCH operand is specified on the RCTLUNIT macro, both the
primary and alternate RCHBLOKS contain an index to the same RCUBLOK. The following message is issued when an RCTLUNIT macro is defined
specifying the ATLCH operand and an RCTLUNIT macro is also defined which
creates an RCUBLOK for the alternate channel address.
CHANNEL TABLE FOR RCUxxx IN USE BY RCUyyy For Example: RDEVICE ADDRESS=250 RDEVICE ADDRESS=350 RCTLUNIT ADDRESS=250,ALTCH=(3) RCTLUNlf ADDRE55=350 RCHANNEL ADDRESS=2 RCHANNEL ADDRESS=3 The ALTCH specification indicates that the RCHBLOK for channel three
should index to the 250 RCUBLOK. The RCTLUNIT macro for 350 causes a
conflict since the RCHBLOK cannot index to both the 250 and 350 RCUBLOKS. In the above configuration, the user must remove the RCTLUNIT macro and RDEVICE macro for 350. 154 IBK VM/370 Planning and System Generation Guide
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