Storage Attached Via Integrated Storage Control - IBM System/370 145 Manual

it controls to be accessed by two or four channels, as discussed for the
3830 Modell. The 3830 Model 2 provides lower cost attachment of two
3330-series strings to a channel than the 3830 Modell, since only one
3830 Model 2 unit is required.
INTEGRATED STORAGE CONTROL
One or two strings of up to eight 3330-series drives each can be
attached to a Model 145 selector or block multiplexer channel via
integrated storage control (ISC) as well as via 3830-Storage Control.
Each string consists of only one 3333 module and up to three 3330
modules. The integrated storage control unit supports the same
functions and string configurations as 3830 Storage Control Model 2,
except for the following:
• ISC is not a stand-alone unit ,and is contained in a 3345 Storage and
Control Frame that is connected. to a Model 145
cpu.
• The Two-Channel switch, Additional feature (for four channel
switching) cannot be attached ·to ISC.
• ISC is powered by the Model 145 CPU
A Model 1"5 configuration can include only one ISC unit, which must
be assigned highest priority on thle channel to which i t is. attached .•
Hence, a maximum of two strings of 3330-series drives can be attached to
a Model 145 via ISC. The strings attached to a channel via ISC operate
just as if they were attached to a channel via 3830-Storage Control
Model 2. Figure 20.10 .• 3 shows a Model 145 configuration with two 3330-
series strings attached via ISC.
3330-Series string
3333
3330 3330
Device-oriented
Cables
~
control
2 drives 2 drives
-
functions and
-
2 drives
_\
CPU with integrated selector 3345 Storage and
~
or block multiplexer channel Control Frame
Cables
3330- Series string
connected to ISC
(Model 3, 4, or 5)
with ISC
3333 3330 3330
Device-oriented
Model 145
control
2 drives 2 drives
functions and
2 drives
Figure 20.10.3. A Model 145
confi~~ration
with 3330-series disk
storage attached via integrated storage control
The ISC unit is contained in a 3:345 Storage and Control Frame ..
Listed below are the five models of the 3345 and their contents:
3345 Model
1
2
3
4
5
128K of processor storage only
256K of processor storage only
ISC only
ISC and 128K of processor storage
ISC and 256K of processor storage
A Guide to the IBM System/310 Model 145
3330
2 drives
3330
2 drives
101