2715 Machine Features; Standard Features For Models 1 And 2; Selective Features For Models 1 And 2 - IBM 2790 Manual

2715 M A CH IN E F E A T U R E S

Standard Features for Models 1 and 2

The 2715 Models 1 and 2 contain as standard features:
2715 Model 1 (Local)
16K bytes of core storage
Integral disk
Real-time clock
2790 adapter
Multiplex Channel
adapter

Selective Features for Models 1 and 2

The following selective features can be attached to the 2715
Model 1 or Model 2.
Expanded Capability
The Expanded Capability feature (32K bytes of core storage)
increases the number of area stations and data entry units
that can be attached to a 2715.
2715 Without Expanded Capability Feature. Without the
Expanded Capability feature (16K bytes of core storage),
the maximum configuration for a 2715 is one of the
following:
• 64 IBM 2791 Area Stations with no data entry units.
• 4 IBM 2791 Area Stations and 120 data entry units.
• Other combinations of area stations and data entry units
that satisfy the statement "2A + D is less than
129" — where A equals the number of IBM 2791 Area
Stations and D equals the number of data entry units.
When using IBM 2793 Area Stations, A is equal to zero
and D shows the number of data entry units that may
be attached.
A 2715 without the Expanded Capability feature pro­
vides the user with 1280 bytes of core storage for user
tables (which contain pointers, index values, transaction
lists, etc.). They are assembled in object format by the
System/360 assembler and sent to the 2715 by a user's
BTAM problem program.
2715 With Expanded Capability Feature. With the Expanded
Capability feature (32K bytes of core storage), the maximum
configuration for a 2715 is 100 area stations in any combi­
nation with 1024 data entry units in any combination.
A 2715 with the Expanded Capability feature provides
the user with 4096 bytes of core storage for transaction
tables, which are loaded into the 2715 via System/360
data link.
2715 Model 2 (Remote)
16K bytes of core storage
Integral disk
Real-time clock
2790 adapter
BSC adapter
Local 2740 adapter
The Expanded Capability feature is required if message
routing from an attached area station or data entry unit
to another attached area station equipped with IBM 1053
Printer is required, independent of the System/360 operation
A transaction entered at a 2791 Area Station or a 2795
or 2796 Data Entry Unit may have any one of the following
routing designations (a through g) if the 2715 has the Ex­
panded Capability feature. If the 2715 does not have Ex­
panded Capability, the routing designations are limited to
any one of items a, b, and c.
Routing Designations
a - To CPU (S/360) or 2715 disk
b - To 2740 printer attached to 2715
c — a and b
d — To 1053 Printer attached to an Area
Station on the loop
e — a and d
f — a and b and d
g - b and d
A 2715 without Expanded Capability provides for
routing (a, b, and c only) of explicit text only. (Explicit
text is that data received from the originating station.)
A 2715 with Expanded Capability provides for routing
of explicit text or explicit-implicit text. (Implicit text is
user-predefined messages stored in 2715 core storage.) One
of these messages may be appended to the explicit text
received from the originating terminal. The combined text
is then routed in accordance with any one of the above
designations. In item d above, the 1053 Printer address
may be implicit or explicit. (For example, if the address
is supplied with the first data entry entered at the origina­
ting station, the address is explicit; but if the address is
supplied within the user tables, the address is implicit.)
The Expanded Capability feature is a prerequisite for
message routing.
The Expanded Capability feature is a prerequisite for
BSC multipoint line control on the 2715 Model 2.
Line Transfer Switch
This feature provides the ability to switch the 2790 trans­
mission lines between two adjacent 2715 TCU's acting as
backup for each other (see Figure 18). All terminals must
be defined identically in the user tables of both 2715's
affected. Only one 2715 requires this feature.
Line Transfer Switch—Third Unit
This feature provides the ability to use a third 2715 as
backup for either of two 2715's (see Figure 19). All ter­
minals must be defined identically in the user tables of both
2715's affected. The other two 2715's must be equipped
with the Line Transfer Switch feature.
IBM 2715 Transmission Control Unit 27