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The 3490-A10 is a 36-track, 1 Control Unit component of an IBM 3490 tape
subsystem. The IBM 3490 Enhanced Capability (3490E) Model A10 Control
Unit supports the Models B20 and B40 Tape Drive Units. The A10 can be
field upgraded to the A20, providing granularity from a minimum 1x2 (A10
x B20) configuration to a maximum 2x16 (A20 x Four B40s) configuration.
Included as standard are: Improved Data Recording Capability, an 8 Mb
buffer and improved utilization of ES Connection* (ESCON*) adapters providing
new possibilities in performance, connectivity, and remote tape operations.
There is one 36-track control unit function and one power supply in each
control unit. The approximate doubling of the cartridge capacity over
the IBM base 3490s is introduced via a 36-track bidirectional Enhanced
Capability tape format. This cartridge capacity improvement reduces tape
cost, as the number of cartridges required for all multiple volume data
sets is reduced by up to half. Archive, backup, master file, and interchange
data all require fewer cartridges for the same amount of data. Total tape
mounts are reduced, cartridge handling and cartridge library space are
reduced, and the data capacity of the cartridge loader is doubled.
In MVS the "LOCATE" function will accommodate the new format, and depending
on the location of the requested record, LOCATE may be faster than with
previous formats and can never take longer than a LOCATE to the physical
end of tape.
An instantaneous data rate of up to 9 MB/second is provided through the
performance enhancement function which is standard on each control unit.
With the performance enhancement function, subsystem throughput of up
to 23 percent improvement can be achieved on parallel channels in environments
with long string lengths and uncompacted or low compacted (IDRC) data.
The performance enhancement function has a significant effect on subsystem
throughput when using ESCON Channels and can show dramatic improvement
(up to 69 percent) with high (IDRC) compaction ratios. Your IBM representative
has access to detailed performance data showing a comparison between a
3490 subsystem prior to the addition of the performance enhancement function,
and a 3490 subsystem with the performance enhancement function. Relative
improvement with both parallel and ESCON Channels is shown. The subsystem
effective data rate is improved, reducing the backup and batch window
time constraints, and reducing the time required for master file creation
and use.
Expanded utilization of ESCON Channels (including ESCON Directors) provides
new possibilities in floor-space planning, configurability, and connectivity.
An A10 Control Unit (fully configured with ESCON adapters) provides up
to 64 logical paths to ESCON Host processors, when ESCON Directors are
employed in the system configuration.
Through the use of ESCON Directors, ESCON channel connected 3490Es can
be installed up to 23 kilometers (14.3 miles) from the host, addressing
remote tape operations requirements, and providing remote site security
advantages. Because tape operations are more efficient, tape drive growth
may decrease, and in some cases, fewer drives may be required. The 3490
Enhanced Model A10 writes the new tape format introduced with this product
and, for ease of migration, reads all 3480 and 3490 IBM Cartridge System
Tape formats. When service is required, devices are serviced from the
rear of the subsystem while the remainder of the subsystem remains operational.
Reliability and availability are improved by advanced electronic packaging:
the number of electronic cards within the control unit are reduced by
half over 3490 base models. Higher reliability of circuit technology,
and the micro code input disk unit, and enhanced Control Unit error recovery
procedures (ERP) all contribute to improved reliability. Up to four channel
adapters may be installed. These can be parallel, ESCON adapters, or a
combination of both.
Growth Enablement
The Enhanced Capability Model A10 provide the additional granularity
and lower cost 1X2 (A10 X B20) configuration required for entry into the
high-end 3490, and can be upgraded later to the A20 and/or B40. In addition,
the customer can add B20s and/or B40s up to a maximum configuration of
2X16 (A20 X four B40s). Mixing of parallel adapters and ESCON Adapters
is allowed. Both adapter types can be field or factory installed.
The improved performance of these 3490E models will reduce the amount
of time required to save or restore data to direct access storage devices
(DASD), resulting in higher availability of production data to users.
Maximum Configuration: One A10 single control unit function supports
up to two model B40 Magnetic Drive Units (8 Drives) or up to four Model
B20 Magnetic Drive Units (8 Drives).
Devices Supported
- 3490 Model B20
- 3490 Model B40
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