| We have a number of options available. The best option is dependent
on the customers needs.
VAXlink can be used to extract data from an IMS database and load it
into an Rdb database. VAXlink provides a <relatively> easy-to-use
menu driven interface to allow the user to select a database, a number
of entities/records, and to specify selection criteria. Once the data
is selected, it is automatically downloaded and loaded into Rdb.
VAXlink does not support updates of the IBM data. VAXlink is also a
low volume tool. It can transfer approximately 1.5 MB/hour.
DTF (Data Transfer Facility) can be used to transfer data in either
direction between VSAM and RMS files. IBM offers a utility called
DXT (Data Extract Tool) which can be used to extract data from IMS
databases into VSAM files. DTF can transfer an entire file, or it
can access a single record from the file -- both read and write.
And look for a SQL interface to DTF sometime in the future. I'm not
sure of this figure, but I think that DTF can transfer approximately
6-8 MB/minute.
If your customer wishes to build new applications on the VAX which
will update the IMS environment, then you'd have to recommend using
a peer-to-peer application communications programming interface.
i.e. the customer will have to develop cooperating applications which
communicate across an SNA Gateway. We offer 3 different programming
interfaces, one for each type of SNA logical unit communications
protocols.
1- DECnet/SNA VMS API -- it uses the LU0 protocol. LU0 is very fast
but very difficult to program.
2- DECnet/SNA VMS 3270 Data Stream PI -- it uses the LU2 protocol,
basically sending 3270 terminal screens back and forth. It's very
easy to program, it allows you to talk directly to existing CICS
applications, but the data transfer rate is very slow.
3- DECnet/SNA VMS APPC/LU6.2 PI -- it uses the LU6.2 protocol, IBM's
strategic communications protocol, designed specifically for
application peer-to-peer communications (APPC). It is much easier
to program than LU0, and works almost as quickly. It can transfer
data approximately 100 times faster that 3270 Data Stream (LU2).
I recommend using LU6.2, although don't rule out LU2. LU2 could save
lots of time if you can make use of existing CICS applications. Just
don't attempt to use LU2 to transfer 10 gigabytes of data every day.
The FLASH Programming Interface (FPI) does not apply in this situation.
FLASH provides peer-to-peer communications between VAX applications and
IMS-DC applications using the LU0 protocol (it's layered on the API).
FLASH makes API much easier to program, but FLASH requires IMS-DC. You
have specified that the customer is using CICS. FLASH is an excellent
alternative to LU6.2 in the IMS-DC environment (IMS-DC does not support
LU6.2).
For more information on interoperability tools, contact me, or look at
a few of our notes files:
CREDIT::VIDA_DB2 (interoperability with DB2)
CREDIT::VIDA (interoperability with IDMS/R)
JOVIAL::VAXLINK (extraction from IMS and VSAM)
SMAUG::SNAGWY (SNA Gateways)
Anne Thomas
DBS Interoperability Product Manager
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