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.t ###############POSSIBLE APPROACH TO A SEPARATE CGC COMPUTER
.ST #################Phil Hannay  5-Dec-83

.p
There is enough room in the current computer room to accomodate
another small computer (like an 11/23+) if we decided to install
it there.  The cooling capacity of the air conditioner would need
to be analyzed to determine if it would be sufficient.

.p
All government programs would run on their computer (I90 and I370).
In addition, they would run an equipment activity logging program
that would take snapshots of the equipment status throughout the
day for later analysis if questions arose.  The government computer
would communicate on a periodic basis with their downtown computer.
The CGC would handle the support of their programs.  Low
overhead communication would be set up between the CGC computer and
the 11/60 (Cargill computer) to pass information between the two.

.p
In addition to the normal computer hardware, three additional 
items would be required.  A modem ($400 US minimum)
for hook up with the downtown computer
would be needed.  A phone line is already available in the computer room
for periodic hookup.  If preferred, another phone may need to be
installed.  A high speed parallel or serial communciation port for
the interprocessor communications (one for each computer) would be needed.  
Possible
examples would be a DR11W (DRV11B? for 11/23) DMA parallel interface
or a DUV11 or DMV11 serial interface.  Any of these run about $2500 US.
Finally, some sort of interface would be required for the equipment
status logging.  It would be impossible to say what type would be
needed.
With a range of 100 to 200 points (items to be shown as on or off)
you can figure a minimum of $20 US per point.

.p
In addition to the normal software that the government will write and
support, there are three additional items that they may prefer to
purchase from outside.  One is the RFX software (third party software)
that permits data
files to be transferred from one DEC computer to another over an
ordinary modem line.  We use it on all our computers that the
Grain Lab supports and it is very reliable.  It could be used
as the method to download information to the downtown computer or
upload it the other way.  It costs about $500 US for one host
site and any number of remote sites (only the host can initiate
a transfer).  Another item is the interprocessor communication
software.  It would transfer information in the form of individual
data records.  The Grain Lab would have the expertise needed to
write this.  A minimum figure would be about $10,000 US.  
Finally, the third item would be equipment status logger driver.
The program would drive the hardware interface and deliver to
the system raw data in a system common or in a file for later
processing by CGC programs.  The Grain Lab also has
the expertise to create this software. Figure a minimum of $10,000 US.
Assuming that the status information is to be only colleceted, and
not analyzed until some later non-busy period, the overhead on
the computer will not be very high.  Adequate file storage area
on disk will be required.  Polling 200 points every 10 seconds
in a 24 hour period will create a raw data file of about 500 blocks
(each block is 512 8-bit bytes).

.p
This is simply a quick study of the a possible implementation of
a separate CGC computer running with the existing Cargill computer.
The dollar figures mentioned are simply very rough estimates.
To come to more realistic figures, formal specifications of the
hardware and software requirements need to be made.  You should
count on spending a certain amount up front for writing these
specifications.