Re: Data Buffers

Hello Nelson,

You wrote:
>I'm writing & updating records to a file with the Force Write Ratio set to
>*NONE and then on the next line in the program chaining out to it to see
>what the trigger did to certain fields and it works fine.  I was wondering
>if this was why it works ok and is this behavior job related. In other
>words, is the file buffer part of the job or attached to the file?  If a
>program in another job stream was trying to access that same record would
>it find it in the buffer also, or only be able to get it from disk?  (I'm
>assuming here the record is still in the buffer and has not yet been
>written to disk.)

It doesn't have to be written to disk.  It does have to be in main storage.
The AS/400 and S/38 have always worked this way.

The buffer is part of the program.  Data in the program buffer are not
visible to other jobs -- also not visible to a journal but that's another
surprise for the unwary.

You are CHAINing to the record, therefore you are using keyed processing,
therefore you have a buffer size of one, therefore the record is NOT in the
buffer ('cause the buffer is automatically flushed when it is filled on a
write or update), therefore the changes are visible when you fetch it
again.  (Simple description but accurate enough for this discussion.)

Regards,
Simon Coulter.

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