Nowadays an ECKD
channel program is built that will never stop searching until it comes to the end
of the directory, although seek time from one cylinder to the next is
involved,
I used to believe this was true, but it turns out it is not. A SEARCH
KEY CCW cannot execute in the domain of a LOCATE RECORD, so the chain is
not strictly ECKD. The description of multi-track SEARCH ID and SEARCH
KEY in the 2105 command manual clearly says that they stop at
End-of-Cylinder.
We recently had a need to study this, and I confirmed this with a GTF
trace. It gets a EOC at the end of each cylinder, and ERP restarts it
for the next cylinder until the extent is exhausted.
--
Bruce A. Black
Senior Software Developer for FDR
Innovation Data Processing 973-890-7300
personal: [EMAIL PROTECTED]
sales info: [EMAIL PROTECTED]
tech support: [EMAIL PROTECTED]
web: www.innovationdp.fdr.com
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