IBM 3741 Data Station Reference Manual page 22

Note: After pressing any search key, except for search
. EOD, but before pressing R EC AD V, the search operation
can be canceled by pressing FUNCT SEL lower and
RETURN TO INDEX or by pressing FUNCT SEL lower
and UPDATE.
Mask is keyed into
the current record
~
brter ar displayed. .
K r ~ : : .
:=;b=":=:r=.:=====.
=, :-"l)
Mask is transferred to
hold buffer at the
t )
\...::::::=====~
start of the search.
Display
Records are read
into~
current record buffer
0 __ ' __
- 1
•
and compared with
the mask in the hold
o
buffer until a match
is found. The record
found is displayed.
Disk
IL-___
~.
(.:::""""n;,
l
Display
Figure 12. Data Flow for Search Mode
Search on Record Address
.,
)
)
Search on record address allows you to search through a data
set using record addresses. Search on record address is
especially useful if specific records have to be updated and
you know the addresses of the records.
To search for a record in a data set, key its track and sector
address. The specified address must have the format TTOSS
where TT is the track number and SS is the sector number.
The record address is keyed into positions 1 through 5 of
the display.
16
The track and sector address specified can be the beginning
of extent address, the end of data address minus one, or
the address of any record between these two addresses.
Select the search mode to do a search by record address
operation from the read index, update, or enter mode.
Selecting the search by record address function from any
other mode causes a mode selection (M) error.
The search stops on the record address specified and the
record at the specified address is displayed. The current
record buffer and the previous record buffer contain the
displayed record at the end of the search and the mode
changes to the update mode. The record can now be
updated or reviewed. Once the record has been updated
or reviewed, another search can be initiated from this address.
A search address (I) error is displayed if the search address
is specified incorrectly, if the address is greater than or
equal to the end-of-data address or less than the beginning-
of-extent address for the data set, or if the address is on
the index track. If an invalid address was entered, the cur-
sor moves to the first position of the data line on the dis-
play screen.
Search on record address can be used to continue a verify
job. This is done by initiating the search and then selecting
verify mode when the record at the specified address is
displayed.
Search to End of Data
Search to end of data is used when you want to search to
the last data record in a data set and begin adding new
records to the data set. To search to the last record of a
data set, press FUNCT SEL lower and then press SEARCH
EOD. Select the search to the end of data function from
the read index, enter, or update mode. Selecting from any
other mode results in a mode selection (M) error.
When the search is completed, the current disk address is
set equal to the last record in the data set and the record
is displayed. The contents of the previous record buffer is
set equal to the current record buffer and the mode of
operation changes to update.