Update via a STEM variable
The use of a STEM variable is likely to be the most common method observed.
Update via the Data Stack
As will be seen using the Data Stack requires more instructions, as the record needs to be moved to a variable to be altered.
Update via a non-STEM variable
The actual process is similar to that when using a STEM variable.
Update using both a STEM variable and the Data Stack
This is possibly the most esoteric method. Here the STEM is used on the read, and the Data Stack on the write, but it could just as easily be the other way around.
The Legac-e Information Site
Legac-e - REXX : Using EXECIO
Updating records
It is possible to update records in situ, provided the records are not spanned, i.e. split across multiple data blocks.
Update in place avoids the need to create a new file or data set, however the size of the updated record must match that of the
record being overwritten.
Opposite are links to four ways the DISKRU/DISKW combination could be used to update a record.