statement and directs the output to the
real or virtual
Then indicate where the DDR program is to obtain its control statements
by responding to prompting messages at the console.
1. Be aware that DDR when run as a standalone program has only the
most elementary error recovery support.
invoked in
is performed by
2.
will enter a wait state, waiting for an interrupt to identify the
console. If any nonconsole-type device is physically connected to
address
will be unpredictable.
DDR
All control statements may be entered from either the console or the
card reader.
data after the last operand in a statement is ignored. An output tape
must have the
therefore, the extents must be entered in sequence by cylinder.
one execution, but up to
be entered. The function statements are delimited by (preceded by) an
not use
specify when the input is read from a card reader or
message
stream will be checked for proper syntax, but no further DDR operations
will be performed. Only those
steps. The
To return to
the prompting message (ENTER:). To return directly to
statements in that they operate on only one data extent at a time and it
is not necessary to respecify the
function, the tape must be positioned at the header record for each
step. The
the console
required.
section