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This document describes the implementation dependent features of ML/I on the IBM 370/165.
This implementation of ML/I contains all the features described in the ML/I User's Manual, 4th Edition, August 1970, plus New Features 1 and 2 as described in the supplements to that manual (startlines and stop markers).
ML/I is normally run using the catalogued procedure
described in the URM. Input is taken from a
FROM, and output is sent to
Messages are sent to
SYSPRINT, and an input listing (if
LIST. Options are given in the
set up as symbolic parameter
OPT in the catalogued procedure.
Input may be in
Concatenation of unlike datasets is supported. The input routine
truncates trailing spaces from input records unless the
option is set. There are no illegal input characters. Upper and lower
case letters are considered as distinct. However, the logic of ML/I
requires that three characters be set aside to represent "newline",
"stopcode" and "startline". These have been assigned to X'15' (NL),
X'37' (EOT) and X'0D' (CR) respectively. The newline character is
appended to every record by the input routine, the stopcode character is
generated when the end of input is reached, and the startline character
is inserted at the start of each record when in startline mode. The
appearance of any of these characters within the input will cause
Output may be in
The DCB parameters
are copied from the input if not supplied except in the case of
unblocked output, when
LRECL is set equal to
BLKSIZE-4 (as appropriate) if not supplied. A new output record
is started when the "newline" character is encountered (the newline
character itself is removed) or if the current record becomes full.
Incomplete fixed length records are padded with spaces. The
"startline" character is ignored when in startline mode.
If the option
SOURCE is on, a line-numbered listing of the first
123 bytes of each input record, or the whole record (whichever is the
shorter) is output to a dataset described by a
DD statement named
Information and error messages are sent to
SYSPRINT. If the
PRENV is on, a print-out of the current environment is
added at the end of processing.
The procedure specifies a region size of 50K by means of the parameter
REG1. The code of ML/I is about 16K bytes long. The rest of the
region is used for access methods, I/O buffers, and the ML/I stack.
Increasing the region size increases the amount of core available for
the stack, and enables more complicated macro structures to be
There are fifty system variables (
S50) in the
environment. They are used for controlling the action of ML/I as
The layout keyword
TAB is not supported.