ML/I User's Manual " Appendix 5 Implementation on the Cambridge
Contents
1. 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 curious effects J 4 Output Output may be in F FB V or VB format The DCB parameters RECFM LRECL BLKSIZE are copied from the input if not supplied except in the case of unblocked output when LRECL is set equal to BLKSIZE or 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 J 5 Listing 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 LIST 2 ML I User s Manual Appendix J Implementation on Cambridge IBM 370 J 6 Messages Information and error messages are sent to SYSPRINT If the option PRENV is on a print out of the current environm2. ML TI User s Manual Appendix J Implementation on the Cambridge IBM 370 P H July 1973 Copyright 1973 P H Permission is granted to copy and or modify this document for private use only Machine readable versions must not be placed on public web sites or FTP sites or otherwise made generally accessible in an electronic form Instead please provide a link to the original document on the official ML I web site http www ml1 org uk J 1 Introduction 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 supple ments to that manual startlines and stop markers J 2 JCL ML T is normally run using the catalogued procedure MLI as described in the URM Input is taken from a DD statement name FROM and output is sent to TO Messages are sent to SYSPRINT and an input listing if requested to LIST Options are given in the PARM field set up as symbolic parameter OPT in the catalogued procedure J 3 Input Input may be in F FB V or VB format Concatenation of unlike datasets is supported The input routine truncates trailing spaces from input records unless the TRAIL 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
3. ent is added at the end of processing J 7 Region size The procedure specifies a region size of 50K by means of the parameter REG1 The code of ML Tis 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 evaluated J 8 Implementation dependent constants a There are 50 permanent variables P1 to P50 b The number N described in Chapter 6 of the ML I User s Manual is 40 c All numbers are held in full words J 9 System variables There are fifty system variables S1 to 50 in the environment They are used for controlling the action of ML T as follows 1 startline switch see the ML I User s Manual 2 contains the line number of the latest line read 53 550 not used at present J 10 Alterations to ML I The layout keyword TAB is not supported
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