MPE/iX Quick Reference Guide (32650-90881)

180 Chapter7

File System

System Deﬁned Files

MPE/iX reserves certain ﬁle designators for system deﬁned ﬁles. System deﬁned ﬁles are

reserved words that refer to a speciﬁc type of system ﬁle.

$STDIN refers to the device that you used to initiate your current session or job.

The device is normally a terminal for a session and spoolﬁle for a job. Data

entries in this ﬁle should not have a colon in column 1. (A colon in column

1 indicates the end-of-data). Use the :EOD command to delimit data.

$STDINX is the same as $STDIN, except that a colon in the ﬁrst column does not

indicate the end of data. Thus $STDINX may contain commands as well as

data. Interactive programs and subsystems often use $STDINX to

reference the terminal as an input ﬁle. Use :EOD or :EOF to indicate the

end of data.

$STDLIST is the device designated as the session or job output device, the device

MPE uses to respond to your commands. This device is normally a

terminal for sessions and line printer for jobs.

$NULL is a ﬁle designator that is used to tell MPE to read from or write to a

non-existent ﬁle as though the input-output operation were successful.

This ﬁle is usually used to discard output.

$NEWPASS is a temporary disk ﬁle. MPE uses $NEWPASS to store information during

the execution of a program. When a program closes $NEWPASS, the

system automatically changes its name to $OLDPASS.

$OLDPASS is a temporary disk ﬁle containing the contents of the last $NEWPASS ﬁle

closed. When a $NEWPASS ﬁle is renamed $OLDPASS, the system

deletes the previous version of $OLDPASS.

You can use $NEWPASS and $OLDPASS when compiling and preparing a program. MPE

compilers write object code to $NEWPASS during compilation. When compilation is

complete, the compiler closes $NEWPASS and the system renames the object code (USL)

ﬁle $OLDPASS. When you prepare the USL ﬁle ($OLDPASS), the system stores prepared

(executable) code in the $NEWPASS ﬁle. When preparation is complete, the system closes

$NEWPASS and renames the executable code ﬁle $OLDPASS. Use the SAVE command to

save the program stored in $OLDPASS to a permanent ﬁle.