Specifies how GT.M handles certain control characters and escape sequences. When USER_WRITE_FILTER is not zero (0), it indicates how ASCII control characters not produced by M format control characters update $X and $Y and whether ANSI escape sequences "count" in maintaining $X and $Y.

This factor can be modified at run-time by using the FILTER= deviceparameter.

0x00000080 causes <BS>, <LF>, <CR> and <FF> to have the effect specified in the standard regardless of how they are produced. By default for efficiency, GTM only maintains $X and $Y for M format control characters and not for control characters produced by $CHAR() or W *.

0x00000001 causes ANSI escape sequences not to increment $X or indirectly affect $Y. By default, GT.M increments $X all characters.

0x00000081 enables both character and escape sequence filtering.

When enabled, each type of filtering requires character by character examination of all terminal output; therefore enabling these filters can have an adverse effect on I/O performance.