Format control for 3770 and SLU 1 printers

Line width

The WIDTH= keyword of the DEV statement is used to specify the maximum width of a print line, relative to column 1. The specified width is used in place of the physical device line width. Specification of a line width also establishes the right margin of the printed page (relative to column 1). Valid values are less than or equal to the physical device line width. For example, if WIDTH=80 is specified, data can be printed in columns 1 through 80.

Left margin position

The left margin operand of the HTAB= keyword of the DEV statement can be used to specify where MFS should set the left margin for the device before sending an output message. A left margin specification should be made if output fields always start at a column position other than column 1 (the default). For example, if fields are always defined in columns 5 through 80, HTAB=(5) and WIDTH=80 can be specified on the DEV statement.

Horizontal tabbing

The HTAB= keyword of the DEV statement is used to specify where MFS should set horizontal tab stops before sending an output message.

MFS can insert tab control characters into the message to reduce the number of characters transmitted. To control when tab control characters are inserted, specify the ONLINE or OFFLINE operand for the HTAB= keyword. OFFLINE specifies that MFS insert the tab control characters during compilation of the control blocks by the offline MFS Language utility program. ONLINE specifies that MFS insert the control characters during online processing of the message. MFS can only be directed to insert tab control characters into messages that have legitimate fill characters specified (FILL=X'hh' or FILL=C'c' in the DPAGE statement), or use the default fill character, X'40'.

Specify OFFLINE when the message definition always supplies data to most defined device fields, or the fill character is not a blank. Specify ONLINE if some device fields do not receive data, or the data contains blanks. Even though the ONLINE specification increases MFS online processing, it reduces character transmission to the device.

Vertical tabbing

The VT= keyword of the DEV statement is used to specify where MFS should insert vertical tab control characters into the page of the output message. MFS assumes that the vertical tab stops are relative to line 1 and have been set at the device by the specification of the VTAB= keyword or other means prior to message transmission. VT= must be specified if vertical tabbing is required. There are no default values. VT= is invalid if page control specifications direct MFS to delete lines that contain no data after formatting. EJECT BGNMSG or EJECT BGNPP should be specified in conjunction with the VT= keyword to ensure proper alignment at the beginning of a page. A specification of VT= without a suitable EJECT operation defined can result in invalid device formatting.

Top and bottom margins

Top and bottom margins can be specified for printers specified as DEV TYPE=SCS1 by using the VTAB= keyword on the DEV statement. VTAB= is invalid if page control specifications (PAGE=n,FLOAT) direct MFS to delete lines that contain no data after formatting.

When used together, the page depth (PAGE=), vertical tab (VT=), and top and bottom margin (VTAB=) specify a set vertical format data stream.

Line density

For printers specified as DEV TYPE=SCS1, the density of lines on an output page can be specified with the SLDx= keyword on the DEV statement, the DFLD statement, or both. Line density can be set in terms of lines per inch or points per inch. If SLDx= is specified on both the DEV and DFLD statements, two SLD data streams are sent, one at the beginning of a message and one within the message, just before the field on which the SLDx specification, was encountered, but after any vertical tabs and new line characters. The SLDx specification within the message changes the line density from that set at the beginning of the message to that specified within the message. The line density specified within the message remains in effect until explicitly reset.