Explanation of Computer Output Reduction (COR) and Options to Circumvent It

Resolving The Problem

This document provides an explanation of Computer Output Reduction (COR) and lists options to circumvent COR processing.

This document was last updated on 26 December 2013.

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What Is Computer Output Reduction (COR) Processing?

Computer Output Reduction (COR) is the operating system function where spooled files with certain attributes can be rotated 90 degrees and the font condensed so that the output will fit the page. The attributes that affect this are: Page Size, Lines Per Inch, Characters Per Inch, and Page Rotation. If the attributes of the spooled file are for a logical page that is larger than the physical page, then COR may occur. The default page size used by this function is letter size (11" x 8.5").

Spooled File Attributes That Support COR Processing

An example of operating system spooled file attributes that can cause COR:

Note: These parameters are on different screens.

Printer device type  . . . . . . . . . :  *SCS
     Page size:
      Length . . . . . . . . . . . . . . . :  66
      Width  . . . . . . . . . . . . . . . :  132
      Measurement method . . . . . . . . . :  *ROWCOL
    Lines per inch . . . . . . . . . . . . :  6
    Characters per inch. . . . . . . . . . :  10
     Overflow line number . . . . . . . . . :  60
    Font:
      Identifier . . . . . . . . . . . . . :  *CPI
      Point size . . . . . . . . . . . . . :  *NONE
    Page rotation  . . . . . . . . . . . . :  *AUTO

A few examples of the system-supplied printer files with these attributes are: QSYSPRT (for print screens ), QPJOBLOG (for job logs), and QPQUPRFIL (for Query/400). To determine the attributes of a spooled file, do the following:

Type the WRKSPLF or WRKOUTQ outq_name command, then select Option 8 Attributes on the spooled file, and page down for the information. The Device File parameter is the name of the printer file that is used to create the spooled file.


How COR Processing Is Handled by Host Print Transform (HPT)

Computer Output Reduction (COR) is handled differently by Host Print Transform (HPT) than by IBM Print Services Facility/400 (PSF/400). HPT is used when printing on ASCII laser printers through a *LAN 3812 device description, a Remote Output Queue (RMTOUTQ), and sometimes when printing through a PC5250 printer session. PSF/400 is used when printing on an IPDS (or Intelligent Printer Data Stream) laser printer when the Advanced function printing (AFP) parameter is set to *YES. AFP(*YES) is optional for most twinax-attached IPDS printers but is required when printing to a LAN attached IPDS printer through a *LAN *IPDS device description. For more information on printing to IPDS laser printers, refer to the section entitled "How COR Processing Is Handled by Print Services Facility/400 (PSF/400)" below.

When the Degree of page rotation (PAGRTT) parameter in the spooled file attributes is *AUTO or *DEVD:

o	If the page width is less than or equal to 8.5 inches, the output prints in portrait.
o	If the page width is greater than 8.5 inches, the output prints in landscape on ASCII laser printers and specific HP DeskJet printers but prints in portrait on all other printers.
o	If the page length is less than 8.5 inches, Host Print Transform (HPT) will not perform Computer Output Reduction (COR) processing.
o	If the page size is *CONT80, or if using a Remote Output Queue (RMTOUTQ) that has a MFRTYPMDL setting for a narrow-carriage line printer, the Characters per Inch (CPI) is compressed if the page width is greater than 8.0 inches or 80 columns so it will fit on narrow-carriage dot matrix and line printers.
o	If the page size is *CONT132, or if using a Remote Output Queue (RMTOUTQ) that has a MFRTYPMDL setting for a wide-carriage line printer, the CPI is not compressed since output will typically fit on wide-carriage dot matrix and line printers without compression. The LPI will not be compressed for narrow-carriage or wide-carriage dot matrix and line printers.
o	For other page sizes, for example *LETTER or *LEGAL, if the page width is greater than 8.5 inches, then the Characters per Inch (CPI) and Lines per Inch (LPI) are compressed to fit on ASCII laser printers and specific HP DeskJet printers without truncation.
o	The Characters per Inch (CPI) is compressed on ASCII laser printers and certain HP DeskJet printers as follows: - 10 CPI fonts print at 17.1 CPI, depending on the settings in the Set Characters Per Inch in COR Mode (CPICOR) tag for CPI=10 (if there is one). - 12 CPI fonts print at 17.1 CPI, depending on the settings in the Set Characters Per Inch in COR Mode (CPICOR) tag for CPI=12 (if there is one). - 15 CPI fonts print at 20 CPI, depending on the settings in the Set Characters Per Inch in COR Mode (CPICOR) tag for CPI=15 (if there is one). - For all other fonts, Host Print Transform (HPT) used to typically print at 13.3 CPI but now will perform its own best fit processing to select the font based on the page size.
o	The Characters per Inch (CPI) is compressed to 15 or 17.1 CPI on narrow-carriage dot matrix and line printers.
o	Page size is set to 11 by 8.5 inches on ASCII laser printers and specific HP DeskJet printers.
o	*AUTO is supported only for spooled files with device type of *SCS, *IPDS, or *AFPDS that are created on the IBM OS/400 or IBM i5/OS. *AUTO is not supported for files with a device type of *USERASCII, *LINE, *AFPDSLINE, or *AFPDS that are not created on an OS/400 or i5/OS.
o	Unpredictable results can occur when page rotation = *DEVD, so this setting is not recommended. If a printer file has PAGRTT(*DEVD) specified, it is strongly recommended that it be changed to *AUTO, *COR, 0, 90, 180, or 270.
o	Do not specify FONT(*DEVD) when using PAGRTT(*DEVD) because the system cannot determine the exact page width. Therefore, the page positioning might not be as intended.
o	If any of the Device Requirements fields are set to Y, COR might not occur.

When the Degree of page rotation (PAGRTT) parameter in the spooled file attributes is *COR:

o	The output prints in landscape on ASCII laser printers and specific HP DeskJet printers but prints in portrait on all other printers.
o	The Characters per Inch (CPI) are compressed on ASCII laser printers and specific HP DeskJet printers as follows: - 10 CPI fonts print at 17.1 CPI. - 12 CPI fonts print at 17.1 CPI. - 15 CPI fonts print at 20 CPI. - All other fonts typically print at 13.3 CPI although there are some exceptions.
o	If the page size is *CONT80 or *CONT132, or if using a Remote Output Queue (RMTOUTQ) that has a MFRTYPMDL setting for a narrow-carriage or wide-carriage line printer, the Characters per Inch (CPI) is compressed. The Characters per Inch (CPI) are compressed to 17.1 if the printer hardware is setup to use IBM Proprinter or 15 CPI if the printer hardware is setup to use Epson emulation.
o	Page size is set to 11 by 8.5 inches on ASCII laser printers and specific HP DeskJet printers.
o	If the spooled file is created on OS/400 or i5/OS as device type *AFPDS and it has any of the Device Requirements fields set to Y, COR might not occur.
o	*COR is not supported for spooled files with a device type of *USERASCII, *LINE (if the spooled file is sent to a printer configured with AFP(*YES)), *AFPDSLINE, nor *AFPDS (if the spooled file was not created on OS/400 or i5/OS).

When the Degree of page rotation (PAGRTT) parameter in the spooled file attributes is 0, 90, 180, or 270 degrees:

o	COR is not performed. The correct page size should be specified in the printer file to ensure that text is not truncated.

When the Degree of page rotation (PAGRTT) parameter in the spooled file attributes is *DEVD:

o

Setting the Degree of page rotation (PAGRTT) parameter to *DEVD is not recommended because it can behave differently depending on whether the spooled file is printed with Host Print Transform (HPT) or printed on an IPDS-capable printer using Print Services Facility/400 (PSF/400). HPT treats PAGRTT(*DEVD) much the same as PAGRTT(*AUTO), so it would enable COR processing regardless of the print quality, but IPDS printers look at the print quality to help determine whether Computer Output Reduction (COR) processing should be performed. For example, HPT treats PAGRTT(*DEVD) much the same as PAGRTT(*AUTO), so it would enable COR processing whether with Draft Quality or Near-Letter Quality (NLQ). On the other hard, specifying PAGRTT(*DEVD) with Draft Quality would enable COR processing, but specifying PAGRTT(*DEVD) with Near-Letter Quality (NLQ) would not enable COR processing. Therefore, to ensure that spooled files print consistently between printing with HPT and printing with PSF/400, generating spooled files with the Degree of page rotation (PAGRTT) parameter set to *DEVD should be avoided.

There are some exceptions to this:

o	Narrow carriage printers that cannot print landscape print portrait in a condensed font.
o	Wide carriage printers print portrait with the CPI listed in the spooled file attributes.
o	If Host Print Transform (HPT) is used, it reduces 10 CPI to 17 CPI, 12 CPI to 17 CPI, and 15 CPI to 17 CPI or 20 CPI.
o	Host Print Transform (HPT) does not perform COR processing on *AFPDS spooled files. If an *AFPDS spooled file is set up with the Degree of page rotation (PAGRTT) parameter set to *AUTO or *COR and is printed using HPT, the AFPDS-to-ASCII Transform code within HPT prints the spooled file in portrait without compressing the font.

Note: Newer MFRTYPMDL settings and system-supplied Workstation Customizing Objects (WSCSTs) are set up without any CPI in COR Mode (CPICOR) tags whatsoever. This causes HPT to perform a type of "Best Fit" function. For example, if using *LEXOPTRAT, *INFOPRINT1140, or their corresponding WSCST objects (QWPLEXOPT or QWPIP1200), 132 columns spooled files that print using COR will print at about 13.3 CPI rather than the usual 17.1 CPI. This same result can be achieved by creating a modified WSCST object where the CPICOR tags have been removed.


How COR Processing Is Handled by Print Services Facility/400 (PSF/400)

Computer Output Reduction (COR) is handled differently by Print Services Facility/400 (PSF/400) than by Host Print Transform (HPT). PSF/400 is used when printing on an IPDS (or Intelligent Printer Data Stream) laser printer when the Advanced function printing (AFP) parameter is set to *YES. AFP(*YES) is optional for most twinax attached IPDS printers but is required when printing to a LAN attached IPDS printer through a *LAN IPDS device description. HPT is used when printing on ASCII laser printers through a *LAN 3812 device description, a Remote Output Queue (RMTOUTQ), or sometimes when printing through a PC5250 printer session. For more information on printing to ASCII laser printers, refer to the section entitled "How COR Processing Is Handled by Host Print Transform (HPT)" above.

When the Degree of page rotation (PAGRTT) parameter in the spooled file attributes is *AUTO:

o	If the page width is not greater than the page length, the output prints in portrait.
o	If the page width is greater than the page length, the output prints in landscape.
o	If the page width and page length are both greater than 8.5 inches or if either the page width or page length is greater than 14.0 inches, the Characters per Inch (CPI) and Lines per Inch (LPI) will be compressed and print in landscape. Note: If the page width is greater than 8.5 inches but the page length is exactly 8.5 inches, the spooled file will print in landscape without compressing the CPI or LPI. That causes spooled files to truncate any text going past the page width. For example, a spooled file set up for Page size (PAGESIZE) parameter = 68 lines x 132 columns, Lines per Inch (LPI) = 8, Characters per Inch (CPI) = 10, Font identifier (FONT) parameter = *CPI, and Degree of page rotation (PAGRTT) parameter = *AUTO will print in landscape but at 10 CPI because the page length = 68 lines / 8 LPI = 8.5 inches.
o	If the Characters per Inch (CPI) is compressed, they are compressed as follows: - 10 CPI fonts print at 13.3 CPI. If no 13.3 CPI font is available, it prints at 15 CPI. - 12 CPI fonts print at 15 CPI. - 15 CPI fonts print at 20 CPI. - All other fonts typically print at 13.3 CPI unless a 13.3 CPI font is not available. In this case, they print at 15 CPI. Note: If your spooled files are printing at 13.3 CPI when printing to an IPDS printer but the font is a bit too small, try generating the spooled file with the Font identifier (FONT) parameter set to either font 400 (Gothic) or font 304 (Gothic Text) and with a pointsize of 9, since the Gothic and Gothic Text are taller than other typefaces. For example, "FONT(400 9)" or "FONT(304 9)". For more information, refer to the following KB document: N1010119: List of Default Font IDs Based on Font Range
o	*AUTO is supported only for spooled files with device type of *SCS, *IPDS, or *AFPDS that are created on the OS/400 or i5/OS. It is not supported for files with a device type of *USERASCII, *LINE, *AFPDSLINE, or *AFPDS that are not created on an OS/400 or i5/OS.
o	Unpredictable results can occur when page rotation = *DEVD, so this setting is not recommended. If a printer file has PAGRTT(*DEVD) specified, it is strongly recommended that it be changed to *AUTO, *COR, 0, 90, 180, or 270.
o	Do not specify FONT(*DEVD) when using PAGRTT(*DEVD) because the system cannot determine the exact page width. Therefore, the page positioning might not be as intended.
o	If any of the Device Requirements fields are set to Y, COR might not occur.

When the Degree of page rotation (PAGRTT) parameter in the spooled file attributes is *COR:

o	Output is rotated 90 degrees.
o	Page size is set to 11 by 8.5 inches.
o	The Characters per Inch (CPI) will be compressed as follows: - 10 CPI fonts print at 13.3 CPI. If no 13.3 CPI font is available, it prints at 15 CPI. - 12 CPI fonts print at 15 CPI. - 15 CPI fonts print at 20 CPI. - All other fonts typically print at 13.3 CPI unless a 13.3 CPI font is not available. In this case, they print at 15 CPI.
o	If the spooled file is created on OS/400 or i5/OS as device type *AFPDS and it has any of the Device Requirements fields set to Y, COR might not occur.
o	*COR is not supported for spooled files with a device type of *USERASCII, *LINE (if the spooled file is sent to a printer configured with AFP(*YES)), *AFPDSLINE, nor *AFPDS (if the spooled file was not created on OS/400 or i5/OS).

When the Degree of page rotation (PAGRTT) parameter in the spooled file attributes is 0, 90, 180, or 270 degrees:

o	COR is not performed. The correct page size should be specified in the printer file to ensure that text is not truncated.

When the Degree of page rotation (PAGRTT) parameter in the spooled file attributes is *DEVD:

o

Setting the Degree of page rotation (PAGRTT) parameter to *DEVD is not recommended because it can behave differently depending on whether the spooled file is printed on an IPDS-capable printer using Print Services Facility/400 (PSF/400) or printed with Host Print Transform (HPT). IPDS printers look at the print quality to help determine whether Computer Output Reduction (COR) processing should be performed, but HPT treats PAGRTT(*DEVD) much the same as PAGRTT(*AUTO), so it would enable COR processing regardless of the print quality. For example, specifying PAGRTT(*DEVD) with Draft Quality would enable COR processing, but specifying PAGRTT(*DEVD) with Near-Letter Quality (NLQ) would not enable COR processing. On the other hard, HPT treats PAGRTT(*DEVD) much the same as PAGRTT(*AUTO), so it would enable COR processing whether with Draft Quality or Near-Letter Quality (NLQ). Therefore, to ensure that spooled files print consistently between printing with PSF/400 and printing with HPT, generating spooled files with the Degree of page rotation (PAGRTT) parameter set to *DEVD should be avoided.

There are some exceptions to this:

o	IPDS line printers always print in portrait.
o	IPDS line printers do not print in a compressed font.

Options to Circumvent COR Processing

If you do not want the spooled file to COR, there are several options to prevent it. These options include changing or overriding the printer file, using a workstation customizing object in the device description or remote output queue description, or specifying a different size paper for the drawer or paper source parameters to make the operating system think the printer has wider paper. This last option is only for dot matrix printers.

PC5250 printer sessions have options other than customizing for HPT including customizing a PDF file or using the BestFit feature.

Caution: These instructions are provided as is. Any assistance with editing the Workstation Customization Table or the PDF is done only with a consulting agreement.

Option 1: Changing or Overriding the Printer File to use Settings that will not COR

One option is to create, change, or override the printer file to have attributes that will not COR. The idea is to generate the spooled file using a combination of settings for the Page size (PAGESIZE), Lines Per Inch (LPI), Characters Per Inch (CPI), Font identifier (FONT), and Degree of page rotation (PAGRTT) parameters that will prevent the need for printing using Computer Output Reduction (COR). This can typically be accomplished by either using the Change Printer File (CHGPRTF) command to change the values in the printer file or using the Override with Printer File (OVRPRTF) command in an application or a CL program to overridge the settings in the printer file.

Suggestions for avoiding Computer Output Reduction (COR):

o

The Degree of page rotation (PAGRTT) parameter affects the orientation of the output. Generating a spooled file with PAGRTT(0) or PAGRTT(180) will force the output to print portrait and generating a spooled file with PAGRTT(90) or PAGRTT(270) will force the output to print in landscape, regardless of the PAGESIZE, LPI, CPI, and FONT parameters. This will also force the spooled file to print using the specified CPI since Computer Output Reduction (COR) processing is not performed when the page rotation is explicitly set to 0, 90, 180, or 270. However, this could cause the output to wrap or truncate if the output extends beyond the border of the paper.

o

When the Degree of page rotation (PAGRTT) parameter is set to *AUTO or *DEVD, COR processing is still dependent on the paper width and the paper length. The paper width is calculated to be the page width (in columns or characters) divided by the Characters Per Inch (CPI) and the paper length is calculated to be the page length (in rows or lines) divided by the Lines Per Inch (LPI). For example: PAGESIZE(66 132 *ROWCOL) LPI(6) CPI(10) would have a page size 13.2 x 11.0 inches, since 132 columns at 10 CPI is 13.2 and 66 lines at 6 LPI is 11.0, which means that COR processing may be performed PAGESIZE(66 85 *ROWCOL) LPI(6) CPI(10) would have a page size of 8.5 x 11.0 inches, since 85 columns at 10 CPI is 8.5, which means that COR processing will not be performed PAGESIZE(66 132 *ROWCOL) LPI(6) CPI(16.7) would have a page size of 7.9 x 11.0 inches, since 132 columns at 16.7 CPI is 7.9, which means that COR processing will not be performed

For more information, refer to the following documents:

N1019453: Drawer Selection Considerations
N1018309: Forcing Spooled Files to Print in Portrait by Changing a Printer File and/or Application

Note: This is also the only option available when printing to an IPDS printer since the other options involve creating a modified Workstation Customizing Object (WSCST), which are only supported with Host Print Transform (HPT).

Option 2: Using a Workstation Customizing Object (WSCST) to force SPLFs to Print in Portrait instead of COR

Another option is to customize HPT for portrait orientation or for font reduction. Customizing for portrait orientation will force all spooled files sent to that writer to print portrait even if the spooled file attributes are for landscape, but the font might still be condensed. Customizing for font reduction will cause it to use the CPI in the spooled file attributes or to reduce the size of the font depending upon what you want to change in the customizing object.

The following document explains how to customize in Portrait orientation, and how to customize 10 CPI to print at 12 CPI, 12 pi to print at 15 CPI, and 15 CPI to remain 15 CPI, or to not reduce.

N1010170: Forcing Spooled Files to Print in Portrait instead of COR Using Host Print Transform (HPT)

The following two documents are for printing landscape but customizing to condense the font. The first document gives an example for HP LaserJet 4 to condense 10 CPI to 13.3 CPI, 12 CPI to 15 CPI, 15 CPI to 20 CPI. The second document includes CPICOR tag information for 10 CPI, 12 CPI, 13 CPI, 13.3 CPI, 15 CPI, and 20 CPI.

N1018530: Controlling the Font that Host Print Transform (HPT) Selects when Performing Computer Output Reduction (COR)
N1010135: Computer Output Reduction (COR) Font Control

Note: This option is not available when printing to an IPDS printer since it involves creating a modified Workstation Customizing Object (WSCST), which are only supported with Host Print Transform (HPT).

Option 3: Not Condensing on Dot Matrix Printers by Specifying 13.2 inch Wide Paper

If the spooled file attributes have Page Size of Width = 132 and CPI = 10, the width of the paper the OS/400 or i5/OS is calculating is 13.2 inches. For dot matrix printers, another option is to make the OS/400 or i5/OS believe the printer has 13.2-inch wide paper by using Host Print Transform with Paper Source 1 set to *CONT132 in the device description. In PC5250 printer sessions, use HPT with Drawer 1 set to Continuous Forms (13.2 inches). In remote output queues, use HPT with MFRTYPMDL *WSCSTCONT132 with the appropriate workstation customizing object for the type of printer being used.

N1018026: Files Print Condensed to Dot Matrix Printers Using Host Print Transform

Note: This option is not available when printing to an IPDS printer since it involves creating a modified Workstation Customizing Object (WSCST), which are only supported with Host Print Transform (HPT).

Option 4: Using a Printer Definition Table (PDT) File or Best Fit Scaling in a PC5250 Printer Sessions

In addition to using a workstation customizing object for HPT, PC5250 printer sessions have two additional options for controlling the output: customize a PDF file to create a PDT or turn on the BestFit option. PC5250 provides PDF files for some printers that can be modified for CPI, LPI, and font ID. If using the Microsoft Windows driver, the BestFit feature can be used to print 198 characters in landscape at 20 CPI. The page rotation must be set to *AUTO. BestFit can also be used for spooled files that are printing too small with extra white space to make the output fill the page.

N1010085: Printing 132 Characters in Portrait Using Printer Definition File (PDT)
N1010118: Printing 198 Characters at 20 CPI Using Printer Definition File (PDT)
N1010105: Using Best Fit Scaling with PC5250 Printer Sessions

Note: This option is not available when printing to an IPDS printer since it involves creating a modified Workstation Customizing Object (WSCST), which are only supported with Host Print Transform (HPT).

References

For more information, refer to the following manuals and Rochester Support Center knowledgebase documents:

Printer Device Programming manual (SC41-5713-01)
IBM OS/400 Printing series IBM Redbooks

N1010140: Instructions for Modifying a Workstation Customizing Object (WSCST)

N1018530: Controlling the Font that Host Print Transform (HPT) Selects when Performing Computer Output Reduction (COR)
N1010135: Computer Output Reduction (COR) Font Control
N1019581: Selecting 16.67 CPI Instead of 17.1 CPI for Printers that Don't Support Scalable Fonts
N1010132: Printing at 20 Characters Per Inch (CPI) on Older HP LaserJet Compatible Printers

N1010138: Breakdown of HP PCL5 Font Strings
N1010125: Manipulating Line Spacing

N1010288: Using Host Print Transform (HPT) with a *LAN Device Description
N1019713: Using Host Print Transform (HPT) with a Remote Output Queue (RMTOUTQ)
N1019712: Using Host Print Transform (HPT) with a *LCL or *RMT Device Description
N1019470: Using Host Print Transform (HPT) with a PC5250 Printer Session
N1019670: Using Host Print Transform (HPT) with a Third Party Emulation Package