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Q86748: Windows: Virtual Printer Memory Defined

Article: Q86748
Product(s): Microsoft Windows 95.x Retail Product
Version(s): WINDOWS:3.1,3.11
Operating System(s): 
Keyword(s): 
Last Modified: 06-DEC-1999

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The information in this article applies to:

- Microsoft Windows versions 3.1, 3.11 
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SUMMARY
=======

The term "virtual memory" when used in connection with PostScript printers
actually refers to a portion of the physical RAM installed in the printer. This
type of printer memory is separate and distinct from the RAM memory on the
computer or the free disk space on the computer's hard disk that Windows 386
enhanced mode uses as its own type of virtual memory.

The following sections discuss the definition and description of printer virtual
memory, virtual memory settings in the Printers section of the Control Panel,
and sources of information about printer virtual memory.

MORE INFORMATION
================

Description of Printer Virtual Memory
-------------------------------------

The phrase "virtual memory" used in the context of PostScript printing describes
the way that the PostScript language uses certain segments of the printer's RAM
memory.

The PostScript usage of memory can be divided into two basic areas. The first
area is the area that is reserved for PostScript operations. This area includes
the PostScript interpreter and three of its stacks: the operand stack, the
dictionary stack, and the execution stack. The second area of memory, the
virtual memory, or VM, area, is the area in which the values for PostScript
composite objects are stored. PostScript objects are simply data, such as
numbers, booleans, strings, and arrays. A composite object may be an array,
dictionary, or string.

The interpreter and its stacks manipulate objects and composite objects during
the PostScript printing process. Therefore, the first area of memory may be
thought of as corrected overhead for operations. The second area of memory is
storage area for data that is dynamically adjustable through the Advanced
Options dialog box for PostScript printers (see below).

Virtual Memory Settings in Control Panel
----------------------------------------

After you install a PostScript printer driver in Windows 3.1, the Advanced button
will be available in the Options dialog box. (To access the Options dialog box,
run Control Panel, choose the Printers icon, choose the Setup button, and choose
the Options button.) If you choose the Advanced button, you will enter the
Advanced Options dialog box, which has a Memory group box in which you can set
the amount of PostScript printer virtual memory. The desired amount is entered
in the Virtual Memory (KB) box.

The default setting that appears in the Virtual Memory box is the one recommended
by the printer manufacturer. The default value is adequate in most cases.
However, when a document uses a large number of TrueType or soft fonts, it may
be useful to reduce the virtual memory setting so that the printer's memory is
cleared more often. This helps to prevent the printer's memory from being
overloaded with unused font information.

The Clear Memory Per Page option performs a similar function. With this option,
the printer's memory is cleared after each page is printed, and the fonts are
downloaded to the printer again. However, these settings have only limited
effectiveness in dealing with PostScript printing problems.

You can determine the actual amount of RAM memory (that is, "virtual memory") on
a PostScript printer by printing the TESTPS.TXT file in the WINDOWS directory.
Adding more physical RAM to the printer will allow you to increase the maximum
effective value in the Virtual Memory box.

Sources of Documentation
------------------------

Although page 334 of the "Microsoft Windows Resource Kit" guide for operating
system version 3.1 implies that more details exist concerning virtual printer
memory in chapter 4 ("Troubleshooting") of the "Getting Started with Microsoft
Windows" guide, no additional information specific to printer virtual memory
exists there. Nonetheless, the "To change a PostScript printer's options"
section on page 84 of the "Getting Started with Microsoft Windows" guide does
provide information about the Clear Memory Per Page check box. Other information
about virtual memory is found by choosing the Help button or by pressing F1
while the insertion point is in the Virtual Memory settings box.

REFERENCES
==========

"PostScript Language Reference Manual," Adobe Systems Inc., pages 18-19, 45-46,
Addison-Wesley, 1990

"Microsoft Windows Resource Kit" for Windows version 3.1, page 334

"Getting Started with Microsoft Windows," version 3.1, page 84

HELP.TXT, Windows version 3.1


Additional query words: vertial vertual random access memory printing fonts post-script post script

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Keywords          :  
Technology        : kbWin3xSearch kbZNotKeyword3 kbWin310 kbWin311
Version           : WINDOWS:3.1,3.11

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