LaserWriter ROMs: PostScript Versions Explained



I have some technical questions about different versions of PostScript:

1) I thought that LaserWriter ROM versions 1.0, 2.0, and 3.0 correspond to
versions 23, 38, and 47 of PostScript. However, in LaserWriter Plus
printers the ROM contains 42.2. What happened to 47.0?

2) Also, when extracting information from a printer, CE Software's Widgets
reports version 47.0 (1) for a LaserWriter IINT and a LaserWriter IINT
which was upgraded to a LaserWriter IINTX. It also reports 51.8 (3) for
a LaserWriter IINTX. What do the numbers in parentheses really stand
for?

3) What is the difference between 47.0 and 51.8?

Adobe Technical Support said that these versions are functionally
identical, which doesn't really answer my question.

1) There is a an error in the LaserWriter Plus ROMs that gives the version
number 42.2 if read from PostScript, even though the ROMs contain
Version 47 of PostScript.

PostScript version 47 is different than PostScript version 38 in the
following ways:

* It is slightly faster.

* It contained miscellaneous bug fixes.

* It added code to support SCSI hard disks (as in the LaserWriter
IINTX).

The Rev 47, PostScript-code-equipped LaserWriters can function up to 25
percent faster when printing text or up to 40 percent faster printing
bit-mapped graphics. PostScript version 38 is functionally equivalent to
PostScript version 47 except for the above details.

2) CE Software's Widgets 3.0.4 issues two PostScript commands to get the
"51.8(3)" from the LaserWriter IINTX with the latest ROMs. The first is
the "version" command. This command returns a string that identifies
the version of the PostScript language and interpreter being used. The
second is the "revision" command. This command returns an integer
designating the current revision level of the machine-dependent portion
of the PostScript interpreter.

3) PostScript version 51.8 allows for the following enhancements:

* The entire font list is no longer searched when looing for a font.
The search stops as soon as the font is found. This can save a lot of
time if there is a hard disk attached and the font is a ROM font.

* Full support of software switching between emulations and ports. It is
now possible to both switch into and out of an emulation mode via
software.

* Improved support of multiple SCSI disks. You can now connect up to 8
SCSI hard disk drives to the LaserWriter IINTX SCSI port. Up to 80
percent of the hard disk with the lowest SCSI ID is used for font
caching with the remainder of that disk and all of any other connected
hard disks used for downloaded fonts. Each hard disk is now formatted
as a separate volume, which lets a user move a disk (other than the
startup disk) between systems without needing to reformat.

* Additional characters in the HP Laser Jet+ emulation. Four characters
have been added that had been left out of the original implementation
of HP Laser Jet+ emulation.

* Improved default settings for HP Laser Jet+ bit map printing.
Previously, bitmaps in HP Laser Jet+ mode were interpreted at 7-bit,
thus ignoring a significant bit. The new ROMs default to 8-bit serial
communications.

Note: These new ROMs are in all LaserWriter IINTX printers with a part
number ending in 6004/A.


Published Date: Feb 18, 2012