🚀 go-pugleaf

In article <psikr01.726769901@convex>,
psikr01@convex.zdv.uni-tuebingen.de (Peter Kretschmar) requested
information on reading files fromn the LN03 and made a comment
about reading on an HP printer.

THE SHORT ANSWER:
What you want cannot be done. I don not know any "standard" PostScript
printers which can read files from their host systems. This would be
possible for certain network-connected printers (although I do not
know of any which implement this), and it would be easy for software-
based rips (e.g. CPSI from Adobe can do this).

THE LONG ANSWER:
The read operator in PostScript allows reading from a file which is
available to the printer. This includes two classes of files:
    1.) Attached disks or virtual disks. These can be internal or
        external. Many cartridges behave as read-only file systems.
        A few printers accept flash-ram cartridges which behave as
        read-write file systems. Software rips generally treat host
        file systems as attached disks.
    2.) I/O devices. currentfile is an operator which allows a
        PostScript program to read from the current job stream.
        On a level 2 printer, read can be issued against any port.
        The simple currentfile case is used commonly in PostScript,
        for example to read image data. The general case requires
        communication via multiple ports, with some manner of
        synchronization if it is to be used generally.

There are two main problems with implementing a printer which can
read from its host's file system:
    1.) Establish a communications protocol which is rich enough
        to allow file I/O. With network connections (at least TCP/IP,
        NETWARE, and Ethertalk over Ethernet, and Localtalk), this is
        possible, but a protocol must be chosen, and published, and
        some S/W must be written to take advantage of it. For serial
        connections, this is problematic, and for unidirectional
        parallel, impossible.
    2.) Establish conventions for file control. This includes file
        names, path names, record conventions, binary interpretation,
        and more esoterica (logical names in VMS, aliases on the Mac,
        translation of volume letters to network references on the PC,
        and so on). If you want to solve this problem in a general way,
        good luck! For simple cases, where the characteristics are
        tightly controlled, it would be easier, but not too useful.

I hope this clears things up, if only in a negative way.

Stephen Zisk (zisk@adobe.com)  Disclaimer: These are my personal views
Adobe Systems Incorporated     and do not represent the position of
Eastern Regional Office        Adobe Systems Incorporated.
24 New England Exec. Park
Burlington, MA 01803           They pay me but they don't muzzle me!