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danr63796688
danr63796688
Participant
October 28, 2015
Question

Fout and .img in PostScript?

  • October 28, 2015
  • 1 reply
  • 1540 views

I get PS files from a client that Distiller (or any third-party utility) can't convert to PDF. Where everything seems to choke is at a line that reads

/Fout (XSFT47.img) (w) file d Fout iData writestring /iData 0 string d Fout flushfile Fout closefile

The number in front of .img changes from file to file (ie FXFTxx.img where xx can be almost any number), but the results are always the same. Any idea as to what's happening here or why? Distiller crashes and says that the error starts with Fout. Just for fun I ran one of these files through GhostScript and it ended up writing an XSFTxx.img file do my desktop. Why on earth is this part of the PS and what possible purpose could it serve?

Thanks in advance

Dan

This topic has been closed for replies.

1 reply

T
Test Screen Name
Legend
October 29, 2015

Does Distiller crash, or does it just give an error? I'd expect an error. This PostScript is indeed trying to write to your hard disk, and this has been blocked for many years by any security-conscious computer-based PostScript. I'd expect a specific one word error code, and then a stack dump with the filename in it.

Why is it part of PostScript? Originally designed for use only inside printers. Printers could sometimes have hard drives to be used for fonts and stuff. This was how they got onto the hard disk. So, intended for special purposes.

Why is the PostScript doing this? My guess is it is writing a file once, and then using it as an overlay, stamp or whatever multiple times, or pass a file to a subsequent job. This was very hard to do in older versions of PostScript, writing files was the easiest way.

J
jdeubert
Participating Frequently
October 29, 2015

With regard to why the file operators exist in PostScript, a bit of history is probably called for.

When Adobe was first designing PostScript, they wanted it to be a full programming language, capable of doing everything any other language could do. (I was at Adobe at the time, by the way; my employee number was 19. It's been a while.)

Thus, the language needed to be able to work with files. The file operator implementation had no real use in printer-installed PostScript at the time, since no printers had hard disks yet. (The same could be said of all the color operators, since color laser printers didn’t come on the market until ’87 or ’88.)

The disk operators became—and remain—very important to people who do variable-data printing. It allows them to stash frequently-used PostScript code and other data (such as image data) on the printer’s hard disk and then execute them from there, rather than embedding that code in each of the 3 million pages that make up the print job.

- John

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John Deubert

Acumen Training

PostScript and PDF

Training and Consulting

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