Re: [9fans] HP: Printing with the Illiterate

["J.R. Mauro" <jrm8005@gmail.com>]

On Fri, Aug 14, 2009 at 9:06 PM, Russ Cox<rsc@swtch.com> wrote:
> On Fri, Aug 14, 2009 at 5:37 PM, J.R. Mauro<jrm8005@gmail.com> wrote:
>> IJS is probably it; that's the PCL driver for the home-office class printers.
>
> IJS is not PCL.
>
> IJS is a custom protocol that is spoken between a bitmap-producing
> program like Ghostscript and a bitmap-printing program like /usr/bin/hpijs
> http://svn.ghostscript.com/ghostscript/branches/mtrender/ijs/ijs_spec.pdf
>
> /usr/bin/hpijs speaks IJS to Ghostscript (or whatever is on standard
> input/output) and speaks a new HP protocol called LIDIL to the printer
> on the other end.  Rather than commit to a full specification of LIDIL
> and have to worry about backwards compatibility in the future,
> HP chose to use IJS as a shim protocol and distribute a binary
> that talks to the printer (source is available but it's still a binary).
>
> PCL is not in the picture.  Getting PCL out of the picture is exactly
> the reason that IJS and LIDIL were introduced, because LIDIL is
> basically "here is a bitmap" whereas PCL is a real language that
> requires actual memory and computing power inside the printer.
> LIDIL moves the memory and computing requirements out of
> the printer into the computer proper.
>
> Russ
>
>

I thought IJS was also used to turn a raster into PCL, since IIRC some
non-business-class HP printers come with a stripped-down PCL 5e or
some such.

I'm probably wrong again, though. I try to not think about the HP PDLs
too much. Probably it's not IJS I'm thinking of and some other cruft
from HP -- it's been a long time.