[Simh] DECWRITE backup set pt 2

[Timothe Litt]

Thinking about DPS some more (was never a mainline thing for me), a few
memories surfaced:

You can go back to VMS 7.2 & either run  there or more the library to 7.3.

But that's just the client side.  The DPS interpreter goes in the X
server (where the display is);
its an 'X extension'.

I don't know that there's a current X server that still includes it.  It
is complicated, ugly and
Adobe licensing was involved.

There may be a ghostscript based extension that will do it, but you'll
have to hunt down a
version of the server that supports/can be built with it.  It looks like
most of the servers
dropped DPS support quite a while ago.

Alternatively, VMS 7.2 with a local graphics card should work, as
DECwindows of that time
included the DPS extension in its server.

SimH has some graphics card support - but I've never played with it, so
I don't know what
luck you'll have that way.

You're going to have the same issue with Alpha; that's not an escape clause.

DPS was a clever idea - basically postscript was the way to get dots
formed on a laser printer
in a typographically sane fashion.  But it was based on the idea that
one composed one
page at a time.  DPS extended the engine so you could have multiple
active composing contexts
(e.g. one per window!).  I think it also allowed for composing partial
pages (clipping to the
visible portion).

The clever part was that this meant that you  could have a real WYSIWUG
(what you saw is
exactly what you got:-) editor.  Unlike now, when what I see in a brower
never prints the
same - because of the layers of different print renderers that are
attached to devices. 

DEC licensed the interpreter from Adobe (as it did for the one in the
LPS series
printers).  I don't think we had a big role in its development; Steve
Jobs apparently
did when he was in exile at NeXT.

I think the complexity and performance killed DPS.  Also, applications
(e.g. DECwrite)
use it via X11, which windoze displaced.  It came fairly late in the
evolution of X.
So there wasn't a huge application base.  PDF is the logical successor.

This from my recollection of conversations with the hardcopy and
workstation groups,
and a little archaeology.  As I say, this wasn't a mainline issue for
me; I touched on it
in terms of how to extract text for assistive technologies.  So this may
not be 100%
accurate.



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