RE: Difference between AFPDS and IPDS

Allen,

What is confusing is that IPDS is the name of both a communication
protocol and a data stream.

*IPDS data stream printers are defined as TYPE(*IPDS) AFP(*NO) 
*AFPDS data stream printers are defined as TYPE(*IPDS) AFP(*YES)

The iSeries uses the IPDS protocol to talk to both types.

The IBM Printing V Redbook is a good source of details about this.

As far as your questions:

1) Does anyone have a good definition of the difference
between AFPDS and IPDS?

While it may not be 100% technically correct, I call the *IPDS data
stream a subset of the *AFPDS data stream.  Which makes it easier to get
across the idea that the *AFPDS data stream can do everything the *IPDS
data stream can do plus a lot more.

2) When should IPDS be used instead of AFPDS to create
printer devices and spooled files?

Never ;-)
Assuming PSF/400 is available and the printer can handle the *AFPDS data
stream, then you are always better off using *AFPDS.  Plus, as you've
found out the iSeries Host Print Transform (HPT) can transform the
*AFPDS datastream into a ASCII stream compatible with ASCII laser
printers.  HPT can't transform *IPDS data streams.  Note that while
PSF/400 is required for a printer defined TYPE(*IPDS) AFP(*YES), it is
not required to use HPT to print *AFPDS data streams to ASCII printers.
In addition, while PSF/400 is not required to print to a twinax
connected printer defined TYPE(*IPDS) AFP(*NO), HPT is required to print
to the same printer connected via the LAN instead of twinax.

From the Redbook mentioned above:

"The IPDS data stream generated by the AS/400 system (when the printer
file
device type parameter is set to *IPDS) is not the full IPDS data stream.
Many
functions are not included in this subset, including the use of external
resources
such as fonts or page segments.

The IPDS data stream generated by Print Services Facility/400 (PSF/400)
includes the full IPDS set of commands and supports a two-way dialog
between
PSF/400 and the printer

The AS/400-generated IPDS is supported by the print writer or
transformed to full
IPDS by PSF/400. AS/400-generated IPDS cannot be transformed to an ASCII
data stream and can only be sent to another AS/400 system. For more
information, see 1.6.2, "IPDS spooled files" on page 24. Because of
these
restrictions, we recommend using device type *AFPDS in place of *IPDS in
the
printer file to allow portability, more conversion possibilities, and
full IPDS
support."

HTH,

Charles Wilt
--
iSeries Systems Administrator / Developer
Mitsubishi Electric Automotive America
ph: 513-573-4343
fax: 513-398-1121
  

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx 
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Allen
Sent: Wednesday, August 02, 2006 7:47 PM
To: MIDRANGE-L@xxxxxxxxxxxx
Subject: Difference between AFPDS and IPDS

Back in the old days (system 36) I used a subroutine subr50
to create IPDS files on the system 36, 38 and AS400
for creating forms and adding graphics to spooled files.

At some point IBM introduced AFP into the midrange world,
and now there are many references to IPDS and AFPDS
and sometimes these terms are interchanged (incorrectly). I
speak to many clients that reference AFP spooled files as
IPDS spooled files and visa versa. 
IPDS and AFP are not the exact same thing.
There are printers that support IPDS and AFP data streams
There are printers that support APFDS data streams but do
not support IPDS data streams.
On the CRTPRTF command you can specify either *AFPDS or
*IPDS.
Some times a printer device description is configured as
Advanced Function Printing *Yes sometime *NO and many times
they will both work sometimes this will cause problems
printing
 
I was asked more then once what is the difference and I
always struggle to explain to a client what the exact
difference is. 
I have had customers that wanted to convert their "AFP"
spooled files to PDF and the program they were using would
not convert them. Come to find out their "AFP" spooled files
were actually IPDS spooled files, changing them to AFP
spooled files (Advanced Function Printing = *YES) and they
convert fine.

My belief has been that IPDS exists only for backward
compatibility and most if not all new software would be
written using AFPDS rather then IPDS except that there are
some programmers that do not understand the difference and
that they should be specifying AFPDS. 

My questions:
1) Does anyone have a good definition of the difference
between AFPDS and IPDS?
2) When should IPDS be used instead of AFPDS to create
printer devices and spooled files?


Allen




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