ijpds formats.book - Kodak

Multiple-File (Very Large) Jobs
File Structure
Appendix D. Indexing and Multi-File IJPDS
Multiple-File (Very Large) Jobs
Multi-file jobs were designed to break the 2-gigabyte barrier of maximum
file size imposed by several factors in the implementation of the printing
system (and by NFS when that is the networking protocol). Multi-file jobs
may not change to the second file until after documents have begun to
appear in the data stream. You may not break the job until after all fonts
and fixed files have appeared.
For a duplex process color job (8 RIPs: CMKY front and CMKY back) this
allows a total of just under 2GB of total fonts in the job, or an average of
128MB per RIP (even though the RIP allows up to 256MB).
Break the job on a document boundary. That is to say, as you are
approaching 2GB (or whatever size at which you want to break) finish up
to the same document number for all RIPs, and then break. (No
document should exist partly on one file and partly on the next file.)
Stop at the end of a 4K block. Begin the next file with what would have
been the next 4K block if you were not splitting files. The next IJPDS
record must have the next cyclic count value after the last record in the
previous file. Do not repeat the JC2 in the subsequent files; do not end
the files before the last file with EOJ (End-Of-Job) records. The structure
should be such that if all the multiple files were concatenated together,
they would look like one (albeit too large) correctly-composed IJPDS job.
The system will keep looking for the next file any time it hits end-of-file
without an IJPDS EOJ record.
File Naming
If a job is named “ralph” then the multiple files are named ralph.a01,
ralph.a02, ralph.a03, etc. The filename extensions do not limit you to 99
files. It goes like this: .a01, .a02, .a03... .a98, .a99, .b00, .b01, .b02 ...
.b98, .b99, .c00, .c01, .c02 ... etc. Note the first file is .a01 but the bxx,
cxx, dxx, etc. files run from 00 through 99 (not 01 through 99).
Reference Guide D - 3