danno@3b2.UUCP (Daniel Notov) (10/19/88)
I hope I'm missing the obvious on this one.
Cast of characters:
AT&T 3B2/400 UNIX SVR3.1 and/or AT&T 6386E 386/UNIX SVR3.1
Texas Intruments Omnilaser 2115
The TI OMNILASER is a postscript printer that also has HP LaserJet+
Emulation. Mode selection can be controlled via PS and HP commands.
I have set up my interface file to swtich into the mode wanted via command
line options. The problem occurs when the file has spooled out to the
printer the printer is still processing, and the next job is sent down
the line.
The next job is stored in its buffer, but when the printer changes modes,
it may lose that info. To combat this problem, I inserted sleep's in the
script at the beginning when I change modes, and at the end when the file
has completed despooling. The first sleep is O.K. because I know
approximately how long it takes to change modes. The ending sleep is n.g.
because, I do NOT know when the job has completed processing.
Playing with cu, I discovered that a ^T <CNTRL-T> causes the printer to
echo the following:
1) In postscript mode, job status:
%%[status: busy; source: serial 25]
or
%%[status: idle]
2) In LaserJet mode, the printer echos nothing. The ^T's are
discarded, and don't interfere with the text being printed.
My idea:
After the file is despooled, and the reset sequences are sent,
periodically poll the printer by sending ^T's. My question, how
do I capture the messages echoed back by the printer? Once I get
it, I can guess on the the following states:
1) Captured: nothing; still processing LaserJet Job
2) Captured: %%[...busy...]; still processing PS Job
3) Captured: %%[...idle...]; all processing complete, exit script.
Sorry for rambling at length. I wanted to get all the facts in. Please e-mail
any responses. I'll summarize if the volume warrants.
Tx.
danno
--
Daniel S. Notov | {monster,uunet}!onm3b2!danno
Ogilvy & Mather, Inc. | (212) 907-4255
New York, NY | robert@shangri-la.gatech.edu (Robert Viduya) (10/20/88)
>danno@3b2.UUCP (Daniel Notov) (danno@3b2.UUCP, <288@3b2.UUCP>): > > I hope I'm missing the obvious on this one. > > Cast of characters: > AT&T 3B2/400 UNIX SVR3.1 and/or AT&T 6386E 386/UNIX SVR3.1 > Texas Intruments Omnilaser 2115 > > The TI OMNILASER is a postscript printer that also has HP LaserJet+ > Emulation. Mode selection can be controlled via PS and HP commands. > > I have set up my interface file to swtich into the mode wanted via command > line options. The problem occurs when the file has spooled out to the > printer the printer is still processing, and the next job is sent down > the line. I've not had any experience with the TI, but I've played with LaserWriter Plus's and IINTX's and I think the solution I'm about to present works with all PostScript printers. I remember reading about this trick in the Red Book, but I'm not sure if it was in the generic language description or in the LaserWriter specific appendix. Anyway, try it and see if it works. A job sent over to the laser printer via the serial line should be terminated with a EOT (control-D). When the printer receives the EOT, it knows that it's got the whole job and when it has completely finished processing and printing that job, it will echo that EOT back to the host. This means that all the host machine has to do to ensure that the printer has finished printing a job before sending another one is: 1. Send a job. 2. Send an EOT terminating job. 3. Wait for the EOT to be echoed back from printer. 4. Repeat from step one. As an example, here's a bit of code I wrote that's part of a LaserWriter driver for a spooling package. The function send_file takes two file descriptors as arguments, the first being the file to send and the second being a file to write any data sent from the printer to the host. The global tty_file is the file descriptor of the tty line attached to the printer. send_file (src_file, result_file) int src_file, result_file; { char ch; int chpid; bool done; /* * fork. The parent process sends the file to the printer, * followed by an EOT. It then hangs around and waits for the * child to finish. The child simply reads characters from the * printer and stuffs them in the result file until it gets an * EOT. It then terminates and the parent is notified and is * allowed to procede. */ switch (chpid = fork ()) { case -1: syslog (LOG_NOTICE, "fork() - %m"); exit (EXIT_RETRY); case 0: /* child - tty input -> result_file */ ch = '\0'; do{ if (read (tty_file, &ch, 1) == 1) (void) write (result_file, &ch, 1); } while (ch != '\004'); /* ^D is eof indicator */ exit (EXIT_OK); /* wake parent up */ default: /* parent - src_file -> tty output */ done = FALSE; while (!done) { switch (read (src_file, &ch, 1)) { case 1: (void) write (tty_file, &ch, 1); break; case 0: (void) write (tty_file, "\004", 1); /* send EOT */ done = TRUE; break; default: syslog (LOG_NOTICE, "read(%s) - %m", data_fn); exit (EXIT_RETRY); } } (void) wait ((int *) 0); /* wait for child */ break; } } Hope all this helps... robert -- Robert Viduya robert@shangri-la.gatech.edu Office of Computing Services Georgia Institute of Technology (404) 894-6296 Atlanta, Georgia 30332-0275