hart@cp1.UUCP (rod hart) (10/25/85)
When printing out a document on the inital print only a half page is printed and the rest of the document is lost. I have checked the print buffer for non printable characters and have not found any characters that could be shuting off the printer or truncating the document. Please contact Al Greene on (301) 236-8029 between 8:30am and 500pm, monday thru friday.-- =========================================================================== Signed by: Rod Hart (WA3MEZ) Minicomputer Technical Support District Chesapeake & Potomac Tel. Co. A Bell Atlantic Company Silver Spring, Md. UUCP: aplvax!cp1!hart - aplcen!cp1!hart - umcp-cs!cp1!hart - gamma!cp1!hart INTERNET: umcp-cs!aplvax!cp1!hart@SEISMO.CSS.GOV ===========================================================================
brian@sdcsvax.UUCP (Brian Kantor) (10/28/85)
In article <1118@cp1.UUCP> hart@cp1.UUCP (rod hart) writes: >When printing out a document on the inital print only a half >page is printed and the rest of the document is lost. I have >checked the print buffer for non printable characters and have >not found any characters that could be shuting off the printer >or truncating the document. There is an interesting misfeature in the HP LaserJet - if you send enough data to it to cause the buffer to fill up and begin printing, you must send the rest of the data quickly before the printed page gets beyond where you are printing. What happens is that the print mechanism will begin to feed paper, and you have to send data fast enough to get it through the printer before the appropriate part of the sheet of paper has passed the print head. Normally the buffer is large enough to handle a page of simple text. But if you are doing plotting or downloading fonts or other fancy stuff it might very well be too small. If you are driving the printer with troff output this might well be your problem. The ugly solution is to build a huge buffer in your lp output filter program and wait until you have the whole page buffered up in the filter before you start writing to the printer. Yeech. I've heard that HP will have an upgrade kit to expand the buffer memory and maybe some other things too. No info on when or how much (the local sales office didn't seem to know anything about it when I called them a while back). Hope this helps. Brian Kantor UC San Diego decvax\ brian@ucsd.arpa akgua >--- sdcsvax --- brian ucbvax/ Kantor@Nosc
henry@utzoo.UUCP (Henry Spencer) (10/30/85)
> There is an interesting misfeature in the HP LaserJet - if you send > enough data to it to cause the buffer to fill up and begin printing, you > must send the rest of the data quickly before the printed page gets > beyond where you are printing. Sorry, not so. You have the right stick, but the wrong end. Like most laser printers, once a piece of paper starts through the LaserJet it cannot stop, so the controller must feed bits at full speed for the full page. However, the LaserJet does this right: it does not print anything until it has the *entire* page in its buffer. That's why it can do things like print multiple copies of a page, or cleanly reprint a page after a paper jam has been cleared. Buffer overflow produces error codes, not a go-ahead-anyway response. The one situation where we see partial printouts (and we use our LaserJets a lot) is after some types of error code have been cleared by pressing the CONT button on the front panel. > Normally the buffer is large enough to handle a page of simple text. > But if you are doing plotting or downloading fonts or other fancy stuff > it might very well be too small. You can't download fonts into a standard LaserJet, although you can get roughly the same effect by drawing the characters each time using graphics. Feeding too much graphics produces an error code. > If you are driving the printer with troff output this might well be your > problem... Done well, driving a LaserJet with troff output is not a big thing, given that the users are restrained about font use. We do a lot of it. > I've heard that HP will have an upgrade kit to expand the buffer memory > and maybe some other things too. No info on when or how much... It costs about US$1600, if I've got the C$->US$ conversion right. Maybe a bit more if you're not educational. It massively increases the buffer memory and adds font downloading, among other things. But it's not going to solve the original problem unless it really is a buffer-overflow problem, which it isn't unless you are getting error codes on the LaserJet front panel. -- Henry Spencer @ U of Toronto Zoology {allegra,ihnp4,linus,decvax}!utzoo!henry