Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!henry
From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: net.dcom
Subject: Re: need info about problem with hp laser jet (26xx)
Message-ID: <6097@utzoo.UUCP>
Date: Wed, 30-Oct-85 15:27:38 EST
Article-I.D.: utzoo.6097
Posted: Wed Oct 30 15:27:38 1985
Date-Received: Wed, 30-Oct-85 15:27:38 EST
References: <1118@cp1.UUCP>, <1165@sdcsvax.UUCP>
Organization: U of Toronto Zoology
Lines: 44

> 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