My hat off to Mr. Colin Bruce for Extreme Cleverness Beyond the Call of Duty.
A couple of questions about the details... see below. > From [EMAIL PROTECTED] Thu Mar 15 14:04:38 2001 > Date: Thu, 15 Mar 2001 21:09:23 +0000 (GMT) > From: Colin Bruce <[EMAIL PROTECTED]> > To: [EMAIL PROTECTED] > Subject: Re: LPRng: Charged printing > > Dear Ron, > > At Coventry University we have developed a system which does this. It is > based on LPRng and IFHP but uses some code written in-house as a front > end to the users. > > It has been in use since the start of this academic year and has worked > pretty well. The biggest problem has been performance. It works as follows: > > There is a single queue (called VIRTUAL) which all jobs are submitted to. > Jobs can be submitted from NT work stations or Unix systems and I believe > there are even some Macs using it. The jobs remain in the virtual queue > until they are released by whoever submitted them. There are about 40 or > so printers in open access rooms around the campus which people can print to. > Each printer location has a workstation next to it (which is actually an > old PC running linux acting as an X term) In most cases there is one such > station to each printer but there are one or two places where such a station > controlls 2 printers. When someone wants to release the print jobs they have > submitted they go to any printer that is convenient and enter their username > and password on the application that is running on the X term. This was > written in-house in C++ using the QT library. They type in username/password > although they could also use a scanner to read ID card information if we had > enough scanners. They are then shown a list of the print jobs that are > in the virtual queue. They pick the ones they want and these are then sent > to the printer next to the station. Of course you will probably have realised > that all we are doing is an lpc move command to move from the virtual queue > to the one that is associated with that printer. Jobs that are not printed > are deleted from the queue after a while. > > We do attempt to estimate the page count before each job is printed and get > the actual count using IFHP afterwards. This works well as we use HP 4/5 > printers everywhere. The database that is used to store the users information > is MYSql which is also freely available. The application uses an in-house > authentication system which is fast and secure. > > The students like the system apparently and it works well apart from one big > problem which is performance. It was running on a single Alpha 800 and the > single virtual queue ended up with many thousands of jobs in it. Today we > made a couple of changes. We moved it to a dual processor alpha 1200 and we > made 100 virtual queues instead of one. We still have the single queue for > people to submit to but all jobs are immediately routed to one of the 100 > virtual queues using a simple hash code based on their username. We found > one that gives a pretty even distribution. We only installed this version > this afternoon but it seems to work a lot better. Hmm... What was the bottleneck? Listing the jobs in the print queue? > > The linux PCs that control the printers are self repairing so require no > maintenance. They can only run the PACS (as we call it) application and > nothing else so they are pretty secure. > > We have plans for several enhancements to the system. > > Anyway, if you would like to come to have a look, we would be happy to show > you what we have done. We are only about 30 miles away. > > best wishes.... > Colin Bruce > > > On Thu, Mar 15, 2001 at 12:48:47PM +0000, [EMAIL PROTECTED] wrote: > > > > Hi is there anybody on the list in a university environment that is using lprng > > to provide charged printing to students ?? > > > > Ron > > > > Ron McKeating > > Computing Services > > Loughborough University > > 01509 222329 > > ----------------------------------------------------------------------------- > YOU MUST BE A LIST MEMBER IN ORDER TO POST TO THE LPRNG MAILING LIST > The address you post from MUST be your subscription address > > If you need help, send email to [EMAIL PROTECTED] (or lprng-requests > or lprng-digest-requests) with the word 'help' in the body. 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