laser-lovers@uw-beaver (03/15/85)
From: Brian Reid <reid@Glacier> The true speed of a Dover is not 60 pages per minute, as advertised. That is just the burst speed of a Dover. Stanford's Dover seems to be able to print. about 15 pages a minute, integrated over time. The Apple LaserWriter has a burst speed of 7 or 8 pages a minute. But the LaserWriter can really and truly be run at its burst speed, while the Dover cannot. Because of the structure of its software, the Dover sits idle, not printing, more than it prints. Dovers spent a lot of time in "Ethernet listen" mode, and a lot of time in "build bands" mode. Surely you have spent a lot of time impatiently standing next to a Dover watching the little display change from E to P0 to S to--finally--P, before your pages start printing. An Apple LaserWriter connected to a time-shared Vax can do all three of those in parallel--listen to the Ethernet, do necessary conversions (such as the Press to Postscript conversion necessary to emulate a Dover), and print pages. I therefore claim that the true speed ratio of a Dover to a Vax-peripheral LaserWriter is not 10:1 but 2:1. Also, a Dover would cost about $160,000 if it were for sale (the last one that I know about being actually sold intact changed hands for roughly that sum). For that price I could buy 22 Apple LaserWriters (paying full list price for them), which would print at 154 pages per minute collectively. They would also be a lot more reliable. As Chuck Hedrick of Rutgers likes to point out from time to time, a single large printer like the 9700, with a full time operator, is a very different beast from an equivalent number of smaller printers, collectively without operators. The LaserWriter is obviously not a substitute for a 9700, even though it is vastly cheaper per page per minute and has vastly better print quality. It is instead a delightful new alternative in the laser printer marketplace.
laser-lovers@uw-beaver (03/15/85)
From: DonWinter.pasa@XEROX.ARPA (i) You must be using awfully old driving software for the Dover, if the waiting period is that long (ii0 That compariosn is only valid for making ONE copy of a short document. In that respect, the Dover is more like the 9700 than it is like the LaserWriter. My comment was meant to indicate that users who expected the printer to produce 10 copies of a five page memo would not be satisifed if a Laserwriter appeared to replac a terminally-ill Dover. [[Editor's note: I have the rather strong impression that we are comparing dissimilar things. The LaserWriter is clearly not as fast a printer as is the Dover. No one expects it to be. The key concept here is that one can afford to buy dozens of LaserWriters for the price of one Dover. Given a choice, I'd prefer my own slower, low volume printer located in my office to a shared faster, high volume printer located across the street. --Rick]]
laser-lovers@uw-beaver (03/15/85)
From: starkweather.pa@XEROX.ARPA Having been the laser scan system and print engine project leader for the DOVER printer the parameters you mention are somewhat off base. A DOVER would NOT be $160K! First, it was never tooled the way the LBPCX Canon engine is. Had it been prepared for production by careful volume engineering etc. the cost would have been more like $40K for the system not $160K. Secondly you disregard the number of pages or copies of a document required. The DOVER system must prepare bands files sure enough but many people want several copies of manuals, documentation etc. A DOVER racing a Canon engine with one complex page per job and one copy of each page is not a typical use scenario. Try comparing typical output when you want 10 copies of a 30 page document. The DOVER under those circumstances runs at nearly full speed. The LaserWriter is for low volume purposes. The DOVER printers at PARC generate about 125,000 prints per month per machine. Some machines print over 250K prints per month. Thats ~40 Canon cartridges a month or more than one a day. Best print your stuff in the morning before the toner gets low in the afternoon. The point is that comparing page rates must be done in light of the print volume required by the average job. The Canon engine would be shot in no time at 100K prints per month. Also 154 Canon printers would be ~ 200 cubic feet of printers (I do not know how you would get the prints out of the ones in the center of the cube). A DOVER is only 50 or so and collectively puts out much less heat. The "cluster" concept of many small printers does not make much sense in reality. As far as reliability goes, the DOVER is excellent. On average I believe that approximately 1 service call or jam clearance per 10,000 sheets is average for our machines. This is dependent on key operator skill and dependability of course. That may seem like a lot but a await the data on a Canon printer putting out 100K prints per month. By the way, how much does the VAX cost in your system? The DOVER printer system went into service in 1977-1978. When a better system is available I will be the first to request it. By the way I have an HP LaserJet and am going to get a LaserWriter but not for several copies of a 50 page document. Cheers, Gary Starkweather/ Xerox PARC