"Abhay_K._Bhushan.osbunorth"@XEROX.COM.UUCP (04/15/87)
I found the message "Summary of Replies" very useful and informative. I would like to correct a misunderstanding the reader may be left with when comparing printers of different speeds. It is a tempting simplification to think that three 8 page per minute printers would do the job of one 24 page per minute printer, or that 15 Apple Laserwriters (8 ppm) would do the job of a Xerox 9700 (120 ppm). A more accurate way to look at performance is not speed but the throughput capability for the printer (described as as AMPV, the recommended or design centerline Average Monthly Page/print Volume). While it is true that many printers may routinely be performing at about 2 to 3 times the AMPV (with more frequent maintenance and possibly higher service costs), AMPV is still a good measure. By using the AMPV comparison, it would take about 20 Apple Laserwriters (8 ppm, 3,000 AMPV) to equal the performance of a Xerox 3700 (24 ppm, 60,000 AMPV), and about 500 Laserwriters to equal the performance of a 9700 (120 ppm, 1,500,000 AMPV). With the higher throughput printers, the user also gets added features such as large paper tray size, handling many different formats, queuing of jobs, extra disk storage at printer, media and channel connections, 2-sided printing, fininshing options etc., not to forget the tremendous saving in labour and service costs (it would take a small army just to maintain and babysit the hundreds of low-speed printers that would be needed to do the job of a production printer such as the 9700). The following is a comparison of printer throughput performance per dollar. I have used the list price for the basic machine in figuring the cost. I am aware that many products can be obtained at discounts, and that the purchase price could even be higher for many of the products depending on the options purchased (such as the copier option on the 4045). Printer Speed(ppm) Base List Price ($) AMPV AMPV/$ Apple LW 8 4,995 3,000 0.6 Apple LW plus 8 6,798 3,000 0.4 Xerox 4045 Mod 50 10 4,995 5,000 1.0 Xerox 4045 Mod 20 10 6,495 5,000 0.8 Xerox 3700 24 29,995 60,000 2.0 Xerox 4050 50 140,500 350,000 2.5 Xerox 8700 70 182,000 750,000 4.1 Xerox 9700 120 313,000 1,500,000 4.8 As can be seen from the preceding table, throughput per dollar goes up with the size of machine. The throughput/$ performance of the 4045 is twice the Laserwriter, the 3700 is about 3 to 5 times the Laserwriter, and the 9700 is about 8 to 12 times the the Laserwriter. There are of course many reasons, such as convenience or low expected usage, as to why a user may wish to purchase a smaller printer. But if the volume is there, and if there is considerable production work to be done, the above methodology may be useful in evaluation. Before some one tells me that they get 10,000 pages/month (instead of the 3,000 AMPV) from their Laserwriter, let me add that there are users who are routinely getting 30,000 pages/month (5000 AMPV) from their Xerox 4045, 150,000 pages/month (60,000 AMPV) from their 3700, and 3 million or more pages/month (1.5 milion AMPV) from their 9700 family. The user should also note that the printers don't always print at the rated speed. This is especially true when it comes to the printers using the advanced capabilities of page description languages such as Postscript. For example, scan converting contour fonts, decompressing bit maps in software, and rotating or scaling graphics all take time, and slows the printer down to some thing like 1 or 2 pages/minute or less. More memory at the printer helps speed things up a little and provide additional features (such as with the Laserwriter Plus or the 4045 Mod 20). Having printer-resident "tuned"bit-map fonts is useful as they provide higher speed and higher quality printing. The "true" speed of a printer is a combination of base engine speed, the ESS efficiency, and the job complexity. For the 4045, most jobs are printed within 5% of the rated speed of 10 pages per minute. However in many other laser printers (especially when using contour fonts), jobs are frequently printed at half or even a quarter of the rated speed. The Interpress page and document description language from Xerox takes these functionality and performance trade-offs into consideration. The Commercial Set of Interpress provides for high throughput printing by using bit-map fonts, and pre-conversion of complex graphics into compressed bit-maps, while the Professional Graphics Set of Interpress provides the functionality of Postscript. Because of their common origins at PARC, Interpress and Postscript are very similar in capability and structure, and for the most part it would be a simple matter to go from one to the other. I would also like to point out that for quite a few years Xerox has been using Interpress and the XNS protocols to provide compatibility among all the Xerox printer and publishing products on Ethernet (including network versions of all the listed printers). Software is also available to provide XNS/Interpress integration to these printers from other environments, including IBM mainframes, IBM PC and compatibles, DEC Vax/VMS, and Unix 4.3 BSD. Interpress and XNS specifications were made public in 1984, and many other vendors have implemented these. Xerox also provides support and integration capabilities for other formats and other environments, as required by customers (for example, Xerox high-speed printers integrate well with the IBM AFPA/SNA environments, and the Xerox Ventura Publisher supports all the leading PDL's: Interpress, Postscript and DDL). To find out more about Xerox standards and integration capabilities and the software tools, you may contact Pam Cance of the Xerox Systems Institute at 475 Oakmead Parkway, Sunnyvale Ca 94086. Tel 408-737-4652. Abhay Bhushan
"Abhay_K._Bhushan.osbunorth"@XEROX.COM (04/18/87)
I found the message "Summary of Replies" very useful and informative. I would like to correct a misunderstanding the reader may be left with when comparing printers of different speeds. It is a tempting simplification to think that three 8 page per minute printers would do the job of one 24 page per minute printer, or that 15 Apple Laserwriters (8 ppm) would do the job of a Xerox 9700 (120 ppm). A more accurate way to look at performance is not speed but the throughput capability for the printer (described as AMPV, the recommended or design centerline Average Monthly Page/print Volume). While it is true that many printers may routinely be performing at about 2 to 3 times the AMPV (with more frequent maintenance and possibly higher service costs), AMPV is still a good measure. By using the AMPV comparison, it would take about 20 Apple Laserwriters (8 ppm, 3,000 AMPV) to equal the performance of a Xerox 3700 (24 ppm, 60,000 AMPV), and about 500 Laserwriters to equal the performance of a 9700 (120 ppm, 1,500,000 AMPV). With the higher throughput printers, the user also gets added features such as large paper tray size, handling many different formats, queuing of jobs, extra disk storage at printer, media and channel connections, 2-sided printing, fininshing options etc., not to forget the tremendous saving in labour and service costs (it would take a small army just to maintain and babysit the hundreds of low-speed printers that would be needed to do the job of a production printer such as the 9700). The following is a comparison of printer throughput performance per dollar. I have used the list price for the basic machine in figuring the cost. I am aware that many products can be obtained at discounts, and that the purchase price could even be higher for many of the products depending on the options purchased (such as the copier option on the 4045). Printer Speed(ppm) Base List Price ($) AMPV AMPV/$ Apple LW 8 4,995 3,000 0.6 Apple LW plus 8 6,798 3,000 0.4 Xerox 4045 Mod 50 10 4,995 5,000 1.0 Xerox 4045 Mod 20 10 6,495 5,000 0.8 Xerox 3700 24 29,995 60,000 2.0 Xerox 4050 50 140,500 350,000 2.5 Xerox 8700 70 182,000 750,000 4.1 Xerox 9700 120 313,000 1,500,000 4.8 As can be seen from the preceding table, throughput per dollar goes up with the size of machine. The throughput/$ performance of the 4045 is twice the Laserwriter, the 3700 is about 3 to 5 times the Laserwriter, and the 9700 is about 8 to 12 times the the Laserwriter. There are of course many reasons, such as convenience or low expected usage, as to why a user may wish to purchase a smaller printer. But if the volume is there, and if there is considerable production work to be done, the above methodology may be useful in evaluation. Before some one tells me that they get 10,000 pages/month (instead of the 3,000 AMPV) from their Laserwriter, let me add that there are users who are routinely getting 30,000 pages/month (5000 AMPV) from their Xerox 4045, 150,000 pages/month (60,000 AMPV) from their 3700, and 3 million or more pages/month (1.5 milion AMPV) from their 9700 family. The user should also note that the printers don't always print at the rated speed. This is especially true when it comes to the printers using the advanced capabilities of page description languages such as Postscript. For example, scan converting contour fonts, decompressing bit maps in software, and rotating or scaling graphics all take time, and slows the printer down to some thing like 1 or 2 pages/minute or less. More memory at the printer helps speed things up a little and provide additional features (such as with the Laserwriter Plus or the 4045 Mod 20). Having printer-resident "tuned"bit-map fonts is useful as they provide higher speed and higher quality printing. The "true" speed of a printer is a combination of base engine speed, the ESS efficiency, and the job complexity. For the 4045, most jobs are printed within 5% of the rated speed of 10 pages per minute. However in many other laser printers (especially when using contour fonts), jobs are frequently printed at half or even a quarter of the rated speed. The Interpress page and document description language from Xerox takes these functionality and performance trade-offs into consideration. The Commercial Set of Interpress provides for high throughput printing by using bit-map fonts, and pre-conversion of complex graphics into compressed bit-maps, while the Professional Graphics Set of Interpress provides the functionality of Postscript. Because of their common origins at PARC, Interpress and Postscript are very similar in capability and structure, and for the most part it would be a simple matter to go from one to the other. I would also like to point out that for quite a few years Xerox has been using Interpress and the XNS protocols to provide compatibility among all the Xerox printer and publishing products on Ethernet (including network versions of all the listed printers). Software is also available to provide XNS/Interpress integration to these printers from other environments, including IBM mainframes, IBM PC and compatibles, DEC Vax/VMS, and Unix 4.3 BSD. Interpress and XNS specifications were made public in 1984, and many other vendors have implemented these. Xerox also provides support and integration capabilities for other formats and other environments, as required by customers (for example, Xerox high-speed printers integrate well with the IBM AFPA/SNA environments, and the Xerox Ventura Publisher supports all the leading PDL's: Interpress, Postscript and DDL). To find out more about Xerox standards and integration capabilities and the software tools, you may contact Pam Cance of the Xerox Systems Institute at 475 Oakmead Parkway, Sunnyvale Ca 94086. Tel 408-737-4652. Abhay Bhushan
root@bellcore.UUCP (04/25/87)
in <8704171902.AA14204@brillig.umd.edu> "Abhay_K._Bhushan.osbunorth"@XEROX.COM: > The user should also note that the printers don't always print at the > rated speed. This is especially true when it comes to the printers > using the advanced capabilities of page description languages such as > Postscript. For example, scan converting contour fonts, decompressing > bit maps in software, and rotating or scaling graphics all take time, > and slows the printer down to some thing like 1 or 2 pages/minute or > less. Where I used to work, our Xerox 9700 only printed 120 ppm when doing computer program listings in a constant width font. When printing troff documents or graphics, its speed fell below 100 ppm, and was as slow as 60 ppm. PostScript isn't the only thing that runs slower when it's working hard. > The Commercial Set of Interpress provides for high throughput printing by > using bit-map fonts, and pre-conversion of complex graphics into > compressed bit-maps, while the Professional Graphics Set of Interpress > provides the functionality of Postscript. When will the Professional Graphics Set be available commercially? Pat Wood Pipeline Associates, Inc. bellcore!phw5!phw