Technical Note PR18

The Effect of Spool-a-page/Print-a-page on Shared Printers

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This technical note discusses drawbacks of using the spool-a-page/ print-a-page method of printing. [May 01 1987]

Introduction

The "spool-a-page/print-a-page" method of printing prints each page of a document as a separate job instead of calling PrPicFile to print the entire picture file. Many applications adopted this method of printing to avoid running out of disk space while the ImageWriter driver was spooling the document to disk. As long as you are printing to a directly connected ImageWriter, you're fine, but if you are printing to remote or shared devices (like the AppleTalk ImageWriter and the LaserWriter), this method may create significant problems for the user.

When a job is initiated by the application, the driver establishes a connection with the printer via AppleTalk. When the job is completed, the driver closes the connection, allowing another job the opportunity to print. If each page is a job in itself, then the connection is closed and reopened between each page, allowing another application to print between the pages of the document, which, as you might imagine, could present a significant problem. If two people are printing to the same AppleTalk ImageWriter at the same time and their applications use the "spool-a-page/print-a-page" method of printing, the pages of each document will be interleaved at the printer.

Although there are good reasons for using this method of printing, it is only useful for a directly connected printer. From a compatibility point of view, this method of printing is built-in device dependence. Also, this method could create serious problems for other types of remote devices. Therefore, we are recommending that applications avoid using this method indiscriminately. You should check available disk space to see how much room you have before you print. If there isn't enough space for your entire document, then print as much as you can (to minimize the interleaving) before starting another job. Whenever possible, applications should use the print loop described on page II-155 in The Printing Manager chapter of Inside Macintosh.

References

Printing Manager

Technical Note M.IM.LaserWriterOpt -- Optimizing for the LaserWriter--Techniques

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