Since more data than just the text for the page, that is, the complete page in PDL form, has to be sent to the printer, older interfaces such as the "Centronics" parallel port and RS-232 serial have been replaced by USB and Ethernet (wired and wireless). "Line printers", or "dumb" printers that accept only plain text are essentially obsolete, having been replaced by "page printers" that accept input in some type of page description language (e.g. (IMO SPOOL is one of the best acronyms coined because it is also an English word (both noun and verb) that can be used as an analogy to describe how the printer service works.) ![]() The "print queue" is the visible part of the printer service/daemon that was originally a program called SPOOL (for Simultaneous Peripheral Operations On-Line) such as for the HASP/OS360 operating system running on IBM 360 mainframes. I ask the last question because on my own cannon seems to request the ink level as if it were a print job: printing: supply levelsĪlso I have heard of HP printers using "fake" print jobs to send a firmware update. What sort of information do most printing protocols support? How is the document transmitted to the printer? ![]() How do printers print documents from multiple machines if each machine is clueless to the fact that others are printing as well? So that must mean the printer has an onboard queue right? So why do we even have printing queues if we can't see what else is being printed?Īny information on how printers actually work nowadays without serial cables would be helpful, but to make this a valid question: The OS printing queue shows us nothing of what other machines are printing because it's a local buffer. The question is, what does an OS printing queue mean if the printer can receive multiple documents? I assume modern printers merely receive a postscript (or some other printing format) doc from the OS, keep it in memory and print from it. Now with network printers, this imagined model falls apart. ![]() I have had trouble finding any actual information of how printers actually handle printing data.Īll OSes as far as I know have a "print queue" which seemingly buffers printed documents out to the printer in the order they were requested.īefore network printers, I would imagine that the actual printer was sent data almost line by line from the connected machine.
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