andyc@bucky.intel.com (Andy Crump) (02/14/91)
I have heard talk about postscript printers with SCSI interface. One
use of the scsi interface is so that the printer can have a local disk
to store fonts. But I have heard talk that the scsi interface can be
used as a communication mechanism. I am not clear on what the
advantage is to a SCSI printer. It seems to me that the speed of the
print mechanism is by far the limiting factor to print speed, not the
I/O port. Unless the SCSI postscript printer has ALOT of local memory
to queue up jobs...
Most printers can't keep up at 9600 baud anyway. Why would
anyone want to use SCSI as their I/O channel to a printer? What
printers implement this and how are they used? How pervasive are SCSI
printers, where SCSI is used as the communication channel? Inquiring
minds want to know.
Thanks,
--
-- Andy Crump
...!tektronix!reed!littlei!andyc | andyc@littlei.intel.com
...!uunet!littlei!andyc | andyc@littlei.uu.net
Disclaimer: Any opinions expressed here are my own and
not representive of Intel Corportation.ben@epmooch.UUCP (Rev. Ben A. Mesander) (02/15/91)
>In article <+++-+TA@b-tech.uucp> zeeff@b-tech.ann-arbor.mi.us (Jon Zeeff) writes: >>advantage is to a SCSI printer. It seems to me that the speed of the >>print mechanism is by far the limiting factor to print speed, not the > >Every try to rapidly print 600K bitmaps on a laser printer? Currently >we have to use a PC with a coprocessor board that talks to the printer >via the video interface. A scsi laserprinter would probably eliminate >the need for the PC and coprocessor. > >-- >Jon Zeeff (NIC handle JZ) zeeff@b-tech.ann-arbor.mi.us I'd like to see SCSI laser printers also. I use a Laserwriter IINTX, and it seems that for straight text, the limiting factor is the print engine speed. However, when I download 900K plot files to it, it takes forever to send it at 9600 baud (I'm going to see if my workstation will reliably send at higher baud rates). I've noticed that several computationally intense postscript demos that have warnings in them that a printer timeout may occur run fast with no timeout on my printer, because the IINTX has a very fast processor in it. I suspect the bottleneck is the serial transfer. I'll attempt to speed up the baud rate and report if that is indeed the problem. Yes, 900K files are a bit excessive, but I do cartography with it, and there's just lots of little vectors. -- ben@epmooch.UUCP ben%servalan.UUCP@uokmax.ecn.uoknor.edu {chinet,uokmax}!servalan!epmooch!ben (Ben Mesander) War in gulf: newpath 288 396 216 0 360 arc 288 612 moveto 288 180 lineto 288 396 moveto 136 244 lineto 288 396 moveto 440 244 lineto 36 setlinewidth stroke showpage
zeeff@b-tech.ann-arbor.mi.us (Jon Zeeff) (02/15/91)
>advantage is to a SCSI printer. It seems to me that the speed of the >print mechanism is by far the limiting factor to print speed, not the Every try to rapidly print 600K bitmaps on a laser printer? Currently we have to use a PC with a coprocessor board that talks to the printer via the video interface. A scsi laserprinter would probably eliminate the need for the PC and coprocessor. -- Jon Zeeff (NIC handle JZ) zeeff@b-tech.ann-arbor.mi.us
vail@tegra.COM (Johnathan Vail) (02/16/91)
In article <ANDYC.91Feb14084414@bucky.intel.com> andyc@bucky.intel.com (Andy Crump) writes: I have heard talk about postscript printers with SCSI interface. One use of the scsi interface is so that the printer can have a local disk to store fonts. But I have heard talk that the scsi interface can be used as a communication mechanism. I am not clear on what the advantage is to a SCSI printer. It seems to me that the speed of the print mechanism is by far the limiting factor to print speed, not the I/O port. Unless the SCSI postscript printer has ALOT of local memory to queue up jobs... Speed of the transfer. SCSI is many orders of magnitude greater than most other interfaces available. Most printers can't keep up at 9600 baud anyway. Why would anyone want to use SCSI as their I/O channel to a printer? What printers implement this and how are they used? How pervasive are SCSI printers, where SCSI is used as the communication channel? Inquiring minds want to know. On your average *printer* this is true. When you get into imagesetting and postscript you start talking about *lots* of data. There the rendering and transfer times can far outweigh the time spent by the output devices. Some color seperations for postscript are easily 40 to 50 *megabytes*. And this is for a single page. In this perspective it is easy to see how transfer times become crucial and why SCSI is one way to attack this. As for use as of today I haven't seen too many of them. This is changing, though. jv "Honesty without Fear" -- Kelvinator _____ | | Johnathan Vail | n1dxg@tegra.com |Tegra| (508) 663-7435 | N1DXG@448.625-(WorldNet) ----- jv@n1dxg.ampr.org {...sun!sunne ..uunet}!tegra!vail
jchin@van-bc.wimsey.bc.ca (Joseph Chin) (02/16/91)
In article <ANDYC.91Feb14084414@bucky.intel.com> andyc@bucky.intel.com (Andy Crump) writes: stuff deleted ... >used as a communication mechanism. I am not clear on what the >advantage is to a SCSI printer. It seems to me that the speed of the >print mechanism is by far the limiting factor to print speed, not the >I/O port. Unless the SCSI postscript printer has ALOT of local memory >to queue up jobs... >Most printers can't keep up at 9600 baud anyway. Why would >anyone want to use SCSI as their I/O channel to a printer? What > > -- Andy Crump > > ...!tektronix!reed!littlei!andyc | andyc@littlei.intel.com > ...!uunet!littlei!andyc | andyc@littlei.uu.net > >Disclaimer: Any opinions expressed here are my own and > not representive of Intel Corportation. Speaking purely from personal experience ... In newer high speed postscript printers, the print mechanism is no longer the limiting factor to print speed. Especially in the case of Postscript printers where most of the information that go over the link from computer to printer are Postscript codes. A high speed link is also extremely crucial when printing bitmapped images. Try printing a 300-dpi 256 grayscale scanned image (approx. 4"x6") ... it takes more than 25 minutes on a LaserWriter NTX hooked up to the serial port on my NeXT (9600 bps). High speed connection to the printer via SCSI is also helpful in a networked environment. The case is even more prevalent on a printer such as the NeXT 400-dpi laser printer where the host computer do the rasterizing and then bitmaps are "blasted" to the printer. :-) Joe jchin@van-bc.wimsey.bc.ca -- ************************************************************** * "Kill the body and the head will die" (Hunter S. Thompson) * * NeXT --> The ultimate electronic publishing platform! * ********** Joseph Chin --> jchin@van-bc.wimsey.bc.ca *********
andyc@bucky.intel.com (Andy Crump) (02/19/91)
>>>>> On 15 Feb 91 15:20:36 GMT, zeeff@b-tech.ann-arbor.mi.us (Jon Zeeff) said: >advantage is to a SCSI printer. It seems to me that the speed of the >print mechanism is by far the limiting factor to print speed, not the Jon> Every try to rapidly print 600K bitmaps on a laser printer? Currently Jon> we have to use a PC with a coprocessor board that talks to the printer Jon> via the video interface. A scsi laserprinter would probably eliminate Jon> the need for the PC and coprocessor. But if the laserprinter is postscript, how does that help you? -- -- Andy Crump ...!tektronix!reed!littlei!andyc | andyc@littlei.intel.com ...!uunet!littlei!andyc | andyc@littlei.uu.net Disclaimer: Any opinions expressed here are my own and not representive of Intel Corportation.