Path: utzoo!attcan!uunet!husc6!xait!mirror!ima!haddock!suitti From: suitti@haddock.ima.isc.com (Steve Uitti) Newsgroups: comp.sys.mac Subject: Re: NeXT secrets Message-ID: <9599@haddock.ima.isc.com> Date: 18 Oct 88 17:27:14 GMT References: <15478@agate.BERKELEY.EDU> <1740@eos.UUCP> <532@gt-eedsp.UUCP> Reply-To: suitti@haddock.ima.isc.com (Steve Uitti) Organization: Interactive Systems, Boston Lines: 72 In article <532@gt-eedsp.UUCP> jensen@gt-eedsp.UUCP (P. Allen Jensen) writes: >In article <1740@eos.UUCP>, lyman@eos.UUCP (Lyman Taylor) writes: >>..... >> A possible solution to this is that perhaps there no COMPUTER inside >> the [laser printer]. >The laserprinter has no computer - Or memory - It uses the NeXT >CPU for everything and sends an image over a "special high-speed" >laser printer interface. Looks like it will only work on the NeXT >box ! For the Mac II, I have the General Computer Personal Laser Printer (PLP). As with the Apple Laserwriter IISC, it connects to the computer via SCSI. There is a processor in the laser printer, but it does not interpret Postscript (or anything else remotely complicated). It does have some memory, but I don't believe it has enough for anything like a page of bits (about a Megabyte is required). As far as I can tell, the host rasterizes the stuff & sends it to the printer. SCSI, the printer's CPU, and the Mac are quick enough to get the data to the drum so that it is not slower than having a CPU & RAM inside the printer. I haven't a clue as to what interface the NeXT machine uses. I hope it is SCSI. The NeXT machine does support SCSI, therefore, it should be possible to support IISC & PLP printers on it, as they describe, at 300 dpi. While this is pretty much Mac specific (Mac II, SE, plus if SCSI is available), it is only due to the software availability on the Mac. If one had SCSI on a PC (clone), and software that could talk to it, these printers should work. The advantages of Postscript (or some sort of language) in the printer are: 1. The data sent to the printer is smaller. 2. The host doesn't have to rasterize the document. The advantages of having the host do it are: 1. If there is a bug in the language, it can be fixed (it is just software). 2. More than one language can be supported (it is just software). 3. It is cheaper. A PLP goes for around $2K. A Laserwriter Plus is $3.5K. This last point is interesting. For the Apple Laserwriter II series, one can upgrade the printer to something stupid like 12 MB of RAM, a 40 MB (80?) hard disk, etc. For people who didn't start with a 16 MHz 68020 (or better), the printer is a much faster machine with better resources than the host. For the PLP, I can upgrade my Mac II to something stupid like 8 MB of RAM and lots of hard disk. Further, I can use this same RAM and disk for things unrelated to printing. One argument goes that having the smarts in the printer allows the host to go on working while the printer prints, thus freeing the host. For the Mac, this isn't generally true. It is probably only true for the last few pages of text. The Mac often has to convert what is doing from quickdraw, or a rasterized bit plane to postscript anyway. Finally, it ships it to the printer, and waits for it to get there. Curiously, for the NeXT machine, it is more true. The OS there is a true multuser OS. Time spent degrades the performance of the rest of the machine (potentially, the network). In a workstation environment (a Mac or NeXT, but not here at the office), the CPU is idle most of the time (otherwise it is not a very good workstation), and so you may as well let it be *able* to do something now and then. One could make a strong argument that a good workstation is one that is able to do lots of stuff, but never seems to spend any time doing anything. I haven't been following the industry too closely, but I'd probably pay real money (but not too much) for a postscript system that will run on my Mac that will talk to my PLP. Now that it has been done for the NeXT machine, it should be easier. I think, though, I'll work on making quickdraw act like it really knows the PLP (at 300 dpi for everything), and devise some scheme for transfering tiny ASCII based text+graphics files around such that they can be used on a variety of machines (host type + printer type) for a variety of applications (including real word processing). Stephen.