Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!decwrl!shelby!polya!rokicki From: rokicki@polya.Stanford.EDU (Tomas G. Rokicki) Newsgroups: comp.lang.postscript Subject: Re: "copy" to Amiga serial port Message-ID: <8848@polya.Stanford.EDU> Date: 30 Apr 89 05:57:02 GMT References: <2994@daisy.UUCP> <775@adobe.UUCP> <8751@polya.Stanford.EDU> <98@snll-arpagw.UUCP> <22489@ccicpg.UUCP> <100@snll-arpagw.UUCP> <798@adobe.UUCP> Sender: Tomas G. Rokicki Reply-To: rokicki@polya.Stanford.EDU (Tomas G. Rokicki) Organization: Stanford University Lines: 44 Not to argue, but: > However, it is simplistic to treat a printer like a file, especially > a PostScript printer. Ah, but the file paradigm is a very nice one for things like printers. (How often I've wished to fopen("|lpr","w") . . .) > Here are three reasons why a simple utility program should be used (if > you only had one, sigh), rather than "copy": > 1. Flow control. Let's not get our levels mixed up. The communication channel is responsible for flow control, not the host application. (Unless you're talking to hardware on an ancient eight-bit PC.) > 2. Control-D. Somebody needs to signal the end of the file/job. This is definitely a valid point. Fclose() works admirably, if it can be arranged. Applications that write the ^D themselves if they are talking directly to a `device' as opposed to a `file' is a reasonble compromise. > 3. Error conditions. Errors are reported back along the serial > connection. If nothing is listening to the serial line, the > errors will be lost. Except, the only reasonably quick way to send files for many of us is via the parallel port (9600 baud? no thank you.) Most PostScript printers that support the parallel port simply don't report errors---even though a parallel port is usually bidirectional. This is a bitch I've got with the vendors, though . . . > but it is better to use the printer spooling software that comes with > UNIX, and it is also easier. Indubitably. On reasonably modern personal computers, such as the Amiga and the IBM PC under OS/2, it is not difficult to write a `PostScript:' device that serves all the functions of the Unix spooling software . . . > Glenn Reid > Adobe Systems -tom