Path: utzoo!attcan!uunet!mcvax!ukc!reading!cf-cm!cybaswan!iiit-sh
From: iiit-sh@cybaswan.UUCP (Steve Hosgood)
Newsgroups: comp.os.os9
Subject: SCF Device Driver Query (68K)
Message-ID: <455@cybaswan.UUCP>
Date: 23 May 89 12:11:38 GMT
Reply-To: iiit-sh@cybaswan.UUCP (Steve Hosgood)
Organization: Institute for Industrial Information Technology
Lines: 27
References:

I wonder if any readers here are familiar with this problem:

I am trying to write a Device Driver. I obtained a skeleton driver and hacked
it about in order to save time and effort. Now I've got a driver which sets
up the device (a parallel port) correctly with the INIT routine, clears it
OK with the TERMINATE routine. The READ routine is a dummy, it just returns
an error, (and this occurs corectly).

The problem is that the WRITE routine never gets called by the file manager.
If I open the device from a program and attempt to write to it, everything
seems to work OK, correct return codes are returned. However, the driver never
gets the call. It's almost as if the file manager is buffering the data, but
I don't think it should be doing that....

This effect even happens when the driver's WRITE routine is hotwired to
return an error code. Weird huh?

I'm running Version 2.2 OS9/68K

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Steve Hosgood BSc,                             | Phone (+44) 792 295213
Image Processing and Systems Engineer,         | Fax (+44) 792 295532
Institute for Industrial Information Techology,| Telex 48149
Innovation Centre, University of Wales, +------+ JANET: iiit-sh@uk.ac.swan.pyr
Swansea SA2 8PP                         | UUCP: ..!ukc!cybaswan.UUCP!iiit-sh
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