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Path: utzoo!utgpu!water!watnot!watdcsu!rsanders
From: rsanders@watdcsu.UUCP
Newsgroups: comp.sys.m6809
Subject: Re: OS9 CHD command
Message-ID: <3197@watdcsu.UUCP>
Date: Tue, 31-Mar-87 09:58:05 EST
Article-I.D.: watdcsu.3197
Posted: Tue Mar 31 09:58:05 1987
Date-Received: Wed, 1-Apr-87 06:20:57 EST
References: <1987Mar30.153438.8840@gpu.utcs.toronto.edu>
Reply-To: rsanders@watdcsu.UUCP (Roger K. Sanderson P.Eng.)
Organization: U. of Waterloo, Ontario
Lines: 34
Summary: Does CHD really WRITE to disk.

In article <1987Mar30.153438.8840@gpu.utcs.toronto.edu> ac@gpu.utcs.toronto.edu (Mark Acfield) writes:
>
>   In the process of trying to debug a problem I am having with my OS9
>level II software (probably due to a bad disk controller) I discovered
>an interesting (mis??)feature of the CHD command.

(Long description of problem ommited)

>Not only does the shell open directories with update for CHD commands but
>it updates the 'last modified' date in the directory's file descriptor.
>In other words, put a disk in a drive, do a CHD to some directory on the
>disk and you just actually wrote on that disk!!!!  This is something of a
>shock since in the past I have occasionally put a master in a drive
>without write protecting it and then used CHD while browsing it.
>I also tried version 1.00.00 and noticed the lack of extra seeking noises
>for protected disks with it so this feature showed up in 1.00.01 or 
>2.00.00.       

He mentions that the problem (CHD writing) is apparent in OS9 Level I 2.00.00
on the CoCo 1 and 2, and OS9 Level II 2.00.01 on the CoCo 3.

Given that I dont get a writeprotect error on 2.00.00 when CHDing to a
protected disk I assume that if CHD cannot write it traps that error
and does not complain.

The question becomes two fold. First is this description really accurate?
How about it Microware? Does CHD really update the Date on the disk?
I know it has to read to get the pointer to the directory. ( ie the shell
does not just remember the pathname). And second, is this a desirable behaviour? 
   
-- 
  Roger Sanderson: {clyde|decvax|ihnp4}-\
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