Re: Cursory analyses of CBM readdir bug (was: [cc65] Re: readdir bug)

From: gsteemso <>
Date: Tue, 1 Jan 2013 11:15:54 -0800
Message-ID: <>
On Tue, January 1, 2013 7:34 am, wrote:
> On 2012-09-24, at 20:40, Spiro Trikaliotis wrote:
>> The 154x and 157x drives can handle up to 3 simultaneous open files
>> (except the directory), with one exception: A relative file counts for
>> two files, making it one relative file and one sequential ("normal")
>> file only.
> How does one check which channels are in use? For sequential one can read
> the SAT table, which should show the (ORed with $60 - why?) sec address
> aka channel

That's the IEEE-488 bus command for a secondary address: $60 OR'd with the
five-bit secondary address. It's probably faster for the drive to compare
it to an incoming command when it includes the high three bits.


The world’s only gsteemso
Seattle Retro-Computing Society agitator-in-chief

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Received on 2013-01-01 21:00:04

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