Re: cbmlink with 3032/3040 pair

From: silverdr_at_wfmh.org.pl
Date: Mon, 5 Mar 2018 22:14:55 +0100
Message-Id: <FC630781-6F9D-404C-BA4D-E32DEE113134@wfmh.org.pl>
> On 2018-03-05, at 22:07, Francesco Messineo <francesco.messineo@gmail.com> wrote:
> 
>>>>> This is usually not a big problem, but the disk needs a VALIDATE
>>>>> command after it has been transferred.
>>>>> Does anyone understand why it happens?
>>>> 
>>>> DOS differences? DOS differs between the two. My guess is that 1541 shows static data stored in the directory sector, while the other one uses actual sector's metadata.
>>> 
>>> I don't get what you mean.
>> 
>> I would have to check exactly what the differences are but there are other people who I bet have them in their heads ;-) while I vaguely recall that the DOS 2.6 in 1541 is not the same as DOS 2.x in other drives. This means there may be nuance differences, and if you write a D64 (from a 1541 disk?) to another drive using DOS 2.x things like you describe may show. Once you re-VALIDATE, the drive updates the metadata to what it expects, rather than what 1541 would expect.
> 
> I would expect that cbmlink just writes sectors, starting from 1,0 and
> ending to 35,16. I don't think it even knows about directory, BAM and
> so on. On a 1541, even disk id (the two characters you give at format
> time) gets changed from the .d64 image. On a 3040 they don't.
> I don't know how much "metadata" is present on a .d64 image though.

D64 is a high-level image so it doesn't contain low-level metadata. Disk ID for example is stored in sector headers during formatting, not only in directory. Actually that one, visible in the directory listing is less important ;-) To preserve the low-level metadata you'd need to use G64 rather than D64. Also have a look at:

http://e4aws.silverdr.com/project64/incdos/

Section 3.3

-- 
SD! - http://e4aws.silverdr.com/


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Received on 2018-03-05 23:05:15

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