RE: Re: Fwd: Hey guys, Im trying to follow the chain from 1581 super side sector to a record. Can someone help me understand the calculation involved?

Maybe have a look at di_rel_navigate() in
https://github.com/fachat/XD2031/blob/master/pcserver/handler/di_provider.c.
It's extremely tested with many test cases against (true drive simulated)
real Commodore DOS.

André

Am 5. Dezember 2019 03:35:00 schrieb Scott Hutter <scott.hutter_at_gmail.com>:
> Thanks Jim – Ive seen this article before.  But what I don’t understand is,
> for instance – when would a seek result in reading (in the super side
> sector) from group 2?  Or 3?  All that the directory entry itself provides
> is the track and sector of the initial super side sector block.  (Clearly
> Im missing something).  Thanks!
>
> Scott
>
>
> Sent from Mail for Windows 10
>
> From: Jim Brain
> Sent: Wednesday, December 4, 2019 7:14 PM
> To: cbm-hackers_at_musoftware.de
> Subject: Re: Fwd: Hey guys, Im trying to follow the chain from 1581 super
> side sector to a record. Can someone help me understand the calculation
> involved?
>
> On 12/4/2019 6:08 PM, Julian Perry wrote:
> If it's anything like the 1540/8050/8250 behaviour, your best bet is to
> read up on Inside Commodore DOS, by Immers and  Neufield.
> It's not very much like the smaller drives.  The 8050/8250 might be
> similar, not sure.
> But, definitely not the 1541/204/3040/4040/2031.
>
> The 1581 uses "super side sectors", explained here:
> http://www.unusedino.de/ec64/technical/formats/d81.html