Re: What is the most used ROM in the brown 1541?

Digging biological memory now. AFAIR the incompatibility you refer to was mentioned in the context of writing the disk formatted with 4040, using 1541 (or the other way around :-) There should be no problem exchanging the disks for read only purposes. I need to check this in my files later. But the authors got something  important wrong too. One of them insisted for a long time, even after the incdos book was published, that save and replace bug was a myth. 
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Sent from mobile device. Please have understanding. 

On 18 June 2015 20:11:06 CEST, Ruud@Baltissen.org wrote:
>Hallo Julian and everyone else,
>
>
>> I wonder just what your reason for the question is....
>
>First a remark on forehand: quite some I time ago I read "Inside 
>Commodore DOS" and that book mentioned that you couldn't exchange 
>floppies between a 1541 and a 4040. I never had problems with 
>exchanging floppy disks between the brown 1541, 1541C, 1541-II and 
>CBM 4040.
>
>I'm still busy with commenting the sources of the various ROMs and I 
>noticed that in version 901229-03 the number of bytes in the header 
>gap was increased from 8 to 9. This meant that 9 is also the value 
>used in 901229-05, -06AA and the 1541-II. And this is the value that 
>was already present in the CBM 4040. 
>
>So it seems it was changed to 8 for the 1540 for one or another 
>reasons. I have a 1540 but, to be honest, I never used it for 
>programming, testing etc., etc.: I considered it too much as an 
>collectors item. The rest of my 1541s have all been equiped with the 
>05, even the older long-boards (not done by me). And I wanted to 
>know if this was a coincidense or was the 05 more wide spread than 
>anything else.
>
>Except changing the checksum, changing the size of the header gap at 
>two places was the only change of version 03. And these 9 bytes 
>triggered me to remember the book. And as said before, I never had 
>any, any problem at all so I thought the author must have it wrong 
>in one or another way. But what?
>It now seems that the author must have been testing using a 01 or 02 
>version.
>
>After remark: this afternoon I got the idea to check my spare 
>storage and that gave me another conformation of what is the most 
>used ROM inside the 1541: I _only_ have 901229-05s ! 
>
>
>--
>   
>Kind regards / Met vriendelijke groet, Ruud Baltissen
>www.Baltissen.org
>
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