[Coco] Answer found for question in NitrOS9 source code

Stephen H. Fischer SFischer1 at Mindspring.com
Tue Sep 4 17:42:54 EDT 2012


Hi,

You have answered the wrong question.

When I click "Help" on Windows I almost always get an answer to the question
"HOW".

What I really want is the answer to the question "WHY".

Following is IMHO the answer to the question "WHY" which is inherent in the 
arithmetic done by the code in Format. (0x4E = 78, 6 / 8 = .75) For 
different sized disks the result might not be exact.

> Christopher R. Hawks
> HAWKSoft
>
> You didn't specify what size disks. On a freshly formatted CoCo disk (35
> tracks, single sided), the least 2 bits in the last byte of the allocation
> map
> are set. That is because 35 tracks * 18 sectors per track (630 sectors) /
> 8
> bits per byte is 78.75 bytes (or 0x4E bytes and 6 more bits). So byte 0x4e
> ('cause we're 0 based) of the allocation map = 0x03.
>

SHF


----- Original Message ----- 
From: "Willi Kusche" <CoCo at wilserv.com>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Tuesday, September 04, 2012 11:25 AM
Subject: [Coco] Answer found for question in NitrOS9 source code


> Hi!
>
>    In the source for the Level 1 "FORMAT" command there is the following
> line:
> "* the format module never gets to this code?"
> The answer is that is it active code in the "FORMATII" command in the
> "CMDS" directory in the disk released for OS-9 for the Apple II.
>
> Willi
>




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