Date   : Sat, 21 Apr 2007 14:55:58
From   : jgh@... (Jonathan Graham Harston)
Subject: Re: Z80 coprocessor cursor keys

>Message-ID: <891909.46162.qm@...>

Greg Cook <debounce@...> wrote:
> J.G.Harston wrote:
>
> > Challenger introduced 640K double density disks.
>
> Erm, 720K.  :-)  640K was ADFS.

2 sides * 80 tracks * 16 sectors * 256 bytes = 655360 bytes

Ok, yes tracks 0-2 were single density, so

157 * 16 * 256 + 3 * 10 * 256 = 650752 bytes = 635.5K


--
J.G.Harston - jgh@...                - mdfs.net/User/JGH
BBC BASIC for 30+ platforms - http://mdfs.net/Software/BBCBasic

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