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From: apratt@atari.UUcp (Allan Pratt)
Newsgroups: net.micro.atari16
Subject: Re: Double-sided disk format and fonts
Message-ID: <401@atari.UUcp>
Date: Fri, 25-Jul-86 14:09:54 EDT
Article-I.D.: atari.401
Posted: Fri Jul 25 14:09:54 1986
Date-Received: Sat, 26-Jul-86 05:24:58 EDT
Organization: Atari Corp., Sunnyvale CA
Lines: 18
Keywords: same as single-sided, ROM TOS

Double-sided disks are in the same logical format as single-sided disks:
the logical sector numbers all have the same interpretation.  The difference
is physical: the sectors are laid out on alternating sides.  Logical sectors
0 to 8 are Track 0, Head 0, Sector 1 through Sector 9. Then you go to the
Head 1 for logical 9 to 17, and back to Head 0 on the next track for 18 to
24.  Since the disk is bigger, the FAT is usually larger, or the cluster
size larger, or both, so you should be careful to interpret the information
in the boot sector correctly (sectors per fat, sectors per cluster, etc).

About Fonts:  There was a font-loader accessory from a magazine (Antic?)
which actually overwrote the font information in RAM.  This worked only
under RAM TOS (obviously).  I am not familiar with font loaders for ROM
TOS, except that they exist.  Perhaps somebody else on the net can speak up?

/----------------------------------------------\
| Opinions expressed above do not necessarily  |  -- Allan Pratt, Atari Corp.
| reflect those of Atari Corp. or anyone else. |     ...lll-lcc!atari!apratt
\----------------------------------------------/