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From: csbrod@medusa.informatik.uni-erlangen.de (Claus Brod )
Newsgroups: comp.sys.atari.st
Subject: Re: 16 meg partition limit
Message-ID: <2425@medusa.informatik.uni-erlangen.de>
Date: 15 Feb 90 12:19:04 GMT
References: <2947@water.waterloo.edu> <1325@crash.cts.com> <20465@watdragon.waterloo.edu> <1990Feb6.223637.15845@sj.ate.slb.com>
Organization: CSD, University of Erlangen, W-Germany
Lines: 22

greg@sj.ate.slb.com (Greg Wageman) writes:

>What Atari has changed, I believe, is to treat the "recno" parameter
>as an UNSIGNED int, with a range of 0 to 65535, and consequently a
>32Mb limit.  However, any software which calls Rwabs() to directly
>access the hard disk (such as disk checkers might do) must understand
>this convention, or else they will get confused by the (apparently)
>negative sector numbers (i.e. any in the second 16 Meg with the
>high-order bit set).

Actually, ATARI did extend the range of sector numbers, but not only
to 2^16 but to 2^32. This is, however, not the reason why partitions
larger than 16 MB became possible. The new ATARI driver supports
larger logical sector sizes. Before, the logical sector size has
been 512 bytes througout all kind of media. Now, the new hard disk#
driver blocks 512 byte sectors to larger logical sectors. A partition
with 24 MB, for instance, has a logical sector size of 1024 bytes.
This trick works with ALL TOS versions, so you don't have to install
TOS 1.4 to use them. (Nevertheless, TOS 1.4 is a must for every
hard disk user because it speeds up everything quite a lot.)

Claus Brod