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From: johnmac@fawlty.towers.oz (John MacLean)
Newsgroups: comp.sys.apple
Subject: I*M M*-D*S disks and AMI*A disks
Message-ID: <507@fawlty.towers.oz>
Date: 11 Oct 89 05:12:26 GMT
Organization: Tower Technology, Lane Cove, NSW
Lines: 26

First of all, this is not another FST posting (at least not directly).

Is it true that 720K 3.5" IBM disks use a different physical low level
format and so *cannot* be read by 800K Apple drives?
If so how can AEs I*M board use the Apple 3.5" - Does it just create
pseudo devices as ProDOS files?

I believe the MACs superdrive (1.44M 3.5 for reading I*M disks etc)
requires a new IWM chip; is this true?

If so does the new IIGS have an upgraded chip in it - if docs do not say
then check out the printing on the top of the chip. It does not make sense
to produce 2 versions of the chip.

If this fails is the IWM chip socketed on the new GS?

I also read under COMP.SYS.AM*GA that the thier 3.5" can read 2 of the 5
variable speeds on an Apple 3.5" (they use a constant speed). This would
seem to imply that an Apple 3.5" is capable of directly reading their
disks. Is this the case? Does anyone have any low level code around?
Note that A*IGA disks use 24? bytes of overhead per 512 byte block!

Low level drivers for these disks will be necessary before there can be
any FSTs (sorry, it slipped out).

Please post knowledge for all, I am sure others will be interested ...