Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!pt.cs.cmu.edu!andrew.cmu.edu!rc3h+ From: rc3h+@andrew.cmu.edu (Ross Ward Comer) Newsgroups: comp.sys.mac Subject: Re: Formatting 800K disks in FDHD drives Message-ID: Date: 12 Apr 90 22:27:55 GMT References: <127@cogsci.ucsd.EDU> Distribution: usa Organization: Class of '91, Carnegie Mellon, Pittsburgh, PA Lines: 20 In-Reply-To: <127@cogsci.ucsd.EDU> Apple's FDHD drive automatically checks which type of disk is in the drive and selects the proper format based on the disk type. The HD disks all have an extra hole opposite the lock-hole. If you insert a disk without that extra hole into an FDHD drive, the Mac will automatically treat it as an 800K disk. When the Mac asks if you wish to format a disk, it asks if you wish to format single or double-sided. Selecting double will give you 1.4M or 800K. Selecting single on a non-HD disk will format it as 400K. What this all means is that the FDHD is completely backwords compatible with Apple's previous drives. You simply need to use the right disk type to determine the format used. And it's incredibly easy to tell which disks are HD when you buy them ;-). ross rc3h@andrew.cmu.edu Carnegie Mellon University