Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!husc6!bu-cs!mit-eddie!genrad!decvax!decwrl!sun!imagen!atari!apratt From: apratt@atari.UUcp (Allan Pratt) Newsgroups: comp.sys.atari.st Subject: Re: A challenge to you disk experts Message-ID: <492@atari.UUcp> Date: Fri, 19-Dec-86 13:49:19 EST Article-I.D.: atari.492 Posted: Fri Dec 19 13:49:19 1986 Date-Received: Sat, 20-Dec-86 06:15:58 EST References: <1866@batcomputer.tn.cornell.edu> Organization: Atari Corp., Sunnyvale CA Lines: 42 Moshe Braner asks about single- and double-sided disks. You could make one physical DS disk into two logical SS disks by writing a device driver for a DS floppy disk drive which would treat one surface as one logical SS disk, and the other surface as another logical SS disk. This would involve linking in to the RWABS vector (like RAMDISKs do) and translating the device and logical record numbers for your two logical devices (M: and N: or whatever) into less-logical record numbers for the physical device (A:). You can also post-process an SS disk to make it a DS disk without copying the original information: you would have to write a device driver which modified the current DS logical record sequence (head 0, then head 1, then on to the next track) into a new one: track 0-79 on head 0, then tracks 79-0 on head 1. That way the existing data on an SS disk would not have to be moved at all. The information on the boot sector would have to be modified to reflect all the new tracks you're getting, and Side 1 would have to be formatted, but otherwise nothing changes: the FATs are the same size for SS and DS. Note that in neither case will the normal desktop format/copy routines work, not only because these disk formats are "foreign" to it, but because it checks explicitly for drive identifiers A and B. Ever notice that you can't copy a 360K RAMDISK to a floppy, except file-by-file? Same reasons. Having said all this, I think it all doesn't matter anyway: it doesn't take THAT long to copy an SS disk file by file. You can just go get a cup of coffee, or read a book, while the copy is taking place. If you have one drive, of course, you want to get a RAMdisk, so you can copy (file by file) from the original to RAM, then from RAM to the backup. Does everybody know that you can copy ALL the files on one disk to another, without selecting the files? If you want to copy B to A file by file, you can open A (the destination), then drag the icon for B into the open window for A. This will copy all the files, one at a time, including (of course) the directory structure. /----------------------------------------------\ | Opinions expressed above do not necessarily | -- Allan Pratt, Atari Corp. | reflect those of Atari Corp. or anyone else. | ...lll-lcc!atari!apratt \----------------------------------------------/