Date: Fri, 8 Sep 1995 15:13:07 +0200 (MET DST) From: J Wunsch <j@uriah.heep.sax.de> To: freebsd-hackers@freebsd.org (FreeBSD hackers) Subject: Re: higher density diskettes Message-ID: <199509081313.PAA13198@uriah.heep.sax.de> In-Reply-To: <199509081007.UAA09665@godzilla.zeta.org.au> from "Bruce Evans" at Sep 8, 95 08:07:08 pm
next in thread | previous in thread | raw e-mail | index | archive | help
As Bruce Evans wrote: > > >Can the 765 read 'raw' tracks, as well as pick sectors out of them? > > Yes. It can do essentially everything that a WD-style floppy controller > can do except write raw tracks. Yno. Sort-of. Reading an entire track will only synchronize on the ID field of the very first sector on the track. You have to perform *bit-level* synchronisation for all subsequent sectors yourself. This is nothing one would like to do except for debugging purposes. I've done it once when writing my CP/M floppy BIOS. Anyway, any caller is free to request any sector with any length from the 765 (as long as he knows how long the sector will be before actually starting the operation -- or he will have to make two passes, one to read all sector IDs and a second one to actually read them). Except, the BIOS doesn't support such weird schemes. See my other reply on OS/2's XDR format for an example of what can be done. Needless to say that currently, FreeBSD is one of the last operating systems that could be installed off a plain 1.2 MB drive. -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ Never trust an operating system you don't have sources for. ;-)
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199509081313.PAA13198>