Path: csiph.com!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: "Carlos E.R." Newsgroups: comp.os.linux.misc,alt.usage.english,alt.english.usage Subject: Re: Floppies Date: Wed, 17 Sep 2025 00:42:55 +0200 Lines: 36 Message-ID: References: <9fjemlxbio.ln2@Telcontar.valinor> <6jefmlxb6j.ln2@Telcontar.valinor> <10884l7$173em$1@dont-email.me> <1089ge2$1fvl9$8@dont-email.me> <10a68ql$16tjt$1@dont-email.me> <68c6bbc5$0$402$426a74cc@news.free.fr> <10a6rp4$1d082$5@dont-email.me> <2d9jplxvcn.ln2@Telcontar.valinor> <10a6t8d$1d082$8@dont-email.me> <4cnjplxbgm.ln2@Telcontar.valinor> <101fck52laaigefq5tubi6i7b0qpccmuic@4ax.com> <9DOdncYo-vBzE1r1nZ2dnZfqnPadnZ2d@giganews.com> <10a8mbc$1q6g1$8@dont-email.me> <10aca8j$2odbt$1@dont-email.me> <20250916133411.00001c32@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Trace: individual.net Fod4WkuZ/2d+6BfPe40wygELCFW7VRcEu2l4oENNPCqVWuztUw X-Orig-Path: Telcontar.valinor!not-for-mail Cancel-Lock: sha1:lsHmxQ9G8u8mGIEe5tKTQ0V6WYM= sha256:j0VtvTD/8hnd61toC/KahNG8PcRoZTMAf2XuomA8mDU= User-Agent: Mozilla Thunderbird Content-Language: es-ES, en-CA In-Reply-To: <20250916133411.00001c32@gmail.com> Xref: csiph.com comp.os.linux.misc:74360 alt.usage.english:1128262 On 2025-09-16 22:34, John Ames wrote: > On Tue, 16 Sep 2025 20:28:35 +0200 > Bertel Lund Hansen wrote: > >>> On the PC the format was handled in software (BIOS or even >>> userland), >> >> The 3½" floppies could hold 720 kByte when used on a PC. If you set >> up config.sys correctly, it could handle 144 kByte. >> >> I haven't tried other formats on a PC, but I would be surprised if it >> could handle other formats - without formatting. > > The standard PC boot sector contains disk geometry info which can > *theoretically* represent a wide range of disk formats; I'm not sure > how far that can practically be pushed. The MS-DOS FORMAT utility > supported a lot more options for disk sizes, but I don't know if it > could read any arbitrary geometry as specified in the boot sector. > > The controller itself imposed some limitations as well (at least some > of the parameters were shared across both drives on the ribbon, which > made for interesting times if one was trying to access a non-standard > format while running off a floppy in a standard format!) And only FM/ > MFM encoding was supported, which meant that GCR-format disks (Apple > II, 400/800KB Mac, most Commodore) couldn't be accessed in any case. I long ago read an article in a magazine that explained and included software to write and read floppies with a lot more capacity. I don't want to write a figure, because I don't remember. It played with gap sizes and numbers. Maybe I was busy at the time and did not do the experiment, I only read it. -- Cheers, Carlos. ES🇪🇸, EU🇪🇺;