Path: csiph.com!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: "Carlos E.R." Newsgroups: comp.os.linux.misc Subject: Re: MSDOS before cyl 1024 Date: Sun, 22 Jan 2023 14:29:57 +0100 Lines: 55 Message-ID: References: <21gv9j-qr1.ln1@jefferson.foo> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Trace: individual.net brmNEc2hiJWRAUm+P5MnrQ1GM7xZIVYKUmbD2KUqBoQjqmzr7s X-Orig-Path: Telcontar.valinor!not-for-mail Cancel-Lock: sha1:XhytTeFBua57xev6NNnEYZRQP/o= User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Content-Language: es-ES, en-CA In-Reply-To: <21gv9j-qr1.ln1@jefferson.foo> Xref: csiph.com comp.os.linux.misc:36793 On 2023-01-22 11:33, Peter 'Shaggy' Haywood wrote: > Groovy hepcat Carlos E.R. was jivin' in comp.os.linux.misc on Sun, 22 > Jan 2023 12:52 am. It's a cool scene! Dig it. > >> On 2023-01-21 14:43, The Natural Philosopher wrote: >>> On 21/01/2023 12:23, Marco Moock wrote: >>>> Am 21.01.2023 um 03:00:51 Uhr schrieb Vilmos Soti: >>>> >>>>> vjp2.at@at.BioStrategist.dot.dot.com writes: >>>>> >>>>>> What is this about MSDOS partition must be before cylinder 1024? >>>>> >>>>> Old BIOS constraint. Long ago, the BIOS encoded the number of >>>>> heads, cylinders, and sectors in only a few bytes. The cylinders >>>>> were encoded in 10 bits. >>>>> >>>>> This is really old stuff -- maybe 40 year old stuff. >>>> >>>> True, but I dunno when BIOS implementations were changed. I assume >>>> late 90s/early 2000s, but I dunno. Does anybody here know? >>>> >>>>>> How do you know on GParted? >>>>> >>>>> I am surprised that this pops up in 2023. >>>> >>>> Many documentation still mentions that issue, so people ask about >>>> it. >>>> >>> At one level or another faced with a disk the operating system or >>> BIOS needs to know how its laid out so there has to be one hard coded >>> sector - sector zero - to  bootstrap everything. That may contain >>> almost anything, I cant remember the boot sequence on a PC. But it >>> has to be understood by legacy BIOS as well as modern BIOS. >> >> Old bios and software accessed disks specifying the cylinder, the >> head, and the sector. So does MsDOS. >> >> Today they only specify the LBA sector. >> >> Maybe FreeDos can use LBA, dunno. > > In fact, (MS)DOS has supported LBA mode for quite some time. Newer > versions of DOS added support for newer BIOS calls that had extended > (hard) drive support. When LBA support came to the BIOS, it soon came > to DOS too. > And even before the BIOS and DOS supported LBA, DOS used it > internally, converting LBA values to their CHS equivalents before > calling CHS based BIOS routines. > And, yes, FreeDOS does indeed support LBA. Ah, I have probably forgotten -- Cheers, Carlos.