Re: MSDOS before cyl 1024

From	"Carlos E.R." <robin_listas@es.invalid>
Newsgroups	comp.os.linux.misc
Subject	Re: MSDOS before cyl 1024
Date	2023-01-22 14:29 +0100
Message-ID	<lbqv9jxpus.ln2@Telcontar.valinor> (permalink)
References	(1 earlier) <lq7cxgrw2k.fsf@mail.soti.ca> <tqglff$2ie4h$5@dont-email.me> <tqgq6a$2k44c$2@dont-email.me> <ea7t9jx7k1.ln2@Telcontar.valinor> <21gv9j-qr1.ln1@jefferson.foo>

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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.

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MSDOS before cyl 1024 vjp2.at@at.BioStrategist.dot.dot.com - 2023-01-20 15:10 +0000
  Re: MSDOS before cyl 1024 Marco Moock <mo01@posteo.de> - 2023-01-20 19:04 +0100
  Re: MSDOS before cyl 1024 Vilmos Soti <vilmos@soti.ca> - 2023-01-21 03:00 -0800
    Re: MSDOS before cyl 1024 Marco Moock <mo01@posteo.de> - 2023-01-21 13:23 +0100
      Re: MSDOS before cyl 1024 The Natural Philosopher <tnp@invalid.invalid> - 2023-01-21 13:43 +0000
        Re: MSDOS before cyl 1024 "Carlos E.R." <robin_listas@es.invalid> - 2023-01-21 14:52 +0100
          Re: MSDOS before cyl 1024 Marco Moock <mo01@posteo.de> - 2023-01-21 17:24 +0100
            Re: MSDOS before cyl 1024 "Carlos E.R." <robin_listas@es.invalid> - 2023-01-21 20:32 +0100
              Re: MSDOS before cyl 1024 Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2023-01-21 19:50 +0000
                Re: MSDOS before cyl 1024 "Carlos E.R." <robin_listas@es.invalid> - 2023-01-21 21:16 +0100
                Re: MSDOS before cyl 1024 Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2023-01-21 20:45 +0000
                Re: MSDOS before cyl 1024 The Natural Philosopher <tnp@invalid.invalid> - 2023-01-22 09:39 +0000
              Re: MSDOS before cyl 1024 "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2023-01-21 15:53 -0500
                Re: MSDOS before cyl 1024 "Carlos E.R." <robin_listas@es.invalid> - 2023-01-22 04:47 +0100
              Re: MSDOS before cyl 1024 The Natural Philosopher <tnp@invalid.invalid> - 2023-01-22 09:35 +0000
                Re: MSDOS before cyl 1024 "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2023-01-22 05:08 -0500
          Re: MSDOS before cyl 1024 Peter 'Shaggy' Haywood <phaywood@alphalink.com.au> - 2023-01-22 21:33 +1100
            Re: MSDOS before cyl 1024 "Carlos E.R." <robin_listas@es.invalid> - 2023-01-22 14:29 +0100
  Re: MSDOS before cyl 1024 vjp2.at@at.BioStrategist.dot.dot.com - 2023-01-22 20:13 +0000
    Re: MSDOS before cyl 1024 Marco Moock <mo01@posteo.de> - 2023-01-23 10:08 +0100
    Re: MSDOS before cyl 1024 Peter 'Shaggy' Haywood <phaywood@alphalink.com.au> - 2023-01-26 14:40 +1100

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