Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.os.linux.misc > #36751 > unrolled thread

MSDOS before cyl 1024

Back to article view | Back to comp.os.linux.misc

Contents

  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

Page 1 of 2  [1] 2  Next page →

#36751 — MSDOS before cyl 1024

What is this about MSDOS partition must be before cylinder 1024?

How do you know on GParted?

thanks

-- 
	 Vasos Panagiotopoulos  panix.com/~vjp2/vasos.htm
  ---{Nothing herein constitutes advice.  Everything fully disclaimed.}---

[toc] | [next] | [standalone]

#36752

Am 20.01.2023 um 15:10:52 Uhr schrieb
vjp2.at@at.BioStrategist.dot.dot.com:

> What is this about MSDOS partition must be before cylinder 1024?

https://en.wikipedia.org/wiki/Cylinder_1024
That is only relevant to old-ass computers.

> How do you know on GParted?

You can create your boot file system (either / or /boot if separated) on
the first partition on the disk.

[toc] | [prev] | [next] | [standalone]

#36753

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.

> How do you know on GParted?

I am surprised that this pops up in 2023.

Vilmos

[toc] | [prev] | [next] | [standalone]

#36754

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.

[toc] | [prev] | [next] | [standalone]

#36757

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.



-- 
I would rather have questions that cannot be answered...
...than to have answers that cannot be questioned

Richard Feynman

[toc] | [prev] | [next] | [standalone]

#36760

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.

-- 
Cheers, Carlos.

[toc] | [prev] | [next] | [standalone]

#36764

Am 21.01.2023 um 14:52:46 Uhr schrieb Carlos E.R.:

> Today they only specify the LBA sector.

Can old disks (non-LBA) still be used with them?

[toc] | [prev] | [next] | [standalone]

#36773

On 2023-01-21 17:24, Marco Moock wrote:
> Am 21.01.2023 um 14:52:46 Uhr schrieb Carlos E.R.:
> 
>> Today they only specify the LBA sector.
> 
> Can old disks (non-LBA) still be used with them?

That's a good question.

I suspect that disks or BIOS had both for years.

However, on MsDOS times common disks had the parallel cable or interface 
(PATA) while now they all use SATA.

I don't remember all the details :-)

There was an even older interface, used by disks with stepper motors on 
the head arm. That's what the IBM PC and compats used.

-- 
Cheers, Carlos.

[toc] | [prev] | [next] | [standalone]

#36774

On Sat, 21 Jan 2023 20:32:09 +0100, Carlos E.R. wrote:

> On 2023-01-21 17:24, Marco Moock wrote:
>> Am 21.01.2023 um 14:52:46 Uhr schrieb Carlos E.R.:
>> 
>>> Today they only specify the LBA sector.
>> 
>> Can old disks (non-LBA) still be used with them?
> 
> That's a good question.
> 
> I suspect that disks or BIOS had both for years.
> 
> However, on MsDOS times common disks had the parallel cable or interface 
> (PATA) while now they all use SATA.
> 
> I don't remember all the details :-)
> 
> There was an even older interface, used by disks with stepper motors on 
> the head arm. That's what the IBM PC and compats used.

Before the advent of a BIOS that recognized Logical Block Addressing ("LBA"),
the BIOS used Cylinder/Head/Sector ("CHS") addressing. There was a limit to this
addressing scheme that meant that it could not access more than 1024
cylinders.

For MSDOS to boot, it's partition needed to be marked "bootable", and be
located within this 1024 cylinder limit, as the BIOS could not reach
a boot partition outside of this limit. Thus, the rule of thumb that
the bootable partition /must/ reside within the first 1024 cylinders
of the disk.

However, when the BIOS implementations (and probably, disk controllers)
moved to LBA, this limit effectively disappeared, as now the bootable
partition had a 32bit disk address space to live in. 

-- 
Lew Pitcher
"In Skills We Trust"

[toc] | [prev] | [next] | [standalone]

#36775

On 2023-01-21 20:50, Lew Pitcher wrote:
> On Sat, 21 Jan 2023 20:32:09 +0100, Carlos E.R. wrote:
>> On 2023-01-21 17:24, Marco Moock wrote:
>>> Am 21.01.2023 um 14:52:46 Uhr schrieb Carlos E.R.:
>>>
>>>> Today they only specify the LBA sector.
>>>
>>> Can old disks (non-LBA) still be used with them?
>>
>> That's a good question.
>>
>> I suspect that disks or BIOS had both for years.
>>
>> However, on MsDOS times common disks had the parallel cable or interface
>> (PATA) while now they all use SATA.
>>
>> I don't remember all the details :-)
>>
>> There was an even older interface, used by disks with stepper motors on
>> the head arm. That's what the IBM PC and compats used.
> 
> Before the advent of a BIOS that recognized Logical Block Addressing ("LBA"),
> the BIOS used Cylinder/Head/Sector ("CHS") addressing. There was a limit to this
> addressing scheme that meant that it could not access more than 1024
> cylinders.
> 
> For MSDOS to boot, it's partition needed to be marked "bootable", and be
> located within this 1024 cylinder limit, as the BIOS could not reach
> a boot partition outside of this limit. Thus, the rule of thumb that
> the bootable partition /must/ reside within the first 1024 cylinders
> of the disk.
> 
> However, when the BIOS implementations (and probably, disk controllers)
> moved to LBA, this limit effectively disappeared, as now the bootable
> partition had a 32bit disk address space to live in.

Reminds me. Linux could use bigger disks, but LILO could not, because it 
used BIOS services to run and load the kernel initially. The trick then 
was to create first a small /boot partition for LILO to live in, and the 
kernel. Then the rest of the system could be beyond that cylinder, 
because the kernel could access it.

So sometimes we had to reduce the size of the partition holding dos or 
windows to make for "/boot" (maybe 100 MB was enough), and then the 
system could be at the end of the disk.

-- 
Cheers, Carlos.

[toc] | [prev] | [next] | [standalone]

#36776

On Sat, 21 Jan 2023 21:16:03 +0100, Carlos E.R. wrote:

> On 2023-01-21 20:50, Lew Pitcher wrote:
>> On Sat, 21 Jan 2023 20:32:09 +0100, Carlos E.R. wrote:
>>> On 2023-01-21 17:24, Marco Moock wrote:
>>>> Am 21.01.2023 um 14:52:46 Uhr schrieb Carlos E.R.:
>>>>
>>>>> Today they only specify the LBA sector.
>>>>
>>>> Can old disks (non-LBA) still be used with them?
>>>
>>> That's a good question.
>>>
>>> I suspect that disks or BIOS had both for years.
>>>
>>> However, on MsDOS times common disks had the parallel cable or interface
>>> (PATA) while now they all use SATA.
>>>
>>> I don't remember all the details :-)
>>>
>>> There was an even older interface, used by disks with stepper motors on
>>> the head arm. That's what the IBM PC and compats used.
>> 
>> Before the advent of a BIOS that recognized Logical Block Addressing ("LBA"),
>> the BIOS used Cylinder/Head/Sector ("CHS") addressing. There was a limit to this
>> addressing scheme that meant that it could not access more than 1024
>> cylinders.
>> 
>> For MSDOS to boot, it's partition needed to be marked "bootable", and be
>> located within this 1024 cylinder limit, as the BIOS could not reach
>> a boot partition outside of this limit. Thus, the rule of thumb that
>> the bootable partition /must/ reside within the first 1024 cylinders
>> of the disk.
>> 
>> However, when the BIOS implementations (and probably, disk controllers)
>> moved to LBA, this limit effectively disappeared, as now the bootable
>> partition had a 32bit disk address space to live in.
> 
> Reminds me. Linux could use bigger disks, but LILO could not, because it 
> used BIOS services to run and load the kernel initially. The trick then 
> was to create first a small /boot partition for LILO to live in, and the 
> kernel. Then the rest of the system could be beyond that cylinder, 
> because the kernel could access it.
> 
> So sometimes we had to reduce the size of the partition holding dos or 
> windows to make for "/boot" (maybe 100 MB was enough), and then the 
> system could be at the end of the disk.

Sort of. With a BIOS that only recognized MBR ("Master Boot Record")
format disks, a bootstrap loader like LILO would live in a reserved
area at the beginning of the drive (the "master boot record"). If
you used a dual-boot system, you either put LILO there, and gave
it options to boot MSDOS, or you left the MSDOS boot loader there,
and gave it options to load Linux.

In either case, these boot loaders still used the BIOS to access
the hard drives (otherwise, they'd be loaded down with their own
disk drivers, and be too big for the MBR). So, not only did LILO
(and the other boot loaders) have to live below cyl 1024, so did
the bootable partitions of any operating systems you wanted to boot.

For me, I'd put LILO in the MBR, the linux /boot directory and
(when I used Windows) the MSDOS/MSWindows partition in low-address
partitions, and other filesystems (the rest of the linux root fs,
MSDOS D: drive, etc) in partitions higher up.

Of course, this changed with LBA, and again with GPT.

-- 
Lew Pitcher
"In Skills We Trust"

[toc] | [prev] | [next] | [standalone]

#36788

On 21/01/2023 20:16, Carlos E.R. wrote:
> On 2023-01-21 20:50, Lew Pitcher wrote:
>> On Sat, 21 Jan 2023 20:32:09 +0100, Carlos E.R. wrote:
>>> On 2023-01-21 17:24, Marco Moock wrote:
>>>> Am 21.01.2023 um 14:52:46 Uhr schrieb Carlos E.R.:
>>>>
>>>>> Today they only specify the LBA sector.
>>>>
>>>> Can old disks (non-LBA) still be used with them?
>>>
>>> That's a good question.
>>>
>>> I suspect that disks or BIOS had both for years.
>>>
>>> However, on MsDOS times common disks had the parallel cable or interface
>>> (PATA) while now they all use SATA.
>>>
>>> I don't remember all the details :-)
>>>
>>> There was an even older interface, used by disks with stepper motors on
>>> the head arm. That's what the IBM PC and compats used.
>>
>> Before the advent of a BIOS that recognized Logical Block Addressing 
>> ("LBA"),
>> the BIOS used Cylinder/Head/Sector ("CHS") addressing. There was a 
>> limit to this
>> addressing scheme that meant that it could not access more than 1024
>> cylinders.
>>
>> For MSDOS to boot, it's partition needed to be marked "bootable", and be
>> located within this 1024 cylinder limit, as the BIOS could not reach
>> a boot partition outside of this limit. Thus, the rule of thumb that
>> the bootable partition /must/ reside within the first 1024 cylinders
>> of the disk.
>>
>> However, when the BIOS implementations (and probably, disk controllers)
>> moved to LBA, this limit effectively disappeared, as now the bootable
>> partition had a 32bit disk address space to live in.
> 
> Reminds me. Linux could use bigger disks, but LILO could not, because it 
> used BIOS services to run and load the kernel initially. The trick then 
> was to create first a small /boot partition for LILO to live in, and the 
> kernel. Then the rest of the system could be beyond that cylinder, 
> because the kernel could access it.
> 
> So sometimes we had to reduce the size of the partition holding dos or 
> windows to make for "/boot" (maybe 100 MB was enough), and then the 
> system could be at the end of the disk.
> 

Mmm. Raspberry Pis still have a /boot section and so does this computer 
(/efi), but thats something to do with EFI.

On all machines the first sector has to be reserved as a table to tell 
the OS what's on the rest of the disk.
How much of that it understands is down to the BIOS.

-- 
"If you don’t read the news paper, you are un-informed. If you read the 
news paper, you are mis-informed."

Mark Twain

[toc] | [prev] | [next] | [standalone]

#36779

On Sat, 21 Jan 2023 14:32:09 -0500, Carlos E.R. <robin_listas@es.invalid> wrote:
> On 2023-01-21 17:24, Marco Moock wrote:
>> Am 21.01.2023 um 14:52:46 Uhr schrieb Carlos E.R.:
>>
>>> Today they only specify the LBA sector.
>>
>> Can old disks (non-LBA) still be used with them?
>
> That's a good question.
>
> I suspect that disks or BIOS had both for years.
>
> However, on MsDOS times common disks had the parallel cable or interface
> (PATA) while now they all use SATA.
>
> I don't remember all the details :-)
>
> There was an even older interface, used by disks with stepper motors on
> the head arm. That's what the IBM PC and compats used.

There are still systems in use that are affected by it. I'm currently using
one. From lshw the bios firmware shows ...
           vendor: American Megatrends Inc.
           version: 1604
           date: 10/16/2012

I have no idea why it's limited in this way. Once grub or whichever boot loader
I'm using takes control, it switches to using lba mode. It's only the loading
of grub stage2 that must be within the first 1024 cylinders.

I have one sata spinning rust drive that I rarely use, and 3 sata sdd drives.
They all use lba mode. The bios is normally set to boot from the first ssd drive.

Regards, Dave Hodgins

[toc] | [prev] | [next] | [standalone]

#36790

On 2023-01-21 21:53, David W. Hodgins wrote:
> On Sat, 21 Jan 2023 14:32:09 -0500, Carlos E.R. 
> <robin_listas@es.invalid> wrote:
>> On 2023-01-21 17:24, Marco Moock wrote:
>>> Am 21.01.2023 um 14:52:46 Uhr schrieb Carlos E.R.:
>>>
>>>> Today they only specify the LBA sector.
>>>
>>> Can old disks (non-LBA) still be used with them?
>>
>> That's a good question.
>>
>> I suspect that disks or BIOS had both for years.
>>
>> However, on MsDOS times common disks had the parallel cable or interface
>> (PATA) while now they all use SATA.
>>
>> I don't remember all the details :-)
>>
>> There was an even older interface, used by disks with stepper motors on
>> the head arm. That's what the IBM PC and compats used.
> 
> There are still systems in use that are affected by it. I'm currently using
> one. From lshw the bios firmware shows ...
>            vendor: American Megatrends Inc.
>            version: 1604
>            date: 10/16/2012
> 
> I have no idea why it's limited in this way. Once grub or whichever boot 
> loader I'm using takes control, it switches to using lba mode. It's only the 
> loading of grub stage2 that must be within the first 1024 cylinders.

It is simple, actually. The boot loader, which is very small, has to use 
the existing BIOS functions to read from the disk, thus it is subject to 
whatever limitations the BIOS has. Once the boot loader has loaded and 
passed control to some larger code that contains "modern" functionality 
to read from disk (usually the kernel), those limitations are gone.

Otherwise, the boot loader would have to be significantly bigger in 
order to replace the bios functionality to read hard disks of any type 
and size.

> 
> I have one sata spinning rust drive that I rarely use, and 3 sata sdd 
> drives. They all use lba mode. The bios is normally set to boot from the first 
> ssd drive.
> 
> Regards, Dave Hodgins

-- 
Cheers, Carlos.

[toc] | [prev] | [next] | [standalone]

#36787

On 21/01/2023 19:32, Carlos E.R. wrote:
> On 2023-01-21 17:24, Marco Moock wrote:
>> Am 21.01.2023 um 14:52:46 Uhr schrieb Carlos E.R.:
>>
>>> Today they only specify the LBA sector.
>>
>> Can old disks (non-LBA) still be used with them?
> 
> That's a good question.
> 
> I suspect that disks or BIOS had both for years.
> 
> However, on MsDOS times common disks had the parallel cable or interface 
> (PATA) while now they all use SATA.
> 
> I don't remember all the details :-)
> 
> There was an even older interface, used by disks with stepper motors on 
> the head arm. That's what the IBM PC and compats used.
> 
SMD, SASI, ST-506, SCSI,  ESDI, PATA (IDE), SATA, SAS... a new one every 
couple of years...

What's the latest bus attached one for SDDs?



-- 
A lie can travel halfway around the world while the truth is putting on 
its shoes.

[toc] | [prev] | [next] | [standalone]

#36789

On Sun, 22 Jan 2023 04:35:33 -0500, The Natural Philosopher <tnp@invalid.invalid> wrote:
> SMD, SASI, ST-506, SCSI,  ESDI, PATA (IDE), SATA, SAS... a new one every
> couple of years...
>
> What's the latest bus attached one for SDDs?

nvme ssd drives are connected using a pcie slot.

Regards, Dave Hodgins

[toc] | [prev] | [next] | [standalone]

#36792

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.

-- 


----- Dig the NEW and IMPROVED news sig!! -----


-------------- Shaggy was here! ---------------
              Ain't I'm a dawg!!

[toc] | [prev] | [next] | [standalone]

#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.

[toc] | [prev] | [next] | [standalone]

#36796

So I can put an MSDOS 6.22 multiboot Gparted/Grub partition anywhere?

Should I expand te MBR and put it there?

I assume I can't revive the Win7 I smashed so am going to put XP like I did
in 2010-14.

-- 
	 Vasos Panagiotopoulos  panix.com/~vjp2/vasos.htm
  ---{Nothing herein constitutes advice.  Everything fully disclaimed.}---

[toc] | [prev] | [next] | [standalone]

#36807

Am 22.01.2023 um 20:13:22 Uhr schrieb
vjp2.at@at.BioStrategist.dot.dot.com:

> I assume I can't revive the Win7 I smashed so am going to put XP like
> I did in 2010-14.

Forget that EoL systems - or use them offline in VM.

[toc] | [prev] | [next] | [standalone]

Page 1 of 2  [1] 2  Next page →

Back to top | Article view | comp.os.linux.misc

csiph-web