On Sat, May 22, 2010 at 5:38 AM, jasse...@itelefonica.com.br
<jasse...@itelefonica.com.br> wrote:
> Recently posted in this list:
>>(Alain Mouette)
>>No it has never been illegal, and it always worked
>>just fine. I use these since forever... what happened
>>is that most tools did not have a way of making them,
>>but if you know how to make them it allways worked
>>since MSDOS-3.
>>(Liam Proven)
>> You have been lucky. I have seen many incorrectly-
>>partitioned systems with multiple primaries where
>>some drives were not visible, on various versions
>>of MS-DOS and up to Windows 95.
>>(Alain Mouette)
>>Not Lucky, just hard work. Partitions were invented
>>without extended partitions, so it worked from the
>>FYI: I started using PC-DOS 1.1... so I have a long
>>history of dos and don'ts...
>  I do not have as long experience as either of you, but
> at least MSDOS 5.0 and PCDOS 6.3 (copies which I keep
> now, in original floppies) look for just one DOS primary
> and one DOS extended partition in each partition table.
> If there are more than one, the others are ignored.

That is as I have observed, yes.

> DRDOS and FreeDOS search all the partition table.

Sounds about right.

>  AFAIK, DOS partitions were invented in MSDOS 3.3, to
> work around the 32 MB disk size limit, and from the
> beginning they had the primary/extended options.

The history was this, as far as I know:

MS-DOS 2, 1st version with hard disk support; 1 × FAT12 32MB partition

MS-DOS 3.0, 1 × FAT16 primary + 1 × extended partition with 1 logical
drive, 2 × 32MB partitions, total 64MB

MS-DOS 3.3, 1 × FAT16 primary + 1 × extended partition with up to 23
logical drives, total of 24 × 32MB partitions, total 768MB

Compaq MS-DOS 3.31, large FAT32 partitions with up to 32 sectors per
cluster for partitions up to 2GB

IBM PC-DOS 4.0 adopted the Compaq scheme and MS followed suit. (DR-DOS
3.4, the first version, was just before, and I think also used the
Compaq scheme.)

Windows 95 OSR2 introduced FAT32.

> The
> reason was that the number of sectors before a partition
> was still limited to 64 Ki so the extended partition was
> needed, in order to provide a new origin in the disk.

This I did not know.

>  Anyway, this discussion is going astray from the
> original problem of Marcos Favero, for FDISK should have
> created the FAT 16 partitions he requested, whether or
> not some DOS versions could find all of them.

Thanks for the extra info!

Liam Proven • Profile: http://www.linkedin.com/in/liamproven
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