🚀 go-pugleaf

In article <1ej06qINNd7g@iraul1.ira.uka.de> S_TILLENBURG@iravcl.ira.uka.de (|S| Stephan Tillenburg) writes:
>I read flopticals can read only MS-DOS standard formats
>( 9 sectors per track on DD and 18  sectors per track on HD )
>but you can't read 10 sectors per track on DD - disks

As I understand it, current flopticals can read MS-DOS discs but not
Acorn discs. This is because the firmware for the floptical drives
assumes that the first sector on each track will be sector 1 (as per
DOS discs). Acorn discs start as sector 0. A recent magazine (BAU
about 2 months ago I think) said that Acorn was trying to get the
floptical manufacturers in the states to change this.

>( As I mentioned before - this is not my own experience with flopticals )

Same here.

Tom.

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Tom Hughes, CS3

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In <1ej06qINNd7g@iraul1.ira.uka.de> S_TILLENBURG@iravcl.ira.uka.de (|S| Stephan Tillenburg) writes:

>I read flopticals can read only MS-DOS standard formats
>( 9 sectors per track on DD and 18  sectors per track on HD )
>but you can't read 10 sectors per track on DD - disks

Is this a limitation of the device driver / filing system software on the
computer, or of the embedded SCSI firmware on the drive? It seems to me that
it is a question of whether the filing system recognises the disks rather
than a limitation of the drives.

The drive must recognise the media type in hardware and make the necessary
adjustments for head flux and transfer / rotational speed (depending on how
it's done). The SCSI driver accesses the drive as a raw sector device, so
any sectors physically present can be read and written. The filing system
is then responsible for making sense of different formats (which directory
entry corresponds to which file and where the file is on the disk). If the
filing system does not support variations on the MSDOS format, it is not
fair to blame the drive. Just because ED floppies are normally formatted
to 36 sectors of 512 bytes, it doesn't mean you can't format them to 23
sectors of 1024 bytes. The only restriction with the MSDOS disk definitions
(apart from the physical limitations of the media in the drive) is that all
tracks must contain the same number of sectors, numbered from 1 to n. Any
sectors which are physically missing from the format must be marked bad in
the FAT and don't expect consistent results if duplicate sectors (with the
same number) are present on the same track of read/write media.

--
Adam David (adamd@rhi.hi.is)

In article <1992Nov21.163437.15129@dcs.warwick.ac.uk>, thughes@dcs.warwick.ac.uk (Tom Hughes) writes:
>
> As I understand it, current flopticals can read MS-DOS discs but not
> Acorn discs. This is because the firmware for the floptical drives
> assumes that the first sector on each track will be sector 1 (as per
> DOS discs). Acorn discs start as sector 0. A recent magazine (BAU
> about 2 months ago I think) said that Acorn was trying to get the
> floptical manufacturers in the states to change this.

Acorn's not the only one. You will notice certain companies being very careful
to say that it can use existing 3.5" media, rather than that it can read
existing Acorn-format discs.

I know at least one company that is holding on to its release of flopticals
until Acorn-format DD and HD discs are supported - the manufacturers HAVE
committed themselves to fixing this problem, but it seems to be taking longer
than expected...

--Clive.