Date : Mon, 09 Feb 2004 21:15:49 -0000
From : "Colin" <cwhill@...>
Subject: Re: BBC floppy / drive formats]
Ooh heck, this is all a bit much for me!
I'm not into the inner workings yet and this is my first encounter with a
disc drive (it's a TEAC FD-55AV-10-U part number 19307200-10 according to
the label inside it).
If I have this right, one can still buy the correct size discs from PC shops
(PC World for instance) but they won't work with the BBC Micro if they have
been formatted as you need to format them on the Beeb?,but you can't format
them on the Beeb as it won't recognise them. Sounds a bit catch 22.
Does that mean I have to shop around on eBay etc for old discs or have I got
the wrong end of the stick? (please reply in very very simple terms)
Thanks for putting up with these dumb questions.
Colin Hill
----- Original Message -----
From: "Jules Richardson" <julesrichardsonuk@...>
To: <cwhill@...>
Cc: <bbc-micro@...>
Sent: Monday, February 09, 2004 4:58 PM
Subject: [Fwd: [BBC-Micro] Re: BBC floppy / drive formats]
> I asked a similar Q a while back in terms of disk formats only - the
> following is Jonathan's (trimmed) response:
>
> xxxxxxxxxxx
>
> See http://www.mdfs.net/Docs/Comp/Disk/Densities and
> http://www.mdfs.net/Docs/Comp/Disk/Format/Formats
>
> In summary:
>
> Disk Formats
> ------------
> Media Mod. Sides Tracks Sectors Numbers BytesPerSector Media Size
> DD FM 1 40 10 0-9 256 100k
> DD FM 2 40 10 0-9 256 200k
> DD FM 1 80 10 0-9 256 200k
> DD FM 2 80 10 0-9 256 400k
> DD MFM 1 40 9 0-8 512 180k
> DD MFM 1 40 9 1-9 512 180k
> DD MFM 2 40 9 0-8 512 360k
> DD MFM 2 40 9 1-9 512 360k
> DD MFM 1 80 9 0-8 512 360k
> DD MFM 1 80 9 1-9 512 360k
> DD MFM 2 80 9 0-8 512 720k
> DD MFM 2 80 9 1-9 512 720k
> DD MFM 1 40 16 0-15 256 160k
> DD MFM 2 40 16 0-15 256 320k
> DD MFM 1 80 16 0-15 256 320k
> DD MFM 2 80 16 0-15 256 640k
> DD MFM 2 80 5 0-4 1024 800k
> HD MFM 2 80 10 0-9 1024 1600k
> HD MFM 2 80 18 1-18 512 1440k
> HD MFM 2 80 15 1-15 512 1200k
>
> Once a disk has been formatted, you can put any filesystem in it. There
> are usual combinations, eg 1*80*10*256 usually has DFS in it and
> 1*80*16*256 usually has ADFS in it, but it's just as easy to put DFS in
> 1*80*16*256, which is one of the options Watford's DDFS gives you.
>
> Filesystem Formats
> ------------------
> DFS:
> Directory Size=&0200
> Free Space Map=implied
> Root =&0000-&0001
> Deblocked =No
>
> Watford DFS:
> Directory Size=&0400
> Free Space Map=implied
> Root =&0000-&0003
> Deblocked =No
>
> ADFS S,M,L:
> Directory Size=&0500
> Free Space Map=&0000,&0001
> Root =&0002-&0006
> Deblocked =No
>
> ADFS D,E,F:
> Directory Size
> Free Space Map= ... check RISC OS PRMs
> Root
> Deblocked =No
>
> Acorn CPM:
> Directory Size=&1000
> Free Space Map=implied
> Root =&001E00
> Deblocked =Yes
>
> HADFS:
> Directory Size=&0300
> Free Space Map=&0046
> Root =&0047
> Deblocked =No
>
> Most Acorn formats use H:C:S numbering, ie:
> logical sector=Side*TracksPerSide+Track*SecPerTrack+Sector
>
> 32bit ADFSs also use C:H:S numbering, ie:
> logical sector=Track*SecPerTrack*Sides+Side*SecPerTrack+Sector
>
> There are many others. I'm updated some documents on my website about
> details of filesystem structures.
>
>
>