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Date   : Thu, 08 Jan 2004 22:26:20 -0000
From   : "Chris Thornley" <C.J.Thornley@...>
Subject: Re: IDE Interface for BBC

Hi,
I just like to bring to you attention this line "32 and 137 (actually,
it's 127) GB limits" where you say its "not 137Gb but 127GB" this is a
wrong conclusion its actual 137GB as orignally stated as it uses 48bit
addressing

References
http://www.maxtor.com/en/documentation/white_papers/big_drives_white_pap
ers.pdf
http://www.pc4d.com/hardware/68/a_interface_standard_that_breaks_the_137
gb_barrier.shtml
http://www.wiebetech.com/ATA6firewire.htm
http://lists.plug.phoenix.az.us/pipermail/plug-discuss/2002-November/032
442.htmplus 

Plus others

I'd actually prefer a PC based format as many people in the past had
there own format which was a pain when you needed to transfer files to
different platforms or backup. Ideally something following the
established real world standards will be ideal. Even
BerkleyFastFilesystem or UFS would be ideal. Few people had hard disks
for the beeb so I don't think there be a big compatibility problem, plus
the size of the disks now in existence some programs will fall over if
they try to determine the free space left on the drive inorder to save a
file. 

I've only recently managed to acquire a SR research Level 3 BBC file
server with a few Winchesters but I need an econect interface to access
this which alters page but that will serve as a good experiment for me
with hard disks.

Page size has always been a problem wish say my BBC B the shift form E00
to 1900 for DFS cause people to try to use allsorts or tricks to get
tape games to run. Few people used ADFS in the earlier days especially
in schools and it only really took of for Archimedes.

To be quite honest you really got to consider what you would like to use
the system for nowadays 12 years since model B. Also does it deserve all
that storage space. I still have my BBC don't get me wrong and I do play
some of the old classic games on it but I don't now do any serious work
on it like word-processing and programming etc. There are no real killer
applications I must use my BBC for. I just have it for nostalgic
purposes and the fact it was my very first computer.

Chris


               />      Christopher J. Thornley is
cjt@...
  (           //------------------------------------------------------,
 (*)OXOXOXOXO(*>=*=O=S=U=0=3=6=*=---------            
                >
  (           \\------------------------------------------------------'
               \>       Home Page :-http://www.coolrose.fsnet.co.uk
 

-----Original Message-----
From: Majordomo List Manager [mailto:majordomo@...] On Behalf
Of Mike Tomlinson
Sent: 08 January 2004 21:37
To: bbc-micro@...
Subject: Re: [BBC-Micro] IDE Interface for BBC


In article <6548626.1073562715248.JavaMail.www@...>, c.j.thornley@
coolrose.fsnet.co.uk writes

>    I found an existing circuit for an IDE interface for the bbc micro.

>    Found @ http://www.chrisward.uklinux.net/6502/circuit.shtml=A0and 
>    picture @ http://www.chrisward.uklinux.net/6502/schematics/ide.png

It's not specifically for the Beeb, and the circuit as shown would need
quite some modification to make it work on a Beeb.

>    This might alleviate problems with 16bit adressing on an 8bit 
>    system.

It works by clocking the 16 bits of data from the drive into two 74LS573
latches, then transferring the contents of those in two chunks onto the
6502's 8-bit data bus.

>    What capcity harddrive will the interface on the list support as 
>    harddrive less that 40Gb are difficult to source at shop and some 
>    machine can have a limt at 32GB and 137GB as the bit addressing 
>    changes.

JGH's suggestion was to modify ADFS to directly work with a simple IDE
interface, thus it's not a question of the PC's 32 and 137 (actually,
it's 127) GB limits, but the maximum drive size that ADFS can address.
Anyone know?

>    Is it best to have an acorn format or a PC or NTFS based one to 
>    allow easy transfer and preping of the drive.

I'd prefer to stick with Acorn format and make it as compatible as
possible with the Acorn Winchesters and ADFS.  It can then be prepped
with SuperForm.  Using a PC format would require a new FS ROM to be
written, and assuming it fitted into 16k, might attract the attention of
Microsoft's landsharks.  After all, if they're now demanding money for
licensing the FAT filesystem...

>    Is the page level altered significantly

With ADFS on the model B, it's raised to &1D00 IIRC.

> and will it be easy to 
>    transfer file from one filesystem to another.

That's what the CopyFiles program is for on the Model B.  On the Master,
you could do it by directing * commands at a particular ROM:

*-disc-Load :0.$.Chuckie 2000
*-adfs-Save :4.$.Games.Chuckie 2000+length 

etc.

Mike

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