B+ DFS & ADFS versions for PAGE E00

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rmbrowngr
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B+ DFS & ADFS versions for PAGE E00

Post by rmbrowngr »

I'm trying to work out which are the correct versions of Acorn DFS & ADFS for the B+ to have PAGE at E00. I'm looking at this page http://mdfs.net/System/ROMs/Filing/Disk/Acorn/. I believe the correct version for ADFS is 1.31 (ADFS131E00). For DFS I know the last version is 2.26 (which I have) and includes SWRAM utils.

I see that some people have both DFS and ADFS installed on their machines. Do both of them sit happily together and what happens to PAGE?

For ADFS131EOO, how do you set this up to work correctly? Does it only work loaded into SWRAM, or can you put it in an EPROM and it will use SWRAM for its work space?

Finally, I believe that ADFS131E00 supports SCSI hard disks, so I guess I can add a BeebSCSI. :D
Last edited by rmbrowngr on Tue May 21, 2019 5:09 pm, edited 1 time in total.
Richard B
Acorn Electrons issue 4 and 6, MRB, Plus 1, AP6, AP5, Pegasus 400, BeebSCSI, Gotek, Raspberry Pi, GoSDC MBE.
BBC B+ 64K (128K upgraded) with Duel OS, Raspberry Pi and Gotek.
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Re: B+ DFS & ADFS versions for PAGE E00

Post by RobC »

rmbrowngr wrote:
Tue May 21, 2019 5:09 pm
I see that some people have both DFS and ADFS installed on their machines. Do both of them sit happily together and what happens to PAGE?

For ADFS131EOO, how do you set this up to work correctly? Does it only work loaded into SWRAM, or can you put it in an EPROM and it will use SWRAM for its work space?
They both need to be installed in SWRAM as they use the space above their rom code as workspace. PAGE then remains at &E00 but you get DFS and ADFS in the machine. I use a DS1230Y 32KB NVRAM to hold them both so that they're available on power-up - that way, they're semi-permanently in SWRAM.
rmbrowngr wrote:
Tue May 21, 2019 5:09 pm
Finally, I believe that ADFS131E00 supports SCSI hard disks, so I guess I can add a BeebSCSI.
Yes - I've had this working with a real SCSI hard drive so no reason to think it won't work with a BeebSCSI.
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Re: B+ DFS & ADFS versions for PAGE E00

Post by cmorley »

It does work with BeebSCSI but there is a downside. A bunch of commands are missing like *DESTROY and there is no help. So I end up using ADFS 1.30 a lot of the time anyway.
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Re: B+ DFS & ADFS versions for PAGE E00

Post by rmbrowngr »

Coming back to this afternoon some time. I suppose you can combine rom and ram with some address decoding on a single board to get page at E00 and not load ADFS or DFS in SW RAM each time you boot?

Also B+ sockets being configurable as 32k you could have both ADFS and DFS on a single plugin board I guess?
Richard B
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Re: B+ DFS & ADFS versions for PAGE E00

Post by jgharston »

Some interfaces did indeed put ROM at 8000-9FFF and RAM at A000-BFFF in the same socket.

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Re: B+ DFS & ADFS versions for PAGE E00

Post by Coeus »

For MMFS (and MMFS2) on the B+ it copies some of it's code into the 12K of spare RAM left over the from the shadow screen and then uses some of that RAM as workspace. As that is based on DFS perhaps the same technique could be applied so a DFS that is not patched to use an SD card.
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Re: B+ DFS & ADFS versions for PAGE E00

Post by rmbrowngr »

I think I read that MMFS is based on DFS 2.26? So I guess that this is an easier mod, than looking at ADFS first.
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Re: B+ DFS & ADFS versions for PAGE E00

Post by daveejhitchins »

Just a thought . . .

ACP produced both a DFS and ADFS E00 for the Electron. DFS was as JGH described above e.g. RAM was overlaid at the top of the 16K block for its workspace, however, ADFS E00 used a second 16K bank within an ABR cartridge. I believe both could be "PLDed" e.g. use a PLD to do the switching-in of the RAM. The current Electron ADFS should be easy to convert - DFS a little more work - but doable, I'm sure. If this can be achieved for all versions of machine (and keeping the SCSI code in the Electron version) it would be brilliant.

ADFS is tight on all models, I believe (?) so the upper block, containing the RAM, could be ROM overlaid with enough RAM for workspace giving more space to contain the less used commands . . . .

I'm not sure why this method hasn't been used more! One hardware implementation, with the software switching method well documented, could be used for all sorts programs. It could easily be designed to hold two such blocks . . . The possibilities are endless :D

Doing it this way would avoid the need for the load-to-RAM. And I bet Chris Morley could get it on a very small board with reprogrammability? - Chris . . . ?

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Re: B+ DFS & ADFS versions for PAGE E00

Post by RobC »

rmbrowngr wrote:
Sun Jan 17, 2021 3:00 pm
Coming back to this afternoon some time. I suppose you can combine rom and ram with some address decoding on a single board to get page at E00 and not load ADFS or DFS in SW RAM each time you boot?

Also B+ sockets being configurable as 32k you could have both ADFS and DFS on a single plugin board I guess?
Or just use a DS1230Y NVRAM like I do - you then only have to load the ROM images in once and it'll be good for years :D
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Re: B+ DFS & ADFS versions for PAGE E00

Post by cmorley »

daveejhitchins wrote:
Tue Jan 19, 2021 8:18 am
Doing it this way would avoid the need for the load-to-RAM. And I bet Chris Morley could get it on a very small board with reprogrammability? - Chris . . . ?
It would be possible to do a board with an surface mount EEPROM on the top (like my 64KB EEPROM module) and 32KB SRAM + 22V10 PLD on the bottom layer. This would package in the footprint of a 28 pin DIP chip with a fly-lead for write strobe (NWDS).

PLD code to switch say the top 8KB from EEPROM/RAM or perhaps lower and upper 8KB separately. It'd need some protection so tools/games which scan for sideways RAM don't trigger a bank change.... all possible.

The problem would be software support. It'd be a major job.

I've looked at patching ADFS & DFS to use an OS RAM to emulate the Master's Hazel workspace (B only for now). Then you could have any ROM with access to high workspace. Problem is you can't run the Master (6512 CPU) ROMs on a 6502 and the lack of commented source for DFS/ADFS makes moving workspaces a bigger job. Perhaps I'll try again at some point... maybe MMFS first.
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Re: B+ DFS & ADFS versions for PAGE E00

Post by daveejhitchins »

cmorley wrote:
Tue Jan 19, 2021 9:04 am
The problem would be software support. It'd be a major job.
Maybe someone else could handle this . . . ?

Dave H.
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