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| How low can you *LOAD in the Acorn DFS on a BBC-B 32K? http://www.retrosoftware.co.uk/forum/viewtopic.php?f=73&t=698 |
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| Author: | PitfallJ [ Fri Oct 28, 2011 11:02 am ] |
| Post subject: | How low can you *LOAD in the Acorn DFS on a BBC-B 32K? |
Hi, I'm sure this has been talked about before - but I couldn't find the post. Anyway I have my Mode7 program at $6000 and want to *LOAD a large data file in at $1900 and then do a *TAPE and relocate it downwards. Unfortunately the file is so long it will overwrite my program. If I *LOAD it in at $1000 things would be ok - I can test this but I don't have a real BBC-B and was wondering how reliable this would be anyway. Is there a breakdown of how the DFS uses $D00-$1900? Also if I'm not using sound or key definitions I can use the memory at $400-$CFF right? Can I *LOAD a file directly into $400-$CFF and as long at I leave $D00-$1900 alone the DFS will continue to function ok? - PJ |
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| Author: | TomW [ Fri Oct 28, 2011 12:02 pm ] |
| Post subject: | Re: How low can you *LOAD in the Acorn DFS on a BBC-B 32K? |
$400-$CFF should be okay I think. The lowest you can normally load is $1100. |
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| Author: | tautology [ Fri Oct 28, 2011 8:08 pm ] |
| Post subject: | Re: How low can you *LOAD in the Acorn DFS on a BBC-B 32K? |
All the detail's at MDFS: http://mdfs.net/Docs/Comp/BBC/Disk/DFSMem In essence, as long as you're careful you can *LOAD into &1400, or maybe even &1300 - but I'd make sure that you make sure that the *LOAD is the only disc access and that all other file handles are closed. You can use DFS to load anywhere in memory - though it'll corrupt the data if you touch between &e00 and &1400. (In theory you may even be able to overwrite &e00 to &fff - as this is just a copy of the current directory, but you may want to try this out first!) |
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| Author: | TomW [ Fri Oct 28, 2011 10:37 pm ] |
| Post subject: | Re: How low can you *LOAD in the Acorn DFS on a BBC-B 32K? |
You can safely load at $1100. *LOAD doesn't use the open file buffers, so you can safely overwrite them. |
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