Date   : Sat, 07 Sep 2002 08:31:36 +0100
From   : Mike Tomlinson <mike@...>
Subject: Re: Regaining disc drive memory work space

In article <001901c255db$aa9fe6c0$02000003@...>, james watson
<james@...> writes

>    When using a disc drive on a BBC micro, Page is moved from &E00 to 
>    &1900 to create memory work space for the disc drive. Is possible  
>    to regain the disc drive work space once the program has loaded. 
>    I.e resetting page back to &E00. Can anybody give an example of 
>    various techniques on how to achieve this.

1. If you don't open any random-access files (i.e. with
A%=OPENOUT("filename"), you can use a disc drive with PAGE set at &1100.
This gains you another 2k of RAM.

2. Many utility ROMs have a command to load a file from disc and then
move it down in memory.  For example, Disc Doctor:  *DOWNLOAD "file"
0E00

3. Use one of the E00 DFSes that provide full disc drive operation while
keeping PAGE at &0E00.

4. Assuming your file is 2000 bytes long, and is called by jumping to
the first byte, put in a function key:

*KEY0 OSCLI "*LOAD file 1900":OSCLI "*TAPE":FOR A%=1 TO 2000 STEP
4:A%!&0E00=A%!&1900:NEXT:CALL &0E00ŚM


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