
<TITLE>PSION Programming Ref.: Chapter 8. OPL and Solid State Disks</TITLE>
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<H1><CENTER>OPL and Solid State Disks</CENTER></H1>
<P>
<P>
<P>
<H3>Types of Solid State Disk</H3> 
<P>
Solid State Disks (SSDs) are explained in detail in the User 
guide. There are two main reasons for using them:
<P>
<UL><LI> To provide more room for storing information.</LI> 
</UL>
<UL><LI> To make backup copies of important information, in case </LI> 
you accidentally change or delete it (or even lose your Series 3a).
</UL>
There are two types  Ram SSDs and Flash SSDs. 
They fit into the SSD drives marked "A" and "B", 
at either side of the Series 3a.
<P>
<UL><LI> Flash SSDs are for storing or backing up information which </LI> 
is infrequently changed. This includes finished OPL programs.
</UL>
<UL><LI> Ram SSDs are for storing or backing up information which </LI> 
changes frequently. This includes OPL programs you are still writing 
or testing.
</UL>
You can, though, save programs and data files to either kind of SSD, 
as you see fit.
<P>
<H3>How to put programs on an SSD</H3> 
<P>
To create a new OPL module on an SSD, use the `New file' option in 
the System screen as before, but set the "Disk" line of the dialog 
to "A" or "B" as required.
<P>
To copy an OPL module onto an SSD, move onto the module name where 
it is listed under the Program icon, and use the `Copy file' option 
on the `File' menu. Set the `To file: Disk' line to "A" or "B". 
If you want this copy to have a different name to the original, type 
the name to use, on the `To file: Name' line. The new copy will appear 
in the list under the Program icon, but with "[A]" or "[B]" 
after its name. 
<P>
To copy the translated version of an OPL module, move onto the 
name in the list under the RunOpl icon (to the right of the Program 
icon), then proceed as before. 
<P>
<H3>SSDs from inside OPL</H3> 
<P>
Your OPL programs can create or use data files on SSDs. To do so, 
begin the name of the data file with "A:" or "B:"  
for example:
<P>
CREATE "B:JKQ",A,X1$,X2$
<P>
tries to create a data file "JKQ" on an SSD in "B", while 
<P>
DELETE "A:X300"
<P>
tries to delete a data file "X300" on an SSD in "A".
<P>
Don't confuse the drive names "A" and "B" with the logical 
names "A", "B", "C" and "D". Logical names are unaffected 
by which drive a data file is on.
<P>
The internal memory can be referred to as "M:", if required. For 
example:
<P>
<UL><PRE>
<B>PROC delx300:</B>
  LOCAL a$(3),c%
  a$="MAB" :c%=1 REM default to "Internal"
  dINIT "Delete X300 data file"
  dCHOICE c%,"Disk:","Internal,A,B"
  IF DIALOG REM returns 0 if cancelled
    DELETE MID$(A$,c%,1)+":X300"
  ENDIF
<B>ENDP</B>
</PRE></UL>
<P>
In this example, "MID$(A$,c%,1)" gives ""M"", ""A"" or 
""B"", according to the choice made in the dialog. This is added 
on the front of "":X300"" to give the name of the file to delete  
""M:X300"", ""A:X300"" or ""B:X300"".
<P>
When using data files with SSDs, follow the same guidelines as with 
OPL programs  Flash SSDs are for one-off or "finished" information, 
while Ram SSDs are for information which is still being changed.
<P>
<H3>Directories and DOS structure</H3> 
<P>
The internal memory and SSDs use a DOS-compatible directory structure, 
the same as that used by disks on business PCs. For more details, 
see the `Advanced Topics' chapter.
<P>
 
<P>
 
<P>
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