APPENDIX II

ROMIT COMPATIBLE COMMANDS

This appendix deals with those filing system commands that are supplied by either the in-built cassette and Rom filing systems, or by any fitted disc filing system. Each is listed together with the relevant pages in the BBC micro User Guide, and the Advanced Uner Guide. If any of the commands require further clarification a number in square brackets is given, and that indicates the relevant paragraph following this list of commands.

CASSETTE/ROM filing system commands

Pages 391 to 390 of the BBC User Guide should bo read if you are unclear on the manner in which the cassette filing system works, as the operation of those commands within the RaFS is virtually identical.

[1| The use of the negative ADVAL command is only of use if you are using the RomIt buffer facilities. For further information on this see the command *BUFFER.

[2] All random access filing commands work in a manner that is not dissimilar to that employed by a DFS, but within the constraints of a serial file environment. This means that once a file has been closed it may only be extended up to the point where the next file header is located. If you try to extend the file past this point the error message 'Can't extend' will be issued. If the file is the last held in the RaFS this problem should not occur. Pages 188 to 193 of the BBC User Guide should be rend in connection with these commands. The filing handle assigned to the RaFS for write operations is hex &4F, and for read operations hex &4E.

[3] This is a BASIC II command, so users with BASIC I will not be able to use it. It opens up a file for both reading and writing.

[4] To gain access to a restricted form of the *INFO command you may use *OPT1,2 followed by *CAT which will give you the file name along with number of blocks in the file, the file length and the load and run addresses. The Flag status is not given as this is Romlt-specific, and supplied by the commands *ACCESS and *LOCK . Note that the load and run addresses are given as the full 32 bits (8 digits) and not as the 24 bits (6 digits) given via *INFO.

DISC filing system commands

There are only four DFS specific commands that might be used with the RaFS, and these are:

*BUILD
*DUMP
*LIST
*TYPE

Please refer to the relevant page of your DFS manual for further details on each command. All four commands work exactly as if they were working with discs. However, *BUILD does require some attention here.

*BUILD

Syntax: *BUILD <filename>
Function: To build an Ascii file.

You will already be aware of how *BUILD works in conjunction with your DFS, and working with the RaFS this remains the same. However, it is worth pointing out that if you build a file under the name of !BOOT you can then boot your RaFS code once it has been blown into an Eprom by pressing SHIFT R BREAK This is exactly the same as pressing SHIFT BREAK to boot a disc.

However, not all makes of DFS use *BUILD as expected. For example, Watford DFS version 1.2 onwards omits the filename, and saves the file with

a null filename. This can quite easily be rectified by using the *RENAME command. Tor instance, if you are building the !BOOT file you would rename the un-named file with:

*RENAME ,!BOOT

Here the comma acts as a delimiter and specifies that the first filename is in fact null, or empty.

If you do not have a DFS fitted to your machine there are various other ways of creating a !BOOT file, and these may he found in Section 3.2 to this manual.

NOTE

You DFS manual will also contain details of how to use random access files, and this should be read in conjunction with the information found in the BBC User Guide.