unlocks
all the files on the current default drive in directory $.
WARNING
Locking
a file does not prevent the files being destroyed by formatting or using
the
command
*BACKUP.
*BACKUP
<source drvsp> <target drvsp>
Abbreviation:
*BAC.
Type:
FS
Related:
*COPY, *ENABLE
The
disc in the source drive is copied in its entirety to the disc in the target
drive,
which
must be of the same density and length.
If
both drive specifications are the same, the user is prompted to insert
alternately
the
source and target discs. Less disc changes will be required if screen mode
7
is
used during this command.
This
command overwrites the data in user memory, and any information on
the
target
disc. The *ENABLE command must be used before the *BACKUP
command
is used.
Example
*ENABLE
-BACKUP 0 1
Copies
the disc in drive Q to the disc in drive 1.
WARNING
The
contents of user memory are overwritten by this command, and the
original
contents
of the destination disc are lost.
*BUILD
<fsp>
Type:
utility
Abbreviation:
*BU.
Related:
*EXEC, *LIST, *TYPE
The
specified file is created directly from the keyboard input. The user is
prompted
for
the input with the current line number. Every character typed is
written
sequentially
to the file. Input is terminated at any time by pressing
20
the
ESCAPE key.
*BUILD
is usually used to create text files, but it is possible to enter
nonprintable
characters
via the keyboard - see the BBC User Guide.
Example
>*BUILD
!BOOT
1 *KEY10
CHAIN"MENU"
|M
2 CHAIN
"MLNU"
3
creates
a text !BOOT file.
*CAT
<drvsp>
Type:
OS Abbreviation: Related: *ACCESS, *DIR, *DRIVE, *FORMAT, *INFO,
*LIB,
*OPT4,
*TITLE
The
catalogue of the specified disc is displayed. Also displayed is the disc
title,
the
drive number, the current default directory, and the current default
library.
The
files are displayed in alphabetic order, with those files in the current
default
directory
being listed first.
Example
21
-CAT
0
GAMES
1 (12)
Drive
0 Option 2 (EXEC)
Directory
:0.$ Library
:0S
!BOOT
L BATBALL
CHASE
L CRUMYANA
A. MENU
L
*COMPACT
<drvsp>
Type:
FS
Abbreviation:
*COM.
Related:
*BACKUP
The
files on the specified disc are compacted so that all free sectors are in
a
single
block at the end of the volume. This becomes necessary when the
free
space
has become fragmented and there is no single block large enough
to
create
a new file.
Compacting
does not destroy any information on the disc. However, if a disc
error
occurs
during compaction, it might be difficult to recover the contents of the file
that
was
being compacted at the time. Therefore it is advisable to make a backup
copy
of
the disc first.
Example
WARNING
This
command overwrites the contents of user memory. If a disc error
occurs
during
compaction the disc is likely to become unreadable. It is wise to make
a
backup
copy of the disc before compaction.
*COPY
<source drvsp> <target drvsp>
<aentsp>
Type:
FS
Abbreviation:
*COP.
Related:
*BACKUP
All
files on the specified source disc matching the ambiguous entry
specification
are
copied, without change of name, to the target disc. If a file of the same
name
already
exists on the target disc, it is overwritten by the copy unless
locked.
Example
22
Copies
all files in directory A from the disc in drive 0 to the disc in drive
1.
WARNING
User
memory is overwritten.
*DELETE
<fsp>
Type:
FS
Abbreviation:
*DE.
Related:
*DESTROY, *WIPE
The
specified file is removed from its catalogue, and all the data in the file is
lost.
Locked
files cannot be deleted without first unlocking them using the
*ACCESS
command.
Example
>*DELETE
A.MENU
Deletes
the file MENU in directory A from the disc in the current default
drive.
*DESTROY
<afsp>
Type:
FS
Abbreviation.
*DES.
Related:
*DELETE, *WIPE
All
unlocked files matching the ambiguous file specification are listed, and
the
user
is prompted as to whether they should be destroyed. If so, all the files
are
removed
from the catalogue, and the data in them is lost. The *ENABLE
command
must be issued immediately prior to this command, or the
message
'not
enabled' will be issued.
Example
23
>*COMPACT
1
Compacting
drive 1
$.!BOOT L 000000 000000 00001A 002
$.CHASE 001900 FF8023 000370 003
A.MENU L 001900 FF8023 000130 007
Disk
compacted 187 free sectors
>*COPY
0 1
A.
>*ENABLE
>*DISTROY
:1.A.*
A.MENU
A.FRED
A.BALL
Delete
(Y/N) ?Y
Deleted
*DIR
<dirsp>
Type:
FS
Abrrev:
*DI.
Related:
*CAT, *DRIVE
The
default drive and directory are set to those in the directory specification. If
any
field
is not specified, the current default remains unchanged.
The
current default values are displayed by the *CAT command.
Example
Sets
the current directory to S on the current default drive.
>*DIR
: 1 A
Sets
the current directory to A on drive 1
-DISC
1 -DISK
TYPE:
utility
Abbreviation:
*DIS.
Related:
*TAPE
The
current filing system (e.g. the tape filing system) is suspended, and the
disc
filing
system becomes the active filing system. Any files open under the tape
filing
system
will remain open, and can be accessed again when the tape filing
system
is
reselected using *TAPE.
DRIVE
<drvsp>
Type:
FS
Abbreviation:
*DR.
Related:
*CAT, *DIR
The
default drive is set to the specified drive number. The current default
values
are
displayed by the *CAT command.
24
*DUMP
<fsp>
Type..
utility
Abbreviation:
*DU.
Related..
*LIST, *TYPE
The
contents of the specified file are displayed (dumped) on the screen. Each
line
of
the display is as follows:
where
<addr>
is the address of the line in the file, in hexadecimal; <hex value> is
the
hexadecimal
representation of the file character; <pvalue> is the
printed
representation
of that character, or a full stop if the character is not printable
(i.e.
has
an ASCII value less than 32 or greater than 126 decimal).
The
display can be stopped by depressing CTRL and SHIFT together, or
page
mode
may be engaged by typing CTRL N.
*ENABLE
Type:
OS
Abbreviation:
*EN.
Related:
*BACKUP, *DESTROY
Filing
system commands which can erase files must be enabled
immediately
before
use. This extra step helps to prevent the accidental erasure of
files.
Example
>*ENABLE
>*BACKUP
0 1
25
>*DIR
S
<addr>
<hex value> <hex value>.. <pvalue>
<pvalue>..
*EXEC
<FSP>
Type:
OS
Abbreviation:
*E.
Related:
*BUILD, *LIST, *TYPE
The
data in the specified file is read character by character as though
those
characters
were being typed in at the keyboard.
Short
command files are usually produced by use of the *BUILD
command.
Programs
may be merged by *SPOOLing one program, loading a second
program,
and *EXECing the spooled first program back into memory.
Example
>*EXEC
PROGTEXT
Further
input is taken from the ASCII file PROGTEXT until the end of the file
is
reached.
WARNING
*EXEC
should only be used with text files; strange and possibly alarming
results
may
otherwise ensue. BASIC program files are not ASCII files and should not
be
*EXECed.
*HELP
Type:
OS Abbreviation: *H.
If
typed alone, a list of keywords on which further help is available is displayed
on
the
screen.
If
*HELP is followed by the name of the disc filing system (e.g. DFS, or DDOS)
the
syntax
specification for all the commands is displayed. If *HELP is followed
by
UTILS
the syntax for the utility commands is given.
*INFO
<afsp>
Type:
FS
Abbreviation:
*1.
Related:
*CAT, *LOAD, *RUN, *SAVE
26
The
catalogue details for all files matching the ambiguous file specification
are
displayed.
Each file is displayed as..
<ent>
[L] <laddr> <eaddr> <byte length> <start
sector>
where
<ent>
is the file's entry name;
L
indicates that the file is locked;
<laddr>
is the file's load address, in hexadecimal, which will be used by
*LOAD
and
*RUN;
<eaddr>
is the file's execution address, in hexadecimal, which will be used
by
*RUN;
<byte
length> is the file's byte length, in hexadecimal;
<start
sector> is the address of the file's first data sector of the file,
in
hexadecimal,
relative to the start of the disc.
Example
>*INFO
BATBALL
$.BATBALL L FF1900 FF8023
00023A 00C
The
file called BATBALL in directory $ has a load address of
&1900, an
execution
address
of &8023, a length of &23A bytes, and starts at sector &C (12) on
the disc.
If
it is a single density disc, there are 1 Q sectors per track, so the file starts
at
track
1, sector 2.
LIB
<dirsp>
Type.
FS
Abbreviation:
*LIB
Related:
*CAT, *RUN
The
library drive and directory are set to those in the directory specification. If
any
field
is not specified, the current library value remains unchanged.
When
an *command is entered, if the command is not recognised by any of
the
sideways
ROMs (including the disc filing system ROM), then the current
default
directory
will be searched for a file of that name. If a file of that name is not
found,
then
the current library directory will be searched for a file of that name. If no
file is
found
in either the current default directory or the library directory, then a 'file
not
found'
message will be issued. If a file of the correct name is found it will
be
loaded
into memory at its load address, and executed from its execution
address.
It
should be a machine code program.
27
The
*RUN command uses the library directory in the same way.
The
current library values are displayed by the *CAT command.
Example
>*LIB
:1 Z
The
library is set to directory Z on drive 1.
*LIST
<fsp>
Type:
utility
Abbreviation:
*LI.
Related:
*DUMP, *TYPE
The
contents of the specified file are displayed as numbered lines of
printable
characters.
*LIST
should be used only with text files, strange and possibly alarming
results
may
otherwise ensue.
BASIC
programs are stored in tokenised form, and cannot be sensibly
displayed
using
the *LIST command. An ASCII text file of a BASIC program may be
obtained
by
*SPOOLing a BASIC program.
Example
>*LIST
!BOOT
1 *KEY
10 CHAIN "MENU" IM
2 CHAIN
"MEW'
The
text file !BOOT on the current default directory, such as that produced by
the
*BUILD
command, is listed.
*LOAD
<fsp> [<load address>]
Type:
OS
Abbreviation:
*L.
Related:
*INFO, *RUN, *SAVE
The
specified file is loaded directly into memory, at the address specified if
given,
otherwise
at the file's load address, as displayed by *INFO. The address
should
be
specified in hexadecimal without the leading &
28
*LOAD
is normally used to load binary program and data files. BASIC
programs
should
be loaded using the BASIC statement LOAD.
Example
>*INFO
FRED
$.FRED L FF1900 FF8023
00023C 002
>*LOAD
FRED
The
file FRED has a load address of &1990, as shown by the use of the
*INFO
command.
The *LOAD command will load the file FRED from the current
default
directory
into memory starting at location &11999 as no load address
was
specified.
>*LOAD
FRED 2500
The
file FRED on the current default directory will be loaded into memory
from
&2500.
*OPT
1 <value>
Type:
OS
Abbreviation:
*0.
Related:
*INFO
This
command controls the information displayed every time a file is accessed.
If
<value>
is zero then no information will be displayed when a file is accessed.
If
<value>
is 1 or greater, then the file information (as displayed by the
*INFO
command)
is displayed every time a file is accessed.
Example
>*OPT
1 1
File
information is enabled.
>*OPT
1 0
File
information is disabled.
29
*OPT
4 <value>
Sets
the action which will occur when the disc in the current default drive
is
present
in drive Q, and a SHIFT/BREAK is pressed.
If
<value> is 0, then no action will take place on auto-start. If
<value> is 1, then the
file
$.!BOOT will be *LOADed. If <value> is 2, then the file $.!BOOT will be
*RUN. If
<value>
is 3, then the file $ABOOT will be *EXECed,
To
use the auto-start feature, insert the disc in the current default drive and
enter
the
*OPT 4 command to set the desired auto-start option. Place the prepared
disc
into
drive 0, and press SHIFT and BREAK together, release the BREAK key
and
then
release the SHIFT key.
If
the auto-start option is active, and no file $.!BOOT is found, the error 'File
not
found'
is reported.
Example
>*OPT
4 3
Sets
the disc in the current default drive to perform an *EXEC of the MBOOT
file
when
the disc is placed in drive 9, and SHIFT/BREAK is pressed.
*RENAME
<fsp> <entsp>
Type:
FS Abbreviation: *RE.
The
directory, and/or the filename of the specified file are changed to those
given
in
the entry specification. The contents of the file are not
changed.
The
command will fail if a file already exists with the new name, or if the file to
be
renamed
is locked.
Example
>*RENAME
A.FRED B.TOM
Renames
the file called FRED in directory A on the disc in the current default
drive
to
TOM in directory B on the same disc.
30
*RUN
<fsp> <parameters>
Type:
OS
Abbreviation:
*R.
Special
abbreviated form: *<fsp> <parameters>
The
specified file is loaded into memory at its load address, and then execution
of
it
commences at its excution address. If the file cannot be found in the
specified
directory,
the library directory is searched for a file with the same
filename.
The
parameters are available to the executing program by using an OSARGS
call
described
in chapter 8.
Use
of a file type other than a binary program may cause strange,
possibly
alarming
and feasibly catastrophic results. In particular, BASIC programs
should
not
be *RUN; the BASIC statements CHAIN or LOAD should be used.
Example
>*RUN
MCODE
Causes
the machine code file called MCODE, which is in the current
default
directory
or the library directory, to be loaded at its load address, and
executed
from
its execution address. The same effect could have been obtained by typing
in
*MCODE.
*SAVE
<fsp> <start addr> <end addr> [<laddr> [<eaddr>]]
*SAVE <fsp> <start
addr>
+<length> [<laddr> [<eaddr>]]
Type.
OS
Abbreviation:
*S.
Related:
*LOAD, *RUN
The
contents of memory starting at <start addr> and finishing at <end
addr>-1 , or
at
<start addr> + <length>-1 , are saved as the specified binary file.
If a file of that
name
already exists, and it is not locked, then it is overwritten.
The
load and execution address of the file are set to <laddr> and
<eaddr>
respectively,
if specified, or to <start addr> if not. These default addresses
are
used
by *LOAD and 'RUN.
31
All
addresses, and <length>, should be specified in hexadecimal without
a
leading
&
Example
>*SAVE
MCODE 1900 +2000 2400 2403
The
contents of memory starting at &11900 of length &2000 is saved to the
file
MCODE
in the current default directory, with a load address of &2400 and
an
execution
address of &2403.
>*SAVE
MCODE 1900 3900 2400 2403
This
command performs the same action, using the alternate form of
specifying
the
length.
*SPOOL
[<fsp>]
Type:
FS Abbreviation: *SP.
When
<fsp> is specified, most subsequent screen output is also directed to
the
specified
file. If a file of that name already exists, and if it is not locked, then it
is
overwritten.
To
avoid infinite loops, output generated by the filing system itself is not sent
to the
spool
file.
*SPOOL
without <fsp> specified closes the spool file and terminates
spooling.
This
command is used to produce ASCII text files of BASIC programs and
for
copying
the output of programs to a text file for subsequent analysis or
for
incorporation
into a document using a word processor.
Example
>*SPOOL
PROGTXT
>LIST
>*SPOOL
The
program currently in memory will be saved as an ASCII text file
called
PROGTXT
in the current default directory.
32
*TITLE
<title>
Type:
FS
Abbreviation:
*TI.
Related:
*CAT
The
title of the disc in the current drive is set to the string <title>. The
title of a disc
is
displayed by *CAT
The
title may comprise a maximum of 12 characters. If less are specified,
the
string
is made up with spaces. If the string is to contain embedded spaces,
it
should
be enclosed by a pair of double quotation marks.
Example
>*TITLE "GAMES
DISW
The
title of the disc in the current drive is changed to 'GAMES
DISC'.
*TYPE
<fsp>
Type:
utility
Abbreviation..
*TY.
Related..
*DUMP, *LIST
The
contents of the specified file are displayed as lines of printable
characters.
*TYPE
should be used only with text files,. strange and possibly alarming
results
may
otherwise ensue.
This
command is similar to the *LIST command, but line numbers are
not
displayed.
Example
>*TYPE I.A.TXT2
Displays
the contents of the ASCII text file called TXT2 in directory A on the disc
in
drive
1 .
33
*WIPE
<afsp>
Type:
FS
Abbreviation:
*W.
Related:
*DELETE, *DESTROY
DDOS
maintains its current default volume through BREAK, allowing use of
the
auto
start feature from any volume on any disc.
Extra
commands are provided to control the extra features of DDOS and
provide
more
information to the user.
Extended
Syntax for DIDOS
All
unlocked files on the disc in the current drive in any directory, which start
with A
will
be listed individually, The user will be prompted to confirm the deletion of
each
file.
Those files for which deletion is confirmed will be removed from
the
catalogue.
6 DDOS
Extended Features and
Commands
DDOS
provides a number of features to help overcome the limitations inherent
in
Acorn
DFS, while maintaining a high degree of compatibility.
The
floppy disc controller fitted with DDOS is capable of operating in both
single
and
double density. DDOS allows the use of both types of disc; single
density
discs
are identical to discs produced on an Acorn DFS system, double
density
discs
provide 89 per cent greater capacity, and up to 248 files.
Volumes
may be explicitely referenced by including a volume letter
immediately
after
a drive number in a file specification for example
.2D.F.JAZZ
specifies
the file called JAZZ in directory F of volume D on drive 2. The
default
volume
can be set by using the *DRIVE command.
34
Additional
Commands available IN DIDOS and CHALLENGER.
*4080
<setting>
Type..
FS
Sets
the filing system so that 40-track discs may be used with an 80-track
drive.
If
setting is ON then only 40-track discs may be used in an 89 track drive. A
disc
error
will be produced if the command is issued when 40-track disc drives
are
used.
If
setting is OFF then only 40-track discs may be used in a 40-track disc drive,
and
only
80-track disc drives may be used in an 80-track disc drives.
If
setting is AUTO then the filing system will allow both 40-track and 80-track
discs
to
be used in an 80-track disc drive.
The
default is OFF.
Example
>*4080
AUTO
Sets
the computer so both 40-track and 80-track discs may be used in
80-track
drives.
35
For
each unlocked file matching the ambiguous file specification, the user
is
prompted
as to whether the file should be deleted,. if so, the entry is removed
from
the
catalogue and its contents are lost.
<vol> volume
name A | B | C | D | E
|
F | G | H
<volsp> volume
specification <drvsp> [<vol>]
<drvol> drive-volume [:[<drv>]
[<vol>].]
<dirsp> directory
specification <drvol> [<dir>]
<fsp> file
specification <drvol> <entsp>
<afsp> ambiguous
file spec <drvol> <aentsp>
DDOS
increases the number of files which may be held on one side of a disc
by
dividing
the disc into up to eight volumes. Each volume is equivalent to a
surface
of
a disc of the Acorn format single density, with the same limit of 31 files, and
the
same
catalogue information.
Example
*WIPE #.A*
*CAT
<volsp>
When
the *CAT command is used with DDOS or CHALLENGER it is assumed
that
the command is folowed by a volume specification. If no volume letter
is
explicitly
included, then the default volume, A, on the specified disc will
be
displayed.
Example
>*CAT
OB
The
catalogue of volume B on drive 0 will be displayed.
>*CAT
1
The
catalogue of the default volume on the disc in drive 1 will be displayed, this
is
volume
A.
*COMPACT
<volsp>
A
volume specification is expected following the *COMPACT command. If
no
explicit
volume letter is used, then the default volume will be
compacted.
*DENSITY
<arguement>
Type.
FS
Abbreviation:
*DEN.
Related:
*CAT
DDOS
by default automatically detects the density of the discs which are
used,
making
it simple to use both single and double density discs. The
protection
system
used by some commercial discs prevents the proper operation of
this
automatic
density detection.
This
command allows the disc interface to be configured so that either only
single
density
discs are readable, or only double density discs are readable.
*DENSITY
AUTO is the default condition. When this condition is set, single
and
double
density discs may be used, and their density is automatically
36
detected.
*DENSITY
SINGLE sets the controller to assume that the disc to be read or
written
is
a single density disc. This allows some protected discs still to be used
with
DDOS.
*DENSITY
DOUBLE sets the controller to assume that the disc to be read
or
written
is a double density disc.
After
power up or a CTRL-BREAK, DENSITY is set to AUTO, a BREAK or
SHIFT-
BREAK
does not change the existing setting of DENSITY.
Example
>*DENSITY
SINGLE
Only
single density discs will now be correctly read and written.
*DRIVE
<volspec>
A
volume specification is expected following the *DRIVE command. This
allows
the
default volume to be set to a volume other than volume
A.
*FIDCSTAT
TYPE:
FS
Returns
the contents of the status register of the floppy disc controller. If
you
discover
an error in the DDOS operating system, enter *F13CSTAT, and note
the
values
returned. Include these values when reporting the error to
Opus.
*FORMAT
Type:
FS
Related:
*VOLGEN
New
floppy discs are usually in an unformatted form. This means that they
cannot
be
used to store information until after they have been formatted. The
utility
*FORMAT
will prepare a disc in either single or double density as required. A
disc
formatted
in single density may be read by any Acorn
37
DFS
compatible disc system. An Acorn DFS system will be unable to read a
disc
formatted
in double density.
The
format program is invoked by typing
*FORMAT
You
will be asked to enter the number of tracks per side (40 or 80), the drive
in
wish
you wish to format the disc, and the density in which you wish the disc to
be
formatted.
You will be given a last chance to change your mind before
formatting
(formatting
wipes all information from a disc!). If an error occurs while formatting
a
disc
you will be given a message 'verify error .
*MAP
<volspec>
Type:
FS
Abbreviation:
*MA.
Related..
*CAT, *STAT, *COMPACT
Displays
a map of the specified volume, showing the tracks and sectors
occupied
by
files on a volume, and the tracks and sectors which are free
space.
Example
>*MAP
OC
Displays
sectors occupied by files and free space on volume C of the disc in
drive
0.
*MICOPY
<source volsp> <target volsp>
Type:
FS
Abbrev..
*MC.
Related..
*COPY, 'BACKUP
All
files on the source volume are copied to the target volume, overwriting
the
previous
contents of the target volume. The command makes maximum use of
the
memory of the BBC computer to maximise the transfer speed, and
this
command
is to be preferred when making backup copies of the files on a
disc.
38
Example
*MCOPY
OA 1C
All
files in volume A on drive Q are copied to volume C on drive 1, overwriting
the
previous
contents.
WARNING
This
command overwrites user memory, and the previous contents of the
target
volume.
*SROM
<value>
Type:
FS
Abbreviation:
*SR.
Related:
*SAVE, *LOAD
Specifies
the socket number (0 - F) of the sideways ROM or RAM which is to
be
read
by the *SAVE command when saving data in the address range &8000
to
&BFFF,
or the sideways RAM which is written to by a *LOAD to the address
range
&8000
to &BFFIF.
Example
>*SROM
F
Selects
socket &F, (15), such that a subsequent *SAVE to disc of the memory
area
&8000
to &BFFF will save the data in the ROM in socket 15.
*STAT
<volsp>
Type:
FS
Abbrev:
*ST.
Related:
*CAT, *XCAT
The
size of the volume and the remaining space in the volume is
displayed
in sectors and Kbytes.
Example
39