CP/M/CPM_CDROM.iso/cpmhelp/du-v75.hlp

Text File | 1994-07-27 | 6KB | 173 lines

DU-V75 Installation
Logging disks; examining disk parameters
Positioning and reading
Viewing data
Writting data
Miscellanea
Examples of command use
Interpreting DU lines
:                  DU-V75.DOC
                 by Ward Christensen
             with additional notes by Ron Fowler
                  (revised 1/23/81)



                 *** Installation ***

The 7.0 and later versions of DU  are designed to be installed with a  minimum
of trouble.  In fact,  in al- most  all cases, no changes  to the source  file
should be necessary to get DU up and running. This is because DU uses the disk
paramter  block  of  CP/M  to  determine  the  characteristics    of  the   disk
environment.  (see the dis- claimer for certain non-standard versions of  CP/M
1.4).

The only parameter that should need to be changed will be the clock speed flag
at 103H.  Leave this byte zero if you  have a 2 mhz clock.  Patch it  non-zero
for 4 mhz.  This is only needed for the "Z" (sleep) command.
:Logging and viewing disk parameters

L    Re-logs in the current disk.  You may pull out a  disk, put in a  new,
    and "L" just to log it in.

Lx    Logs in disk 'x', such as: LB

Ux    Logs user 'x' for next F command.  Gives '?' error if not CP/M version
    2.x.

#    Prints the disk parameters

Fname    Print directory  for  file "name",  then  positions to    its  directory
    sector. (Won't position under CP/M 2.x, but see = command below.)

M    Dumps a map of the group allocations for files.  Mn    Shows  which
    file is allocated to group "n".
:Positioning and reading

Tnn    Seek to track nn (no read)

Snn    Position to sector nn, and read

Gnn    Position to group nn and read.

G    Shows current position

=string    Ascii search, starting at current sector. <xx> hex may be imbedded, or
    used alone:  To find "IN 0FEH":   =<db><fe> Ignores bit 7 unless  <xx>
    is used.

+    advance 1 sector (if below track  2, this advances to next  numerical,
    if  2  or  >,  advances  based    on  CP/M's  normal  sector  scrambling
    algorithm, i.e. so + will get the next logical sector of the file

-    backs up 1 logical sector

Note + and - may take an amount:   for example, +F steps in 15 sectors.   Note
also that "-" issued at the first logical sector of the disk will wrap back to
the last.  Note "+"  issued at last sector will  wrap forward to  the first.

R    Reads the sector currently positioned  to into memory.    Note R    (Read)
    is implicit in    the G, +,  and - commands,  but N-O-T in  the S and  T
    commands (I did it because I was tired of disk reading after T command
    before I had a chance to issue the S command)

<    Saves current sector in a save buffer

>    Gets saved buffer.  < and  > may be used to  move a sector to  another
    place.
:Viewing data

V    Views the current sector.  (assumes ASCII data)

Vnn    Views nn sectors

D    Dump sector, hex + ASCII

A    Dump sector, ASCII only

H    Dump sector, hex only

Note all dump commands (D, A, H) may be optionally followed by a starting  and
ending address:

            D0,7F    is the same as just D
            D3,5
            A20,3F
:Altering data

CHaddr,val,val,val... change hex in sector

CAaddr,char string... change ASCII in sector

    NOTE that <xx> may be hex imbedded in the Ascii:  ca0,OK<d><a><1a>

    Use W to write changes  to disk.  Note that  the C command echoes  the
    overlaid data for verification.

CHaddr-addr,byte  or  CAaddr-addr,byte    repeats a change

W    Write back the    current sector    (N-O-T-E may not  be used  after an  F
    command, as CP/M was used to find the file in the directory
:Miscellanea

?    Gives command summary

N    Resets  CP/M via  the BDOS.   This may  make it  possible under  some
    implementations of  CP/M to  change the  disk format  (e.g.,  density,
    sides, etc)

X    Exit back to CP/M (Must press return).    Ctl-c was too easy to hit over
    modem lines, so I decided on 2-byte (X, CR) to exit.

P    Toggle printer switch on/off

Z    Sleep - causes the program to pause, such as to look at a dump.  Z  is
    1 sec.    Znn is nn tenths of a second on a 2 MHz 8080.

/    Repeats entire command.  Defaults or /nn     to "forever".    NN  may
    be 2 to 65535
:Examples

Multiple commands may be separated by ";"

Any valid  command string  may be  placed as  an operand  of the  original  DU
command, i.e.:

             A>DU G0;D;G2;=OK<D><A><1A>;D

Example: the following commands will erase the    b disk directory to all E5's:

    lb        log in b drive
    g0        position to dir.
    ch0-7f,e5    fill with e5
    <        save the sector
    >;w;+;/16    restore, write, next,
            repeat 16

This could be shortened to:

    lb;g0;ch0-7f,e5;<
    >;w;+;/16
:INTERPRETATION OF DIRECTORY DATA PRESENTED BY THE DU PROGRAM

The following explains the format  of a CP/M directory    entry as shown by  DU,
using either the  "F" (find file)  command, or    just doing "D"    (dump) of  the
directory sectors, which are  located in groups  0 and 1  on a single  density
disk. Sample result of "FSID.COM" command:

First        40    00534944 20202020  20434F4D 0000003A  *.SID    COM...:*
line        ||    |||             |  ||      ||    |      |
        ||    ||^----hex file name-----^  ||      ||    ^file name^
        ||    ||                ||      ||     in ASCII
        ||    ||             extent-^^      ||
        ||    ||                  ||
        ||    ||         file size in sectors-^^
        ||    ||
        ||    ^^-00 = file active
        ||       E5 = file erased
        ^^-displacement of line in directory sector

Second        50    33343536 3738393A  00000000 00000000  *3456789:........*
line        |                   |
        ^---allocation group numbers-------^