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- 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-------^