Conference noted::hackers_v1

re: 514.0

	i think the SHOW DEV command of VMS runs in executive mode
	and starts at SCS$GQ_CONFIG.  it then scans through a linked
	list of system blocks which each have a linked list of device
	data blocks which each have a linked list of unit control blocks.

	this should find you every type of device attached to a cluster
	i believe.

	- marty

    Where would I find the offsets for the fields in UCB's and DDB's?
    These are things such as DDB$L_LINK, DDB$L_UCB, ...
    
    PASTOOLS suggests getting them from LIB.MLB (in text form) and writing
    a program to interpret the output.  I'd rather not do this if there
    is another way.
    
    							Michael

re: .2

	You can easily get these symbols defined by inserting the
	following in your (macro) program:

		.library	/sys$library:lib/

		$UCBDEF		; define all UCB$... symbols
		$DDBDEF		; same for DDB$...

	If you want to see the actual macro text to these macros,
	do a    $ libr/extr=$xxxDEF/macro/out=TT: sys$library:lib

		Hope that helps...

			Marc.

    There is also a tool (called PICTURE maybe?) that will take
    the output of a $xyzDEF and draw you a pictue of the associated
    data structure(s).  Also sometimes the $xyzDEF macros are in
    STARLET.  I have a simple com file that checks STARLET, then LIB,
    for a particular macro.

    Check out the toolshed, METOO::SW_TOOLS_CATALOG I believe.

            Rico

    I wrote a program to go thru the I/O database (WHAT's SHOW DEV command
    does the same thing too), however I am not finding all the devices
    that SHOW DEV of VMS finds (and neither does WHAT).  The I/O database
    has devices like MBA1:, PEA0:, DUA1:... while SHOW DEV (on a LAVC)
    reports MBA1:, PEA0:, SPENDR$DUA1:, JAWA$DUA1:...
    
    Where is this info, in a cluster data structure somewhere?
    
    						Michael Campanella

I th��ink the problem is that you are not finding
cluster wide devices, Do you start to scan the IO database
at IOC$GL_DEVLIST ? is so you should start at SCS$GQ_CONFIG,
this is the cluster block, which in turn points at a block
(CLU ?) for each node, that in turn points at a IOC$GL_DEVLIST
for e��ach node, there is an example of this in the code
in the note about what files has a user opened (the 'what'lock
program


Peter Bailey

     I hate to join in a high level intellectual discussion like this with
   a question that will bring it down to a rather more elementary level,
   but that is exactly what I am about to attempt to do.

     How does one go about scaning the I/O database in the first place?


                                       /Lars Jonsson

	as a sample of a bliss program that does some scanning of the
	I/O data base you can look at the following routine.  for this
	routine to work it should be run in executive mode ($CMEXEC).
	it finds all the disks in a cluster.

	- marty
--------------------------------------------------------------------------

ROUTINE foo =
BEGIN

EXTERNAL SCS$GQ_CONFIG;

OWN
sb_addr,
ddb_addr,
ucb_addr;

sb_addr = .SCS$GQ_CONFIG;
while (.sb_addr NEQ SCS$GQ_CONFIG) do
    BEGIN
    BIND sb_blk = .sb_addr : block[SB$C_LENGTH, byte];

    ddb_addr = .sb_blk[SB$L_DDB];
    while (.ddb_addr NEQ 0) do
	BEGIN
	BIND ddb_blk = .ddb_addr : block[DDB$C_LENGTH, byte];

	ucb_addr = .ddb_blk[DDB$L_UCB];
	while (.ucb_addr NEQ 0) do
	    BEGIN
	    BIND ucb_blk = .ucb_addr : block[UCB$C_LCL_DISK_LENGTH, byte];

	    if (.ucb_blk[UCB$B_DEVCLASS] EQL DC$_DISK) then
		BEGIN

		! PUT SOME USEFUL CODE HERE

		END;

	    ucb_addr = .ucb_blk[UCB$L_LINK];
	    END;

	ddb_addr = .ddb_blk[DDB$L_LINK];
	END;

    sb_addr = .sb_blk[SB$L_FLINK];
    END;

RETURN 1;
END;

     Thank for the BLISS program! Unfortunately I don't know the first
   thing about BLISS. I was wondering if you could either show me a MACRO
   version of the same program or just simply explain (in broad terms) what
   your routine actually does.


                                       /Lars Jonsson

    
    Try reading the "Guide to writing a Device Driver for VAX/VMS" (one
    of those orange manuals on your shelf) to get some details about
    what data structures are in the "I/O database".
    
    What this program does is to look through the database looking for
    Unit Control Blocks with a device class of "Disk".
    
    Trev
    

    If you want assembler from Bliss then compile it.

	i'd hoped that the routine wouldn't necessarily require a
	BLISS programmer to decipher.  it just shows the linked
	list structures that you have to go through in order to
	obtain information on disks.

	the program would probably look very similar in PASCAL or C
	or FORTRAN ...

	- marty

And you guys call yourselves hackers?  Quit whining about what language the
program is written in and go decipher it.

--PSW