Library /sys$common/syshlp/helplib.hlb  —  LD  New features V8.0
 	A physical disk may be connected to a logical disk, whereby it
 	can be specified which lbn range of the physical disk to use.

 	For example, we want to connect a device LDA1 to blocks 1000
 	through 20000 of a physical device:

 	  $ LD CONNECT DKA0: LDA1:/LBN=(START=1000,END=20999)

 	Or we can specify a number of blocks to use:

 	  $ LD CONNECT DKA0: LDA1:/LBN=(START=1000,COUNT=20000)

 	This will map lbn's 1000 through 20999 of DKA0: which can be
 	accessed as a disk through LDA1:

 	This functionality may also be used clusterwide by adding
 	/SHARE. All nodes sharing a disk this way must specify the
 	same parameters. Geometry is calculated by the driver and
 	cannot be specified. Multiple ranges may be used for multiple
 	LD devices, as long as there's no overlap. The range check
 	is done on all cluster members.

 	An example can be to partition a disk without any file structure
 	on it:

 	  $ LD CONNECT DKA0: LDA1:/LBN=(START=0,COUNT=100000)
 	  $ LD CONNECT DKA0: LDA2:/LBN=(START=100000,COUNT=100000)
 	  $ LD CONNECT DKA0: LDA3:/LBN=(START=200000,COUNT=100000)
 	  $ LD CONNECT DKA0: LDA4:/LBN=(START=300000,COUNT=100000)

 	This can also be shared:

 	  $ LD CONNECT DKA0: LDA5:/LBN=(START=400000,COUNT=100000)/SHARE

 	In that case the partition can be accessed from other cluster
 	members as well.

 	Notice that the physical disk in question will be protected
 	by a lock, and may not be mounted anywhere.

 	A new locking protocol is in use between LDDRIVER's on different
 	nodes in a cluster. The new V8.0 driver can deal with connected
 	devices by old LDDRIVER's, old drivers however may not be able
 	to connect to shared resources of the new drivers. If one driver
 	is the first to connect to a resource it will establish the
 	locking version in use. This means that if an old driver connects
 	as the first one, the connection will work. Example:

 	oldsys> ld connect d1 lda1/share/log
 	%LD-I-CONNECTED, Connected $7$LDA1: to $8$DUA15:[LD]D1.DSK;1 (Shared)

 	newsys> ld connect d1 lda1/share/log
 	%LD-I-CONNECTED, Connected $7$LDA1: to $8$DUA15:[LD]D1.DSK;1 (Shared)
 	  (Old driver connected on other node)

 	Notice that the new driver will tell us that an old driver
 	has connected to the resource, and that an upgrade may be
 	required. If the new driver connects first the old driver will
 	issue a different error message:

 	newsys> ld connect d1 lda1/share/log
 	%LD-I-CONNECTED, Connected $7$LDA1: to $8$DUA15:[LD]D1.DSK;1 (Shared)

 	oldsys> ld connect d1 lda1/share/log
 	%LD-F-FILEINUSE, File incompatible connected to other LD disk in cluster

 	This makes connection to a shared resource dependent on the order
 	of the nodes where the connection occurs. For this reason it is
 	advisable to install the new LD version on all nodes in a cluster if
 	shared resources are used.

 	The include file for the callable interface has changed.
 	It used to be LD_DEFINES.H and is still included, but the new definitions
 	are now in LDDEF.H created from and sdl source file. It is preferred
 	to use the new definitions as they will become part of VMS in the
 	future.
Close Help