MF write-link. If another user already has write access to
the disk, a read-link is to be done. Note: Unpredictable results can occur when one user has a RIO-link to a device that is being updated by a user who
has the device in read/write status. MW Write-link. This link is established in all cases. More than one user writing to the same virtual device
can result in permanent loss of data.
If the mode is omitted, the default is R if the userid is
another user. If you are linking to one of your own disks,
the default is the "user access mode" as specified in the VM/370 directory for your disks. PASS= password is a one-to eight-character string that must match the access mode password for device vaddr1 in the VM/370 directory for
the user (userid) specified. The password should be specified only when the LINK is executed by a virtual machine (for
example, from CMS), since printing of the password is not
suppressed when included with the LINK command. The access
mode password cannot be the same as any of the access modes
(R, RR, W, WR, M, MR, or Mi) if the default mode is to be used. The access mode password should not be confused with a
user password.
1. If link to one of your own disks, no password is required.
Also, if the link is to a device whose password is ALL, meaning
that the device can be used by all users, the password is not
required. if the link is to any other userid, a password
for the desired device must be provided. If a LINK command is
issued from a CMS batch job, a password must be provided, even if
the device password is ALL.
2. When linking to a 2305 device, you gain access only to the virtual address specified and not to all eight addresses associated with
the device. 3. The access allowed by the LINK command to the vaddr1 device
belonqing to userid is summarized below. You read the columns down
to deteLmine the type of link that results. The first row
indicates the primary (and, optionally, the alternate) access mode
requested. The second row indicates whether read, write, or
multiple passwords exist in the VM/370 directory for the disk being
linked. The third row indicates whether the disk is already being
used, and if so, the mode of its access. The last row indicates
the type of link established. For example, the third column is inteLpLeted as follows: if you request a read access link (R) to a
disk that has a read password defined and that already is accessed
in read mode, you can establish a read link.
4. ViLtual Leserve/release processing cannot be requested by appending
a V to the mode operand of the LINK command line. Virtual reseLve/release processing can only be requested by means of the MDISK statement of the directory program. 92 IBM CP Command Reference for General Users

LINK
r----------------------------------------------------------------------, I Primacy access requested: R R R R R W W W W W W M M M M M M 1Alternate access (if any): R R R R W 1---------------------------------------------------------------------- IRead in directory: N Y Y Y Y I write in directory: N Y Y Y y Y IMult. password in directory: N Y Y Y Y Y 1---------------------------------------------------------------------- IAny existinq links: N R W W N R R W W N R W W W 1====================================================================== 1 Access established: N R R N R N W N R N R N W W N R W 1---------------------------------------------------------------------- N=no or none; R=read; w=write; Y=yes L----------------------------------------------------------------------J
Figure 9. Password Requirements on the LINK Command
ENTER READ PASSWORD: Jl1nIKIJ:IM Type the read password over the mask to obtain read access to the desiced disk.
ENTER WRITE PASSWORD: 11UIHIIIUI Tvpe the write password over the mask to obtain write access to the desiced disk.
ENTER MULT PASSWORD: 111UIIIII Type the multiple password over the mask to obtain write access to
a disk for which other users may already have access. If the LOGON/AUTOLOG/LINK journaling facility is activated, unsu=cessful link attempts, due to invalid passwords, are recorded. When a pre1efined system threshhold value for attempts is exceeded,
an installation userid receives a message. There is another system
threshhold value that disables the LINK command when a user
continues to enter trial passwords to obtain a link to a minidisk.
The default is ten incorrect passwords before the command is
disallowed for the remainder of the terminal session. DASD vadar2 LINKED RIO This response indicates that a read-only link to the given disk is establishe1 for a LINK request with a mode of R or RB, and that no
other users are linked to the same disk in read/write mode. DASD vaddr2 LINKED R/W This response indicates that a read/write link to the given disk is
established for a LINK request with a mode of W, WR, M, MR, or MW, Section 5. Format of CP Commands 93