DISCRPS



DISCRPS

     Enables or disables the rotational position sensing (RPS)
     feature on a specified logical device.  It requires special
     firmware upgrade CS-80 disk drives.  (CM)

SYNTAX

     DISCRPS ldev {,ENABLE[,value,value] }
                  {,DISABLE              }


PARAMETERS

ldev                The logical device number of the specified CS-80
                    disk drive.

ENABLE              Enables rotational position sensing on the device.

DISABLE             Disables rotational position sensing on the device.

value               Allows the time-to-target and window size to be
                    tuned, in hundreds of micro seconds. If you specify
                    one value you must specify both values.  The first
                    is interpreted as the time-to-target value; the
                    second is interpreted as the window size value.
                    This parameter works only in conjunction with
                    ENABLE.

                                               (micro seconds)
                                               ---------------
                    Default  time-to target 90 (9000         )
                             window size    30 (3000         )

CAUTION

Do not vary from the default values for time-to-target and window size
unless you have a clear understanding of their meaning and the
consequences of using different values.


OPERATION

     The DISCRPS command allows you to enable or disable the
     Rotational Position Sensing feature for CS-80 disk drives.
     With RPS enabled, the disk drive signals its availability to
     do an I/O only when it is a small rotational distance away
     from the target data.  This improves system performance when
     more than one drive is connected to the same HP-IB channel.

     This command may be issued from a session, job, in BREAK, or
     from a program.  Pressing [Break] has no effect on this
     command.  It may be executed only from the console unless
     it has been distributed to users with the ALLOW or ASSOCIATE
     command.


EXAMPLE(S)

     To enable the RPS feature on logical device 1 and display
     the drive's status, enter

     DISCRPS 1,ENABLE
     SHOWDEV 1
     LDEV       AVAIL       OWNERSHIP    VOID   DEN ASSOCIATION
     1          DISC  (RPS) 50 FILES

To use the value parameter with ENABLE to set time-to-target and window
size, enter

     DISCRPS ldev,ENABLE,90,30

ADDITIONAL INFORMATION

Commands:   SHOWDEV

Manuals :   CS/80 Instruction Set Programmers Manual(5955-3442)