User`s guide

SET MUx

(MU)

Sets the speciﬁed unit of the MU magtape handler (TMSCP magtape devices).

Format

SET MUx condition

Condition

CSRy=n

(Valid only if you create the speciﬁed MU controller handler during system

generation) Modiﬁes the MU device unit y to use n as the CSR address for a

controller. y can be 0, 1, 2, or 3. SET MU CSR0=n is the same as SET MU

CSR=n.

DEFALT

Returns magtape unit n to the default density of 6250 bits for each inch. Valid

only with 9-track TMSCP magtapes and sets only the speciﬁed magtape unit.

DENSE=n

Sets density for only 9-track TMSCP magtapes and for only the speciﬁed magtape

unit. n can be 1600 or 6250. Setting DENSE=1600 speciﬁes 1600 bpi (phase

encoded). Setting DENSE=6250 speciﬁes 6250 bpi (group code recording).

PORT=n

(Valid only if the handler is assembled for multiple ports) Deﬁnes which port

to access when magtape unit x is speciﬁed. The variable n is an integer in the

range 0–3 and corresponds to the variable y used with the SET MU CSRy=n and

SET MU VECy=n commands. By default, the port variable n is the same as the

magtape unit x.

UNIT=n

Deﬁnes which TMSCP unit number to access when magtape unit x is speciﬁed.

The variable n is an integer in the range 0–255. The default value for n is 0.

Since each TMSCP unit requires a controller, this modiﬁcation is optional and is

used only if you have multiple TMSCP devices and you have modiﬁed the unit

number on the device front panel.

VECy=n

(Valid only if you create the speciﬁed MU controller handler during system

generation) Modiﬁes the MU device unit y to use n as the vector for a controller.

y can be 0, 1, 2, or 3. SET MU VECTOR=n is the same as SET MU VEC0=n.

256 RT–11 Command Descriptions