.th TM11 VI 4/21/86
.sh NAME
TM11 - kernel interface to DEC TM11 magnetic tape system
.sh DESCRIPTION
The TM11 device is the KSOS interface to the magnetic tape system
produced by DEC.  There can be up to eight drives per controller
supported.  The KSOS device driver supports only one controller per
system.
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The TM11 magnetic tape system is a pre-MASSBUS oriented controller.
Tapes are written and read using the standard 7-track coding
convention.  Only 800 bpi recording density is supported.  Variable
sized records can be read or written; however, the minimum size for a
data transfer is 12 bytes and the maximum size is 8191 bytes.
.s3
The TM11 devices are identified to the kernel by their seids.  The
first two components of an TM11 seid are always the same: the name
space field is 'device_nsp' and the unique id 0 field is 12.  The
unique id 1 field corresponds to the drive unit number.  
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There are eight basic functions of the KSOS TM11 device driver.
They are implemented with the following system calls:
K_open, K_read_block, K_write_block, K_device_function and K_close.
.s3
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K_open	Before any data may be pass between a TM11 and a user process,
that process must open the device using the K_open kernel call.
Opening a TM11 device is a higher level function of the kernel I/O
system and has no effect on the device itself or the device driver.
.s3
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K_read_block	The K_read_block kernel call is used to read characters
from a TM11 device.
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K_write_block	The K_write block kernel call is used to write characters
to a TM11 device.
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K_device_function	The TM11 supports the following functions: READ,
WRITE, WRITEMARK, REWIND, and UNLOAD.
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K_close	Closing a TM11 device is a higher level function of the kernel I/O
system and has no effect on the device itself or the device driver.
.i0
.sh "SEE ALSO"
K_device_function(II),
K_read_block(II),
K_write_block(II),
K_open(II),
K_close(II),
ioFunction(IIa),
ioStatus(IIa)
