These keys are created by the device allocator key {(p2,bdevice)}.

DIO(0,ccw-string;SEGMENT==>c) - Start channel program

Starts the channel program "ccw-string" on the device. All input/output data is taken from read/write pages in SEGMENT. CCW-string is one or more ccw's. Each CCW is formatted as ((1,op),(3,segment-offset),(2,flags),(2,length)) where:
"op" is the operation code {see the device manual for the device for detailed meanings}. TIC operations must be to CCW's within the ccw-string. "segment-offset" in TIC operations are the offset within the ccw string. There may be additional operations that are restricted for particular devices. {The intention is to restrict the ability to load diagnostic micro code into shared controllers that might impact other devices on the same channel.}

"segment-offset" is the offset in SEGMENT to the data affected by the operation.

"flags" are the CCW flags with the following restrictions:

Data chaining, PCI, indirect data address words, and suspend must not be used.

Pages must exist, even if SKIP is specified.

If a CCW is not a TIC and is not the last CCW it must specify command chaining. If a CCW is not a TIC and is the last CCW it must not specify command chaining.

"length" is the maximum amount of data to be processed in the operation.

"SEGMENT" is an lss3 node key to a node whose slots hold read/write page keys for those addresses required by the channel program.

Return codes:
0 - SIOF issued

1 - An interrupt has occurred since the last one reported. A SIOF was not issued. Use order code 1 to get the csw and sense information. Order 0 on BDEVICE (device) for this device does not clear an interrupt. Order 7 on this key (DIO) clears interrupts.

2 - Invalid CCW string

3 - CCW string too long, not a multiple of eight in length, or none provided

100 - access rescinded {the device’s associated "b" number is different from the device key’s}

101 - device has not been gen’ed into the kernel

KT+3 - The SEGMENT key provided was not a lss=3 read/write node key to a node with sufficient read/write page keys to cover the area referred to by the CCW’s.

Waits for the next interrupt from the device and returns the csw and sense.

"csw" is ((1,cc),(3,ccw-offset),(2,status),(2,residual-count)) where:

"cc" is the condition code received by the SIOF instruction {either immediate or deferred}. If it is 0 then "csw" and "sense" represent an interrupt from the channel. If it is 1 then a CSW was stored as the immediate result of a SIOF instruction. If it is 3 then the device does not exist and the rest of the csw is zero.

"status" in "csw" is ((1,Unit status),(1,Channel status)). These fields are defined by the hardware. The bits in Unit-status are called:]
Attention, Status modifier, Control-unit end, Busy, Channel end, Device end, Unit check, Unit exception.] The bits in Channel status are called:]
Program-controlled interruption, Incorrect length, Program check, Channel-data check, Protection check, Channel-data check, Channel-control check, Interface-control check, Chaining check.

If the csw includes the unit check bit then "sense" sense data will be provided. The sense data is the result of issuing the channel command "sense" (command code 04) to the device just after the interrupt that presented the unit check. The meaning and amount of sense data are device dependent.

Return codes:

0 - Interrupt occurred, CSW provided

1 - Operation ended with order 3 (by another domain) on this key.

100 - access rescinded {the device’s associated "b" number is different from the device key’s}

101 - device has not been gen’ed into the kernel

If there is an operation in progress on the device it is halted with a HDV instruction.

Return codes:

0 - operation halted

1 - No operation in progress

100 - access rescinded {the device’s associated "b" number is different from the device key’s}

101 - device has not been gen’ed into the kernel

If there is a domain waiting for an interrupt, it is started with return code 1. If not, the next domain to wait for an interrupt will get return code 1 immediately {i.e., the wake up is held pending}. Return codes:
0 - Domain started {or will be started}

1 - There is already a wake up pending

100 - access rescinded {the device’s associated "b" number is different from the device key’s}

101 - device has not been gen’ed into the kernel

If there is a wake up pending, it is canceled. Return codes:
0 - There was no pending wake up.

1 - A pending wake up was canceled.

100 - access rescinded {the device’s associated "b" number is different from the device key’s}

101 - device has not been gen’ed into the kernel

Issues a CP RESET command for the device. The device address used is the first address gen’ed for the device.

c=0: The Gnosis system is running in a virtual machine. A RESET command was issued for the device. "s" is ((4,completion_code),(1,flag),(n,response)). "completion_code" is the completion code from the RESET command. If "flag" = 0, "response" is CP’s response {that would normally go to the VM console} in EBCDIC. If flag = 1, CP’s response was too large to be captured and "response" is empty.

c=1: The Gnosis system is not running in a virtual machine, or the device address is greater than X'FFFF'. "s" is null.

c=100: The ID in the device I/O key did not match the SERIAL in the device. "s" is null.

c=101: The device did not exist. "s" is null.

Issues a CP SPOOL command for the device. "parameters" are command parameters to follow the device address. The device address used is the first address gen’ed for the device.

c=0: The Gnosis system is running in a virtual machine. The SPOOL command was issued for the device. "s" is ((4,completion_code),(1,flag),(n,response)) as above.

c=1: The Gnosis system is not running in a virtual machine, or the device address is greater than X'FFFF'. "s" is null.

c=2: "parameters" is longer than an implementation limit, currently 123 bytes. "s" is null.

c=100: as above.

c=101: as above.

c=0: a CLRIO instruction was issued to the device (at each of the addresses where it is known) and any pending interrupt was cleared. The condition code from the CLRIO is ignored. On some models a busy channel may cause the CLRIO to be ignored. (Perhaps this order should be changed to return the cc or a new order provided to do that.)

c=100: as above.

c=101: as above.

Retrieve Disk Format Descriptor. The first 12 bytes of the format descriptor {covered by dsect FMTDESC} are returned for disk devices

Return codes

1 - Device is not a disk known by the kernel {not gen’ed}

Retrieve Cylinder Translate Table. The entire CTT for the type of disk is returned. This table is described by dsect CYLTABNT

Return codes

1 - Device is not a disk known by the kernel

2 - CTT is more than 4096 bytes

"device-address" is the hardware device address and may be used to identify the device to operators and repair people.

Returns the type of the device. The following have been defined:

Loose end

{ni}Perhaps a 256 bit vector should be returned indicating valid commands for this device.