A central facility is available to allocate device keys for those facilities that require them. This arrangement concentrates knowledge of the configuration of the system into one place. A subsystem (terminals or tapes) that requires device keys must provide a factory and a receptionist to the Device Allocator. Whenever a device is initialized by calling the DEVALOC key (p2,devalloc)) the Device Allocator calls the Device factory as follows:

DEVDVRF(0;SB,M,SB==>c;DEVDVR)

DEVDVR(0;devicekey,receptionist,logger ==> rc,(string))
Initiate a device driver. The device driver will log recoverable errors using the logger key and return with rc= 3 or 4 for non-recoverable errors.

The Device driver might call the receptionist key with SIK SOK CCK (for instance) or the receptionist might be another allocator mechanism as in the tape system (p2,drive-allocate).

DEVDVR remains busy while the device is being used.

String is returned when the device driver recognizes an unrecoverable error. The string is used to log the event.

Return codes

0 - no error, device key was rescinded for some reason and a new one is requested. A new DEVDVR is not requested from the factory, instead the current DEVDVR is "called" with a new device key.

1,2 - Factory return codes

3 - Unrecoverable Outboard error, the string is defined as follows. The current DEVDVR is called with kt+4 to destroy it and a new one is obtained from the DEVDVRF for this device. After 32 successive calls with return code greater than 2, the device is marked as disabled and will not be reinitialized until the Device Allocator is called to do so.

TOD 8 bytes

VOLID 6 bytes

CCW 8 bytes the failing ccw

CSW 8 bytes the failing csw

SENSE the remaining bytes in the string represent the device sense data

4 - inboard (channel or logic error, string is undefined at this time

>4 catastrophic error, do not retry.

If rc > 4 then call will not be retried until after intervention.

KT+5 - The device driver called back to obtain a companion Device Key
The offered string is a 4 byte number of the companion device (1,2,3... for the first, second, etc companion device)

The device driver requires a pair of Device Keys and wants to obtain the Device Key for the Device with the next sequential address from the Device Key on the DEVDVR invocation. The companion key is only returned if it is not assigned to some other device driver (not in the Devalloc database). If it is not available DEVALOC will return rc=1 else it will return with rc=0. The availability of a compainion device is part of the policy of the Device Allocator (DEVALOC) as determined by the ordercode on the assignment

Slot 0 DEVDVR key

Slot 1 Prompt spacebank key (used on factory requestor call)

Slot 2 the meter used on the factory requestor call

SLot 3 The second spacebank used on the factory requestor call

Slot 7 The DEVDVRF key

Slot 8 the RECEP key used on the DEVDVR key

SLot 9 a Start key to the device allocator

Slot 12 Datakey with the Device key bits (7 bytes)

Slot 13 Datakey with the device type

Slot 14 Datakey with the device address

Slot 15 Format key

Produce a device allocator key. There is normally only one of these in the system. DEVALOC is in the SYSNODE structure (devaloc-home). The Wombkeeper gets the initial device allocator and uses it to initialize the non-network terminal devices on the system.

In all calls described below the "devad" is a two byte device address and "device-type" is the string returned from "sense ID" I/O order code {see POP} without the initial X'FF', such as x'32741Bxxxxxx'.

DEVALOCF(0;SB,METER,DEVAL ==> 0;DEVALOC)

Produce device allocator with knowledge of the system configuration at the time of the call. The configuration information is derived from an as yet unspecified Sense Configuration key. DEVAL is described at (bdevice). DEVALOC assumes that no one else uses DEVAL.

Return Codes are the standard factory requestor return codes

DEVALOC(0,device-type;DEVDVRF,receptionist[,node] ==> c)
Initialize all devices known with the device type specified. If a device driver already exists for one of the specified devices, it will notice that its device key is rescinded and when it returns for a new one, it will be destroyed (called with KT+4). This call is used by the Wombkeeper to initialize all 3270 devices and can be used to replace the device drivers of any class of devices.

NODE is optional and contains the resource keys for use in calling the DEVDVRF keys. If it is not specified then the resources of the device allocator will be used. Node is described as follows:

Slot 0 a prompt spacebank

Slot 1 a meter

Slot 2 a spacebank

Return codes
1 device type string less than 2 bytes

2 device type string greater than 7 bytes

6 database full

DEVALOC(1;logger ==>)
Accept a logger key. Logger is given to all subsequent DEVDVR calls and is used for return codes of 3 and 4 from the device drivers.

DEVALOC(2,(devad,device-type);DEVDVRF,receptionist,[node] ==> c)
Enable or add a single device as in order code 0. If the device was not previously known to the device allocator, it is added to its database.

Return codes

1 input string less than 4 bytes

2 input string longer than 9 bytes

3 device with address specified is of the wrong type (if prevously known)

4 cannot get a device key for this device (such as in use by kernel or not configured to the kernel)

5 DEVDVRF does not behave correctly

6 database full

DEVALOC(3,devad ==> c)
Disable a device. The device key is rescinded and the device is marked as disabled so that it won't be reinitialized until a call of order code 0 or 2

Return codes

1 string not exactly 2 bytes

3 device unknown

DEVALOC(4,device-type ==>)
Disable all devices of the specified type.

DEVALOC(5,devad ==> c,(22,deviceblock);node)
Return status or specified device

The device block is returned and the devices node as described above is returned. The DEVDVR key can be fetched from this node for debugging purposes. THe device block is described as follows.

Deviceaddress xl2

Devicetype xl8 return from sense deviceid without the FF

devicekeybits xl8 the bits used in the DEVAL call

Deviceflags flags

x'80' don't allocate this device (device disabled)

x'40' device failed (unrecoverable error)

x'20' cannot build driver

Return codes
1 Input string not 2 characters

3 device not located

DEVALOC(6 ==> c)
Initialize the device records according to the configuration as supplied by the kernel (through the as yet non-existent Sense Configuration key). Existing devices are not affected but a new configuration may be in effect.

Return codes

6 record collection full

DEVALOC(7,device-type;DEVDVRF,receptionist ==>c)
Replace the DEVDVRF and RECEP keys in the device records for all devices of this type so that the next reallocation of a device (after a restart or device failure) will cause the device driver to be called with KT+4 and a new device driver to be built with this DEVDVRF and RECEP keys

Return codes

1 string to short (less than 2 bytes)

2 string to long (greater than 2 bytes)

DEVALOC(8,(devad,device-type);DEVDVRF,receptionist ==> c)
As in ordercode 7 but for a single device

Return codes

1 string to short (must be at least 4 bytes)

2 string to long (greater than 9 bytes)

7 device not active

DEVALOC(kt;==>X'37';)