The Tape System for Gnosis is described in three sections that follow. These sections discuss the details of tape operation and the actual operator interface to these functions.

Tape Librarian Interface

The Tape Librarian function (selection 1 of the Tape Manager task) uses the TAPEMAN (p2,tapemanager) key to manage the tape library. This function is menu driven.

The Gnosis tape library functions a little differently than the VM tape library. In Gnosis a tape must be in the library before it can be assigned to a user. The user has access to a capability that will assign an available tape to a user when he/she requests it. Once assigned, the tape belongs to that user until it is released. When released, the tape returns to the pool of available tapes and may be reassigned to another user. The tape library capability makes sure that tapes are assigned to a single user at a time (it is up to the users to share a tape by explicit action on their part), and that a user may (_never) request a tape to be mounted to which he/she does not have access.

Two types of tapes are introduced into the Gnosis tape library. The first type is a scratch tape. This tape is labelled and then made available for any user to claim for use. Because it is labelled when it is introduced to the library, no data can be read from this tape by the user who claimed it.

The second type of tape is a private tape. This tape is introduced into the library without writing a label on it. It may only be claimed by the owner that presented to tape to the human acting as tape librarian because the tape is assigned a password when it is introduced into the Gnosis tape library. This password is given to the owner of the tape so he/she can claim it from the Gnosis tape library for use.

A private tape may be labelled when it is introduced. This would be the case if the tape was intended as a tape to be exported to another system.

NOTE that a blank tape should not be entered into the Gnosis tape library. Such a tape can never be mounted by a user. All tapes mounted for users must have some data on them (either a label or some user data) so that the tapes can be verified when they are mounted.

The available librarian functions are:

1. Introduce a scratch tape
   The operator is prompted for the Volume ID of the tape and a description of the tape. The Volume Id should be the Slot Number of the VM library as this will be the identification of the tape as request by a user when mounting the tape. The description has little meaning as the tape does not belong to any user at this time. The date that the tape was introduced is a nice description.

   Once the VOLUME ID and description are entered, the tape is mounted and labelled. The operator will have to switch to the Tape Operator function to respond to the mount. The mechanics of running the various Tape Manager functions will be described later.

   A tape must be introduced into the library (_before) it can be used by a Gnosis user. This is a departure from the procedures used with the VM library.

2. Introduce a user tape without labelling it
   Again the VOLUME ID and description are entered via prompts. The tape is not mounted at this time. A password is assigned and printed. Give this password to the owner of the tape. Only the user that knows the password assigned may claim this tape.

3. Introduce a user tape and label it
   As in selection 2 but the tape is mounted and a label is written on it. Only the user that knows the password assigned may claim this tape.

4. Withdraw a tape from the library
   The tape VOLUME ID is prompted for. The tape is withdrawn from the library and all users that have access to this tape no longer have access to it.

5. Backup the tape library database
   The database that determines what tapes have been assigned to users and what tapes are available is sent to a CMS system for storage. This must be done so that the tape library can be saved over Gnosis rebuilds. This is not to protect the library over Gnosis crashes but over Gnosis rebuilds which are a rare occurrence.

   The operator is prompted for a system number. The only number that is currently acceptable is 85.

6. Restore the tape library database
   Restore the library after a Gnosis rebuild. This is normally done by the team that rebuilds Gnosis. There is no known reason for doing this at other times.

7. Generate a report of the number of tapes in the library
   Prints a small report giving the number of each of three kinds of tapes: Available, Private user tapes, and Inuse tapes. Of particular interest is the number of available tapes. If this number is very low (like 1 or 2) some tapes (like 5 or 10) should be entered. To do this assign the tapes to the user GNOSIS on system 85 and then enter the tapes into the Gnosis library on host 2686.

8. Generate a complete detail list of the tape library
   Generate a list of all tapes in the library grouped by the three types.

9. Help function
   Some explanations of the librarian commands.

Gnosis runs without the intervention of an operator. Once the system has been IPL'd, Gnosis runs on its own. The mounting of tapes, however, does require that a human operator take action on behalf of a Gnosis user. For this purpose there is a tape manager's terminal associated with Gnosis. This terminal is attached to the Gnosis tape manager process. This process handles all aspects of tape management including tape library functions. Tape access is validated by this process long before the tape mount is requested of the human operator. This document describes the tape manager terminal interface.

Interaction with VM

When Gnosis runs on its own machine, tape drives are permanently attached. However, when Gnosis runs under VM, tape drives are attached at the discretion of the VM operator. The Gnosis Tape Manager will assign any tape drives it has been told are available whether or not the drive is currently attached to the Gnosis virtual machine. If the VM operator does not leave the tape drive permanently attached to the Gnosis virtual machine, the tape mount process involves an extra step.

When a Gnosis task requests a tape mount, the Tape Manager task assigns an available drive and issues a mount message to the terminal. Under VM it is necessary for the VM operator to attach a tape drive to the Gnosis virtual machine at the designated address before mounting the tape and responding to the mount request.

On a real machine it is only necessary to mount the tape on the designated drive and respond to the mount request message.

Tape Operator Commands
The following commands constitute the entire repertoire of the Tape Manager commands. No other commands are understood. These commands change the availability of the tape drives to the Tape Manager for assignment to users and control the assignment of tape drives after the tape has been mounted.

ADD (Seldom if ever used)

ADD unit-number

Inform the Tape Manager process that the tape unit indicated is now online. The unit is not available for allocation. This command merely allocates table space in which the Tape Manager keeps track of the drive status.

There is no command to delete a drive. However, if the drive is not made available for use (via the SET command), it will not be assigned to a Gnosis task.

Example

ADD 481

SET
SET unit-number UP/DOWN

This command changes the status of a Gnosis tape drive. A drive in the UP state will be assigned to a Gnosis task. A drive in the DOWN state will not be assigned to a Gnosis task.

A drive that is in use may not be set to the DOWN state. However, a drive in the MOUNTING state (a user requesting a tape mount on the drive) may be set to the DOWN state. This will cause the mount request to be repeated on another drive.

A drive in the DOWN state, and not in use, may be taken offline (detached by the VM operator) for maintenance.

Example

SET 480 DOWN

SET 481 UP

MOUNT
MOUNT unit-number

When a task requests a tape, the Tape Manager assigns a drive (from those in the UP state that are not in use) and issues a MOUNT REQUEST message on the terminal. After the tape has been mounted by the human operator (and attached to the Gnosis virtual machine if under VM), The human operator enters the "MOUNT unit-number" command to inform the waiting task that the tape is ready for use. The tape label is validated by the waiting task.

Example

MOUNT 481

NOMOUNT
NOMOUNT unit-number

On those occasions where the tape cannot be located, after repeated attempts to mount the tape it becomes apparent that the tape label is not valid, or the drive fails to mount the tape properly, the NOMOUNT command is used to inform the waiting task that it must reissue the request.

Example

NOMOUNT 481

MOUNT?
MOUNT?

This command will cause all outstanding requests to be listed at the terminal. The form of the display is identical to the original mount request message.

Example

MOUNT?
PLEASE MOUNT VOLUME 666666 on unit 485 with RING

PLEASE MOUNT VOLUME 555555 on unit 486 with NORING

STATUS
STATUS

The status of all drives known by the Gnosis Tape Manager task is displayed on the terminal.

Example

STATUS
480 IN USE 123456 (in use with reel mounted)

481 AVAILABLE 654321 (no longer in use but reel is still mounted)

482 AVAILABLE (available with no known tape mounted)

483 DOWN (unit is online but not available)

484 UNAVAILABLE (unit is not online)

485 MOUNTING 666666 (a mount request is outstanding)

Tape Operator Messages and ACTIONS
The following is a summary of all the messages (with explanations) issued by the Tape Manager process.

PLEASE MOUNT VOLUME xxxxxx ON DRIVE xxx WITH RING/NORING

The Tape Manager has assigned the specified DRIVE to a Gnosis task. The indicated tape should be mounted and a MOUNT command entered. If Gnosis is running under VM the drive may have to be attached to the Gnosis virtual machine.

ACTION - Mount the requested tape on the drive indicated. Enter the "MOUNT unit-number" command with unit-number equal to the drive indicated. Example: MOUNT 481.

UNIT xxx IS NOW AVAILABLE
The task that was using the drive has released it. If the same tape volume is requested before the drive is used for another tape volume, the drive will be assigned to the task without operator intervention.

ACTION - NONE

DRIVE xxx MOUNTED
Either the response to a MOUNT command indicating that the Tape Manager has understood the request, or a previously mounted tape has been assigned to a Gnosis task automatically because the tape is still mounted.

ACTION - NONE.

DRIVE xxx NOT REQUESTING MOUNT
No mount request is outstanding for the unit specified on a MOUNT or NOMOUNT command.

ACTION - retype the MOUNT command with the correct unit-number.

DRIVE xxx MOUNT REFUSED
Response to a NOMOUNT command.

ACTION - NONE

UNIT xxx DOES NOT EXIST
The unit specified is outside the range allowed.

ACTION - retype the MOUNT command with the correct unit-number.

INVALID REQUEST
The command entered is not recognized.

ACTION - Issue a correct command.

GNOSIS RESTART - ALL DRIVES UNLOADED
Gnosis has undergone a restart (due to some software error) and all tape drives are unloaded. This is done because Gnosis does not know how long it has been down and the tapes on the tape drives may no longer be the ones that were mounted by specific request.

ACTION - NONE

Other Tape Messages
The following Messages are issued by the task requesting the tape mount. The task has no idea what drive has been assigned, so its messages are identified by the VOLID of the tape that is supposed to be mounted.
xxxxxx DRIVE NOT READY OR OFFLINE
The assigned drive seems not to be working. This message will be followed by a new MOUNT request message.

xxxxxx INSERT RING AND REMOUNT
The task expects a ring in the tape. This message will be followed by a new MOUNT request message.

xxxxxx REMOVE RING AND REMOUNT
The task does not want a ring in the tape. This message will be followed by a new MOUNT request message.

xxxxxx VOLUME LABEL INVALID - REMOUNT
The volume label did not verify. All tapes have some sort of label. Tapes must have the correct label or they will not be mounted. It is in this fashion that Gnosis insures that only the correct tasks gain access to tapes. This message will be followed by a new MOUNT message.

Tape Operator Logon/Logoff
In Gnosis, tasks like the Tape Manager are permanent. Once these tasks are started (usually right after a Gnosis system is built) they continue even though Gnosis may crash or is shutdown for maintenance. Logging on to these permanent tasks is a fiction. What is really happening is a terminal is being connected to a running task or disconnected from one.

There are many positive aspects to this type of operation, but there may also be some confusion. For instance, after "logon" there may not be any sort of greeting or herald. If Gnosis crashed (thus breaking the terminal connection) and the terminal is reconnected (via logon) the task is in the exact state it was at the time of the crash (usually waiting for input). The task actually does not know that Gnosis crashed. It is usually necessary to "poke" the task to find out what it is (was at the time of the crash) doing. A null input (just type carriage return) will get the task to repeat its prompt.

The Tape Manager task is a menu driven concurrent activity task. There are two functions (tape operator and tape librarian) that may be active at the same time. The terminal is switched between these two activities through a main menu. The ESCAPE key is used to affect the switch. The best thing to do when logging on to the Tape Manager task after a crash is to press the ESCAPE key, which will present the main menu. The desired activity is selected by entering a number. Usually the Tape Operator activity is selected.

Logoff is accomplished from the main menu. Select the logoff activity by number (usually 0) and the terminal will be disconnected. This does not affect any activities that are running, it merely disconnects the terminal in such a way as to present the main menu when the terminal is reconnected via logon. Reset of the terminal (power off) will also disconnect the terminal but the main menu will not appear at logon (press the ESCAPE key in this case to see the main menu). Examples will be presented later.

Instructions for Gnosis under VM
The following is an example of the steps to take for normal tape operation with Gnosis running under VM.

1. LOGON to GNOTAPE:2686;tape.op

2. Select the Tape Operator function (enter a 2).

3. Type "STATUS" to see the state of all tape drives.

4. Wait for the bell to ring (indicating some action required).

5. When the following message appears:

PLEASE MOUNT VOLUME xxxxxx ON UNIT yyy WITH NORING

1. Attach a tape drive to GNOSIS2 at the indicated address (yyy).

2. Verify that userid GNOSIS2 has access to the indicated volume (xxxxxx).

3. Mount the tape on the indicated drive (yyy).

4. Enter the command "MOUNT yyy".

6. When the following message appears:
UNIT yyy IS NOW AVAILABLE

1. Detach the tape drive from GNOSIS2

7. If away from the terminal for an extended period enter the command "MOUNT?" and take actions as in (5) above.

Instructions for Gnosis on a real machine
The following is an example of the steps to take for normal tape operation with Gnosis on a REAL machine.

1. LOGON to GNOTAPE:2686;tape.op

2. Select the Tape Operator function (enter a 2).

3. Type "STATUS" to see the state of all tape drives.

4. Wait for the bell to ring (indicating some action required).

5. When the following message appears:

PLEASE MOUNT VOLUME xxxxxx ON UNIT yyy WITH RING

1. Mount the tape on the indicated drive (yyy).

2. Switch the drive to Gnosis. If the request is for some drive that cannot be switched to Gnosis, then change the status of the Gnosis drives (via the SET command) to make sure that the one that can be switched to Gnosis is the one that is available. The requestor will then ask for a mount on that drive.

3. Enter the command "MOUNT yyy".

6. If away from the terminal for an extended period enter the command "MOUNT?" and take actions as in (5) above.

The Tape Operator Terminal is connected to a Concurrent Activity Monitor (gnosisdoc,activity-monitor,). A brief discussion of its behavior is included here for completeness.

The Tape Manager Task consists of three parts; (1) The main menu, (2) The tape operator function, (3) The tape librarian function. The main menu is always active and can be reached at any time by pressing the ESCAPE key. The two activities (operator and librarian) are activated from the main menu by entering a number that corresponds to that activity. Once the activity is selected the terminal is switched to that activity. If the other activity has some output for the terminal (such as a mount request while in the librarian activity), the bell will sound. Pressing the ESCAPE key will take the terminal to the main menu. The activity with unseen output will be indicated by an "*".

To switch to the activity with the output, enter the activity number from the main menu. The terminal will be connected to that activity.

The terminal can be switched at any time (you need not wait for a bell) between the activities. Simply press ESCAPE and then enter type activity number from the main menu.

Example of main menu with one active function

Tape Operator Activity

Current date and time

0 LOGOUT

1 Tape Library Function

2 Tape Operator Function ACTIVE

Enter selection number ___

This screen greets the operator when first logging on to the userid GNOTAPE.

The "ACTIVE" indicates that the tape operator function is active. To switch to that activity and wait for mount requests, simply enter a "2" followed by carriage return. NOTE since the function is already active, there will be no prompt when the terminal is switched to it. Simply press the carriage return key and the function will reissue its prompt.

All commands described in the previous section are available from this prompt.

To start a tape librarian function simply enter a 1 followed by carriage return.

The ESCAPE key will always take the terminal to the Main menu.

DO NOT cancel (use a negative number) the Tape Operator function unless instructed to do so by a Gnosis systems person. If you need the terminal, simply logoff by entering a "0" (followed by carriage return). This disconnects the terminal but leaves the functions active.

Example of main menu reached via ESCAPE while connected to the librarian function when a bell rings

Tape Operator Activity

Current date and time

0 LOGOUT

1 Tape Library Function ACTIVE

2 Tape Operator Function ACTIVE *

Enter selection number ___

Entering a 2 will switch the terminal to the tape operator function where the message that was waiting (usually a mount request message) will print out.

There is a version of the Tape Operator that uses Full Screen mode on a 3270 to present a more friendly interface. This operator has slightly less function than (p3,tapeoperator) but provides a continuously updated display of tape activity and automatic volume mounting. The use of FSTAPEOP is optional and augments the capabilities of tape operation. The task described in (p3,tapeoperator) and (p3,tapetask) is still required.

FSTAPOPF(1;sb,m,allocator,mountfile,meter ==>c;FSTAPOP,FSTAPOPDOM) - Create Master Full Screen Tape Operator

Where ALLOCATOR is the key described in (p2,allocate), MOUNTFILE is a record collection used by the tape operator program described in (p3,tapeoperator) to record pending mounts (and save the NODE key of the tapekey waiting for the mount) see (p2,tapeallocate)

METER is a meter that will outlast the FSTAPOP instance as it will be used as the meter for ACCESSF. The spacebank for ACCESSF comes from the TAPEKEY node slot 11.

FSTAPOPF(0;sb,m,allocator,mountfile,meter ==>c;FSTAPOP,FSTAPOPDOM) - Create Slave Full Screen Tape Operator
This operator object has all the power of the Master operator but this object does not attempt to do any automatic mounts. There should be only a single Master object for each ALLOCATOR, MOUNTFILE combination.

FSTAPOP(0;SIK3,SOK3,CCK3) - Initialize Full Screen Tape Operator
The screen image of FSTAPOP is updated every 30 seconds. If there is any mount outstanding then the Master Operator will attempt to respond to the mount request with an ACCESS key. The assumption is that the drive will become ready when the requested tape is mounted

The top area of the screen shows the defined drives (via DEVALOC (p2,devalloc)) and their status. If more than 8 drives are available then PF8 and PF7 can be used to scroll through the drives.

The message area of the screen (below the list of drives with their status but above the command input area) will show a history of the last 100 messages (other than mount operations) that users have sent to the tape operator using the TAPEKEY(10) operation. The slave operators may not show all the messages. New messages are highlighted.

PF9 and PF10 are used to review old messages. When a message is pushed off the screen (acknowledged) highlighting is removed.

Commands may be entered in the command input area but this is not necessary under normal conditions. As a result the commands are limited.

MOUNT xxx
Cause the requestor to attempt to validate the lables and use the drive. This command is implied every screen update for any outstanding mount for the Master Operator only. Screen updates are every 30 seconds or when ENTER is typed. Therefore on the Master console simply hitting ENTER will cause all outstanding mounts to be attempted.

NOMOUNT xxx
Refuse the mount. The caller of TAPEKEY will be given return code 3.

REELUNAVAILABLE xxx
Refuse the mount because the reel cannot be located. The caller of TAPEKEY will be given return code 7.

SET xxx UP|DOWN
Change the status of the drive. If the drive is set DOWN and a mount was pending for that drive, the mount request will come up on another available drive.