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SEMI E30-1103 © SEMI 1992, 2003 63 4.11 Spooling — Spooling is a capability whereby the equipment can queue m essages intended for the host during tim es of comm unication failure and subsequently deliver these m essages…

SEMI E30-1103 © SEMI 1992, 2003

The host employs the “Date and Time Set Request”

message (S2,F31) to initialize the value of Clock to the

value contained in the TIME data item. Similarly, the

equipment may employ the “Date and Time Request“

message (S2,F17) to obtain a new initialization time for

Clock. As before, the value of TIME returned by the

host is used to set Clock. Note, in the event that the

precision of TIME is seconds and that for Clock is

centiseconds, in both cases the initial value of Clock

shall contain “00” for its Centisecond digits upon

initialization. Additionally, for any field in TIME that is

not supported by the equipment, the local value of this

field is equipment dependent. For example, Equipment

that cannot resolve time to less than a second might

round or ignore centiseconds and always set the

Centisecond field to “00”.

4.10.4 Requirements

— The resolution and update rate of the internal time

reference must be sufficient to distinguish between

two nearly simultaneous collection events and/or

alarms.

— The equipment supplier shall provide

documentation describing the resolution of the

internal time reference.

— The equipment supplier shall provide

documentation describing how centisecond values

are assigned, including the case of unresolvable

simultaneous events.

4.10.5 Scenarios

Equipment Requests TIME (Optional Scenario):

COMMENTS HOST EQUIPMENT COMMENTS

<--S2,F17 Equipment requests a time value

from the host.

Host responds with a TIME value S2,F18-->

Equipment sets its internal

time reference to the value of

TIME received from the host.

Host Instructs Equipment to Set Time:

COMMENTS HOST EQUIPMENT COMMENTS

Host instructs equipment S2,F31-->

to set its time.

<--S2,F32 Equipment sets its internal

time reference to the value of

TIME received from the host and

acknowledges completion.

Host Requests Equipment’s Current Time Value:

COMMENTS HOST EQUIPMENT COMMENTS

Host requests equipment time. S2,F17-->

<--S2,F18 Equipment returns its internal

time reference value to the

host.

SEMI E30-1103 © SEMI 1992, 2003

4.11 Spooling — Spooling is a capability whereby the

equipment can queue messages intended for the host

during times of communication failure and

subsequently deliver these messages when

communication is restored. Spooling is limited to

primary messages of user-selected streams.

4.11.1 Purpose — The purpose of spooling is to

provide a method for retaining equipment message data

that might otherwise be lost due to communication

failure. The motive for producing this functionality is to

retain valuable data used to track material and to

improve product quality. The spooling capability fills a

gap in the SEMI E5 standard. In the past, without a

spooling capability, the equipment has typically

discarded messages that could not be delivered, or

turned messaging off altogether. It is intended that the

host initiate the spool unload process immediately

following the reestablishment of communications.

4.11.2 Definitions

MaxSpoolTransmit — An equipment constant

containing the maximum number of messages that the

equipment shall transmit from the spool in response to

an S6,F23 “Transmit Spooled Messages” request. If

MaxSpoolTransmit is set to zero, no limit is placed on

the messages sent from the spool. Multi-block

inquire/grant messages are not counted in this total.

OverWriteSpool — A boolean equipment constant used

to indicate to the equipment whether to overwrite data

in the spool area or to discard further messages

whenever the spool area limits are exceeded.

Send Queue — Refers to the queue into which

equipment generated SECS messages are placed in

preparation for transmission to the host.

Spool — The spool is an area of non-volatile storage in

which the equipment stores certain messages that

cannot be delivered to the host (when the equipment is

in the NOT COMMUNICATING substate of

COMMUNICATIONS ENABLED). The spool area

can be thought of as a sequential “ring” buffer. The

term spool is also used to denote the action of placing

messages into the spool area.

SpoolCountActual — A status variable used to keep a

count of the messages actually stored in the

equipment’s spool area. Multi-block inquire/grant

messages are not spooled and not included in this

count.

SpoolCountTotal — A status variable used to keep a

count of the total number of primary messages directed

to the spool, regardless of whether placed or currently

retained in the spool. Multi-block inquire/grant

messages are not spooled and not included in this

count.

SpoolFullTime — A status variable containing the

timestamp when the spool last became full. If the spool

was not filled during the last spooling period, this will

contain a time value prior to the current

SpoolStartTime.

SpoolStartTime — A status variable containing the

timestamp from when spooling was last activated.

4.11.3 Description

4.11.3.1 Spooling State Model — There are two major

states of spooling: SPOOL INACTIVE and SPOOL

ACTIVE. SPOOL ACTIVE has two components:

SPOOL UNLOAD and SPOOL LOAD. These are each

broken into substates. A description of all spooling

states, substates, and applicable state transitions

follows. The POWER OFF and POWER ON parent

states are common to all equipment subsystems. They

are shown here to illustrate the retention of spooling

context during a power down situation.

NOTE 20: Disabling SECS communications does not affect

the current spooling state since no messages are generated

until communications are subsequently enabled. Spooling is

effectively frozen in this case.

POWER OFF

The equipment has lost power for any reason (e.g.,

power failure, power switch set to off).

POWER ON

The equipment is powered up.

SPOOL INACTIVE

This is the normal operating mode. No spooling occurs.

The spool area is empty. Primary SECS-II messages are

transmitted normally.

SPOOL ACTIVE

All primary SECS-II messages ready for sending and

for which spooling is enabled (see S2,F43) are directed

to the spool area. All other primary messages, except

Stream 1, are discarded. The equipment shall attempt to

send any secondary messages that are generated and

discard these messages should the attempt to send fail.

Spool state transitions from SPOOL INACTIVE to

SPOOL ACTIVE if the communications state changes

from COMMUNICATING to NOT COMMUNI-

CATING (Communication State Transition Table, #14)

or from WAIT CRA to WAIT DELAY

(Communication STATE Transition Table, #6).

SEMI E30-1103 © SEMI 1992, 2003

Figure 4.11

Spooling State Diagram

Once communications are established, the host must

initiate the spool unload sequence to restore full

functionality (see below). Since the equipment will

deliver secondary messages, the host may inquire for

information or send commands as needed.

The SPOOL ACTIVE state has two AND states:

SPOOL LOAD and SPOOL UNLOAD. This means

that they operate independently, though sharing data

and some state change stimuli. See Section 3.1 for

explanation of state model terms and notation.

SPOOL LOAD

The SPOOL LOAD component enters messages into

the spool area. It is divided into two substates: SPOOL

NOT FULL and SPOOL FULL. SPOOL NOT FULL is

the default entry substate of the parent state SPOOL

LOAD.

SPOOL NOT FULL

As primary SECS-II messages are directed to the spool

area, the equipment shall “write” the SECS-II message

to the end of the spool. Status variables

SpoolCountTotal and SpoolCountActual shall be

incremented each time a message is placed in the spool

area.

SPOOL FULL

In this state, all of the allocated spooling area is filled.

Choice of the following options shall be controlled by

the setting of a Boolean equipment constant called

“OverWriteSpool.” The first message to be dealt with is

that which could not be fit into the spool prior to

transition from SPOOL NOT FULL (see transition

table below).

OverWriteSpool is True: The equipment deletes as

many of the “oldest” records (e.g., SECS-II messages)

contained in the spool area necessary to make space for

the new message and then adds the message. Status

variable SpoolCountTotal shall be incremented

whenever a message is submitted to the spool area.

Status variable SpoolCountActual shall be manipulated

to keep an accurate count of the number of messages

contained in the spool area. For example, if it is

necessary to delete three messages in the spool area to

spool one message, SpoolCountActual would have

three subtracted and then one added to the total.

OverWriteSpool is False: Any subsequent primary

messages shall be discarded. When such a message is

discarded, SpoolCountTotal is incremented.

SPOOL UNLOAD

The SPOOL UNLOAD component of SPOOLACTIVE

deals with movement of messages out of the spool. It

has an active substate (SPOOL OUTPUT) and a

passive substate (NO SPOOL OUTPUT). NO SPOOL

OUTPUT is the default entry substate, since the

equipment is NOT COMMUNICATING at the time

spooling is initiated. When communications between

equipment and host are restored, there is an opportunity

for the host to recover spooled messages. No action is

taken until the host initiates the spool output process

via the S6,F23 (Request Spooled Data). The host has

the option to either receive the spooled messages (see

substate TRANSMIT SPOOL) or discard all messages

in the spool (see substate PURGE SPOOL).

NO SPOOL OUTPUT

In this state, no messages are removed from the spool.

SPOOL OUTPUT

The SPOOL OUTPUT state encompasses the removal

of messages from the spool. Its substates are TRANS-

MIT SPOOL and PURGE SPOOL.

TRANSMIT SPOOL

The host elects to receive all messages contained in the

spool area. The equipment is expected to keep track of

the oldest record (i.e., message) within the spool area.

When communications are re-established with the host

and transmission of the spool area is started, the oldest

record must be the first record transmitted, then the

next oldest record, etc. There is no prioritization of

messages to be sent from the spool.

As each spooled message is successfully transmitted to

the host, it is removed from the spool area upon

successful completion of the transaction. Spool-

CountActual is decremented as each message is

removed from the spool. The equipment shall transmit