A X An attention-generating action (e.g., program access key
(80) has been pressed) was performed by the operator, or an
inbound data stream has been prepared by the 3290 and is ready for transmission.
DE X X The control unit-to-device buffer transfer is completed
(04) on a Write, Write Structured Field, Erase/Write, or
Erase/Write Alternate command which did not start a printer, or the 3290 has completed processing a Write-type command.
The device becomes "not busy" after completing an Erase All Unprotected command or the printer becomes
"not busy" after completing a printout.
The device-to-control unit buffer transfer is completed on a Select command, or the 3290 has completed preparation of a Read Modified (RM) data stream in response to a Select
command.-An attention-generating action (for example, a pro-gram access key was pressed) was performed by the operator after a Unit Exception, or Busy, condition had been reported to the host.
A device changes from "not available" to "available"
or from "not ready" to "ready".
A device becomes "not busy" after having previously sent Unit Exception when the control unit attempted to execute a command with the device when it was "busy".
Powering-on the 3274 causes each active 3290 logical terminal to present DE to the channel.
Powering-on the 3290 or exiting from Test or Setup mode while the 3274 is on causes each active logical terminal to present DE to the channel.
A,DE X An attention-generating action was performed by the
(84) operator after a Unit Exception status !that is, a busy
condition) had been reported to the host.
A,UC DC, US X X 1 An idle device detected a parity check or cursor check
(82) (OC) in its buffer, or an idle device on a 3274 has been
dis-abled because of control-unit-detected errors. (UC,IR may be reported on the next retry since the device requires a Power On Reset.)
A, DE, UC IR X 6 The addressed printer became Not Ready (out of paper
(86) (40)
.
or cover open) before completion of a print operation.DE,UC IR X 6 A command attempting to start a printer found it Not
(06) (40) Ready.
A,DE,UC IR, EC, US X 6 A printer became mechanically disabled during a
(86) (54) printout and an automatic recovery was not successful,
the printer CARRIAGE MOTOR POWER switch was off, or the switch fuse was blown.
DE, UC IR, EC, US X 6 A command attempted to start a print operation, but
(06) (54) the printer CARRIAGE MOTOR POWER switch was
off.
A,DE,UC EC,US X 7 A printer character generator or·sync check error
(86) (14) occurred, or the printer became mechanically disabled
during printout, but restored itself.
Figure 3-6 (Part 1 of 2). Asynchronous Status and Sense Conditions for 3274 Band D Units
Chapter 3. Local Operations (3274 Band D Units) 3-9
Status I
Sense Error Recovery
(Hex) (Hex) Display Printer Procedure Condition
DE,UC DC X X 10 During a Select, Erase/Write, or Erase/Write Alternate
(06) (08) command the control unit (1) detected a parity or
cursor error, or (2) detected a parity check on data received from the addressed device in response to an internal poll during a command.
DE,UC DC X X 1 During a Write or Write Structured Field command,
(06) (08) the control unit (1) detected a parity or cursor error,
or (2) detected a parity check on data received from the addressed device in response to an internal poll during a command.
DE, UC DC, US X X 1 The addressed device detected a parity or cursor check
(06) (OC) while executing a Select, Write, Write Structured Field,
Erase/Write, Erase/Write Alternate, or Erase All Unpro-tected command. Also, the control unit may disable the device because of error. (UC, I R is reported on the retry since the device requires a Power On Reset to be reenabled.)
DE,UC OC X X 3 A Write, Erase/Write, Write Structured Field, or
(06) (01 )2 EraselWrite Alternate command containing a wce with
a Start Print bit is chained to a subsequent command, or a WSF command was chained to a subsequent command.
The 3274 D unit or 3290 received an invalid buffer address in data stream of Write-type command, or data stream ended before providing all characters required for an SBA, RA, SF, or EUA order on a Write-type
Erase/Write Alternate, or Erase All Unprotected command, a display was in test mode, the device's security key was in the off position, or a printer was assigned as a local copy device. (UC, IR will be reported on a subsequent operation.) The addressed 3290 was not available for a control-type command or was performing a local copy operation.
DE,UE X 9 The control unit attempted to perform a Select or
(05) Erase All Unprotected command, but found, after
returning initial status, that the addressed device was busy.
CUE X X The control unit had been addressed while busy, but
(20) is now not busy and is free to accept a new command.
Ilf this asynchronous status is attacked by the channel, an asynchronous CUE could be generated and combined with it before the stacked status is accepted by the channel.
2The 3274 B units set oe upon receipt of a wce ~ X'88'; the 3274 D units do not set OC upon receipt of a wee ~ X'88'.
3 A 3274 D unit updates the device buffer as it processes the data stream. A 3274 B unit does not change the device buffer until the total data stream has been processed.
Figure 3-6 (Part 2 of 2). Asynchronous Status and Sense Conditions for 3274 B and D Units
/ '
!
(f ", ,,~o.)
Error-Recovery Procedures
( 3274
Band D Unit Device-Detected Errors(
Error conditions detected by the control unit or by an attached device are
indicated to the program by Unit Check status. The program must respond to this status by using a Sense command for further definition of the condition. If a Sense command is not performed and the sense conditions still exist, the control unit will not honor any other interrupts from the devices. Subsequent recovery operations are then determined by the combined configurations of Unit Check status bits and associated sense bits.
Referenced Error-Recovery Procedures
The recovery procedures referenced in the Error Recovery Procedure column of Figures 3-4, 3-5, and 3-6 are as follows:
1. Reconstruct the entire buffer image and retry the failing chain of commands.
The sequence of commands used to reconstruct this image should start with an Erase/Write command (or Erase/Write Alternate on a 3274). However, if the failing command is a Write Structured Field command, do not issue Erase/Write, just retry the Write Structured Field command. If, after two retries, the problem is not corrected, follow procedure 4.
2. The error indicates the device is "unavailable." Request and wait for operator intervention to "ready" the device; then, upon receipt of DE status, retry the chain of commands.
3. A nonrecoverable program error has occurred. Examine the data stream to locate the problem.
4. Request maintenance for the device that is giving trouble. After the repair, reconstruct the buffer image, starting with an Erase/Write command (or Erase/Write Alternate).
5. Record the error for future reference, and continue with the program. This error occurred while the control unit was "idle" and is not indicative of a data error.
6. The error indicates the printer is out of paper, has the cover open, or has a disabled print mechanism. Request operator intervention to "ready" the printer; then, upon receipt of DE status, retry the print operation by issuing a Write command with the proper WCC and no data stream. (There is no data error; the data is still intact in the device buffer and can be reused.) If this procedure is unsuccessful, follow procedure 1.
7. The error occurred during a printout and indicates either a character generator or sync check error or a disabled print mechanism. There is no buffer data error. The proper error recovery procedure is
application-dependent, since the user mayor may.not want a new printout.
Because the buffer contents are still good, procedure 6 may be followed.
8. A data error occurred at the device during a printout. This indicates a data error at the device; procedure 1 should be followed.
Chapter 3. Local Operations (3274 Band D Units) 3-11