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7340 HYPERTAPE DRIVE (Continued)
Diagnostic Modifiers
Bit Position
0 1 2 3 4
Read or
)
Read-backward
O O O
0
Write
0 0
0
0
0
0 0
0
0
0
0
0
1
0
0
0
0
0
0
0 0
0
0
0
*
Diagnostic modifier
0
0
0
+
Forces Loop Write to Read On
Sense Bits
Meaning
Interrupt on Correctable Error
No Interrupt on Correctable Error
Write Start-Stop
Write Continuous
*:fWrite Clock Fast - On
Write Clock Fast - Off
*Loop Write to Read -
On
Loop Write to Read - Off
Byte 0, Bit 0 - Command Reject is set when:
A Write, WTM, or Erase Command is addressed to a File
Protected Drive or a drive at EOT (End of Tape)
A Read, Space, Space File or Read Backward Command is
addressed to a tape drive at EOT (End of Tape)
A Read Backward, Backspace Record, or Backspace File is
addressed to tape drive at BOT (Beginning of Tape)
Any
tape motion into either BOT or EOT occurs, except during
a free-running operation.
Byte 0, Bit 1 - Intervention Required is set when:
A command other than Sense, Test I/O, or Write with a Loop
Write to Read modifier bit is addressed to a tape drive that
is Not Ready or Nonexistent.
The 2 802 could not properly perform the previous command
and will not be able to do so until some sort of manual inter-
vention is performed. For example, Change Cartridge to a
drive without a Ready Cartridge Loader.
Byte 0, Bit 2 - Bus-6ut Check is set when a parity error is de-
tected on Bus-OU:t except during Address Out.
Byte 0, Bit 3 - Equipment Check is set whenever improper machine
functioning is detected. This includes improper response from
the drive to control unit commands.
Byte
O,
Bit 4 - Data Check is set whenever any Sense Byte 3 bit
other than 5 or 6 is set, and whenever any byte 3 is set when
an
11
Interrupt on Correctable Errorn modifier is effective.
Byte 0, Bit 5 - Overrun is set during a Read, Read Backward, or
Write Operati6n whenever the chaIUlel does not respond to a
Service
In
within the allotted time. Overrun cannot occur
during a Sense, Control, or Test I/O operation.
106
S/360
IBM CONFIDENTIAL
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