M2488 PRODUCT GUIDE TAPE UNIT PARAMETERS
April 1997 CG00000-011503 REV. A 5-7
5-2.4 Disconnect/Reconnect Control Parameters
These parameters provide the initiator with the means to tune the SCSI bus.
Table 5-7. Page 02 - Disconnect/Reconnect Parameters
BITS MODE
SENSE
DEFAULT
VALUES
BYTES 7 6 5 4 3 2 1 0
0
PS * Reserved Page Code 82h
1
Additional Page Length 0Eh
2
Read Buffer Full Ratio 00h
3
Write Buffer Empty Ratio 00h
4-5
Bus Inactivity Time 0000h
6-7
Disconnect Time Limit 0000h
8-9
Connect Time Limit 0000h
10-11
Maximum Burst Size 0000h
12
Reserved
DTDC 0000h
13-15
Reserved 0000h
* The PS bit must be set to 0 on a MODE SELECT command.
Note: Changeable fields in this page are shaded.
Table 5-8. Page 02 - Disconnect/Reconnect Parameters Field Description
BYTE BIT VALUE DESCRIPTION
2-3 0 The Read Buffer Full Ratio and Write Buffer Empty Ratio fields indicate how full
the buffer should be on a read command or how empty the buffer should be on a
write command before the target attempts reselection.
These fields are not supported, and are reported as NOT changeable on a MODE
SENSE command. The default values are zero.
4-5 0 The Bus Inactivity Limit field indicates the maximum time, in 100 microsecond
increments, that the target is allowed to maintain the bus busy without handshakes
until it must disconnect. A value of zero in this field indicates that there is no Bus
Inactivity Limit.
The Bus Inactivity Limit field is reported as not changeable on a MODE SENSE
command, and the default value is zero.
6-7 >0
0
A non-zero value in the Disconnect Time Limit field indicates the minimum time, in
100 microsecond increments, that the target remains disconnected for the specified
LUN until it attempts to reconnect.
A value of zero in this field indicates that the target is allowed to reconnect immedi-
ately.
The Disconnect Time Limit field is reported as changeable on a MODE SELECT
command, and the default value is zero.
