M2488 PRODUCT GUIDE

TAPE UNIT PARAMETERS

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

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BYTES

7

6

 

5

 

4

 

3

 

2

1

 

 

0

DEFAULT

 

 

 

 

 

 

VALUES

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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

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.

 

 

0

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.

 

 

 

 

April 1997

CG00000-011503 REV. A

5-7

Page 243
Image 243
Fujitsu M2488 manual Disconnect/Reconnect Control Parameters, Disconnect/Reconnect Parameters, Dtdc