Scope
This chapter describes the overall features and specifications of the VL2-350-SC-DS .
Features
The VL2-350-SC-DS incorporates one or two very compact winchester disk drives within a single module. The hard
disk drive(s) is a high-performance winchester type with embedded disk drive control electronics. This microprocessor
controlled embedded controller is on the hard disk and is compatible with ANSI X3.131-1986 SCSI commands. The
hard drive is a very high performer, with a 1-to-1 interleave and an average track-to-track access times of 10 millisec-
onds or less. It incorporates an embedded at least 8 megabytes of cache buffer which is operated in “look ahead”
mode, providing buffering for sequential sector operations. The hard drive(s) has been carefully packaged with suitable
control cables and power distribution connectors for direct attachment to single board computers in the VME chassis or
to external devices.
Ultra 320 SCSI Interface Description
In order to provide a method of embedding the disk drive control electronics within the hard disk drive, several disk
drive manufacturers jointly defined an interface specification. This specification for the Small Computer System Inter-
face has become known throughout the industry as “SCSI”. Basically, the SCSI interface consists of the required
address, data and control signals from a wide SCSI Host Adapter. Since a goal of the specification is to allow the disk
drive to be connected via standard cable, the specification required buffering of all signals so that the drive could be
mounted a suitable distance from the board interface. This distance, however, is limited to twelve meters. The specifi-
cation provides all signals via a 68-pin header connector for use with standard 68 conductor ribbon cable and connec-
tors. Table 2-2 is a description of the Ultra320 SCSI pin definitions. The direction indicated is relative to the host.
Pin
Signal
Pin
Signal
Direction
Description
1
+DB(12)
35
-DB (12)
In/Out
Bidirectional data line 12
2
+DB(13)
36
-DB (13)
In/Out
Bidirectional data line 13
3
+DB(14)
37
-DB (14)
In/Out
Bidirectional data line 14
4
+DB(15)
38
-DB (15)
In/Out
Bidirectional data line 15
5
+DB(P1)
39
-DB (P1)
In/Out
Bidirectional data line parity1
6
+DB(0)
40
-DB (0)
In/Out
Bidirectional data line 0
7
+DB(1)
41
-DB (1)
In/Out
Bidirectional data line 1
8
+DB(2)
42
-DB (2)
In/Out
Bidirectional data line 2
9
+DB(3)
43
-DB (3) I
n/Out
Bidirectional data line 3
10
+DB(4)
44
-DB (4)
In/Out
Bidirectional data line 4
11
+DB(5)
45
-DB (5)
In/Out
Bidirectional data line 5
12
+DB(6)
46
-DB (6)
In/Out
Bidirectional data line 6
13
+DB(7)
47
-DB (7)
In/Out
Bidirectional data line 7
14
+DB(P)
48
-DB (P) I
n/Out
Bidirectional data line parity
15
GND
49
GND
-
Ground reference
16
DIFFSENS
50
GND
-
SCSI Sense/Ground reference
17
TERMPWR
51
TERMPWR
-
Terminator Power
18
TERMPWR
52
TERMPWR
-
Terminator Power
19
RESERVED
53
RESERVED
-
Reserved for future use
20
GND
54
GND
-
Ground reference
21
+ATN
55
-ATN
In/Out
Attention
22
GND
56
GND
-
Ground reference
23
+BSY
57
-BSY
In/Out
Busy
24
+ACK
58
-ACK
-
In
Acknowledge
25
+RST
59
-RST
In
Reset
26
+MSG
60
-MSG
Out
Message
27
+SEL
61
-SEL
In/Out
Select
28
+C/D
62
-C/D
Out
Control/Data
29
+REQ
63
-REQ
Out
Request
30
+I/O
64
-I/O
Out
Input/Output
31
+DB(8)
65
-DB (8)
In/Out
Bidirectional data line 8
32
+DB(9)
66
-DB (9)
In/Out
Bidirectional data line 9
33
+DB(10)
67
-DB (10 )
In/Out
Bidirectional data line 10
34
+DB(11)
68
-DB (11)
In/Out
Bidirectional data line 11
Table 2-2: SCSI Pin Definition
NOTES:
(1)
The minus sign next to the signals indicates active low.
Features and Specifications
2-3
Summary of Contents for VL2-350-SC-DS
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Page 18: ...Chapter 5 Product Support Service and Warranty...
