Phoenix VX3-350-SCW-DAT, Техническая информация

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Scope
This chapter describes the overall features and specifications of the VX3-350-SCW-DAT.
Features
The VX3-350-SCW-DAT incorporates a very compact winchester disk drive and a DDS-4 DAT drive within a single
module. The tape drive is physically compact, occupying only 3 1/2” of panel in the half-height form factor. The hard
disk drive is a high-performance winchester type with embedded disk drive control electronics. This embedded con-
troller is on the hard disk and the tape drive are microprocessor controlled and compatible with ANSI X3.131-1986
SCSI commands. The hard drive is a very high performer, with an average track-to-track access times of less than 6
milliseconds. It incorporates at least an embedded 2 Mbyte buffer which is operated in “look ahead” mode, providing
buffering for sequential sector operations. The tape drive is DDS-4 compatible. Both the hard drive and the tape drive
have 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.
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 an 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 12 meters. The specification pro-
vides all signals via a 68 pin header connector for use with standard 68 conductor cable and connectors. Table 2-2 is a
description of the Ultra-160 SCSI pin definition. The direction indicated is relative to the host(IN=From Host/Out=To
Host).
Pin Signal Direction Description Pin Signal
1 +DB (12) In/Out Bidirectional data line 12 35 -DB(12)
2 +DB (13) In/Out Bidirectional data line 13 36 -DB(13)
3 +DB (14) In/Out Bidirectional data line 14 37 -DB(14)
4 +DB (15) In/Out Bidirectional data line 15 38 -DB(15)
5 +DB (P1) In/Out Bidirectional data line P1 39 -DB(P1)
6 +DB (0) In/Out Bidirectional data line 0 40 -DB(0)
7 +DB (1) In/Out Bidirectional data line 1 41 -DB(1)
8 +DB (2) In/Out Bidirectional data line 2 42 -DB(2)
9 +DB (3) In/Out Bidirectional data line 3 43 -DB(3)
10 +DB (4) In/Out Bidirectional data line 4 44 -DB(4)
11 +DB (5) In/Out Bidirectional data line 5 45 -DB(5)
12 +DB (6) In/Out Bidirectional data line 6 46 -DB(6)
13 +DB (7) In/Out Bidirectional data line 7 47 -DB(7)
14 +DB (P) In/Out Bidirectional data line P 48 -DB(P)
15 GND - Ground reference 49 GND
16 DIFFSNS (1) - 50 GND
17 TERMPWR - Terminator Power 51 TERMPWR
18 TERMPWR - Terminator Power 52 TERMPWR
19 RESERVED - Reserved for future use 53 RESERVED
20 GND - Ground reference 54 GND
21 +ATN In/Out Attention 55 -ATN
22 GND - Ground reference 56 GND
23 +BSY In/Out Busy 57 -BSY
24 +ACK - In Acknowledge 58 -ACK
25 +RST In Reset 59 -RST
26 +MSG Out Message 60 -MSG
27 +SEL In/Out Select 61 -SEL
28 +C/D Out Control/Data 62 -C/D
29 +REQ Out Request 63 -REQ
30 +I/O Out Input/Output 64 -I/O
31 +DB (8) In/Out Bidirectional data line 8 65 -DB(8)
32 +DB (9) In/Out Bidirectional data line 9 66 -DB(9)
33 +DB (10) In/Out Bidirectional data line 10 67 -DB(10)
34 +DB (11) In/Out Bidirectional data line 11 38 -DB(11)
Table 2-2: SCSI Pin Definition
NOTES:
(1) The DIFFSNS voltage level determines single-ended or LVD operation.
(2) The minus sign next to the signals indicates active low, plus indicates active high.
Features and Specifications 2-3