DOCUMENT:Q103436 08-AUG-2001 [winnt] TITLE :Small Computer System Interface (SCSI) Bus Configuration PRODUCT :Microsoft Windows NT PROD/VER:3.1 3.5 3.51 OPER/SYS: KEYWORDS:kbhw kbHardware ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Server version 3.1 - Microsoft Windows NT Workstation version 3.1 - Microsoft Windows NT Advanced Server, version 3.1 - Microsoft Windows NT Workstation versions 3.5, 3.51 - Microsoft Windows NT Server versions 3.5, 3.51 ------------------------------------------------------------------------------- The following table describes the configuration attributes of the standard SCSI interface. Bit Cable Pin Max Transfer Max SCSI Standard Width Name Cnt. Rate MB/sec Devices Description ----------------------------------------------------------------- SCSI-1 8 A 50 5 8 Asynchronous SCSI-2 8 A 50 10 8 fast SCSI-2 16 A+B 50+68 20 8 fast+wide ** SCSI-2 32 A+B 50+68 40 8 fast+wide ** SCSI-3 8 A 50 10 8 fast SCSI-3 16 P 68 20 16 fast+wide * SCSI-3 32 P+Q 68+68 40 32 fast+wide ** * = with 1 cable ** = with 2 cables NOTE: Windows NT currently supports only eight SCSI IDs. Standard: The name of the SCSI standard as defined by ANSI. Bit width: The number of bits that gets transferred by the SCSI bus during the data transfer phases. Cable Names: A is most common, P is getting more popular, A+B is currently not popular due to cost and space issues. Pin Count: The number of pins in the cable. Refer to the above table for specific numbers. Max Transfer Rate (MB/sec): Number of bits transferred over the SCSI bus in one second. Max SCSI Devices: The Maximum number of devices that can be connected to the SCSI bus with one host adapter installed. Description: Asynchronous: A handshaking protocol that requires a handshake for every byte transferred (Synchronous transfers a series of bytes before handshaking occurs, which speeds data transfer rate) Fast: Fast SCSI is an option that doubles the synchronous data transfer speed. The speed is achieved by removing excess margins from certain times and delays. To use the fast SCSI option, high quality cables are required. This option is compatible with normal synchronous SCSI and has: - Up to 10 (megabytes) MB/second over an 8 bit bus. - Synchronous Data transfer negotiation required. - Single-ended implementation recommendations: max cable length of 3 meters and active terminators. Wide: Wide SCSI is an option that adds a second SCSI cable of 68 conductors. This cable provides a data path for 16- or 32-bit data. This path has separate handshake signals and is for data transfer only. The transfer rate is two or four times the present transfer rate of SCSI-1. With the second cable, SCSI-2 remains compatible with the 8-bit SCSI. Additional query words: prodnt 3.10 specification summary port Connection daisy chain address ====================================================================== Keywords : kbhw kbHardware Technology : kbWinNTsearch kbWinNTWsearch kbWinNT351search kbWinNT350search kbWinNTW350 kbWinNTW350search kbWinNTW351search kbWinNTW351 kbWinNTW310 kbWinNTSsearch kbWinNTS351 kbWinNTS350 kbWinNTS310 kbWinNTAdvSerSearch kbWinNTAdvServ310 kbWinNTS351search kbWinNTS350search kbWinNTS310search kbWinNT310Search kbWinNTW310Search Version : 3.1 3.5 3.51 ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2001.