Path: utzoo!utgpu!watmath!att!tut.cis.ohio-state.edu!gem.mps.ohio-state.edu!samsung!uunet!ncrlnk!ncrwic!encad!entec!jlohmeye From: jlohmeye@entec.Wichita.NCR.COM (John Lohmeyer) Newsgroups: comp.periphs Subject: Re: SCSI question Message-ID: <423@entec.Wichita.NCR.COM> Date: 20 Nov 89 01:13:23 GMT References: <39190@srcsip.UUCP> <437@intelisc.nosun.UUCP> Reply-To: jlohmeye@entec.Wichita.NCR.COM (John Lohmeyer) Organization: NCR Corporation, Wichita, KS Lines: 54 Keywords: In article <437@intelisc.nosun.UUCP> cfj@intelisc.UUCP (Charlie Johnson) writes: > >There are a couple of documents which in describe SCSI (commands & interface) >in gross detail. They are : > > COMMON COMMAND SET (CCS) of the Small Computer System Interface (SCSI) > X3T9.2/85-52 Rev 4.B (Is there a new revision???) > >and > American National Standard for information systems - small > computer system interface (SCSI) > ANSI X3.131-1986 > >Both of these are ANSI documents. Well, almost. The first, CCS, is not an ANSI standard. Its not even an ANSI document (whatever that is?). CCS is (more like was) a working document of the X3T9.2 task group of ANSI-accredited standards committee, X3. (If that sounds like lawyer talk -- it is.) Groups like X3 are accredited by ANSI, but are not part of ANSI. Anyway, many SCSI products were designed to both documents, but CCS does not have any real status as a standard. I would recommend using SCSI-2 for new product design -- at least it is in the approval process to become an ANSI standard. SCSI-2 includes all of the worthwhile concepts from CCS plus many more useful features. The official designation for SCSI-2 is X3.131-198x. It will replace SCSI-1 upon its approval. Note that the 198x should really be 199x as the earliest that SCSI-2 will be approved is 1990. All three of these documents can be purchased from Global Engineering Documents at (800) 854-7179. They know these documents as: SCSI-1 X3.131-1986 CCS CCS SCSI-2 X3.131-198x These documents (except CCS) are available on the SCSI BBS (316-636-8700) in electronic format (ZIP'd WordStar files). >I haven't found them real useful from a >software standpoint. Much more useful has been just the manuals for the >particular SCSI device you are interested in. They tell which SCSI commands >that device supports and usually gives an overview of SCSI. While I would agree that the standards are not as easy to read as a device manual, be careful that you do not write your software so that it only works with that vendor's product. This is exactly how Apple got in trouble with the early MACs. -- John Lohmeyer J.Lohmeyer@Wichita.NCR.COM NCR Corp. uunet!ncrlnk!ncrwic!entec!jlohmeye 3718 N. Rock Rd. Voice: 316-636-8703 Wichita, KS 67226 SCSI BBS 316-636-8700 300/1200/2400 24 hours