X3T9.2/90-037 March 1, 1990 Messrs. Tony Robertson and Stephen Cornaby Micropolis Corporation 21211 Nordhoff Street Chatsworth, CA 91311 Subject: Response to BSR X3.131-198x (SCSI-2) Public Review Comment #4 Dear Messrs. Robertson and Cornaby, Thank you for your public comment (X3T9.2/89-144) concerning the SCSI-2 draft proposed standard. The 16-bit single-cable option is not included in SCSI-2 because the X3T9.2 committee feels that it is not sufficiently stable at this time. In particular, the method by which a 16-bit single-cable system may be expanded to 32 bits needs more study. X3T9.2 plans to have a single-connector 16-bit solution in SCSI-3 including a method of expanding to 32 bits. A draft working document is expected later this year. Your suggestion that we avoid major modifications to the body of the SCSI-2 standard by documenting the "P" cable in an appendix is appreciated. However this would not avoid the need for another public review period and its attendant delay in publication of SCSI-2. X3 considers the addition of such a major feature as a "substantive" change, no matter whether it is done in the body of the standard or in an appendix. In order to alert SCSI-2 implementors of the potential for changes in this area, a note will be included in SCSI-2 saying that X3T9.2 is documenting an alternative 16-bit single-cable solution and an alternative 32-bit solution and expects to be able to remove the "B" cable in a subsequent version of SCSI. Please send a written statement to the X3 Secretariat (Attn: Lynn Barra) within fifteen working days saying whether you accept or reject this response. If you do not respond within fifteen working days, the Secretariat will assume that you have withdrawn the comment. Sincerely Yours, Del Shoemaker, X3T9 Chairman cc: L. Barra, X3 Secretariat J. Lohmeyer, X3T9.2 Chairman J. Ryland, SPARC Liaison