Path: utzoo!yunexus!geac!syntron!jtsv16!uunet!lll-winken!lll-tis!ames!pacbell!att!iwtpm!rjv
From: rjv@iwtpm.ATT.COM (Verbiscer)
Newsgroups: comp.sys.att
Subject: Re: 3B2 SCSI drives (was: First impressions: 3B2 120MB SCSI tape drive)
Summary: 3B2 SCSI info
Keywords: 3B2 SCSI ESDI
Message-ID: <166@iwtpm.ATT.COM>
Date: 28 Oct 88 14:05:58 GMT
Article-I.D.: iwtpm.166
References: <899@vsi.COM> <539@ctisbv.UUCP> <901@vsi.COM> <543@ctisbv.UUCP>
Organization: AT&T Bell Laboratories - Naperville, Illinois
Lines: 67

In article <543@ctisbv.UUCP>, pim@ctisbv.UUCP (Pim Zandbergen) writes:
> In article <901@vsi.COM> friedl@vsi.COM (Stephen J. Friedl) writes:
> >In article <539@ctisbv.UUCP>, pim@ctisbv.UUCP (Pim Zandbergen) writes:
> >
> >They are the same thing; *all* the drives are ESDI.
> >
> 
> I think you think I was referring to the DM94/E, the DM/135E, the DM/147E
> and the DM/300E packages. They need the Disk Controller Module (DCM/4E).
> 
> But I was referring to something else.
> |
> |       On May 9, 1988, AT&T announced the third	release	of SCSI
> |       peripherals for the AT&T	3B2 computer family.  Included in
> |       the announcement	were:
> .
> .
> |	       DM/300S	- A package containing 1 300 MB	(formatted)
> |			  disk with a built-in single-ended SCSI
> |			  interface.
> |	       DM/300DS	- A package containing 1 300 MB	(formatted)
> |			  disk with a built-in differential SCSI
> |			  interface.
> 
> Are these also ESDI devices? I don't think these are a DCM/4E
> and a DM/300E put together in a box.
> It was my hunch that the "E" in DM/300E stands for ESDI
> and the "S" in DM/300S for SCSI.
> -- 
AT&T offers many different devices for the 3B2 SCSI sub-system.
Here is a quick list:

DM/147E, DM/300E  -  Package containing a single ESDI drive, 147MB or
		     300MB formatted capacity.  (The E is for ESDI.)
DCM/4E            -  Package containing an SCSI-to-ESDI bridge controller,
		     capable of supporting 4 ESDI disk packages.
XM/900S		  -  Package containing 3 300MB ESDI drives and a 
		     SCSI-to-ESDI bridge controller.  The interface
		     presented at the outside of the box is SCSI,
		     hence the S at the end of XM/900S.
DM/300S, DM/300DS -  Package containing a single 300MB embedded SCSI drive.
		     The suffix S is for single-ended SCSI, the DS is for
		     differential SCSI.
TM/60S, TM/120S   -  Package containing a single, single-ended embedded 
		     SCSI quarter inch cartridge tape drive, either 60 or 
		     120MB capacity.  (The TM/120S can READ tapes written
		     on the TM/60S.)
1600bpi 9-track   -  A very big package containing a single-ended SCSI
		     1600bpi 9-track tape unit.
1600/6250S or DS  -  A table top, auto-loading, 1600/6250 bpi
		     9-track tape unit available with either a
		     single-ended SCSI interface or a differential
	 	     SCSI interface.   (We never did come up with a
		     catchy name for the 9-tracks.)
Single-ended HA   -  aka. HA1, CM195W  -  Single-ended SCSI for 3B2
		     models 300 thru 700.
Differential HA   -  aka. HA2, CM521A  -  Differential SCSI for 3B2
		     models 500 thru 700.

Some of the items mentioned in the previous articles are no longer
sold (for example, the 147E is the same price, more capacity, and faster
than the 135E).

If you have questions about functionality, PEC codes, comcodes, etc.
(not prices) and you can't reach an AT&T sales person, please send email.

Bob Verbiscer
AT&T 3B2 SCSI Development