pim@ctisbv.UUCP (Pim Zandbergen) (10/26/88)
In article <901@vsi.COM> friedl@vsi.COM (Stephen J. Friedl) writes: >In article <539@ctisbv.UUCP>, pim@ctisbv.UUCP (Pim Zandbergen) writes: >> While I'm on the subject of comparing SCSI devices for the 3B2, >> AT&T sells both native SCSI hard disks and ESDI hard disks that >> need a SCSI-to-ESDI thing like the ones that come with the >> 3B2/600. Does anybody have experience with both types? >> How do they compare in speed? > >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. This is from a rather old posting in this group: |From: rjv@iwtpm.ATT.COM (Verbiscer) |Newsgroups: comp.sys.att |Subject: AT&T 3B2 SCSI Announcement |Keywords: 3B2 SCSI |Message-ID: <132@iwtpm.ATT.COM> |Date: 13 May 88 16:01:56 GMT |Organization: AT&T Bell Laboratories - Naperville, Illinois | | | 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: | | | Differential Host Adapter - Provides a differential | SCSI interface for 3B2/500, 3B2/600, and | 3B2/700 Computers. | | 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. [other announcements deleted] 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. -- --------------------+------------------------------------+--------------------- Pim Zandbergen | CTI Software BV | Phone: +31 70 542302 pim@ctisbv.UUCP | Laan Copes van Cattenburch 70 | Fax: +31 70 512837 ..!mcvax!ctisbv!pim | 2585 GD The Hague, The Netherlands | Telex: 32133 CTI NL
rjd@occrsh.ATT.COM (Randy_Davis) (10/28/88)
Yes, AT&T is selling a few peripheral disk packages whose drives are *embedded* SCSI, i.e. the 50-pin SCSI bus plugs directly into the drive. Whether this on-board controller converts it to ESDI, then uses the old disk controller architecture, I don't know. The disadvantage is that the new embedded drives use up a whole SCSI bus ID, so instead of getting four disks per SCSI bus ID with the Emulex SCSI to ESDI converter, you only get one. If you are not planning to put more than seven disks per SCSI bus, then no problem.... Randy Davis UUCP: ...(att!)ocrjd!randy ...(att!)occrsh!rjd
rjv@iwtpm.ATT.COM (Verbiscer) (10/28/88)
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