H9273 backplane - Revision history

Jnc: Better cat

2022-12-06T11:51:37Z

Better cat

Jnc: content better left in BA11-N

2022-07-05T09:55:34Z

content better left in BA11-N

Jnc: Gives a place to hold the FMPS link

2022-07-05T01:36:51Z

Gives a place to hold the FMPS link

New page

The '''H9273 backplane''' is a 9-slot [[QBUS#Backplanes|Q/CD]] [[QBUS]] [[backplane]], the standard backplane in the [[BA11-N mounting box]]. It could hold [[DEC card form factor|quad-sized]] cards.

It was a [[QBUS#Variable_address_size|Q18]] backplane, but it is relatively easy to [[upgrading QBUS backplanes|upgrade it to Q22]].

The manual says the BA11-N was for [[PDP-11/03L]]'s, but the [[LSI-11]] used in that machine was only Q16 capable, making the Q18 backplane superfluous, like that in the [[BA11-M mounting box]]. Once the [[PDP-11/23]] appeared, BA11-N's could be used with it (and perhaps the BA11-N was looking forward to this machine) - but after the -A revision of the /23's [[KDF11-A CPU]] (Q18 only), later revisions really were better off with a Q22 backplane, as in the uprated [[BA11-S mounting box]].

Since it was a Q/[[CD interconnect|CD]] backplane, dual-width [[QBUS]] cards could only be placed in the left-hand slots, and quad QBUS-only cards had to not use any pins on the [[DEC edge connector contact identification|right-hand C/D connectors]]. (The only DEC card with a problem with this seems to have been the [[MMV11-A QBUS core memory|MMV11-A]].)

==External links==

* [http://www.bitsavers.org/pdf/dec/qbus/EK-BA11N-UG-001_BA11-N_Mounting_Box_Users_Guide_Jan78.pdf BA11-N mounting box user's guide] (EK-BA11N-UG-001) - the H9273 is covered on pp. 10-13
* [http://www.bitsavers.org/pdf/dec/qbus/MP00740_1123_schem_Oct81.pdf PDP11/23 Field Maintenance Print Set] (MP00740) - The H9273 is covered in the BA11-N Field Maintenance Print Set (MP00487) on pp. 41-51

[[Category: DEC Hardware]]

← Older revision		Revision as of 11:51, 6 December 2022
Line 10:		Line 10:
	* [http://www.bitsavers.org/pdf/dec/qbus/MP00740_1123_schem_Oct81.pdf PDP11/23 Field Maintenance Print Set] (MP00740) - The H9273 is covered in the BA11-N Field Maintenance Print Set (MP00487) on pp. 41-51		* [http://www.bitsavers.org/pdf/dec/qbus/MP00740_1123_schem_Oct81.pdf PDP11/23 Field Maintenance Print Set] (MP00740) - The H9273 is covered in the BA11-N Field Maintenance Print Set (MP00487) on pp. 41-51

−	[[Category: ~~DEC Hardware~~]]	+	[[Category: QBUS Backplanes]]

← Older revision		Revision as of 09:55, 5 July 2022
Line 2:		Line 2:

	It was a [[QBUS#Variable_address_size\|Q18]] backplane, but it is relatively easy to [[upgrading QBUS backplanes\|upgrade it to Q22]].		It was a [[QBUS#Variable_address_size\|Q18]] backplane, but it is relatively easy to [[upgrading QBUS backplanes\|upgrade it to Q22]].
−
−	The manual says the BA11-N was for [[PDP-11/03L]]'s, but the [[LSI-11]] used in that machine was only Q16 capable, making the Q18 backplane superfluous, like that in the [[BA11-M mounting box]]. Once the [[PDP-11/23]] appeared, BA11-N's could be used with it (and perhaps the BA11-N was looking forward to this machine) - but after the -A revision of the /23's [[KDF11-A CPU]] (Q18 only), later revisions really were better off with a Q22 backplane, as in the uprated [[BA11-S mounting box]].

	Since it was a Q/[[CD interconnect\|CD]] backplane, dual-width [[QBUS]] cards could only be placed in the left-hand slots, and quad QBUS-only cards had to not use any pins on the [[DEC edge connector contact identification\|right-hand C/D connectors]]. (The only DEC card with a problem with this seems to have been the [[MMV11-A QBUS core memory\|MMV11-A]].)		Since it was a Q/[[CD interconnect\|CD]] backplane, dual-width [[QBUS]] cards could only be placed in the left-hand slots, and quad QBUS-only cards had to not use any pins on the [[DEC edge connector contact identification\|right-hand C/D connectors]]. (The only DEC card with a problem with this seems to have been the [[MMV11-A QBUS core memory\|MMV11-A]].)