Difference between revisions of "RH750 Massbus Adapter"

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The '''RH750 Massbus Adapter''' was a [[MASSBUS]] [[device controller]] for the [[VAX-11/750]]'s [[CPU Memory Interconnect | CPU Memory Interconnect (CMI)]].
+
The '''RH750 Massbus Adapter''' was a [[MASSBUS]] [[device controller]] for the [[VAX-11/750]]'s [[CPU/Memory Interconnect]] (CMI).
  
It was implemented on one [[DEC card form factor|extented hex]] card, which mounts in the VAX-11/750 [[backplane]] in one of the three CMI option slots.
+
It was implemented on one [[DEC card form factor|extended hex]] card, the L0007 MASSBUS Adapter (MBA), which mounts in the VAX-11/750 [[backplane]] in one of the three [[VAX-11/750#Backplane_configuration|CMI option slots]]. A VAX-11/750 could have up to three RH750 Adapters; the first one goes into CMI slot 9, the second into slot 8, and the third in slot 7.
  
A VAX-11/750 could have up to three RH750 Adapters, the first one goes into CMI slot 9, the second into slot 8, and the third in slot 7.
+
It was common practice to have two separate RH750s, one for [[magnetic tape|tape]], and another for [[disk]] devices. Combining both on one RH750 was possible, but tape usage had a negative impact on disk performance.
  
It was common practice to have two separate RH750s, one for tape and another for disk devices.
+
==Further reading==
Combining both on one RH750 was possible, but tape usage had a negative impact on disk performance.
 
  
== CMI Option Slot Configuration Rules ==
+
* ''RH750 Massbus Adapter Technical Description'' (EK-RH750-TD) - not available online
 +
* ''VAX Hardware Handbook (1980-81)'' (EB-17281-20) - the RH750 is covered in some detail in Chapter 10, pp. 175-190
  
CMI option slots can be used for other adapters, too:
+
==External links==
  
* [[CI750 Computer Interconnect Interface | CI750 Computer Interconnect Interface (CI)]]
+
* [https://vt100.net/mirror/hcps/si75fin1.pdf VAX-11/750 Installation Manual] (EK-SI75F-IN-001) - the RH750 is covered in Chapter 10 (pp. 133-143 of the PDF)
* [[DW750 Second Unibus Interface]]
+
* [http://www.bitsavers.org/pdf/dec/vax/750/MP01045_RH750_Engineering_Drawings_198102.pdf RH750 Field Maintenance Print Set] (MP-01045)
* [[DR750 Parallel Interface]]
+
* [https://web.archive.org/web/20071004184551/http://computer-refuge.org/compcollect/dec/vax/11750/L0007-big.jpg L0007 (MBA)] - MASSBUS Adapter image
  
Allowable Configurations of CMI Slots 7, 8, & 9:
+
[[Category: CMI]]
{| class="wikitable"
 
! Slot 7 !! Slot 8 !! Slot 9
 
|-
 
| RH750 || RH750 || RH750
 
|-
 
| DW750 || RH750 || RH750
 
|-
 
| DR750 || RH750 || RH750
 
|-
 
| DW750 || DR750 || RH750
 
|-
 
| DW750 || CI750 || RH750
 
|-
 
| CI750 || RH750 || RH750
 
|}
 
 
 
'''NOTES:'''
 
# Combination of DR750 and CI750 is not allowed
 
# Only one DR750 per system is allowed
 
# Only one DW750 per system is allowed
 
# Only one CI750 per system is allowed
 
 
 
== External links ==
 
 
 
* [http://storage.datormuseum.se/u/96935524/Datormusuem/VAX11-750/MP01045_RH750_Feb81.pdf RH750 Field Maintenance Print Set] (MP-01045)
 
 
 
[[Category: VAXen]]
 
[[Category: MASSBUS Controllers]]
 
The '''RH750 Massbus Adapter''' was a [[MASSBUS]] [[device controller]] for the [[VAX-11/750]]'s [[CPU Memory Interconnect | CPU Memory Interconnect (CMI)]].
 
 
 
It was implemented on one [[DEC card form factor|extented hex]] card, which mounts in the VAX-11/750 [[backplane]] in one of the three CMI option slots.
 
 
 
A VAX-11/750 could have up to three RH750 Adapters, the first one goes into CMI slot 9, the second into slot 8, and the third in slot 7.
 
 
 
It was common practice to have two separate RH750s, one for tape and another for disk devices.
 
Combining both on one RH750 was possible, but tape usage had a negative impact on disk performance.
 
 
 
== CMI Option Slot Configuration Rules ==
 
 
 
CMI option slots can be used for other adapters, too:
 
 
 
* [[CI750 Computer Interconnect Interface | CI750 Computer Interconnect Interface (CI)]]
 
* [[DW750 Second Unibus Interface]]
 
* [[DR750 Parallel Interface]]
 
 
 
Allowable Configurations of CMI Slots 7, 8, & 9:
 
{| class="wikitable"
 
! Slot 7 !! Slot 8 !! Slot 9
 
|-
 
| RH750 || RH750 || RH750
 
|-
 
| DW750 || RH750 || RH750
 
|-
 
| DR750 || RH750 || RH750
 
|-
 
| DW750 || DR750 || RH750
 
|-
 
| DW750 || CI750 || RH750
 
|-
 
| CI750 || RH750 || RH750
 
|}
 
 
 
'''NOTES:'''
 
# Combination of DR750 and CI750 is not allowed
 
# Only one DR750 per system is allowed
 
# Only one DW750 per system is allowed
 
# Only one CI750 per system is allowed
 
 
 
== External links ==
 
 
 
* [http://storage.datormuseum.se/u/96935524/Datormusuem/VAX11-750/MP01045_RH750_Feb81.pdf RH750 Field Maintenance Print Set] (MP-01045)
 
* [https://oldcomputers.dyndns.org/public/pub/rechner/dec/manuals/decimages/750f.pdf VAX-11/750 F Field Maintenance Print Set] (MP-01377)
 
 
 
[[Category: VAXen]]
 
 
[[Category: MASSBUS Controllers]]
 
[[Category: MASSBUS Controllers]]

Latest revision as of 20:13, 17 May 2024

The RH750 Massbus Adapter was a MASSBUS device controller for the VAX-11/750's CPU/Memory Interconnect (CMI).

It was implemented on one extended hex card, the L0007 MASSBUS Adapter (MBA), which mounts in the VAX-11/750 backplane in one of the three CMI option slots. A VAX-11/750 could have up to three RH750 Adapters; the first one goes into CMI slot 9, the second into slot 8, and the third in slot 7.

It was common practice to have two separate RH750s, one for tape, and another for disk devices. Combining both on one RH750 was possible, but tape usage had a negative impact on disk performance.

Further reading

  • RH750 Massbus Adapter Technical Description (EK-RH750-TD) - not available online
  • VAX Hardware Handbook (1980-81) (EB-17281-20) - the RH750 is covered in some detail in Chapter 10, pp. 175-190

External links