RK11-C disk controller - Revision history

Jnc: /* External links */ Standardize URL

2026-10-08T14:34:17Z

External links: Standardize URL

← Older revision		Revision as of 14:34, 8 October 2026
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	* [http://www.bitsavers.org/pdf/dec/unibus/RK11-C/RK11-C_schemFeb1971.pdf RK11-C moving head disk drive controller engineering drawings]		* [http://www.bitsavers.org/pdf/dec/unibus/RK11-C/RK11-C_schemFeb1971.pdf RK11-C moving head disk drive controller engineering drawings]
	* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/dload/RK11-C-DB_EngrDrws_Dec72.pdf RK11-C-DB Double Buffer Disk Control Engineering Drawings]		* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/dload/RK11-C-DB_EngrDrws_Dec72.pdf RK11-C-DB Double Buffer Disk Control Engineering Drawings]
	* [~~https~~://www.bitsavers.org/pdf/dec/unibus/5408458_ind_panel/rk11c_conn.tif RK11-C Indicator Connections]		* [http://www.bitsavers.org/pdf/dec/unibus/5408458_ind_panel/rk11c_conn.tif RK11-C Indicator Connections]
	* [https://fritzm.github.io/unix-v6-trouble-1.html PDP-11/45: V6 Unix Troubleshooting, Part I] [https://fritzm.github.io/unix-v6-trouble-2.html Part II] - a wonderful, lengthy and painful example of [[Vonada's Engineering Maxims\|Vonada's Maxim #12]] at work on an RK11-C		* [https://fritzm.github.io/unix-v6-trouble-1.html PDP-11/45: V6 Unix Troubleshooting, Part I] [https://fritzm.github.io/unix-v6-trouble-2.html Part II] - a wonderful, lengthy and painful example of [[Vonada's Engineering Maxims\|Vonada's Maxim #12]] at work on an RK11-C

	[[Category: UNIBUS Storage Controllers]]		[[Category: UNIBUS Storage Controllers]]

Jnc: /* External links */ +RK11-C Indicator Connections

2026-10-05T15:11:47Z

External links: +RK11-C Indicator Connections

← Older revision		Revision as of 15:11, 5 October 2026
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	* [http://www.bitsavers.org/pdf/dec/unibus/RK11-C/RK11-C_schemFeb1971.pdf RK11-C moving head disk drive controller engineering drawings]		* [http://www.bitsavers.org/pdf/dec/unibus/RK11-C/RK11-C_schemFeb1971.pdf RK11-C moving head disk drive controller engineering drawings]
	* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/dload/RK11-C-DB_EngrDrws_Dec72.pdf RK11-C-DB Double Buffer Disk Control Engineering Drawings]		* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/dload/RK11-C-DB_EngrDrws_Dec72.pdf RK11-C-DB Double Buffer Disk Control Engineering Drawings]
			* [https://www.bitsavers.org/pdf/dec/unibus/5408458_ind_panel/rk11c_conn.tif RK11-C Indicator Connections]
	* [https://fritzm.github.io/unix-v6-trouble-1.html PDP-11/45: V6 Unix Troubleshooting, Part I] [https://fritzm.github.io/unix-v6-trouble-2.html Part II] - a wonderful, lengthy and painful example of [[Vonada's Engineering Maxims\|Vonada's Maxim #12]] at work on an RK11-C		* [https://fritzm.github.io/unix-v6-trouble-1.html PDP-11/45: V6 Unix Troubleshooting, Part I] [https://fritzm.github.io/unix-v6-trouble-2.html Part II] - a wonderful, lengthy and painful example of [[Vonada's Engineering Maxims\|Vonada's Maxim #12]] at work on an RK11-C

	[[Category: UNIBUS Storage Controllers]]		[[Category: UNIBUS Storage Controllers]]

Jnc: /* External links */ Bitsavers has reorganized a bit

2026-10-02T17:06:45Z

External links: Bitsavers has reorganized a bit

← Older revision		Revision as of 17:06, 2 October 2026
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	==External links==		==External links==

	* [http://www.bitsavers.org/pdf/dec/unibus/RK11-C_manual1971.pdf RK11-C moving head disk drive controller manual] (DEC-11-HRKA-D)		* [http://www.bitsavers.org/pdf/dec/unibus/RK11-C/RK11-C_manual1971.pdf RK11-C moving head disk drive controller manual] (DEC-11-HRKA-D)
	* [http://www.bitsavers.org/pdf/dec/unibus/RK11-C_schemFeb1971.pdf RK11-C moving head disk drive controller engineering drawings]		* [http://www.bitsavers.org/pdf/dec/unibus/RK11-C/RK11-C_schemFeb1971.pdf RK11-C moving head disk drive controller engineering drawings]
	* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/dload/RK11-C-DB_EngrDrws_Dec72.pdf RK11-C-DB Double Buffer Disk Control Engineering Drawings]		* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/dload/RK11-C-DB_EngrDrws_Dec72.pdf RK11-C-DB Double Buffer Disk Control Engineering Drawings]
	* [https://fritzm.github.io/unix-v6-trouble-1.html PDP-11/45: V6 Unix Troubleshooting, Part I] [https://fritzm.github.io/unix-v6-trouble-2.html Part II] - a wonderful, lengthy and painful example of [[Vonada's Engineering Maxims\|Vonada's Maxim #12]] at work on an RK11-C		* [https://fritzm.github.io/unix-v6-trouble-1.html PDP-11/45: V6 Unix Troubleshooting, Part I] [https://fritzm.github.io/unix-v6-trouble-2.html Part II] - a wonderful, lengthy and painful example of [[Vonada's Engineering Maxims\|Vonada's Maxim #12]] at work on an RK11-C

	[[Category: UNIBUS Storage Controllers]]		[[Category: UNIBUS Storage Controllers]]

Jnc: /* External links */ Vonada's Maxim #12 at work on an RK11-C

2023-03-26T12:44:24Z

External links: Vonada's Maxim #12 at work on an RK11-C

← Older revision		Revision as of 12:44, 26 March 2023
Line 222:		Line 222:
	* [http://www.bitsavers.org/pdf/dec/unibus/RK11-C_schemFeb1971.pdf RK11-C moving head disk drive controller engineering drawings]		* [http://www.bitsavers.org/pdf/dec/unibus/RK11-C_schemFeb1971.pdf RK11-C moving head disk drive controller engineering drawings]
	* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/dload/RK11-C-DB_EngrDrws_Dec72.pdf RK11-C-DB Double Buffer Disk Control Engineering Drawings]		* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/dload/RK11-C-DB_EngrDrws_Dec72.pdf RK11-C-DB Double Buffer Disk Control Engineering Drawings]
			* [https://fritzm.github.io/unix-v6-trouble-1.html PDP-11/45: V6 Unix Troubleshooting, Part I] [https://fritzm.github.io/unix-v6-trouble-2.html Part II] - a wonderful, lengthy and painful example of [[Vonada's Engineering Maxims\|Vonada's Maxim #12]] at work on an RK11-C

	[[Category: UNIBUS Storage Controllers]]		[[Category: UNIBUS Storage Controllers]]

Jnc: +img, redirs, etc

2022-04-04T16:49:43Z

+img, redirs, etc

← Older revision		Revision as of 16:49, 4 April 2022
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			[[Image:DBRK11C.jpg\|350px\|thumb\|right\|RK11-C disk controller, Double Buffered version]]

	The '''RK11-C''' is the earliest known version of the [[RK11 disk controller]]. (Nothing is known of the -A and -B, if they ever existed as products, although see [[RK11 disk controller#Early RK11 version\|here]] for more about the RK11-C's predecessor). It is mostly [[program compatible]] with the replacement [[RK11 disk controller#RK11-D\|RK11-D]].		The '''RK11-C''' is the earliest known version of the [[RK11 disk controller]]. (Nothing is known of the -A and -B, if they ever existed as products, although see [[RK11 disk controller#Early RK11 version\|here]] for more about the RK11-C's predecessor). It is mostly [[program compatible]] with the replacement [[RK11 disk controller#RK11-D\|RK11-D]].

	Although the drive interface is slightly different between the RK11-C and RK11-D, the RK11-C can handle both the earlier [[RK02/03 disk drive]]s, and the later [[RK05 disk drive\|RK05s]] (the latter primarily intended for use with the RK11-D - see below).		Although the drive interface is slightly different between the RK11-C and RK11-D, the RK11-C can handle both the earlier [[RK02/03 disk drive]]s, and the later [[RK05 disk drive\|RK05s]] (the latter primarily intended for use with the RK11-D - see below).

	Like many of the earlier large [[device controller]]s for the [[PDP-11]], it was a large custom [[wire-wrap]]ped [[backplane]] which bolted into the front or back of a 19 inch rack, such as an [[H960]]; into it plugged about 40 small M-Series [[FLIP CHIP]]s.		Like many of the earlier large [[device controller]]s for the [[PDP-11]], it was a large custom [[wire-wrap]]ped [[backplane]] which bolted into the front or back of a 19 inch rack, such as an [[H960 rack\|H950]]; into it plugged about 40 small M-Series [[FLIP CHIP]]s.

	The backplane is wired for connection to a standard [[DEC indicator panel]], but no inlay for such has even been sighted, although the RK11-C Engineering Drawings allow one to work out exactly what such an inlay would have looked like. It does however appear than the hypothesized earlier version (above) did have such an indicator panel.		The backplane is wired for connection to a standard [[DEC indicator panel]], but no inlay for such has even been sighted, although the RK11-C Engineering Drawings allow one to work out exactly what such an inlay would have looked like. It does however appear than the hypothesized earlier version (above) did have such an indicator panel.
Line 9:		Line 11:
	==Drive buses and RK05 compatibility==		==Drive buses and RK05 compatibility==

	The RK11-C has two different drive buses, each which can handle up to four of . (The buses are not independent - most lines are shared between the two; so only one can be active at a time.) The only lines not in common are the 'drive select' lines (A-D on bus 1 - slot 12 on the backplane, and E-F, H, J on bus 2 - slot 10). Each select line is assigned to one drive; to select that drive, the corresponding line is asserted.		The RK11-C has two different drive buses, each which can handle up to four drives. (The buses are not independent - most lines are shared between the two; so only one can be active at a time.) The only lines not in common are the 'drive select' lines (A-D on bus 1 - slot 12 on the backplane, and E-F, H, J on bus 2 - slot 10). Each select line is assigned to one drive; to select that drive, the corresponding line is asserted.

	RK11-D's use a different, but upwardly compatible drive select mechanism, and RK05's can detect whether they are connected to an RK11-C or RK11-D, and respond appropriately.		RK11-D's use a different, but upwardly compatible drive select mechanism, and RK05's can detect whether they are connected to an RK11-C or RK11-D, and respond appropriately.
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	[[Image:RK11-C-DB_DataPaths.jpg\|295px\|right\|thumb\|RK11-C-DB data paths (from the last page of the engineering drawings)]]		[[Image:RK11-C-DB_DataPaths.jpg\|295px\|right\|thumb\|RK11-C-DB data paths (from the last page of the engineering drawings)]]

	There is also a rare variant of the RK11-C, the 'Double Buffer' RK11-C. It adds two 16-bit buffer registers (ABUF and BBUF), which are chained in an alternate data path to the RKDB buffer register from the two sources that can feed it (the UNIBUS and the DSB - Data <!-- DEC docs also give 'Disk SB' expansion -->~~Serial Buffer~~, where data to/from the disk is serialized).		There is also a rare variant of the RK11-C, the 'Double Buffer' RK11-C. It adds two 16-bit buffer registers (ABUF and BBUF), which are chained in an alternate data path to the RKDB buffer register from the two sources that can feed it (the UNIBUS and the DSB - Data Serial Buffer<!-- DEC docs also give 'Disk SB' expansion -->, where data to/from the disk is serialized).

	The motivation is not explicitly known (no documentation other than the engineering drawings is now extant), but it likely prevented under-run/over-run errors when there was considerable competing UNIBUS [[DMA]] traffic.		The motivation is not explicitly known (no documentation other than the engineering drawings is now extant), but it likely prevented under-run/over-run errors when there was considerable competing UNIBUS [[Direct Memory Access\|DMA]] traffic.

	===Engineering drawings===		===Engineering drawings===
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	* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/dload/RK11-C-DB_EngrDrws_Dec72.pdf RK11-C-DB Double Buffer Disk Control Engineering Drawings]		* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/dload/RK11-C-DB_EngrDrws_Dec72.pdf RK11-C-DB Double Buffer Disk Control Engineering Drawings]

	[[Category:UNIBUS Storage Controllers]]		[[Category: UNIBUS Storage Controllers]]

Jnc: drive bus and RK05 compatibity

2021-12-12T21:31:15Z

drive bus and RK05 compatibity

← Older revision		Revision as of 21:31, 12 December 2021
Line 1:		Line 1:
	The '''RK11-C''' is the earliest known version of the [[RK11 disk controller]]. (Nothing is known of the -A and -B, if they ever existed as products, although see [[RK11 disk controller#Early RK11 version\|here]] for more about the RK11-C's predecessor.)		The '''RK11-C''' is the earliest known version of the [[RK11 disk controller]]. (Nothing is known of the -A and -B, if they ever existed as products, although see [[RK11 disk controller#Early RK11 version\|here]] for more about the RK11-C's predecessor). It is mostly [[program compatible]] with the replacement [[RK11 disk controller#RK11-D\|RK11-D]].

	~~Like many of~~ the ~~earlier large peripheral controllers for~~ the ~~[[PDP~~-~~11]]~~, ~~it was a large custom [[wire~~-~~wrap]]ped~~ [[~~backplane~~]] ~~which bolted into~~ the ~~front or back of a 19 inch rack, such as an~~ [[~~H960~~]]~~; into it plugged about 40 small M~~-~~Series [[FLIP CHIP]]s~~.		Although the drive interface is slightly different between the RK11-C and RK11-D, the RK11-C can handle both the earlier [[RK02/03 disk drive]]s, and the later [[RK05 disk drive\|RK05s]] (the latter primarily intended for use with the RK11-D - see below).

	The backplane is wired for connection to a standard [[DEC indicator panel]], but no inlay for such has even been sighted, although the RK11-C Engineering Drawings allow one to work out exactly what such an inlay would have looked like. It does however appear than the earlier version did have such an indicator panel.		Like many of the earlier large [[device controller]]s for the [[PDP-11]], it was a large custom [[wire-wrap]]ped [[backplane]] which bolted into the front or back of a 19 inch rack, such as an [[H960]]; into it plugged about 40 small M-Series [[FLIP CHIP]]s.

			The backplane is wired for connection to a standard [[DEC indicator panel]], but no inlay for such has even been sighted, although the RK11-C Engineering Drawings allow one to work out exactly what such an inlay would have looked like. It does however appear than the hypothesized earlier version (above) did have such an indicator panel.

			==Drive buses and RK05 compatibility==

			The RK11-C has two different drive buses, each which can handle up to four of . (The buses are not independent - most lines are shared between the two; so only one can be active at a time.) The only lines not in common are the 'drive select' lines (A-D on bus 1 - slot 12 on the backplane, and E-F, H, J on bus 2 - slot 10). Each select line is assigned to one drive; to select that drive, the corresponding line is asserted.

			RK11-D's use a different, but upwardly compatible drive select mechanism, and RK05's can detect whether they are connected to an RK11-C or RK11-D, and respond appropriately.

	==Double Buffered RK11-C==		==Double Buffered RK11-C==

Jnc: /* External links */ follow standard

2021-12-08T22:13:40Z

External links: follow standard

← Older revision		Revision as of 22:13, 8 December 2021
Line 207:		Line 207:
	In the ordinary RK11-C, slots C08 and D08 hold pass-through connectors, which allow [[KM11-A Maintenance Set]]s to be plugged in and used from the outside of the rack holding the RK11-C. A pair of [[Flexprint cable]]s connect them to the 'usual' KM11 locations, in slots A30 and B30.		In the ordinary RK11-C, slots C08 and D08 hold pass-through connectors, which allow [[KM11-A Maintenance Set]]s to be plugged in and used from the outside of the rack holding the RK11-C. A pair of [[Flexprint cable]]s connect them to the 'usual' KM11 locations, in slots A30 and B30.

	==~~Documentation~~==		==External links==

	* [http://www.bitsavers.org/pdf/dec/unibus/RK11-C_manual1971.pdf RK11-C manual~~, 1971~~]		* [http://www.bitsavers.org/pdf/dec/unibus/RK11-C_manual1971.pdf RK11-C moving head disk drive controller manual] (DEC-11-HRKA-D)
	* [http://www.bitsavers.org/pdf/dec/unibus/RK11-C_schemFeb1971.pdf RK11-C ~~schematics, February 1971~~]		* [http://www.bitsavers.org/pdf/dec/unibus/RK11-C_schemFeb1971.pdf RK11-C moving head disk drive controller engineering drawings]
	* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/dload/RK11-C-DB_EngrDrws_Dec72.pdf RK11-C-DB Double Buffer Disk Control Engineering Drawings~~, December 1972~~]		* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/dload/RK11-C-DB_EngrDrws_Dec72.pdf RK11-C-DB Double Buffer Disk Control Engineering Drawings]

	[[Category:UNIBUS Storage Controllers]]		[[Category:UNIBUS Storage Controllers]]

Jnc: /* Module count table */ +links

2021-04-06T12:38:06Z

Module count table: +links

← Older revision		Revision as of 12:38, 6 April 2021
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	\| M002 \|\| 1 \|\| 3 \|\| 15 Loads		\| M002 \|\| 1 \|\| 3 \|\| 15 Loads
	\|-		\|-
	\| M105 \|\| 1 \|\| 1 \|\| Address selector		\| M105 \|\| 1 \|\| 1 \|\| [[M105 Address Selector\|Address selector]]
	\|-		\|-
	\| M111 \|\| 2 \|\| 5 \|\| Inverter		\| M111 \|\| 2 \|\| 5 \|\| Inverter
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	\| M623 \|\| 3 \|\| 3 \|\| Bus driver		\| M623 \|\| 3 \|\| 3 \|\| Bus driver
	\|-		\|-
	\| M782 \|\| 1 \|\| 1 \|\| Interrupt control		\| M782 \|\| 1 \|\| 1 \|\| [[M782 Interrupt Control\|Interrupt control]]
	\|-		\|-
	\| M784 \|\| 3 \|\| 3 \|\| UNIBUS receivers		\| M784 \|\| 3 \|\| 3 \|\| UNIBUS receivers

Jnc: /* Module Utilization chart */ Pass-through connectors

2021-02-09T14:50:03Z

Module Utilization chart: Pass-through connectors

← Older revision		Revision as of 14:50, 9 February 2021
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	<br>		<br>
	6775 = Cable to indicator panel		6775 = Cable to indicator panel

			In the ordinary RK11-C, slots C08 and D08 hold pass-through connectors, which allow [[KM11-A Maintenance Set]]s to be plugged in and used from the outside of the rack holding the RK11-C. A pair of [[Flexprint cable]]s connect them to the 'usual' KM11 locations, in slots A30 and B30.

	==Documentation==		==Documentation==

Jnc: /* Double Buffered RK11-C */ Bah, DEC docs give two different expansions

2021-02-09T12:47:41Z

Double Buffered RK11-C: Bah, DEC docs give two different expansions

← Older revision		Revision as of 12:47, 9 February 2021
Line 9:		Line 9:
	[[Image:RK11-C-DB_DataPaths.jpg\|295px\|right\|thumb\|RK11-C-DB data paths (from the last page of the engineering drawings)]]		[[Image:RK11-C-DB_DataPaths.jpg\|295px\|right\|thumb\|RK11-C-DB data paths (from the last page of the engineering drawings)]]

	There is also a rare variant of the RK11-C, the 'Double Buffer' RK11-C. It adds two 16-bit buffer registers (ABUF and BBUF), which are chained in an alternate data path to the RKDB buffer register from the two sources that can feed it (the UNIBUS and the DSB - Disk Serial Buffer, where data to/from the disk is serialized).		There is also a rare variant of the RK11-C, the 'Double Buffer' RK11-C. It adds two 16-bit buffer registers (ABUF and BBUF), which are chained in an alternate data path to the RKDB buffer register from the two sources that can feed it (the UNIBUS and the DSB - Data <!-- DEC docs also give 'Disk SB' expansion -->Serial Buffer, where data to/from the disk is serialized).

	The motivation is not explicitly known (no documentation other than the engineering drawings is now extant), but it likely prevented under-run/over-run errors when there was considerable competing UNIBUS [[DMA]] traffic.		The motivation is not explicitly known (no documentation other than the engineering drawings is now extant), but it likely prevented under-run/over-run errors when there was considerable competing UNIBUS [[DMA]] traffic.