BM873 ROM - Revision history

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

2026-10-04T22:14:33Z

External links: Bitsavers has reorganized a bit

← Older revision		Revision as of 22:14, 4 October 2026
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	==External links==		==External links==

	* [http://www.bitsavers.org/pdf/dec/unibus/DEC-11-H873A-B-D_BM873_Restart_Loader_Apr74.pdf BM873 restart/loader] (DEC-11-H873A-B-D)		* [http://www.bitsavers.org/pdf/dec/unibus/BM873/DEC-11-H873A-B-D_BM873_Restart_Loader_Apr74.pdf BM873 restart/loader] (DEC-11-H873A-B-D)
			* [http://www.bitsavers.org/www.computer.museum.uq.edu.au/pdf/EK-BM873-TM-004%20BM873%20Restart%20&%20Loader.pdf BM873 restart/loader] (EK-BM873-TM-004)
	* [http://shop-pdp.net/~stuff/PDFs/DEC/DEC_BM873_Restart_Loader_RevA_Feb74.pdf BM873 Restart Loader engineering drawings]		* [http://shop-pdp.net/~stuff/PDFs/DEC/DEC_BM873_Restart_Loader_RevA_Feb74.pdf BM873 Restart Loader engineering drawings]
	* [http://pdp-10.trailing-edge.com/BB-H311C-RM/01/swskit-documentation/kl873.mem.html KL873.MEM] - ''KL10 BM873 Bootstrap ROMs''		* [http://pdp-10.trailing-edge.com/BB-H311C-RM/01/swskit-documentation/kl873.mem.html KL873.MEM] - ''KL10 BM873 Bootstrap ROMs''
	* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/ROMs/M873-YA.mac M873-YA.mac] - Dis-assembled and commented dump of BM873-YA boot ROMs		* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/ROMs/M873-YA.mac M873-YA.mac] - Dis-assembled and commented dump of BM873-YA boot ROMs

	~~==Reference==~~

	* EK-BM873-TM-004, ''BM873 restart/loader''

	[[Category: UNIBUS ROMs]]		[[Category: UNIBUS ROMs]]

Jnc: /* External links */ +Manual, eng drws

2021-11-19T23:02:54Z

External links: +Manual, eng drws

← Older revision		Revision as of 23:02, 19 November 2021
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	==External links==		==External links==

			* [http://www.bitsavers.org/pdf/dec/unibus/DEC-11-H873A-B-D_BM873_Restart_Loader_Apr74.pdf BM873 restart/loader] (DEC-11-H873A-B-D)
			* [http://shop-pdp.net/~stuff/PDFs/DEC/DEC_BM873_Restart_Loader_RevA_Feb74.pdf BM873 Restart Loader engineering drawings]
	* [http://pdp-10.trailing-edge.com/BB-H311C-RM/01/swskit-documentation/kl873.mem.html KL873.MEM] - ''KL10 BM873 Bootstrap ROMs''		* [http://pdp-10.trailing-edge.com/BB-H311C-RM/01/swskit-documentation/kl873.mem.html KL873.MEM] - ''KL10 BM873 Bootstrap ROMs''
	* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/ROMs/M873-YA.mac M873-YA.mac] - Dis-assembled and commented dump of BM873-YA boot ROMs		* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/ROMs/M873-YA.mac M873-YA.mac] - Dis-assembled and commented dump of BM873-YA boot ROMs

Jnc: /* External links */ link to online copy of KL8873.MEM

2021-10-15T12:30:06Z

External links: link to online copy of KL8873.MEM

← Older revision		Revision as of 12:30, 15 October 2021
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	[[Image:BM873.jpg\|250px\|right\|thumb\|A BM783 card, showing the connector to the [[front panel]] cable, and diode array]]		[[Image:BM873.jpg\|250px\|right\|thumb\|A BM783 card, showing the connector to the [[front panel]] cable, and diode array]]

	The '''BM873 ~~[[Read-only memory\|~~ROM]]''' card was a [[UNIBUS]] card for the [[PDP-11]] series of computers; it was a [[DEC card form factor\|quad]] format card, and contained 256 [[word]]s of memory (optionally limited to 128 words), contained in four [[PROM]] [[integrated circuit\|chips]] (two, when the limitation option was selected).		The '''BM873 ROM''' card was a [[UNIBUS]] [[Read-only memory\|ROM]] card for the [[PDP-11]] series of computers; it was a [[DEC card form factor\|quad]] format card, and contained 256 [[word]]s of memory (optionally limited to 128 words), contained in four [[PROM]] [[integrated circuit\|chips]] (two, when the limitation option was selected).

	The board appeared at [[address]]es from 773000 to 773776; if the 128-word limitation is enabled, the top address is 773376. Several of the computers it was intended for use with ([[PDP-11/40]], [[PDP-11/45]]) could be configured so that the host computer jumped to the code on the board on power-on.		The board appeared at [[address]]es from 773000 to 773776; if the 128-word limitation is enabled, the top address is 773376. Several of the computers it was intended for use with ([[PDP-11/40]], [[PDP-11/45]]) could be configured so that the host computer jumped to the code on the board on power-on.
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	* BM873-YB - As above, with the addition of [[RS03/04 disk drive\|RS0x]] and [[RP04 disk drive\|RP0x]] [[disk]]s and [[TU16 magtape drive\|TU16]] tapes; in addition, booting from units other than 0 (with the unit being specified in the console switch register)		* BM873-YB - As above, with the addition of [[RS03/04 disk drive\|RS0x]] and [[RP04 disk drive\|RP0x]] [[disk]]s and [[TU16 magtape drive\|TU16]] tapes; in addition, booting from units other than 0 (with the unit being specified in the console switch register)
	* BM873-YC - As the -YA variant, with added support for the [[DU11 synchronous serial line interface\|DU11]] synchronous line interface		* BM873-YC - As the -YA variant, with added support for the [[DU11 synchronous serial line interface\|DU11]] synchronous line interface
	* BM873-YD - [[KL10]] 1080 front end; supported booting from, and dumping to, TC11, RP0x, and [[DTE20 ~~Interface\|DTE20 10/11 interface~~]]		* BM873-YD - [[KL10]] 1080 front end; supported booting from, and dumping to, TC11, RP0x, and [[DTE20 Ten-Eleven Interface‎‎]]
	* BM873-YE - Unknown		* BM873-YE - Unknown
	* BM873-YF - KL10 2040 console; same capabilities as -YD, except the [[RX11 floppy disk controller\|RX11]] replaced the TC11		* BM873-YF - KL10 2040 console; same capabilities as -YD, except the [[RX11 floppy disk controller\|RX11]] replaced the TC11
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	==External links==		==External links==

	* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/ROMs/M873-YA.mac Dis-assembled and commented dump of BM873-YA boot ROMs]		* [http://pdp-10.trailing-edge.com/BB-H311C-RM/01/swskit-documentation/kl873.mem.html KL873.MEM] - ''KL10 BM873 Bootstrap ROMs''
			* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/ROMs/M873-YA.mac M873-YA.mac] - Dis-assembled and commented dump of BM873-YA boot ROMs

	==Reference==		==Reference==

	* EK-BM873-TM-004, ''BM873 restart/loader''		* EK-BM873-TM-004, ''BM873 restart/loader''
	* KL873.MEM, ''KL10 BM873 Bootstrap ROMs''

	[[Category: UNIBUS ROMs]]		[[Category: UNIBUS ROMs]]

Jnc: /* Variants */ +links, avoid redirs

2021-08-02T00:11:38Z

Variants: +links, avoid redirs

← Older revision		Revision as of 00:11, 2 August 2021
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	===Variants===		===Variants===

	* BM873-YA - Boot from disks ([[RF11]], [[RK11]], [[RP11]], [[RC11]]), [[TC11]] [[DECtape]], [[TM11]] magnetic tape, [[TA11]] casette magnetic tape, ~~serial line, and~~ high-speed paper tape reader		* BM873-YA - Boot from disks ([[RF11 disk controller\|RF11]], [[RK11 disk controller\|RK11]], [[RP11 disk controller\|RP11]], [[RC11 disk controller\|RC11]]), [[TC11 DECtape controller\|TC11]] [[DECtape]], [[TM11 magtape controller\|TM11]] [[magnetic tape]], [[TA11 Magnetic Tape Cassette controller\|TA11]] casette magnetic tape, [[PC04/PC05 High-Speed Paper-Tape Reader/Punch\|PC05]] high-speed [[paper tape]] reader, and [[asynchronous serial line]]
	* BM873-YB - As above, with the addition of RS0x and RP0x ~~disks~~ and TU16 tapes; in addition, booting from units other than 0 (with the unit being specified in the console switch register)		* BM873-YB - As above, with the addition of [[RS03/04 disk drive\|RS0x]] and [[RP04 disk drive\|RP0x]] [[disk]]s and [[TU16 magtape drive\|TU16]] tapes; in addition, booting from units other than 0 (with the unit being specified in the console switch register)
	* BM873-YC - As the -YA variant, with added support for the [[DU11]] synchronous line interface		* BM873-YC - As the -YA variant, with added support for the [[DU11 synchronous serial line interface\|DU11]] synchronous line interface
	* BM873-YD - [[KL10]] 1080 front end; supported booting from, and dumping to, TC11, RP0x, and [[DTE20 Interface\|DTE20 10/11 interface]]		* BM873-YD - [[KL10]] 1080 front end; supported booting from, and dumping to, TC11, RP0x, and [[DTE20 Interface\|DTE20 10/11 interface]]
	* BM873-YE - Unknown		* BM873-YE - Unknown
	* BM873-YF - KL10 2040 console; same capabilities as -YD, except the [[RX11]] replaced the TC11		* BM873-YF - KL10 2040 console; same capabilities as -YD, except the [[RX11 floppy disk controller\|RX11]] replaced the TC11
	* BM873-YG - DN87 communications; supported booting from a [[DL11]] and the DTE20, and dumping to the latter		* BM873-YG - DN87 communications; supported booting from a [[DL11 asynchronous serial line interface\|DL11]] and the DTE20, and dumping to the latter
	* BM873-YH - 10xx/20xx console; supported booting from TC11, RX11, RP0x, and possibly the DTE20 10/11 interface (the documentation is contradictory)		* BM873-YH - 10xx/20xx console; supported booting from TC11, RX11, RP0x, and possibly the DTE20 10/11 interface (the documentation is contradictory)
	* BM873-YJ - 10xx/20xx console/communications; supported booting from TC11, RX11, RP0x, DL11 and the DTE20, and dumping to the latter		* BM873-YJ - 10xx/20xx console/communications; supported booting from TC11, RX11, RP0x, DL11 and the DTE20, and dumping to the latter

Jnc: typo

2021-01-28T10:24:04Z

typo

← Older revision		Revision as of 10:24, 28 January 2021
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	[[Image:BM873.jpg\|250px\|right\|thumb\|A BM783 card, showing the connector to the [[front panel]] cable]]		[[Image:BM873.jpg\|250px\|right\|thumb\|A BM783 card, showing the connector to the [[front panel]] cable, and diode array]]

	The '''BM873 [[Read-only memory\|ROM]]''' card was a [[UNIBUS]] card for the [[PDP-11]] series of computers; it was a [[DEC card form factor\|quad]] format card, and contained 256 [[word]]s of memory (optionally limited to 128 words), contained in four [[PROM]] [[integrated circuit\|chips]] (two, when the limitation option was selected).		The '''BM873 [[Read-only memory\|ROM]]''' card was a [[UNIBUS]] card for the [[PDP-11]] series of computers; it was a [[DEC card form factor\|quad]] format card, and contained 256 [[word]]s of memory (optionally limited to 128 words), contained in four [[PROM]] [[integrated circuit\|chips]] (two, when the limitation option was selected).
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	Most versions were used for [[bootstrap]]ping the machine, from [[disk]], [[paper tape\|paper]] and [[magnetic tape]], etc, but it could be used for any purpose.		Most versions were used for [[bootstrap]]ping the machine, from [[disk]], [[paper tape\|paper]] and [[magnetic tape]], etc, but it could be used for any purpose.

	In addition to an un-programmed variant, which the user could program as they wanted, the board came from DEC in several pre-programmed variants, designated BM783-Yx (where 'x' is a capital letter, starting with 'A'), set up to perform various functions. Many of the later variants were used to boot the PDP-11/40 used as the [[front-end]] processor in the [[KL10]].		In addition to an un-programmed variant, which the user could program as they wanted, the board came from DEC in several pre-programmed variants, designated BM783-Yx (where 'x' is a capital letter, starting with 'A'), set up to perform various functions. Many of the later variants were used to boot the PDP-11/40 used as the [[front end]] processor in the [[KL10]].

	===Variants===		===Variants===

Jnc: M783 is UNIBUS transceivers; +links

2021-01-28T10:22:39Z

M783 is UNIBUS transceivers; +links

← Older revision		Revision as of 10:22, 28 January 2021
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	[[Image:BM873.jpg\|250px\|right\|thumb\|~~An M783~~ card, showing the connector to the [[front panel]] cable]]		[[Image:BM873.jpg\|250px\|right\|thumb\|A BM783 card, showing the connector to the [[front panel]] cable]]

	The '''BM873 [[Read-only memory\|ROM]]''' card was a [[UNIBUS]] card for the [[PDP-11]] series of computers; it was a [[DEC card form factor\|quad]] format card, and contained 256 ~~words~~ of memory (optionally limited to 128 words), contained in four [[PROM]] chips (two, when the limitation option was selected).		The '''BM873 [[Read-only memory\|ROM]]''' card was a [[UNIBUS]] card for the [[PDP-11]] series of computers; it was a [[DEC card form factor\|quad]] format card, and contained 256 [[word]]s of memory (optionally limited to 128 words), contained in four [[PROM]] [[integrated circuit\|chips]] (two, when the limitation option was selected).

	The board appeared at ~~addresses~~ from 773000 to 773776; if the 128-word limitation is enabled, the top address is 773376. Several of the computers it was intended for use with ([[PDP-11/40]], [[PDP-11/45]]) could be configured so that the host computer jumped to the code on the board on power-on.		The board appeared at [[address]]es from 773000 to 773776; if the 128-word limitation is enabled, the top address is 773376. Several of the computers it was intended for use with ([[PDP-11/40]], [[PDP-11/45]]) could be configured so that the host computer jumped to the code on the board on power-on.

	In addition, an edge connector provided four external input lines, each of which (when pulled low) forced ~~(via a simulated power-fail restart, and then forcing the first two read cyles after the power-up to read data specially provided by the board)~~ the computer to jump to a particular address (configured by a group of 8 ~~diodes~~, four groups in total - one for each input line) within the card's address space.		In addition, an edge connector provided four external input lines, each of which (when pulled low) forced the computer to jump to a particular address (configured by a group of 8 [[diode]]s, four groups in total - one for each input line) within the card's address space. This was done via a simulated power-fail restart, and then forcing the first two read cycles on the UNIBUS after the power-up to read data specially provided by the board.

	==Jumpers==		==Jumpers==

	Jumpers W1 and W2 adapt the board to variations in fetching the new PS/PC after power-up - the bus cycles which the board interferes with, to force the new PC to go to a specific location within the board. Some machines, like the -11/40, fetch the PS before the PC; others, like -11/45, fetch the PC first.		Jumpers W1 and W2 adapt the board to variations in fetching the new [[Processor Status Word\|PS]]/[[Program Counter\|PC]] after power-up - the bus cycles which the board interferes with, to force the new PC to go to a specific location within the board. Some machines, like the -11/40, fetch the PS before the PC; others, like -11/45, fetch the PC first.

	Jumper W3, when installed, limits the card to 128 words.		Jumper W3, when installed, limits the card to 128 words.
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	==Versions==		==Versions==

	Most versions were used for [[~~bootstrapping~~]] the machine, from [[disk]], paper and magnetic tape, etc, but it could be used for any purpose.		Most versions were used for [[bootstrap]]ping the machine, from [[disk]], [[paper tape\|paper]] and [[magnetic tape]], etc, but it could be used for any purpose.

	In addition to an un-programmed variant, which the user could program as they wanted, the board came from DEC in several pre-programmed variants, designated ~~BM792~~-Yx (where 'x' is a capital letter, starting with 'A'), set up to perform various functions. Many of the later variants were used to boot the PDP-11/40 used as the front-end processor in the [[KL10]].		In addition to an un-programmed variant, which the user could program as they wanted, the board came from DEC in several pre-programmed variants, designated BM783-Yx (where 'x' is a capital letter, starting with 'A'), set up to perform various functions. Many of the later variants were used to boot the PDP-11/40 used as the [[front-end]] processor in the [[KL10]].

	===Variants===		===Variants===
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	* BM873-YB - As above, with the addition of RS0x and RP0x disks and TU16 tapes; in addition, booting from units other than 0 (with the unit being specified in the console switch register)		* BM873-YB - As above, with the addition of RS0x and RP0x disks and TU16 tapes; in addition, booting from units other than 0 (with the unit being specified in the console switch register)
	* BM873-YC - As the -YA variant, with added support for the [[DU11]] synchronous line interface		* BM873-YC - As the -YA variant, with added support for the [[DU11]] synchronous line interface
	* BM873-YD - [[KL10]] 1080 [[front end]]; supported booting from, and dumping to, TC11, RP0x, and [[DTE20 Interface\|DTE20 10/11 interface]]		* BM873-YD - [[KL10]] 1080 front end; supported booting from, and dumping to, TC11, RP0x, and [[DTE20 Interface\|DTE20 10/11 interface]]
	* BM873-YE - Unknown		* BM873-YE - Unknown
	* BM873-YF - 2040 console; same capabilities as -YD, except the [[RX11]] replaced the TC11		* BM873-YF - KL10 2040 console; same capabilities as -YD, except the [[RX11]] replaced the TC11
	* BM873-YG - DN87 communications; supported booting from a [[DL11]] and the DTE20, and dumping to the latter		* BM873-YG - DN87 communications; supported booting from a [[DL11]] and the DTE20, and dumping to the latter
	* BM873-YH - 10xx/20xx console; supported booting from TC11, RX11, RP0x, and possibly the DTE20 10/11 interface (the documentation is contradictory)		* BM873-YH - 10xx/20xx console; supported booting from TC11, RX11, RP0x, and possibly the DTE20 10/11 interface (the documentation is contradictory)
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	==External links==		==External links==

	* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/ROMs/M873-YA.mac Dis-assembled and commented dump of ~~M873~~-YA boot ROMs]		* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/ROMs/M873-YA.mac Dis-assembled and commented dump of BM873-YA boot ROMs]

	==Reference==		==Reference==

Jnc: /* Variants */ +links

2019-08-13T16:22:42Z

Variants: +links

← Older revision		Revision as of 16:22, 13 August 2019
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	* BM873-YB - As above, with the addition of RS0x and RP0x disks and TU16 tapes; in addition, booting from units other than 0 (with the unit being specified in the console switch register)		* BM873-YB - As above, with the addition of RS0x and RP0x disks and TU16 tapes; in addition, booting from units other than 0 (with the unit being specified in the console switch register)
	* BM873-YC - As the -YA variant, with added support for the [[DU11]] synchronous line interface		* BM873-YC - As the -YA variant, with added support for the [[DU11]] synchronous line interface
	* BM873-YD - 1080 ~~console~~; supported booting from, and dumping to, TC11, RP0x, and [[DTE20]] 10/11 interface		* BM873-YD - [[KL10]] 1080 [[front end]]; supported booting from, and dumping to, TC11, RP0x, and [[DTE20 Interface\|DTE20 10/11 interface]]
	* BM873-YE - Unknown		* BM873-YE - Unknown
	* BM873-YF - 2040 console; same capabilities as -YD, except the [[RX11]] replaced the TC11		* BM873-YF - 2040 console; same capabilities as -YD, except the [[RX11]] replaced the TC11

Jnc: /* External links */ ROM dump

2019-08-13T13:55:03Z

External links: ROM dump

← Older revision		Revision as of 13:55, 13 August 2019
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	* [[UNIBUS boot ROMs]]		* [[UNIBUS boot ROMs]]

			==External links==

			* [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/ROMs/M873-YA.mac Dis-assembled and commented dump of M873-YA boot ROMs]

	==Reference==		==Reference==

Jnc: Add image

2019-05-06T20:37:56Z

Add image

← Older revision		Revision as of 20:37, 6 May 2019
Line 1:		Line 1:
			[[Image:BM873.jpg\|250px\|right\|thumb\|An M783 card, showing the connector to the [[front panel]] cable]]

	The '''BM873 [[Read-only memory\|ROM]]''' card was a [[UNIBUS]] card for the [[PDP-11]] series of computers; it was a [[DEC card form factor\|quad]] format card, and contained 256 words of memory (optionally limited to 128 words), contained in four [[PROM]] chips (two, when the limitation option was selected).		The '''BM873 [[Read-only memory\|ROM]]''' card was a [[UNIBUS]] card for the [[PDP-11]] series of computers; it was a [[DEC card form factor\|quad]] format card, and contained 256 words of memory (optionally limited to 128 words), contained in four [[PROM]] chips (two, when the limitation option was selected).

Jnc: /* Reference */ +cat

2018-12-07T02:22:36Z

Reference: +cat

← Older revision		Revision as of 02:22, 7 December 2018
Line 39:		Line 39:
	* EK-BM873-TM-004, ''BM873 restart/loader''		* EK-BM873-TM-004, ''BM873 restart/loader''
	* KL873.MEM, ''KL10 BM873 Bootstrap ROMs''		* KL873.MEM, ''KL10 BM873 Bootstrap ROMs''

			[[Category: UNIBUS ROMs]]