Floating device address space - Revision history

Jnc: probable explanation for base units

2023-02-08T13:44:49Z

probable explanation for base units

Jnc: Link board

2023-02-08T03:02:34Z

Link board

Jnc: add a bunch of devices from a later version

2022-08-30T01:59:05Z

add a bunch of devices from a later version

Jnc: /* Further reading */ +PDP-11 Architecture Handbook

2022-08-30T01:17:42Z

‎Further reading: +PDP-11 Architecture Handbook

Jnc: /* External links */ dates on cover

2022-08-29T20:27:25Z

‎External links: dates on cover

Jnc: /* External links */ +peripherals handbook (1981)

2022-08-29T19:22:30Z

‎External links: +peripherals handbook (1981)

Jnc: a few later addns

2021-08-25T18:39:11Z

a few later addns

Jnc: Avoid redir

2021-08-01T23:49:25Z

Avoid redir

Jnc: Mostly there

2021-07-27T18:20:32Z

Mostly there

New page

The '''floating device address space''' is a block of [[address space]] in the I/O page of the [[UNIBUS]] (and later the [[QBUS]]) used to hold the control [[register]]s of [[peripheral]]s. Originally, each specific peripheral was assigned a fixed address for its registers; once the number of different device types became large, circa 1975, this was no longer feasible (or scalable), and the 'floating' approach was adopted instead.

In this, a block of address space (on the UNIBUS, from 0760010 to 0763776) is allocated for 'floating' devices. Within that block, devices are assigned in a fixed order, with all the devices of any type in a contiguous group. There is an empty minimum-sized group for each type of which there are no devices of that type present, and a gap between each group of devices (to mark the end of each group). (Each actual group must start on an address of the required modulus; e.g. if there is one DJ11 and one DH11, the DJ11 would be at 0760010, the 'end of DJ11s gap' would be at 0760020, the DH11 could not be at 0760030, but would have to be at 0760040.)

Floating devices, in assignment order:

{| class="wikitable"
! Rank !! Device !! Size<BR>(modulus) !! Comment
|-
| 1 || [[DJ11 asynchronous serial line interface|DJ11]] || 010
|-
| 2 || [[DH11 asynchronous serial line interface|DH11]] || 020
|-
| 3 || [[DQ11]] || 010
|-
| 4 || [[DU11]] || 010
|-
| 5 || [[DUP11 synchronous serial line interface|DUP11]] || 010
|-
| 6 || [[LK11]] || 010
|-
| 7A || [[DMC11]] || 010
|-
| 7B || [[DMR11]] || 010
|-
| 8 || [[DZ11 asynchronous serial line interface|DZ11]] || 010
|-
| 9 || [[KMC11]] || 010
|-
| 10 || [[LPP11]] || 010
|-
| 11 || VMV21 || 010
|-
| 12 || VMV31 || 020
|-
| 13 || [[DWR70]] || 010
|-
| 14 || [[RL11 disk controller|RL11]] || 010 || Only extra
|-
| 15 || [[LPA11]] || 020 || Only extra
|-
| 16 || [[KW11-C]] || 010
|-
| 17 || Reserved || 010
|-
| 18 || [[RX11 floppy disk controller|RX11]] || 010 || Only extra
|-
| 19 || [[DR11-W]] || 010
|-
| 20 || [[DR11-B parallel interface|DR11-B]] || 010 || After second
|}

==See also==

* [[Floating device vectors]]

[[Category: UNIBUS]]
[[Category: QBUS]]

@@ Line 70: / Line 70: @@
 | 30 || [[TU81 magtape drive|TU81]] || 04 || Only extra
 |}
 ==See also==

@@ Line 66: / Line 66: @@
 | 28 || KMS11 || 20
 |-
-| 29 || VS100 || 20
+| 29 || [[VS100]] || 20
 |-
 | 30 || [[TU81 magtape drive|TU81]] || 04 || Only extra

@@ Line 56: / Line 56: @@
 | 23 || [[ISB11]] || 010
 |-
-| 23 || [[DMV11 Synchronous Controller|DMV11]] || 020
+| 24 || [[DMV11 Synchronous Controller|DMV11]] || 020
 |}

← Older revision		Revision as of 01:17, 30 August 2022
Line 62:		Line 62:

	* [[Floating device vectors]]		* [[Floating device vectors]]
		+
		+	==Further reading==
		+
		+	* ''PDP-11 Architecture Handbook'' (not online); 'Floating CSR Address Devices', in Appendix A

	==External links==		==External links==

@@ Line 65: / Line 65: @@
 ==External links==
-* [http://www.bitsavers.org/pdf/dec/handbooks/EB-20443-20_Peripherals_Handbook_1981.pdf peripherals handbook (1981)] - Appendix D, 'Floating CSR Address Devices' (pg. 494 of the PDF]
+* [http://www.bitsavers.org/pdf/dec/handbooks/EB-20443-20_Peripherals_Handbook_1981.pdf peripherals handbook (1981-82)] - Appendix D, 'Floating CSR Address Devices' (pg. 494 of the PDF]
 [[Category: UNIBUS]]
 [[Category: QBUS]]

@@ Line 49: / Line 49: @@
 |-
 | 20 || [[DR11-B parallel interface|DR11-B]] || 010 || After second
 |}

@@ Line 14: / Line 14: @@
 | 3 || [[DQ11]] || 010
 |-
-| 4 || [[DU11]] || 010
+| 4 || [[DU11 synchronous serial line interface|DU11]] || 010
 |-
 | 5 || [[DUP11 synchronous serial line interface|DUP11]] || 010