The RX01 has two 8" drives capable of single density only.
Inside the drive are two boards: a controller (M7726) and a read/write board (M7727).
Through an interface board this RX01 was connected to the computer system.

    full size RX01 option bulletin (785x1038 pixels, 284 kb)

 
The RX02 has also two 8" drives, but can read and write double density floppies. The two boards inside this drive are the controller (M7744) and the read/write board (M7745). The controller board inside the RX02 has two DIP switches and thus the drive could be configured to work as an RX02 for a PDP-11 (or LSI-11) with data transfer using DMA, as an RX01 for all three systems using programmed I/O data transfer, or as RX02 for the PDP-8 only with data transfer on programmed I/O basis.

full size RX02 User Guide (785x1038 pixels, 625 kb)

The interface logic for the RX01 is the following. bus system   subsystem     interface   OMNIBUS PDP-8 RX8E M8357   LSIBUS   LSI-11 RXV11 M7946 UNIBUS   PDP-11   RX11 M7846

The interface logic for the RX02 is the following. bus system   subsystem     interface   OMNIBUS PDP-8 RX28 M8357   LSIBUS   LSI-11 RXV21 M8029 UNIBUS   PDP-11   RX211 M8256

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• RX11 Floppy Disk System (OPTION BULLETIN - JULY 1975)
  1. RX11 Disk Option Bulletin (TIF file, 2.2 Mb)
• RX02 Floppy Disk System User's Guide (EK-RX02-UG-001)
• RX01/RX02 Pocket Service Guide (EK-RX012-PS-002)
• RX211 Field Maintenance Print Set (MP00626)
  1. RX211 Field Maintenance Print Set MP00626 part-1 (TIF file, 5.3 Mb)
  2. RX211 Field Maintenance Print Set MP00626 part-2 (TIF file, 5.2 Mb)
• RX02 Field Maintenance Print Set (MP00629)
  1. RX02 Field Maintenance Print Set MP00629 part-1 (TIF file, 6.7 Mb)
  2. RX02 Field Maintenance Print Set MP00629 part-2 (TIF file, 6.1 Mb)
  3. RX02 Field Maintenance Print Set MP00629 part-3 (TIF file, 5.9 Mb)
  4. RX02 Field Maintenance Print Set MP00629 part-4 (TIF file, 4.9 Mb)
  5. RX02 Field Maintenance Print Set MP00629 part-5 (TIF file, 4.8 Mb)
• RX01 Engineering Drawings
  1. RX01 drive Engineering Drawings part-1 (TIF file, 5.7 Mb)
  2. RX01 drive Engineering Drawings part-2 (TIF file, 4.0 Mb)
  3. RX01 drive Engineering Drawings part-3 (TIF file, 3.4 Mb)
  4. RX01 drive Engineering Drawings part-4 (TIF file, 3.4 Mb)
  5. RX01 drive Engineering Drawings part-5 (TIF file, 3.7 Mb)
  6. RX01 drive Engineering Drawings part-6 (TIF file, 8.9 Mb)
  7. RX01 drive plenum fan Field Maintenance Print Set MP00284 (TIF file, 7.7 Mb)

• 3,5 A max at 115 Vac/60 Hz or
• 2,5 A max at 230 Vac/50 Hz.

The upper board inside the RX02 drive is the M7744 controller.

full view of the M7744 board (122 kb)

In the middle of this board is a 2-way DIP switch.
Click on the image at the right for more detail.
With these DIP switches the RX02 drive can be configured into the following modes of operation:

subsystem	system	S1-1	S1-2	*
RX211   RXV21	PDP-11   LSI-11	OFF	ON	note 1
RX8E   RX11   RXV11	PDP-8   PDP-11   LSI-11	ON	OFF	note 2
RX28	PDP-8 only	OFF	OFF	note 2

      * note 1: data transfer using DMA
      * note 2: data transfer using programmed I/O

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The media used on the RX02 floppy disk system is compatible with the IBM 3740 family of equipment. The diskette is encased in a plastic envelope with a large slit for the read/write head, a centre hole for the drive spindle hub and a hole for track index sensing. The diskette is soft-sectored, and the media is preformatted in an industry-standard compatible format.

If you have a system with an RX02 installed, you can "reformat" RX01 disks. The formatting process, however, is not actually a real "format writing". It accepts a pre-formatted disk with the 128-byte single density data sectors (and the single density headers), and rewrites the data sectors as 256-byte block sectors.

The RX11 UNIBUS controller for the RX01 drive has the number M7846 on the handle.
Here should come an explanation, XXXXXXX, the chips on the board, etc.

Note that the RX01 is a polled-I/O device, so the NPR wire must be intact!

The RX211 UNIBUS controller is for the RX02 drive and has M8256 on the handle. The RX211 controller board for UNIBUS has the code M8256.
The default CSR, (Command & Status Register - the base address), is 177170 (octal of course) and this is set by the 10-way DIP switch. SW1 is on the left and is for A3, SW10 is for A12.
When the switch is in the "off" position it represents a binairy '1'.
So the standard RX211 address is 1111001111 on this DIP switch. The 10-way DIP switch is in the picture at the bottom on the opposite side of the BERG connector which accepts the flatcable going to the drive.

The 7-way DIP switch is for setting the interrupt vector. For the RX211 it defaults to 264.
When the switch is in the "off" position it represents a binairy '0'.
SW1 is vector bit 2, SW7 is vector bit 8. So the standard RX211 vector is 1011010 on this DIP switch. This 7-way DIP switch is located between the backplane connectors C and D.

The priority level is standard set to BR5 and can be changed by inserting another plug in the socket located near backplane connector D and below the 7-way DIP switch.

As the RX02 is normally configured as a DMA device you must cut the NPR jumper on the backplane for the slot where the M8256 is seated. The NPR jumper wire is on pins CA1 - CB1.
The M8256 controller represents 2 bus loads on the UNIBUS, and needs 1.8 A. maximum at 5 Vdc.

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The RX11 (M7846) subsystem has two diagnostics:

«-»	ZRXA(x)	system reliability test
«-»	ZRXB(x)	interface diagnostic

 
The RX211 (M8256) subsystem has four diagnostics:

«-»	ZRXD(x)	RX02 performance exerciser
«-»	ZRXE(x)	RX02 formatter program
«-»	ZRXF(x)	RX02 function/logic
	ZRXC(x)	RX02 utility driver (Brutus)

 
The (x) represents the revision level.
ZRXC is primarily an engineering tool, ZRXE set media density only and does not write headers.

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Loading or toggling in this data enables the PDP to boot from the floppy disk.
This bootstrap is taken from the RX01/RX02 Pocket Service Guide, EK-RX012-PS-002.
As I have not (yet) connected the RX11 controller with the RX01, I can not check this code at the moment. It requires a system generation if you want to have two floppy disk controllers in a single system. I want to add the RX11 to the RX211 which is already in the PDP-11/35. If I only had time ....

    How to load a bootstrap program and start the execution.

The start address is 001000.

Loading or toggling in this data enables the PDP to boot from the floppy disk.
This bootstrap is taken from the RX01/RX02 Pocket Service Guide, EK-RX012-PS-002.
I have entered this code and my PDP-11/34A and my PDP-11/35 just boot fine.

    How to load a bootstrap program and start the execution.

The start address is 002000.