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Полная версия: AZ controller for PDP-11 QBUS verison
MAXIOL > Техника > DEC hardware / software > AZ controller for PDP-11
Us developed a pseudo disk controller on MicroSD

This controller is intended for modern and reliable replacement of KZD (DW) in computers of the DVK-1 series; DVK-2; DVK-3; DVK-4; Electronics-60; Electronics 60M; Slavutich PC-1 and similar PDP-11 compatible.

Photo of the controllers:
from above - for QBUS
from below - for MPI BUS (soviet clone QBUS but of a different size):
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Photo of the controller QBUS with a network card
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Emulation of 8 disks with a volume of 65534 blocks for the correct operation of RT-11; thus the total usable storage capacity is 262136K;
The controller supports MicroSD- and MicroSDHC; SDXC cards are not supported by our device;
The ability to install 2 controllers with different addresses is supported;

Connecting the controller to the network
AZ series controllers for DVK UKNTs, etc. have the ability to connect an external network adapter via SPI interface based on ENC28J60
This Ethernet network adapter allows the controller to be connected to the network at a speed of up to 10Mbit.

To connect you need:
- 10pin connecting cable with IDC connectors, no longer than 20cm.
- Etherent network adapter based on ENC28J60
- network Ethernet cable
- a router or other device / service that distributes an address via DHCP

- presence of an NTP server in the network

A ready-made 10pin module based on ENC28J60 is used as a network card
connected by a 10-core loop with IDC 2x5 connectors

User's manual
The proposed controller emulates up to eight AZ disk devices on one microSD card. Each emulated disk (pseudo-disk) is represented on the card by a file from the PC's point of view, so there are no questions about placing pseudo-disks on a large storage device - just place the card in the card reader, connect it to the PC, copy files of the required size (and with the required content) to the card , move it to the controller, and that's it! Moreover, after working with the card on the DVK, you can remove it from the controller, put it back in the card reader and copy the generated disk image file to a PC, where you can work with them by any means - for example, connect to an emulator, archive it and put it somewhere on storage, send to conference, etc. It is also not difficult to copy some material found on the network to a card, rearrange it into a controller and use this material at PDP-11.

The controller occupies addresses 177220-177226 on the IPI (word, byte access is prohibited). 177220 - command and status register (RKS, CSR), 177222 - data register, 177224 and 177226 - registers (one-word ROM) bootloaders.

The controller supports MicroSD and MicroSDHC cards. We tested SDHC cards from different manufacturers and sizes, the difference was only in the write speed to a pseudo disk. We barely managed to find an ancient micro-SD (not HC) at 512M, yes, it writes slowly, but it works and the reading speed is almost the same as that of SDHC. SDXC cards are not supported by our device.

Transfer the image files AZ0-AZ7 to the MicroSD card. These are AZ000.DSK files - AZ007.DSK. Insert the card into the slot on the controller until it clicks.

Turn on your computer. Most likely, the screen will display 6 octal digits and, in the next line, the "@" icon, the cursor will blink next to it. This is a signal that the processor is in Halt-Mode and is awaiting a remote command from you.

Let's serve it. The command is like this:


This is an instruction to the processor to start executing the program from address 177226. This address contains the one-word ROM of the OS startup program from the AZ0 disk. RT-11 should start. After that, you can reboot from any other disk with the BO AZx command:
you can also use the full address command:


There is an alternative command - start from the address 177224, i.e. 177224G. So far, its action is exactly the same as that of the main launch command, but some changes are planned further, in particular, one of them will simply start the OS from AZ0, and the second will ask which disk to boot from.

The size of each of the disks (files from the PC point of view) must be strictly 32767K (65534 blocks), so the total capacity of the drive will be 262136K. In the next new version of the firmware, a change of disks (file-images) will be added directly from RT-11, with a special program, then on the micro-SD it will be possible to have as many file-images as it will fit, however, only 8 of them will be available at the same time, those. 262136K, this is the RT-11 limitation.

It is possible to install two controllers, for this, an alternative set of controller addresses is provided, switching is performed by DIP switch # 1 on the controller board. The main set of addresses (177220-177226) is effective when this switch is off, the alternative (177200-177206) is effective when this switch is on. The rest of the switches are reserved for further functionality expansion.

Product development prospects
This controller is equipped with a powerful enough STM32F407VET6 microcontroller, which allows you to implement the expansion of the controller's capabilities without changing the hardware platform.

Accordingly, I will designate an approximate set of functionality for development:

1. realize the network connection using an external network card based on ENC28J60 [implemented]
1.1 connection will allow you to remotely access data on the SD card - that will be FTP server WEBDAV server [implemented]
through which it will be possible to change information on the disk remotely [implemented]
1.2 FTP server WEBDAV server will provide access at the level of FS RT11 itself [implemented]
1.3 Firmware update via the Internet
1.4 Managing network settings via ini file

2. Development of the functionality of mounting images through an ini file
2.1 Mounting images via SET AZ command
2.2 Mounting images on SMB / NFS-share
2.3 Expanding Supported Disks for RSX-11 Operation
2.4 Update via SD card image
2.5 External loader, those user code that is downloaded into the machine and launched (convenient for developing your extensions based on AZ - for example, the boot menu)

3. Clock

4. Development of the AZX.SYS driver for the XM monitor [implemented]

5. Development of a driver for RSX

If you have any questions, you can ask them by writing us a letter to radioshop@maxiol.com
The firmware release of May 24, 2020 includes the following networking features:

DHCP client, default DHCP name AZNET-1-101 MAC 00 0e 35 22 05 01
TCP / IP stack
NTP client
HTTP server serving the contents of the SD card for reading
WEBDAV-server allowing to perform the following operations
- read / write files on SD card
- copy / rename files on SD card
- layer of interaction with files inside RT11 images
supported methods
emulated methods
not supported methods
- authorization on WEBDAV is not supported

1. Implementation features and limitations of the WEBDAV server on the file layer on the SD card
1.1. Only Latin is supported
1.2. Name format 8 + 3 (MSDOS)
1.3. Reserved file names and extensions
"INDEX.HTM" - used to create an index when uploading files via HTTP
"* .XML" - WEBDAV server creates XML files with information in accordance with the standard
these files are not visible through WEBDAV and HTTP servers
".F11" and "LDX" - virtual extensions for virtual directories of the RT11 imaging layer
are created by the system automatically, it is forbidden to create by hand.
".DELETED" - virtual extension for remote files in RT11 images, created by the system automatically, it is forbidden to create by hand.
"unused.space" - a virtual file indicating the total amount of free space in the RT11 image
1.4. RT11 disk images must have a ".DSK" extension
1.5. RT11 logical drives must have a ".DSK" extension
1.6. There must always be free space on the SD card, at least 10%, to be able to create temporary files of the WEBDAV server.
1.7. Tested WEBDAV clients:
-neon / 0.30.2 (included with netbox - FAR3)
-built-in client in TotalCommander
-FileZilla Pro and others - see the section about WEBDAV clients
these clients allow you to fully manipulate files
1.8. Supported operations: copy in both directions, create directories and files, delete directories and files, rename directories and files, duplicate files.
1.9. File duplication operations are performed on the server side and with a large file size can take time exceeding the timeout of the TCP / IP exchange operation. Therefore, a timeout error does not indicate a problem with this operation.
1.10. Removing directories only works for empty directories [done specifically to protect information]
1.11 Network co-operation with RT11: any read operations are allowed, however co-writing or modification is strictly prohibited. For example, you cannot overwrite the image from which RT11 is loaded.

2. Implementation features and limitations of the WEBDAV server on the file layer inside DSK images

2.1. Only Latin characters are supported with restrictions according to Radix50 encoding
2.2. Name format 6 + 3 (RT11)
2.3. RT11 image disks are presented in the form of files - those with the DSK extension, but also in the expanded form - in the form of directories with the additional extension ".F11"
2.4. Nested logical drives in the form of DSK files are also displayed in double form - both as files and as directories with an additional extension ".LDX"
2.5. Batch modification operations with the contents of the directories [n3 and n4] and simultaneously with images are prohibited due to the fundamental lack of the possibility of ensuring the consistency of the operation. Batch reading is not limited.
2.6. Removing virtual directories with ".LDX" and ".F11" extensions is not supported because they are virtual.
2.7. Renaming of virtual directories with the extensions ".LDX" and ".F11" is not supported because they are virtual. If you need to rename an image, you must rename it as a file.
2.8. Transferring files within images is not supported. Only renaming files is supported.
2.9. Deleted files are displayed with the virtual extension ".DELETED". deleted files are available for reading.
2.10. The total amount of free space in the image is displayed as a virtual file "unused.space.file". unfortunately, some clients hide it.
2.11. File without extension is not supported
2.12 Network co-operation with RT11: Any read operations are allowed, however co-writing or modification is strictly prohibited.
2.13 When overwriting a file with a different size (on disk and a new one), the old file is unconditionally deleted (it will be displayed with an additional ".DELETED" extension) regardless of the success of the new one - for example, a window of the required size will not be found.

Features of WEBDAV clients
supported clients

FAR - fully supports functionality

TC - fully supports functionality
hides the virtual file "unused.space.file"

Filezilla Pro - fully functional
hides the virtual file "unused.space.file"
does not update the directory after deleting files, but just hides the deleted file

WinSCP - fully supports functionality
hides the virtual file "unused.space.file"

CrossFTP PRO - fully supports functionality

Cyberduck - fully functional

davutils - fully supports functionality
hides the virtual file "unused.space.file"

Windows - everything works, but ".DELETED" files will appear when writing to the image due to the fact that winfodws first sends a request to create a file with zero length (those 1 block at least), and only then with real length.

WEBDAV clients, examples of working with the AZNET WEBDAV server

not supported clients
davfs2 - works partially and only for reading.

Features of collaboration with files opened in AZ

3.0 We are talking about sharing the same image file using RT11 and AZNET.
3.1 AZ controller opens images specified in AZ.INI
3.2 Any joint read operations are allowed, which do not modify the information in any way.
3.3 Combining writing with reading is not recommended due to the receipt of inconsistent information.
3.4 Any combined write / modify operations are prohibited as they may cause damage to the directory and data.
For example, you cannot overwrite the RT11 system files of a loaded system from the network.
You cannot write files from the network and RT11 tools at the same time.
The atomicity of network operations will provide a one-time blocking of the data segment, but RT11 is not ready for this because it communicates in blocks and this can lead to data corruption.
Accordingly, at the time of recording information over the network - do not perform any action on the DCK / UKNTs.
3.4 Correctly single out one image as an exchanger, in order, in principle, to eliminate the risks of damage to system partitions. Consider this a strong recommendation. Remember, AZNET is a powerful tool, but it must be used wisely.
3.5 When working with the emulator through a mounted image from a controller, it is recommended to use a small exchange file - 400KB, for example, since Windows works with the image as with a regular file and constantly overwrites it.

Working with AZNET
The network is automatically turned on after booting OS RT11, and the new version of AZ.SYS driver controls the network operation.
You can also turn on the network by hand:
writing in 177220 / 17777220 the value 110
you can turn off the network by writing 0 to this register
Manual activation allows you to upload information to a blank Micro SD card and prepare the controller for operation. It is also recommended for writing information to system partitions.

How do I purchase a controller?
writing us a letter to radioshop@maxiol.com
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