How to decompress this .dsk floppy disk format?

[jplr]

Hello,

Sorry if this is the wrong forum.

I looked at MOS-32M which is a Russian clone of DEC's MicroVMS 4.5 operating system on this website:

PDP-11.RU Mirrors Archive MAXIOL: /_vax/_MOC-32/MOC-32M45/

Mirrors Archive MAXIOL: /_vax/_MOC-32/MOC-32M45/

mirrors.pdp-11.ru

Ideally, I would have been interested in finding MOS-32M sources, as it is supposed to be a clone (as opposed to a rogue copy) of Vax VMS.

Yet decompiling the executables may be a fun project, one problem is that I can't decompress the .dsk files.
To me, it looks like these .dsk files are floppy images because of their size (409kb).
I included one in this post.

Is there any software tool to decompress this file format?

Many thanks!
Jean-Pierre

 

[jplr]

I tried os8xplode, but to no avail.
(thanks Vincent Slyngstad to make such an interesting website)

 

[jplr]

Thanks Al Kossow.
Your website is a fantastic resource !
I am not sure those .dsk files are from Apple because I looked at a DEC MICRO/RSX RX50 archive and they have the same size: 409.6kb.
Thanks anyway for having taken the time to read and test them.

 

[konc]

I don't know if it is of any help but the instructions and google translate say that the pre-installed image can be used with the platform simulator. In fact downloading moc-32m.vdisk, vax780.exe, vax780.ini and vmb.exe allows to boot the system (the .ini file has the necessary commands inside).

 

[Al Kossow]

"I am not sure those .dsk files are from Apple"

They are not. Applesauce misidentified them because of the .dsk extension.
Images that are not self-identifying are the bane of my existence.

 

[Bob-O-Rama]

Is there any software tool to decompress this file format?

This is where Linux is useful, kinda:

bob@BOBSTOP:~/Downloads> file d1.dsk d1.dsk: Files-11 On-Disk Structure (ODS-2); VAX/VMS or OpenVMS file system; volume label is 'SYSTEM_1 '

So I think its just a raw disk image and you can likely use it directly in a floppy emulator specifying the appropriate geometry, or if you can dd the image out to a physical floppy. My only experience with DEC disks in with an RT-11 FS which is a much simpler on disk structure, I didn;t have to tools to mount it to really dig into it.