If the disk is from a MINC-11, then it was almost definitly running RT-11. However, I suspect it was an RX02 drive that it was written in.

Unfortunatly I'm not that familiar with PUTR, having only used it a couple times, and I don't know what it might support in the way of 8" floppy drives. If you can make a disk image of the floppy, you might have better luck accessing that with PUTR.

Zane

Both drives are single sided. Zane

--- Don Maslin <donm(a)cts.com> wrote: A MINC-11 is just a PDP-11 in a special box that lets you mount laboratory modules in the front and connect lab I/O leads inside and from module to module. It also came with drivers for numerous modules and typically an IBV11 GPIB card. It's not OS8. It might be RT11, but AFAIK, all MINCs shipped with RX02 drives and those are an odd duck for format. You will probably need a real RX02 drive to read them. It's not a software formatting issue, it's a hardware formatting issue. You are getting data errors in all likelyhood because your hardware can't decode the bits themselves. Changing tools won't help. ISTR the headers are single density, but the data portion of the track is double density, but I've never tried to read them in anything but a real RX02 drive.

If you have the real hardware, you could copy the files onto RX01 disks and read _them_ in your PC. -ethan __________________________________________________ Do You Yahoo!? Yahoo! Auctions - buy the things you want at great prices http://auctions.yahoo.com/

> I have been asked to see if I can transfer the contents of some 8" > disks to PC compatible disks. A CP/M disk has offered no challenge, > but I am stopped dead on a disk whose label indicates that it was > for use on a DEC Minc 11.

Thing is, though, every floppy-based MINC I have ever heard of has RX02 drives. The standard format for those is 26 _256 byte_ sectors/track, but using DEC's strange double-density encoding. The only things that can read them are either a DEC RX02, or one of the 3rd party controllers (the only ones I've seen are for Q-bus) that were designed to read RX02 disks. AFAIK, no standard single-chip floppy controller can read them. -tony

The RX02 'drive' is a lot more that what is normally meant by a disk drive. It's a rackmount chassis containing 2 floppy drive mechanisms (these are standard, 77 track units, but without the normal circuit boards on them), a power supply, and 2 DEC-designed PCBs. The lower PCB contains the electronics you'd normally expect to find on a floppy drive (stepper motor drivers, read amplifier, write driver, etc). The upper PCB is the disk controller -- it's an embedded computer using 2 2901 ALU chips, 3 2911 sequencers (or are they 2909s -- I don't have the prints to hand), 1K of control store ROM, RAM, TTL, and so on. This communicates with the interface card in the Qbus slot (or Unibus, or Omnibus, or..) via a special TTL level serial link. There is some buffer RAM on the controller board in the drive box. The interface can send commands to transfer the contents of the RAM to/from the host computer, or to read/write a given sector on the disk to/from the RAM. Reading a sector is thus a 2-stage operation. First you send the command to read the sector into the buffer RAM on the controller board. Then you send the command to transfer the RAM contents to the host. Writing is much the same in reverse. Point is, the RX02 data format is determined by the microcode on the controller board in the RX02 chassis itself. It can basically do 2 formats -- the special RX02 one, and an RX01 one, which is compatible with other manufacturer's single-density disks (IBM 3740, etc). That's why an RX02 can read (and write) RX01 disks. The reverse is not true, and nor is it true that other machines that can read/write RX01s can read RX02s. It can. In much the same way that many double-density systems can read single-density disks.