3B1 and 60386 floppies

[Peter Fales]

In article <4137 at csd4.csd.uwm.edu>, peter at csd4.csd.uwm.edu (Peter J Diaz de Leon) writes:
> 
> We have at work some ATT 3B1's and a 20MHz ATT 60386 box.
> Both are running ATT Sysyem V.  Is there any way to get
> a floppy that was formated on a 3B1 read on a 60386
> and vise versa.

There is some compatibility, but it is limited.  First of all, there
is no way to read a mountable disk from one system on the other, the
file systems are just too different, so you are limited to cpio.

Second, the 6386 does not read the 3b1 VHB, so the only disk 
format that the 6386 can read is the 8 sector/track, no loader
format.  (i.e.  the disk was created on the 3b1 with fdfmt.nl).

The easier direction is to go from the 3b1 to the 6386.  The
disk is created on  the 3b1 using "fdfmt.nl" then written to
using "cpio -ocv > /dev/rfp021"   Then you can read it back
on the 6386 using "cpio -icv < /dev/rdsk/f05d8u"  (or f15d8u
for drive 1).  You can use the -B option on cpio if the archive
does not span more than one disk, but if it takes multiple disks 
you can not use -B.  The problem is that when the 3b1 writes the
last 5120 byte block on the first disk, and it doesn't fit, it
writes the entire 5120 bytes on the next disk.  The 6386, on the
other hand, expects to see part of the block on the first disk
and the remainder on the second.

It is slightly more difficult to go the other way, because 
you have to make sure that there is a VHB on the 3b1 disk.  One 
way is to format on the 3b1, then write the disk on the 6386, 
finally reading it back in on the 3b1.  Alternatively, you can
keep on copy of the 3b1 boot track on the 6386 and write it out
when necessary.  This would be the procedure:

#insert a floppy created on the 3b1 with fdfmt.nl into the 6386
dd if=/dev/rdsk/f05d8t of=7300.loader count=8

#insert the new floppy into the 6386, and format if necessary
format -vV /dev/rdsk/f05d8t

#write the VHB and loadee onto the new disk
dd if=7300.loader of=/dev/rdsk/f05d8t

#put files on the disk
find xxxxx -print |cpio -ocvB > /dev/rdsk/f05d8u


(Move to the 3b1)
cpio -icvB < /dev/rfp021
-- 
Peter Fales			AT&T, Room 5B-420
				2000 N. Naperville Rd.
UUCP:	...att!peter.fales	Naperville, IL 60566
Domain: peter.fales at att.com	work:	(312) 979-8031