floppies for Ultrix and IBM PC

[wheels at mks.UUCP]

In article <336 at morgoth.UUCP>, glidden at morgoth.UUCP (Ken A. Glidden) writes:
> We have a DEC uVAX II running Ultrix.  We often tar to RX50 floppies.
> Does anyone know of a way (source code, too?) to allow the use of those
> floppies on the IBM PC? I would like the uVAX to read floppies written
> on the IBM PC and visa versa.

I don't know about tar format, but I can tell you about the physical
differences of the disks -- the RX50 (used in uVAXen, Rainbows, and
others) write 80 tracks, single sided. IBM-type 360k drives write
40 tracks, double sided. Further, the DEC controller (here I'm most
familiar with the Rainbow) writes 10 sectors per track, whereas IBM
writes 9.

Therefore, to physically be able to read RX50 disks, you will need
an 80-track drive, and if it's double sided you'll need to tell your
software to only use one side. Also you'll need to tell your software
(probably the disk driver) to read 10 sectors per track, or you'll
miss some of your data.

Once you have all this solved, you'll need to untar the data, but I
recommend you find a tar expert for that.
-- 
Gerry Wheeler                  {allegra,decvax,ihnp4}!watmath!mks!wheels
Mortice Kern Systems Inc.