6386 300Mb Hard Disk

[Ted Powell]

In article <1990Sep22.050826.22895 at smcnet.smc.edu> lawrence at smcnet.smc.edu (Lawrence Roney, Telecomm Dept) writes:
>We just bought a Micropolis 1558-15 300Mbyte hard disk for our 6386E Unix
>box.  I'm installing it as a second hard disk in the system.  The unit came
>with a 135Mbyte.  I set the drive type in the system's CMOS config RAM to 
>31--304 Mbyte.  I then ran the Low Level Format program that comes with the
>6386.  It finds what looks to be the proper hard disk and proceeds to format
>the 15 heads and 1221 cylinders.  Everything is going fine so far.  I then
>reboot the Unix system off of the existing HDU and run the Unix FDISK program
>to set up a partition on the new HDU (/dev/rdsk/1s0)
>
>FDISK only sees 814 cylinders.   Why????  

This is the correct number of cylinders for disk type 31.
You don't say what type your hard disk controller is. If it is a
WD 1007A-WAH or WD 1007A-WA2, then removing jumper W8 will tell it to
fake your 1221-cylinder, 34-sector disk as an 814-cylinder disk with
some larger number of sectors per track.

At least as of rev 1.14, the ROM BIOS is unable to handle more than about
1023 cylinders; hence the kludge.

I've installed three of these drives in 16mHz 6386's (the original ones
manufactured by Olivetti) with no problems. This was, however, with the
drive being the only one in the machine. I don't know what removing W8
would do to your first (135mb) drive. Perhaps they are separately
configurable, in which case W8 is for the first drive.

If you haven't already, you also need to remove W3 to disable the PROM
that's on the controller, and you need to have BIOS 1.14 or later.

Send mail if the above doesn't get you going.  Good luck!

-- 
ted at eslvcr.wimsey.bc.ca   ...!ubc-cs!van-bc!eslvcr!ted    (Ted Powell)