Microport Support for RLL

[Robert Bradbury]

I am running a Compaq 386/16 with a WD1007A-WAH controller attached to
a Miniscribe 9380 Drive (15 hds, 34 sec/trk, 1224 trks) with about 195 Mb
available to UNIX and 64 Mb (in 2 partitions) available to DOS.  I am
running UNIX 5.3 R2.2 with the new ESDI disk driver (beta release) and
have Merge 1.0 running under it.

... and believe me it was a S!$% load of work to get it working.  I think
I reloaded the system a total of 9 times from floppies.

My recomendations would be:

 - Get a good controller (like the WD1007).  It handles 1:1 interleave,
   has an on-board track cache, an on-board BIOS to format the disk, 
   setup alternate sectors (in the same track) from the manufacturers
   defect list or can scan the entire disk if necessary.  It increases
   disk I/O speed on my machine from something like 323Kb/sec to 793Kb/sec
   (using the Coretest utility).  I think it cost me $220 from my local
   Western Digital distributor.

 - Throw out the standard Microport INSTALL script.  It isn't going to
   configure it the way you want anyway.  The standard UNIX layout has
   the boot cylinder (with the VTOC & Alternate sectors), followed by DOS,
   followed by UNIX.  It makes much more sense if you have to assign
   alternate sectors (in UNIX) to have the UNIX partitions as close to
   the alternates as possible and stick the DOS partition(s) after UNIX.
   The best way to do this is to make a copy of the boot disk, setup the
   files /tmp/partitions, /tmp/fdisk.data and /tmp/mkfs.data on it the
   way you want your disk configured and then edit the install script
   to use them (instead of using disksetup).  The 3 key steps are:
      - use mkpart to initialize the boot cylinder (-i)
      - use fdisk to setup the partition table
      - use mkpart to setup the VTOC and and write /etc/boot to the 
        boot track on the root
   Then proceed with the mkfs's and copies as they are done in the
   install script.  It is easy if you are doing the configuration
   to a 2nd hard drive.  It is hard if you have to configure the boot
   floppy to do things right after you have reformatted your only
   hard disk.  You might want to add some files; cat, ls, mknod, ed
   to the standard boot floppy and fix /etc/inittab so you can boot
   the floppy in single user mode (with a shell).

 - MAKE SURE YOU HAVE EXTRA COPIES OF THE BOOT FLOPPY!!  If UNIX
   crashes or hangs when you are trying to setup the new hard disk
   it will more than likely trash your floppy.  Usually it "unformats"
   track 1 of the floopy (don't ask me why cus I don't know).

 - Don't try to use more than 1024 cylinders on the disk.  None of the
   software (UNIX, mkpart, fdisk, etc.) gives errors with larger cylinder
   numbers but I'm fairly sure that those cylinders end up overlapping
   lower ones.

 - Ignore the documentation Microport sends out with the beta release
   of the ESDI driver.  Most of the files listed are not in the link
   kit and one which is not listed (fd.o) but is on the disk will prevent 
   you from relinking with UNIX with Merge included.  You *MUST* use the
   new ESDI hd.o and the Merge link kit fd.o if you want to link UNIX
   with Merge.  (Microport doesn't think you can do this but it seems to
   work for me.)

 - Delete your old UNIX systems when you have the new system running.
   Booting an old system can scramble your file systems.

I'd advise anyone undertaking a reconfiguration/reinstall be fairly
adventursome and be willing to spend some time with this.  Though the
driver itself seems to be good the process of configuring the system
can be a nightmare.

-- 
Robert Bradbury
Oracle Corporation
(206) 784-9726                            hplabs!oracle!rbradbur