
                     Installing a Miniscribe 3650 Hard Drive,
                         Using a Perstor 180 Controller
                          (or another  RLL Controller)

         * ------- by Jim Russ, Orlando, Florida, (305) 851-0705 -------*

    OK, guys (and gals), listen up 'real' good...  Here's a way  to  get  AT
    LEAST 77.9 Megabytes from a Miniscribe 3650 Hard Drive if you use it  in
    conjunction with a Perstor 180 Controller Board  (available from Richard
    Driggers, SYSOP of the  Sparta  BBS,  voice  1-201-729-9409).  Actually,
    these half-height drives are sold as 40-Megabyte units, but they take to
    RLL formatting and to the Perstor 180 board like a duck takes to  water.
    At only $314 each, I ordered  two...  the total was $628 for the  drives
    and another $8 for shipping, with the total outlay running  $636!   Sold
    my two Seagate hard drives, recovering $500 of this cost,  so  my  final
    out-of-pocket expense was $136, and I now have  over  155  Megabytes  of
    writeable hard disk space.  (My supplier's address is on page 3.)

    With this procedure, a Miniscribe 3650, and an Adaptec  2070A  RLL  con-
    troller you can get nearly 63 megs of writeable  space; when  used  with
    a Western Digital or an OMTI RLL controller, you can format  about  65.5
    Megs, but the Perstor 180 will obtain 78 Megabytes PLUS a file  transfer
    rate of about 180 KB/Second!  (Although I have yet to try it, a  Perstor
    200 board should be able to format  the  Miniscribe  3650  out  to  85.6
    Megabytes!  If I get my hands on one, I'll try it out...hint, hint). And
    all this WITHOUT the use of the Perstor compression and WITHOUT the need
    to use the ONTRACK Disk Manager programs *.  Heck, you can get well over
    100 Megabytes on a single Miniscribe Half-height 3650 Drive if  you  opt
    to run the Perstor Compression Software!  (I tried this once, and  ended
    up with a total of 126+ Megs, but reverted to  the  procedure  described
    here as most of my files are already archived, and the  tricky  compres-
    sion procedure gains me very little in its process.)       * You'll need
    DOS 3.2 or higher, otherwise you need ONTRACK Disk Manager!

    First, open your computer (mine is  an  AT&T  PC  6300).   Replace  your
    existing controller with the Perstor 180.   Next, install the Miniscribe
    3650 in place of your existing  hard  drive  (Seagate??).   The  striped
    lead on both the 34-conductor and the 20-conductor  ribbon  cables  must
    be toward the REAR of the computer when connected to the  Perstor  card.

    Although Miniscribe touts their 3650 as having  809  cylinders,  I  have
    discovered that  this  drive  can  actually  be  formatted  out  to  820
    cylinders, therefore Table 4, describing jumper settings  for  JMP6,  as
    listed on page 6 of the Perstor owners' manual  shows  the  proper  set-
    settings.  Just jumper (short) pins 3-4, 7-8, 13-14,  and  15-16.   This
    will set you up not only  for  Physical Drive 0  (jumper 7-8),  but  for
    another, later Physical Drive 1 (jumper 3-4).

    Next, boot "Vanilla," using MS-DOS 3.2 or later  (PC-DOS  3.2  or  later
    probably works, too...); you should  also  have  FDISK.COM,  FORMAT.COM,
    CORETEST.EXE ( V E R Y   important!), and Perstor's PS2FMT.COM available
    for use after you have booted; for OTHER controllers, have DEBUG.COM for
    the low-level format, using the addresses described  in  the  literature
    which comes with your RLL controller. (For your information, the address
    to be used with an Adaptec 2070A RLL Controller  is  c800:CCC,  for  the
    Western Digital RLL Controller, it is c800:5, and  for  the  OMTI  5527A
    Controller, it is c800:6.  After executing DEBUG,  you  will  receive  a
    - prompt; you just type in g=(address) and, generally, just  follow  the
    prompts which are generated by  the  BIOS  chip  internal  to  your  own
    particular controller.)






    As the interleave factor is  important  if  you  wish  to  optimize  the
    controller-computer interface for optimum (fastest) file  transfer  rate,
    you will want to follow Richard Driggers'  methodology  for  determining
    the best interleave factor; his method is described below:

          1.  Boot "Vanilla."

          2.  Insert the diskette containing the PS2FMT program into the
              A: drive.  Type PS2FMT, then press <ENTER>.

          3.  As the default for your first run should be an interleave
              factor of "4" just select that default on your first try,
              and start the low-level format.

          4.  After about 1 1/2 minutes, place your boot diskette into
              drive A: and press your reset button.  Run CORETEST now
              (never mind that the drive has not been high-level formatted;
              CORETEST does not care, and will test it anyway).  Record
              the results.

          5.  REBOOT.

          6.  THIS time, select "5" for the interleave factor.  Again,
              run PS2FMT for 1 1/2 minutes, then reboot and run CORETEST,
              again recording the results (probably will be higher).

          7.  Keep cycling through this procedure until the transfer rate
              in KB/Seconds DROPS.  Then, back up to the LAST interleave
              factor you selected and low-level the ENTIRE disk with that
              interleave.  (In my case, "5" was the optimum... )

           8.  If the format program encounters any bad sectors during the
               low-level format, it will display the track and head numbers.
               You should carefully monitor this entire procedure, and when
               prompted to do so enter these data so those tracks will be
               marked as bad...

           9.  Next, figure out how large you want each of your partitions
               to be...  This can be calculated very simply with the fol-
               lowing formula:

        GENERIC:  Cylinders  X Heads X Sectors/Cylinder X 512 bytes =
                                                             Writeable Bytes
        Perstor 180 with
        Miniscribe
           3650:    820      X   6   X      31          X 512 bytes =
                                                          * 78,090,240 Bytes

             * As this is too large to be recognized as a single drive (DOS
               limits you to 32 Megabytes per partition), you must make your
               partitions no larger than 351 cylinders each (on the
               Miniscribe 3650)...  In my case, I elected to use 273
               cylinders each for two partitions plus another partition for
               the remainder.  The first partition became my DOS partition
               (drive C), and the remaining two became DOS DATA partitions
               (drives D & E).  IF you add a second Miniscribe 3650, ALL of
               partitions must be DOS DATA partitions!

          10.  Run FDISK, then partition the drive in the way you have
               selected.  Be SURE to make partition #1 (DOS) Active before
               backing out of the FDISK program.

                                       -2-







          11.  REBOOT.

          12.  At the A: prompt, type FORMAT C: /S and press <ENTER>, then
               answer Y when the warning that all data on the hard drive
               will be lost.  Let the format proceed.

          13.  Next, type FORMAT D: and press <ENTER>, again answering Y
               at the warning.

          14.  Type FORMAT E: and press <ENTER>, again answering Y at the
               warning.

         (15.  If you created four [maximum under DOS 3.2] partitiions, then
               you should format that partition as well, as the F drive.)

         Throughout all of this, I  have  presumed  that  you  are  using  a
    Perstor Controller.  If not, then you will have to substitute the  DEBUG
    command for the PS2FMT command, using the address peculiar to  your  own
    controller, and trying the low-level format  with  different  interleave
    factors as shown above.  Most RLL controllers allow deviation  from  the
    "standard" interleave factors; however, some are inflexible.   Just hope
    yours will allow you to select the optimum  factor  for  interface  with
    your own computer.

         If all has gone well during this procedure - and you were using the
    Perstor 180 controller card - you should now have one bootable DOS drive
    and two DOS DATA drives with a total writeable space of around  78 Megs!
    (With the Adaptec 2070A RLL, you'll get  about  63 Megs,  and  with  the
    Western Digital or OMTI RLL controllers you should  be  able  to  get  a
    total of 65.5 Megs.)

         Whatever controller you use in this procedure, have  fun!   If  you
    should have any problems with my instructions or  this  procedure,  just
    call me at home (305) 851-0705 (you'll get  my  answering  machine,  but
    just speak up and if I'm home I'll pick up), or at work  (305) 660-4084.



                                        Jim Russ
                                        1121 Appleton Avenue
                                        Orlando, FL 32806

    P. S.  This is not intended as an indorsement for any particular sup-
           plier of hard drives, and the  prices  may  vary  (...probably
           DOWNward) from what I have listed in this document.   However,
           I bought my own Miniscribe 3650 half-height  drives  from  the
           firm listed below:

                          HARD DRIVES INTERNATIONAL
                          1208 E. Broadway Rd. #110
                          Tempe, AZ 85282
                          -------------------------
              To Order:      1 (800) 541-8387  (MC, VISA & American
              In Arizona:    1 (602) 967-3334            Express OK)
                          -------------------------
                       Tech Support:  1 (602) 967-7435


                                       -3-






           Other prices, as listed on Page 335 of the December 1987 Computer
    Shopper for this firm, are as listed below:

    ITEM                            PRICE           SHIPPING
    ----                            -----           --------
    ST225 20 MB XT KIT
       Hard Drive (1/2 Height) 65ms
       WD Controller
       Cables & Manual              $259.00           $8.00

    ST238 30 MB XT KIT
       Hard Drive (1/2 Height) 65ms
       WD or Adaptec Controller
       Cables & Manual              $289.00           $8.00

    ST251 40 MB
       Hard Drive (1/2 Height) 28ms
       ONTRACK Disk Manager Diskette (Ver. 3.2)
       Cables & Manual              $374.00           $8.00

    ST4096 80 MB
       Hard Drive (1/2 Height) 28ms
       ONTRACK Disk Manager Diskette (Ver. 3.2)
       Cables & Manual              $849.00           $8.00

    Miniscribe 3438 30MB XT KIT
       Hard Drive
       Controller
       Cables & Manual              $289.00           $8.00

    Miniscribe 3650 40MB
       Hard Drive (1/2 Height) 52ms
       ONTRACK Disk Manager Diskette (Ver. 3.2)
       Cables & Manual              $314.00           $8.00

    Miniscribe 6053 40MB
       Hard Drive (1/2 Height) 28ms
       ONTRACK Disk Manager Diskette (Ver. 3.2)
       Cables & Manual              $575.00           $8.00

    Miniscribe 6085 71MB
       Hard Drive (Full Height) 28ms
       ONTRACK Disk Manager Diskette (Ver. 3.2)
       Cables & Manual              $775.00           $8.00















                                       -4-


