Re: Northstar Advantage disk problem...PLS help!

On Sun, 04 Sep 2005 02:54:32 GMT, Barry Watzman
<WatzmanNOSPAM@xxxxxxxxxx> wrote:

>Another idea that has been proposed is to build a small circuit on an
>auxilliary board that lies between the drive and the controller that
>"generates" the sector pulses and simulates a hard sector disk from a
>soft-sector disk.

I tried that years back.
The setup was a clocked osc and counter chain that was reset off the
softsector index. The clock was scaled to match nominal rpm and a
good direct drive (teac FD55B) was used) this also worked. It assumed
the rotation rate was exact and didn't drift much per rotation.

It worked meaning it formatted and read and wrote media
with passable error rate, though not as good as the real thing.
Also it didn't work at all (no logic to differentiate) with hardsector
as there were too many "index" pulses. Also I'd only tried it with
the SD controller not the later DD controller.


Allison



>
>And yet another idea is to build a "sector hole punch"
>
>There are various solutions, none ideal or perfect.
>
>
>Lee Hart wrote:
>> Allison wrote:
>>
>>>>I'll bet your using the wrong media. NS* Advantage is hardsector
>>>>media not PC soft sector. The difference is the number of sector
>>>>holes (11 for NS and 1 for the softsector stuff).
>>
>>
>> Andrea wrote:
>>
>>>You are so right! This morning I checked all disks and they are
>>>soft sectored Apple II or Commodore disks. Later I found another
>>>box with disks I had used with the Advantage and they are all
>>>hard sectored and they work fine.
>>
>>
>> Just an aside. Heath H8 and H89 computers used these same
>> 10-hard-sectored disks with their hard-sector controller. At one time I
>> looked into rewriting the BIOS to use soft-sector disks in the
>> hard-sector controller. I played with it enough to see that it looked
>> workable.
>>
>> The stock Heath BIOS has ten 256-byte single-density sectors per track.
>> What I did was to increase the sector size to 3k bytes, so each track
>> had was just one large sector. It required a large sector buffer (3k of
>> precious RAM!), but read/write was considerably faster. It also
>> increased disk capacity from 40 x (10 x 256) = 100k to 40 x 3k = 120k
>> bytes.
>>
>> I used a single byte checksum per sector (same as the stock system). The
>> only drawback I found in limited testing was that the error rate was
>> higher. I thought about rewriting it to use a 16-bit CRC check (which
>> would have to be calculated in software), but never got around to it. it
>> wasn't hard enough to get hard-sector disks at the time to bother
>> pursuing.
>>
>> Maybe now that hard-sector disks are harder to get, it would be worth
>> re-thinking this idea? Would the Northstar controller also be capable of
>> such a trick?

.

Relevant Pages

  • Re: Northstar Advantage disk problem...PLS help!
    ... A better approach would be to use the index pulses to determine the exact actual rotation rate, instead of assuming the nominally correct 300rpm. ... auxilliary board that lies between the drive and the controller that "generates" the sector pulses and simulates a hard sector disk from a soft-sector disk. ... Later I found another box with disks I had used with the Advantage and they are all hard sectored and they work fine. ...
    (comp.os.cpm)
  • Re: Reading a bad sector does not report failure as read error but hangs PC with Machine Check Excep
    ... array of 5 disks in RAID 5. ... tried to read that sector with the following error on ... Kernel panic - not syncing: ... Note that kernels 2.6.20 and later use ADMA mode on the nForce4 SATA controller whereas previous versions used it essentially like a PATA controller, so it is not surprising that the behavior is different. ...
    (Linux-Kernel)
  • Re: Northstar Advantage disk problem...PLS help!
    ... Another idea that has been proposed is to build a small circuit on an auxilliary board that lies between the drive and the controller that "generates" the sector pulses and simulates a hard sector disk from a ... Later I found another box with disks I had used with the Advantage and they are all hard sectored and they work fine. ... 10-hard-sectored disks with their hard-sector controller. ... At one time I looked into rewriting the BIOS to use soft-sector disks in the hard-sector controller. ...
    (comp.os.cpm)
  • Re: Detecting Double Sided Disks in Single Sided Floppy Drive
    ... NST was writing several periods ... What leads me to suspect the disks are bad is that I can ... Swap in different drives. ... I have one disk with reliable sector read ...
    (comp.sys.northstar)
  • Re: 6.2 not compatible with new sata drives ?!
    ... Some combinations of controller and drive do not play well ... I assume that the new failing disks are ... If your controller works well with your Samsung drives, ... Decided to try my origonal 6.2amd64 iso again, ...
    (freebsd-questions)