Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss
looking for s/w for the Northstar Dimension
34 views
Skip to first unread message
Chris
Jun 15, 2012, 9:43:13 PM6/15/12
to
I have a set of disk that came w/a ringed binder, but I don't have anything running at the moment to attempt and image them. Soon hopefully. Will these disks image readily w/a 486/pentium box and ImageDisk?
Clu
Aug 8, 2012, 12:33:14 AM8/8/12
to
First I have heard of this, but then I would have been quite young when
the computers of the mid to late 70's were being made. If you get a
moment tell me more about this.
Were the Northstar Disks generally compatable across other computers
that were using the Northstar operating system?
John Crane
Aug 8, 2012, 10:53:02 AM8/8/12
to
system. But I suppose it could happen. Especially if you put a
Northstar disc controller into another S-100 machine.
Beyond that, they used hard sector diskettes in a particular layout. You
can't use hard sector diskettes in drives that require soft sectored
diskettes. And you can't use then in just ANY hard sector drive either.
For example, Northstar and Micropolis both use hard sectored diskettes,
but they are incompatible because the sector numbers are different - and
therefore the number of holes in the disks is different.
--
-John
email: john_crane_Z@yahoodotcom
where: Z=12*5-1
Martin Brown
Aug 8, 2012, 3:05:50 PM8/8/12
to
On 8-Aug-2012, John Crane <john...@nowhere.net> wrote:
> > Were the Northstar Disks generally compatable across other computers
> > that were using the Northstar operating system?
> >
>
> I've never seen a non-Northstar computer run the Northstar operating
> system. But I suppose it could happen. Especially if you put a
> Northstar disc controller into another S-100 machine.
into Sol-20s.
> Beyond that, they used hard sector diskettes in a particular layout. You
> can't use hard sector diskettes in drives that require soft sectored
> diskettes. And you can't use then in just ANY hard sector drive either.
> For example, Northstar and Micropolis both use hard sectored diskettes,
> but they are incompatible because the sector numbers are different - and
> therefore the number of holes in the disks is different.
failures
of old memory, but supplemented by Wikipedia).....
5 inch diskette drives started out with 48 tracks per inch (TPI) based on a
standard started
by Shugart. Micropolis doubled that, but 96 wasn't a round number, so they
made their drives
100 TPI. So when Shugart and other started making 96 TPI drives, the
Micropolis drives were
not compatible with those new drives.
There were also soft-sectored disks, 10-sector hard sectored disks
(Northstar), and
16-sector hard sectored disks. The drives would support any of those, it
depended
on the controller and system software which ones you needed.
CompuColor even made disk systems which required pre-formatted diskettes and
completely ignored the index hole on the disk. You had to buy special
diskettes from
CompuColor. They charged something like $20 per diskette. It wasn't around
very long.
John Crane
Aug 9, 2012, 12:30:55 AM8/9/12
to
On 08/08/2012 12:05 PM, Martin Brown wrote:
> On 8-Aug-2012, John Crane <john...@nowhere.net> wrote:
>
>>> Were the Northstar Disks generally compatable across other computers
>>> that were using the Northstar operating system?
>>>
>>
>> I've never seen a non-Northstar computer run the Northstar operating
>> system. But I suppose it could happen. Especially if you put a
>> Northstar disc controller into another S-100 machine.
>
> I think it was fairly common. Lots of Northstar disk controllers were put
> into Sol-20s.
You're absolutely right! I recall now when I got my Sol-20, it came
> On 8-Aug-2012, John Crane <john...@nowhere.net> wrote:
>
>>> Were the Northstar Disks generally compatable across other computers
>>> that were using the Northstar operating system?
>>>
>>
>> I've never seen a non-Northstar computer run the Northstar operating
>> system. But I suppose it could happen. Especially if you put a
>> Northstar disc controller into another S-100 machine.
>
> I think it was fairly common. Lots of Northstar disk controllers were put
> into Sol-20s.
with Northstar drives and controller. Never could get the thing to
work. I eventually swapped it out for a Micropolis set. Then I
encountered the 10 vs 16 sector incompatibility. The blank diskettes
were not interchangeable between systems.
Herbert Johnson
Aug 14, 2012, 10:33:40 AM8/14/12
to
There's still a bit of confusion in this thread, about hard sectored versus soft sectored; and then about various "incompatibilities".
Hard sectored diskettes have multiple sector holes in addition to the one index hole that all 8-inch and 5.25 inch diskettes have. Soft sectored disks have one index hole to mark the "beginning" of a track of data. With a very few exceptions among old 8-inch floppy drives, it's the CONTROLLER, NOT THE DRIVE, which "determines" whether that controller expects hard sectored (or soft) diskettes. For the most part, there ARE NO "HARD SECTORED" DISKETTE DRIVES.
As was pointed out, there were 10-sectored and 16-sectored 5.25-inch hard sectored diskettes. I'm not aware of any controller or any OS which used BOTH; they used one scheme or the other. That's one kind of incompatibility.
In addition, both soft and hard-sectored diskettes must be formatted; arrangements of sectors and sometimes other information on the track. In the pre-IBM-PC days, diskette formats varied from brand to brand and even among models, sometimes even OS versions. That's another kind of incompatibility, with controller's software and their disk format schemes.
5.25-inch drives supported either 40 tracks or 80 tracks; the very oldest drives only supported 35 tracks. Almost all of these drives used a 48 track per inch spacing, or a 96 TPI for 80-track drives. Exceptions were some of the VERY earliest Micropolis and Tandon drive models (some also used on Commodore computers) which supported a 100TPI spacing. The 48/96 TPI scheme allowed 80 track drives to support 40-track diskettes and to format 40-track diskettes (with a subtle issue of track width). 35 track drives are 40 track except the innermost 5 tracks unused or inaccessible. 100TPI drives produce disks only other 100TPI drives can even hope to read. So this scheme IN THE DRIVE produces another kind of incompatibility.
I cover this stuff as best I can in boring and technical detail on this Web page:
http://www.retrotechnology.com/herbs_stuff/drive.html
I hope the above summary is correct, but my Web page should have it right, and further details. I welcome any corrections or further information. Don't write to my throw-away "google" email posting address; check my Web page for contact information.
Herb Johnson
retrotechnology.com
Hard sectored diskettes have multiple sector holes in addition to the one index hole that all 8-inch and 5.25 inch diskettes have. Soft sectored disks have one index hole to mark the "beginning" of a track of data. With a very few exceptions among old 8-inch floppy drives, it's the CONTROLLER, NOT THE DRIVE, which "determines" whether that controller expects hard sectored (or soft) diskettes. For the most part, there ARE NO "HARD SECTORED" DISKETTE DRIVES.
As was pointed out, there were 10-sectored and 16-sectored 5.25-inch hard sectored diskettes. I'm not aware of any controller or any OS which used BOTH; they used one scheme or the other. That's one kind of incompatibility.
In addition, both soft and hard-sectored diskettes must be formatted; arrangements of sectors and sometimes other information on the track. In the pre-IBM-PC days, diskette formats varied from brand to brand and even among models, sometimes even OS versions. That's another kind of incompatibility, with controller's software and their disk format schemes.
5.25-inch drives supported either 40 tracks or 80 tracks; the very oldest drives only supported 35 tracks. Almost all of these drives used a 48 track per inch spacing, or a 96 TPI for 80-track drives. Exceptions were some of the VERY earliest Micropolis and Tandon drive models (some also used on Commodore computers) which supported a 100TPI spacing. The 48/96 TPI scheme allowed 80 track drives to support 40-track diskettes and to format 40-track diskettes (with a subtle issue of track width). 35 track drives are 40 track except the innermost 5 tracks unused or inaccessible. 100TPI drives produce disks only other 100TPI drives can even hope to read. So this scheme IN THE DRIVE produces another kind of incompatibility.
I cover this stuff as best I can in boring and technical detail on this Web page:
http://www.retrotechnology.com/herbs_stuff/drive.html
I hope the above summary is correct, but my Web page should have it right, and further details. I welcome any corrections or further information. Don't write to my throw-away "google" email posting address; check my Web page for contact information.
Herb Johnson
retrotechnology.com
Clu
Sep 7, 2012, 10:40:39 PM9/7/12
to
On 6/16/12 5:43 AM, Chris wrote:
Northstar Dimension?
First I have heard of this, but then I would have been quite young when
the computers of the mid to late 70's were being made. If you get a
moment tell me more about this.
First I have heard of this, but then I would have been quite young when
the computers of the mid to late 70's were being made. If you get a
moment tell me more about this.
0 new messages